report of the committee on paul r. warndorf, · report of the committee on ... drake a. drobnick,...

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Report of the Committee on

Electrical Equipment of Industrial Machinery

Michael I. Callanan, ChairNational Joint Apprentice & Training Committee, MD [L]

Rep. International Brotherhood of Electrical Workers

William E. Anderson, The Procter & Gamble Company, OH [U]John F. Bloodgood, JFB Enterprises, WI [SE]Dick Bromstad, Commonwealth Electric of Minnesota, MN [IM] Rep. National Electrical Contractors AssociationFrank C. DeFelice, Jr., Cytec Industries, Inc., CT [U]Paul Dobrowsky, Eastman Kodak Company, NY [U]Drake A. Drobnick, Visteon Corporation, MI [U]Craig J. Fabbo, Speedline Technologies, Inc., MA [M]Bruce Faust, Earth Tech Microelectronics, CA [RT]David S. Fisher, Allen-Bradley Company, Inc., WI [M] Rep. National Electrical Manufacturers AssociationJohn Freudenberg, Teradyne, MA [M] Rep. Northeast Product Safety Society, Inc.Glyn R. Garside, TUV Rheinland of North America, Inc., IL[RT]Thomas J. Garvey, State of Wisconsin, WI [E] Rep. International Association of Electrical InspectorsJohn Knecht, Intertek Testing Services, NA Inc., IL [RT]Robert E. Lichtner, Underwriters Laboratories Inc., IL [RT]Gary J. Locke, Lockheed Martin Systems Integration, NY [U]Robert C. Monteith, Milacron Inc., OH [M] Rep. Society of the Plastics Industry Inc.Larry D. Munson, Universal Instruments Corporation, NY [M]Doug Norman, Electro-Test, Inc., Kobe [RT]Carl E. Padgett, Jr., Milford, OH [M] Rep. The Association for Manufacturing TechnologyThomas Pilz, Pilz Automation Safety L.P., MI [M]Daniel L. Roberson, Delphi-Delco Automotive System, IN [U]Marvin A. Salzenstein, Polytechnic Inc., FL [SE]Melvin K. Sanders, Things Electrical Co., Inc. dba (TECo., Inc),IA [U]Lynn F. Saunders, GM Worldwide Facilities Group, MI [U]Wayman L. Withrow, Cincinnati Inc., OH [M]

Alternates

James C. Carroll, Square D Company, TN [M] (Alt. to D. S. Fisher)Pat Hodge, Canton, MI [U] (Alt. to D. A. Drobnick)Thomas J. Kiihr, Jr., Delphi Automotive Systems, MI [U] (Alt. to D. L. Roberson)Loren Mills, Van Dorn Demag Corporation, OH [M] (Alt. to R. C. Monteith)Jim F. Pierce, Intertek Testing Services NA Inc., OR [RT] (Alt. to J. Knecht)

Warren Stanford, General Motors Corporation, MI [U] (Alt. to L. F. Saunders)Paul R. Warndorf, AMT-The Association For ManufacturingTechnology, VA [M] (Alt. to C. E. Padgett)Marvin J. Winrich, Underwriters Laboratories Inc., NY [RT] (Alt. to R. E. Lichtner)

Staff Liaison: Joseph V. Sheehan

Committee Scope: This Committee shall have primaryresponsibility for documents intended to minimize the potentialhazard of electric shock and electrical fire hazards of industrialmetalworking machine tools, woodworking machinery, plasticsmachinery and mass production equipment, not portable by hand.Reports to the Association through the Technical CorrelatingCommittee of the National Electrical Code Committee.

This list represents the membership at the time the Committee wasballoted on the text of this edition. Since that time, changes in themembership may have occurred. A key to classifications is found at thefront of this book.

The Report of the Technical Committee on Electrical Equipmentof Industrial Machinery is presented for adoption.

This Report was prepared by the Technical Committee onElectrical Equipment of Industrial Machinery and proposes foradoption, amendments to NFPA 79, Electrical Standard forIndustrial Machinery, 1997 edition. NFPA 79-1997 is published inVolume 4 of the 2001 National Fire Codes and in separatepamphlet form.

This Report has been submitted to letter ballot of the TechnicalCommittee on Electrical Equipment of Industrial Machinery,which consists of 26 voting members. The results of the balloting,after circulation of any negative votes, can be found in the report.

This Report has been submitted to letter ballot of the NationalElectrical Code Technical Correlating Committee which consistsof 11 voting members; of whom all 11 voted affirmatively.

NFPA 79 — May 2002 ROP — Copyright 2001, NFPA

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(Log #CP4)79- 1 - (Entire Document): AcceptSUBMITTER: Technical Committee on Electrical Equipment ofIndustrial MachineryRECOMMENDATION: Gobally replace the term "safety relatedfunction" with "safety function" throughout the entire document.SUBSTANTIATION: Utilize a defined term as it appears inClause 3.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Seems editorial in nature. Need to verify eachusage before final determination.

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79- 2 - (Entire Document): Accept in PrincipleSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Revise text as follows: "In all clauses the International SI Units based on [m] meter,[sec] second, [kg] kilogram shall be used."SUBSTANTIATION: SI Units are International Standards.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: SI units will appear in the publisheddocument according to the NFPA Manual of Style. See CommitteeProposal 79-5 (Log #CP2), which deals with the NFPA Manual ofStyle.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Support use of the style manual as long asboth SI and English units are shown.

___________________(Log #102)

79- 3 - (Entire Document): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Divide NFPA-79 into two - a generalpurpose industrial machine tool section, and a specific section toapply to the machine tools identified by ANSI B11 series ofStandards.SUBSTANTIATION: The standard has become very general innature to cover all varieties of industrial machinery, fromtraditional manufacturing shops to "electronic component cleanrooms." What is appropriate for one "industrial manufacturingclimate" is not suitable for the other.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposal does not comply withthe Regulations Governing Committee projects, Section 4.3.3(c)since the submitter has not provided the specific recommendedtext.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: NFPA 79 is a generic standard applicableacross many different industries and NFPA rules have noclassifications to ensure equal representation of each industry.NFPA needs a plan to action to either ensure equal committeerepresentation or a plan of action to generate industry specificstandards.

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(Log #138)79- 4 - (Entire Document): Accept TCC NOTE: The TCC notes that the submitter’srecommendation is not practical to implement for a singledocument within an entire family of codes and standards. TheTCC directs that the proposal be reported as "reject" and that theproposal be forwarded to the NFPA Standards Council forconsideration as part of the NFPA Manual Style.

SUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Identify definitions where usedthroughout the text of the standard. Defined words can be highlighted with capitals, bold font,underline, or any other manner acceptable to the NFPA Stylemanual.SUBSTANTIATION: User of the document may be unaware ofdefinitions when interpreting the requirements of each sectionoften misunderstanding the intended meaning of the section whendefined words are used.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee desires that theeditorial staff of NFPA somehow identify (italics, bold, or anyother method) each defined term in Clause 3 where it appearselsewhere in the body (or Annexes) of the document.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: Since there are 122 proposed definitions andeach term is used an average of over 10 times this will result in alarge number of ‘highlighted’ terms which will either be ignoredor cause confusion. In either case I do not feel that this is helpfulto the user of the standard <2>COMMENT ON AFFIRMATIVE: ANDERSON: Words are defined in the document because theintended meaning is different than normal usage [e.g. Webster'sCollegiate Dictionary, 10th edition]. The defined word, a technicalterm, is used in this document in a special sense and, I suggest,would fall under two type of "Special Terminology" in TheChicago Manual of Style, 14th edition. First type is for the word found in the definition chapter, this casewould fall under "TECHNICAL TERMS IN SPECIAL SENSES"6.73, "...In such instances the term is often enclosed in quotationmarks:" Thus following the proposal, words whose definition isfound in chapter 3 would be shown in quotations. Thus as anexample the definition for "emergency switching off" is in 3.39 andif the present 9.2.5.4.1 would be revised to remove the secondsentence, which duplicates 3.39, then 9.2.5.4.1 would read: 9.2.5.4.1 General. This standard specifies the requirements forthe emergency stop and "emergency switching off" functions, eachof which is, in this standard, initiated by a single human action.For other safety related stop functions see 11.3.4. Second type is for words defined in the immediate text and wouldfall under "TECHNICAL TERMS" 6.72, "...A technical term,especially when accompanied by its definition, is often set in italicsthe first time is appears in a discussion, and in roman thereafter:"Thus as an example the definition for "emergency switching off" inthe present 9.2.5.4.1 would read: 9.2.5.4.1 General. This standard specifies the requirements forthe emergency stop and emergency switching off functions, each ofwhich is, in this standard, initiated by a single human action.Emergency switching off is an emergency operation intended toswitch off the supply of electrical energy to all or a part of aninstallation where a risk of electric shock or another risk ofelectrical origin is involved. For other safety related stop functionssee 11.3.4. DOBROWSKY: This is an excellent proposal. Other documentsaccomplish this by using italics. In this standard italics areprimarily used for exceptions which are required to be completesentences. Highlighting terms that are defined in this documentdoes not create a conflict and will improve usability. FREUDENBERG: A simple editorial process to somehowidentify defined words is extremely useful to all users of thedocument, especially first time users who are unaware of definedwords and its significant impacton the meaning of a givenrequirement.

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(Log #CP279- 5 - (Entire Document): AcceptSUBMITTER: Technical Committee on Electrical Equipment ofIndustrial MachineryRECOMMENDATION: Restructure entire document to complywith the NFPA Manual of Style as follows: 1. Chapter 1 to contain administrative text only. 2. Chapter 2 to contain only referenced publications cited in themandatory portions of the document. 3. Chapter 3 to contain only definitions.

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4. All mandatory sections of the document must be evaluated forusability, adoptability, and enforceability language. Generatenecessary committee proposals. 5. All units of measure in document are converted to SI unitswith inch/pound units in parentheses. 6. Appendices restructured and renamed as "Annexes."See draft of NFPA 79 starting on page 1835.SUBSTANTIATION: Editorial restructuring, to conform with the2000 edition of the NFPA Manual of Style.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Support use of the style manual.

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(Log #34)79- 6 - (Preface [Preface]): Accept in PrincipleSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Retain current preface with minoreditorial changes and new title (Introduction) as follows: NFPA 79: 2002 Introduction (proposed) <0> Introduction <1>This edition of NFPA 79, Electrical Standard for IndustrialMachinery, was prepared by the Technical Committee onElectrical Equipment of Industrial Machinery and acted on by theNational Fire Protection Association, Inc., at its Annual Meetingheld May 16-18, 1994, in San Francisco, CA. It was issued by theStandards Council on July 14, 1994 , with an effective date of August5, 1994 , and supersedes all previous editions. <2>The 2002 edition of this document has been approved by theAmerican National Standards Institute. <3> Changes other than editorial are indicated by a vertical rulein the margin of the pages on which they appear. These lines areincluded as an aid to the user in identifying changes from theprevious edition. Origin and Development of NFPA 79 <4> This standard was first submitted at the 1961 NFPA AnnualMeeting under the title Electrical Standard for Machine Tools andwas tentatively adopted subject to comments. It was extensivelyrevised and resubmitted at the 1962 Annual Meeting where it wasofficially adopted. In 1965 a revised edition was adopted,reconfirmed in 1969, and in 1970, 1971, 1973, 1974, 1977, 1980,1985, 1987, 1991, 1994 and 1997 revised editions were adopted. <5> In September 1941, the metalworking machine tool industrywrote its first electrical standard to make machine tools safer tooperate, more productive, less costly to maintain, and to improvethe quality and performance of their electrical components. Thatparticular standard served as an American "War Standard." <6> To study the special electrical problems involved withmachine tools, in 1941 the Electrical Section of the National FireProtection Association sanctioned a Special Subcommittee onWiring, Overcurrent Protection, and Control of Motor-OperatedMachine Tools. This Subcommittee, cooperating with machinetool builders, manufacturers of control equipment, andUnderwriters Laboratories Inc., conducted tests and investigatedthe peculiar conditions involved with machine tools that mightwarrant exception to certain specific National Electrical Code-requirements. This investigation resulted, on August 4, 1942, in aTentative Interim Amendment and first appeared in a 1943supplement to the 1940 edition of the National Electrical Code asArticle 670, "Machine Tools." It remained essentially unchangedthrough the 1959 edition. <7> Meanwhile, manufacturers of other types of industrialequipment erroneously began to follow the specialized practicespermitted by Article 670. Late in 1952, a Technical Subcommitteeon Fundamentals of Electrically Operated Production Machineryand Material Handling and Processing Equipment for FixedLocations was organized to attempt to group the specialrequirements of this broad field into one article. The extremelybroad scope introduced so many problems that, in December1956, this Technical Subcommittee was reorganized into an NFPACommittee whose scope was limited to machine tools and whoseobjective was the preparation of this NFPA standard withcorresponding revisions in Article 670 in the National ElectricalCode. <8> Modern machine tool electrical equipment may vary fromthat of single-motor machines, such as drill presses, that performsimple, repetitive operations, to that of very large, multimotoredautomatic machines that involve highly complex electrical controlsystems, including electronic and solid-state devices and

equipment. Generally these machines are especially designed,factory-wired, and tested by the builder and then erected in theplant in which they will be used. Because of their importance toplant production and their usually high cost, they are customarilyprovided with many safeguards and other devices not oftenincorporated in the usual motor and control application ascontemplated by the National Electrical Code. <9> Although these machines may be completely automatic, theyare constantly attended, when operating, by highly skilledoperators. The machine usually incorporates many special devicesto protect the operator, protect the machine and building againstfires of electrical origin, protect the machine and work in processagainst damage due to electrical failures, and protect against lossof production due to failure of a machine component. To providethese safeguards, it may be preferable to deliberately sacrifice amotor or some other component,rather than to chance injury to the operator, the work, or themachine. It is because of such considerations that this standardvaries from the basic concepts of motor protection as contained inthe National Electrical Code. <10> As NFPA 79 evolved, it became apparent that certain classesof light industrial machinery (e.g., small drill presses, benchgrinders, sanders) were not appropriately covered. The 1977edition of the standard recognized this problem and purposelyexcluded tools powered by two horsepower or less. <11> Subsequent to publication of the 1977 standard, a lightindustrial machinery standard development activity was initiated bythe Power Tool Institute. The 1985 edition of NFPA 79 reflects thisactivity, and appropriate requirements are now included in thestandard. <12> In 1975, the Society of the Plastics Industry requested thatthis standard be enlarged in scope to include plastics machinery. Aformal request was received by NFPA in September 1978, and,through the combined efforts of the NFPA 79 committee andrepresentatives of the Society of the Plastics Industry, the scope wasbroadened to include such machinery in the 1980 edition. <13> In June 1981, the Joint Industrial Council (JIC) Board ofDirectors acknowledged the dated state of the electrical andelectronic standards and requested that NFPA 79 incorporate intoits standard the material and topics covered by the JIC electrical(EMP-1-67, EGP-1-67) and electronic (EL-1-71) standards with theintention that the JIC standards eventually would be declaredsuperseded. The NFPA Standards Council approved the requestwith the stipulation that the material and topics incorporated fromthe JIC standards be limited to areas related to electrical shockand fire hazards. The 1985 edition reflected the incorporation ofthe appropriate material from the JIC electrical (EMP-1-67, EGP-1-67) standards not previously covered. The 1991 edition includesadditional references to international standards. <14> The 1994 edition was reorganized to align with the ANSIstyle manual which included the moving the terms and definitionsto clause 3 thus making them part of the normative text. <15> The 2002 revision was significantly modified so that theNFPA 79 standard was in closer alignment with the Internationalstandard IEC 60204-1. These modifications are based largely onthe work done by the SAE/HS 1738 Committee. To better coordinate its work, this Committee reports to theAssociation through the Correlating Committee of the NationalElectrical Code Committee. The primary reason is to correlate thisstandard and the National Electrical Code, especially with respectto Article 670 thereof.SUBSTANTIATION: <0, 1, 2>Editorial New dates - to be filled in <14, 15> To bring the Introduction up to date.COMMITTEE ACTION: Accept in Principle. Editorially revise the last sentence of <13> to read as follows: "The 1991, 1994 and 1997 editions include additional referencesto international standards and reflect the committee's efforts inharmonization."COMMITTEE STATEMENT: Editorial corrections were made torevise the last sentence. The committee understands that thecontents of the pubished Preface is the sole function of NFPA staffand the final selection of text contained in the Preface is NOT acommittee function. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: The Northeast Product Safety Society (NPSS)concept of harmonization is to facilitate shipment of one productworldwide without modification by eliminating conflicts andreducing differences between NFPA79 and other standards.


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Modifications to adopt automobile industry practices fromSAE/HS 1738 is somes cases supported harmonization and othercases prevented harmonization.

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(Log #33)79- 7 - (Foreword [Forward]): Accept in PrincipleSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Use foreword from current documentwith minor editorial revisions. Delete second paragraph of currenttext: Foreword This edition of NFPA 79 has been reformatted in accordancewith the ANSI style manual (8th edition), which includes the useof the following terms: - Clause for the term Chapter - Subclause for the term Section - Annex for the term Appendix. The referenced standards previously found in chapter 19 are nowfound in Clause 2 - Normative references. The definitions(previously found in Appendix A) have been moved to Clause 3 -Definitions, making the terms and their definitions part of thisstandard. Figures and tables have been numbered consecutivelystarting with 1. Annexes (appendices) A, B, C, D, E, F and G are provided forinformational purposes and should not be considered as part ofthe requirements of this standard. This standard is intended to apply to electrical equipment usedwith a wide variety of machines and a group of machines workingtogether in a coordinated manner. Therefore, the requirementsand recommendations in this standard may not be relevant in allcases. The risks associated with the hazards relevant to the electricalequipment should be assessed as part of the overall requirementsfor risk assessment of the machine. This will determine theacceptable level of risk and necessary protective measures forpersonnel who can be exposed to these hazards while stillmaintaining an acceptable level of performance of the machineand its equipment. Hazards can include but are not limited to the following: - Failures or faults in the electrical equipment resulting in thepossibility of electrical shock or electrical fire. - Failures or faults in control circuits (or components anddevices associated with these circuits) resulting in malfunctioningof the machine. - Disturbances or disruptions in external power sources as well asfailures or faults in the power circuits resulting in themalfunctioning of the machine. - Electrical interferences (e.g., electromagnetic, electrostatic,radio interference) either from outside the electrical equipment orinternally generated. - Stored energy (either electrical or mechanical). - Audible noise at levels that cause health problems to personnel. Safety measures are a combination of the measures incorporatedat the design state and those measures required to be implementedby the user. Design and development should be the first consideration in thereduction of risks. Where this is not possible, safeguarding shouldbe considered. Safeguarding includes the use of safeguards,awareness means, and safe working procedures. This edition of NFPA 79, Electrical Standard for IndustrialMachinery, was prepared by the Technical Committee onElectrical Equipment of Industrial Machinery and acted on by theNational Fire Protection Association, Inc., at its Annual Meetingheld May 16-18, 1994, in San Francisco, CA. It was issued by theStandards Council on July 14, 1994, with an effective date of August5, 1994, and supersedes all previous editions. Changes other than editorial are indicated by a vertical rule in themargin of the pages on which they appear. These lines areincluded as an aid to the user in identifying changes from theprevious edition. This edition of this standard has been approved by the AmericanNational Standards Institute. SUBSTANTIATION: No longer required, was pertinent to 1997edition.COMMITTEE ACTION: Accept in Principle. Accept the proposed text. In addition, insert this text as a newsecond to last sentence to read as follows: "Terms may have been provided, in parenthesis, for some termsto provide an equivalent or approximately equivalent term that isused in some other countries."

COMMITTEE STATEMENT: The new paragraph was inserted toprovide guidance in the use of the document and provides clarityin use of terms throughout the standard. The committeeunderstands that the contents of the pubished Forward is the solefunction of NFPA staff and the selection of text contained in theForward is NOT a committee function. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: MONTEITH: Based on the extensive changes to this standardand the time it takes manufacturers to change their productdesigns, we believe the effective date of this standard should be twoyears from the date of issuance. This time period would allowmanufacturers to be aware of the standard and to have time tocomply with the standard. The effective date is also common practice in many ANSIstandards. Note: Supporting material available for review upon request atNFPA headquarters.COMMENT ON AFFIRMATIVE: BLOODGOOD: I believe the word is ‘Foreword’ as in thepreface or introduction to a book, story or document not‘Forward’ which is as in to move in the desired direction (Motto ofthe State of Wisconsin). The penultimate paragraph waserroneously carried forward from a previous edition and should bedeleted or modified. The list of annexes in the 3rd paragraph willhave to modified.I strongly support the addition of the new second to the lastsentence proposed by the Committee and prefer this to themodification (2 paragraph of Note) to Clause 3 (see Proposal 79-11(Log #37). DOBROWSKY: (1) The first paragraph including the threebulleted items should be deleted. (2) The term "Clause" should be replaced with the term"Chapter" to comply with the NFPA Manual of Style. (3) The phrase "and requirements" (in the second sentence ofthe fourth paragraph) should be deleted becauserecommendations are not permitted in this standard. (4) I’m not sure if the word "should" is appropriate in a"Foreword". (5) The Committee desired to match the numbering format ofIEC 60204-1 as much as possible. Adding a statement in theForeword or elsewhere, describing the concept in 3.7.2.8 of theNFPA MOS, then inserting the dashes at the appropriate vacantcells would help maintain this concept. FREUDENBERG: The explanation of USA terminology with IECterminology in parenthesis adds clarity.

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(Log #3579- 8 - (Clause 1 [Clause 1]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Retain current text with editorial changesas follows: NFPA 79: 2002 (Proposed) 1 Scope 1.1 The provisions of this standard shall apply to theelectrical/electronic equipment, apparatus, or systems ofindustrial machines operating from a nominal voltage of 600 voltsor less, and commencing at the place point of connection of thesupply to the electrical equipment of the machine. NOTE 1: In this standard, the term "electrical" includes bothelectrical and electronic equipment. Requirements that apply onlyto electronic equipment shall be so identified. NOTE 2: The general terms "machine" and "machinery" as usedthroughout this standard mean industrial machinery. NOTE 3: See Annex A for examples of industrial machinescovered by this standard. 1.2 This standard shall does not include the additionalrequirements be considered adequate for machines intended foruse in hazardous (classified) locations areas defined as by NFPA70, National Electrical Code®. <editorial> 1.3 This standard is not intended to apply to:- Fixed or portable tools judged under the requirements of atesting laboratory acceptable to the authority having jurisdiction.- Machines used in dwelling units. 1.4 The size and overcurrent protection of the supply conductorsto a machine is covered by NFPA 70, National Electrical Code,Article 670. The wiring between component machines of an


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industrial manufacturing system is covered by NFPA 70, NationalElectrical Code. Exception: Wiring of component machines of an industrialmanufacturing system that is supplied by the manufacturer and isan integral part of the system, is adequately protected andsupported, and meets the requirements of this standard. 1.5 On any point for which specific provisions are not made inthis standard (e.g., some requirements for the application ofDesign E motors) the provisions of NFPA 70, National ElectricalCode, are to shall be observed. NOTE: Motor design letter designations are found inANSI/NEMA MG 1 and ANSI/IEEE 100. 1.6 The purpose of this electrical This standard is to provideprovides detailed information for the application ofelectrical/electronic equipment, apparatus, or systems supplied aspart of industrial machines that will promote safety to life andproperty. 1.7 This standard is not intended to limit or inhibit theadvancement of the state of the art. Each type of machine hasunique requirements that shall be are to accommodated toprovide adequate safety.SUBSTANTIATION: 1.1 Editorial - the word shall is notappropriate in the Scope. The Committee felt that the word 'point'is more appropriate than place. 1.2 Editorial the word shall is not appropriate in the Scope 1.5 editorial - the word 'shall' is not appropriate for the scope 1.6 Editorial 1.7 Editorial - the word 'shall' is not appropriate for the scopeCOMMITTEE ACTION: Accept.1. Editorially correct by adding the additional strikethrough in 1.1of the word shall to read as "...The provisions of this standard shallapply...". 2. Editorially correct by adding the word "be" in 1.7 to read as"are to be accommodated."COMMITTEE STATEMENT: The corrections are only editorial.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Paragraph 1.2 does not adequately exclude alltypes of hazardous process material (HPM).Not all hazardousprocess material is considered a hazardous (classified) locationfor the risk of explosion. Need new "1.X This standard does notinclude the additional requirements for machines which usehazardous process materials".COMMENT ON AFFIRMATIVE: DOBROWSKY: Section 1.5 should be revised as follows: "If specific provisions are not covered by this Standard, see NFPA70, National Electrical Code." or delete the parenthetical phrase. Reason: All of the information in the NEC does not need to beincluded in this Standard. Issues that are commonly encounteredon machinery should be provided and the NEC should bereferenced for the remaining requirements.

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(Log #18)79- 9 - (1.1 [1.1]): Accept in PrincipleSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Revise text to read as follows: 1-1 The provisions of this standard shall apply to theelectrical/electronic equipment, apparatus, or systems ofindustrial machines operating from a nominal voltage of 600 voltsor less, and commencing at the place point of connection of thesupply to the electrical equipment of the machine. 1-2 This standard shall does not include the additionalrequirements be considered adequate for machines intended foruse in hazardous (classified) locations areas defined as by NFPA70, National Electrical Code®. 1-5 On any point for which specific provisions are not made inthis standard (e.g., some requirements for the application ofDesign E motors) the provisions of NFPA 70, National ElectricalCode, are to shall be observed. 1-6 The purpose of this electrical This standard is to provideprovides detailed information for the application ofelectrical/electronic equipment, apparatus, or systems supplied aspart of industrial machines that will promote safety to life andproperty.

SUBSTANTIATION: 1-1 Editorial. The word "shall" is notappropriate for the Scope (A Scope does not containrequirements); the word "point" is a better descriptor than "place" 1-2 Editorial. The word "shall" is not appropriate for the Scope(A Scope does not contain requirements); remaining change ofwords better describes the intent. 1-5 Editorial. The word "shall is not appropriate for the Scope(A Scope does not contain requirements); 1-6 Editorial. Closer alignment to Style manual and grammar.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-8 (Log #35).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Paragraph 1.2 does not adequately exclude alltypes of hazardous process material (HPM).Not all hazardousprocess material (HPM) is considered a hazardous (classified)location for the risk of explosion. Need new "1.X This standarddoes not include the additional requirements for machines whichuse hazardous process materials (HPM)".

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(Log #3679- 10 - (Clause 2 [Clause 2]): Accept in Principle TCC NOTE: The TCC directs the committee to review theNormative Reference list and remove references that are notreferenced for mandatory compliance. Definitions accepted inNFPA 79 that are similar or identical to a definition in anotherdocument, does not make that document a mandatory reference.The following standards from the list do not appear to bemandatory references in NFPA 79: IEC 34-1, IEC 34-5, IEC 34-11, IEV 191, IEV 441, IEV 826, IEC 73,IEC 60204-1, IEC 60332-1, IEC 60417M, IEC 60529, IEC 60536, IEC60947-5-1, IEC 60947-7-1, ISO 3864, ANSI/UL 498, IEEE 100,ASTM B 8, ASTM B 33. This action will be considered by the committee as a publiccomment.SUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Modify Clause 2 in accordance withreferences cited in the revised normative text. 2 Normative references The following normative documents contain provisions that,through reference in this text, constitute provisions of thisstandard. At the time of publication, the editions indicated werevalid. All normative documents are subject to revision, and partiesto agreements subject to this standard should apply the mostrecent editions of the normative documents listed below. 2.1 IEC 34-1: 1983, Rotating electrical machines - Part 1: Ratingand performance. 2.2 EC 34-5: 1991, Rotating electrical machines, - Part 5:Classification of degrees of protection provided by enclosures ofrotating electrical machines (IP codes). 2.3 IEC 34-11: 1978, Rotating electrical machines - Part 11: Built-in thermal protection. 2.4 IEV 191: 1990, International Electrotechnical Vocabulary -Chapter 191: Dependability and Quality Service I2.5 EV 441: 1984, International Electrotechnical Vocabulary -Chapter 441: Switchgear, Control Gear, and Fuses 2.6 IEV 826: 1982, International Electrotechnical Vocabulary -Chapter 826: Electrical Installation of Buildings 2.7 IEC 73: 1991, Coding of indicating devices and actuators bycolours and supplementary means. 2.8 IEC 60204-1: 1997, Safety of machinery - Electrotechnicalaspects- Part 1: General requirements 2.9 IEC 60309-1: 1988, Plugs, socket-outlets, and couplers forindustrial purposes - Part 1: General requirements. IEC 60332-1: 1979, Tests on electric cables under fire conditions,- Part 1: Test on a single vertical insulated wire or cable. 2.11 IEC 60417M: 1985, Graphical Symbols for Use on Equipment- Index, Survey, and Single Sheets 2.12 IEC 80529: 1989, Degrees of protection provided byenclosures (IP Code). 2.13 IEC 60536: 1976, Classification of electrical and electronicequipment with regard to protection against electric shock. 2.14 IEC 60947-5-1: 1990, Low-voltage switchgear and controlgear- Part 5: Control circuit devices and switching elements - SectionOne - Electromechanical circuit devices. 2.15 IEC 60947-7-1: 1989, Low-voltage switchgear and controlgear- Part 7: Ancillary equipment,


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2.16 ISO 3864: 1984, Safety Colors and Safety Signs 2.17 ANSI/UL 1682-Plugs, receptacles,, and Cable Connectors ofthe Pin and Sleeve Type 2.18 ANSI/UL 498- Attachment Plugs, Receptacles 2.21 IEEE 100 1992, Standard Dictionary of Electrical andElectronic Terms 2.22 ANSI/IEEE 315-1989, Graphical Symbols for Electrical andElectronics Diagrams 2.23 ANSI/NEMA FB 1-1988, Fittings, Cast Metal Boxes, andConduit Bodies for Conduit and Cable Assemblies 2.24 ANSI/NEMA ICS-2: 1988, Industrial Control Devices,Controllers, and Assemblies 2.25 ANSI/NFPA 70-1999, National Electrical Code 2.26 ANSI/UL 1063-1986, Standard for Safety Machine - ToolWires and Cables 2.27 ASTM B 8-1986, Standard for Concentric - Lay - StrandedCopper Conductors Hard, Medium-Hard, or Soft 2.28 ASTM B 33-1981 (R 1985), Tinned Soft or Annealed CopperWire for Electrical Purposes 2.29 ASTM B 174-1971 (R 1985), Specification for Bunch-Stranded Copper Conductors for Electrical Conductors 2.30 ASTM B 286-1989, Copper Conductors for Use in HookupWire for Electronic Equipment NOTE: A list of standards that may provide additionalinformation related to electrical equipment of industrial machinesis found in annex A - Bibliography.SUBSTANTIATION: Changes in the normative text have resultedin changes to the normative references. 2.1 Reference to this standard is found in the normative part ofthe document 2.2 Reference to this standard is found in the normative part ofthe document 2.3 Reference to this standard is found in the normative part ofthe document 2.4 Reference to this standard is found in the normative part ofthe document 2.5 Reference to this standard is found in the normative part ofthe document 2.5 Reference to this standard is found in the normative part ofthe document 2.7 Reference to this standard is found in the normative part ofthe document 2.9 Reference to this standard is found in the normative part ofthe document 2.10 Reference to this standard is found in the normative part ofthe document 2.12 Reference to this standard is found in the normative part ofthe document 2.13 Reference to this standard is found in the normative part ofthe document2.14 Reference to this standard is found in the normative part ofthe document2.15 Reference to this standard is found in the normative part ofthe document2.17 Reference to this standard is found in the normative part ofthe document2.18 Reference to this standard is found in the normative part ofthe document2.19 Reference to this standard is no longer found in the normativepart of the document2.20 Reference to this standard is no longer found in the normativepart of the documentCOMMITTEE ACTION: Accept in Principle. Modify Clause 2 in accordance with references cited in therevised normative text. Clause 2 to read as follows: 2 Normative references The following normative documents contain provisions that,through reference in this text, constitute provisions of thisstandard. At the time of publication, the editions indicated werevalid. All normative documents are subject to revision, and partiesto agreements subject to this standard should apply the mostrecent editions of the normative documents listed below. 2.1 IEC 34-1: 1983, Rotating electrical machines - Part 1: Ratingand performance. 2.2 EC 34-5: 1991, Rotating electrical machines, - Part 5:Classification of degrees of protection provided by enclosures ofrotating electrical machines (IP codes). 2.3 IEC 34-11: 1978, Rotating electrical machines - Part 11: Built-in thermal protection. 2.4 IEV 191: 1990, International Electrotechnical Vocabulary -Chapter 191: Dependability and Quality Service 2.5 IEV 441: 1984, International Electrotechnical Vocabulary -Chapter 441: Switchgear, Control Gear, and Fuses

2.6 IEV 826: 1982, International Electrotechnical Vocabulary -Chapter 826: Electrical Installation of Buildings 2.7 IEC 73: 1991, Coding of indicating devices and actuators bycolours and supplementary means. 2.8 IEC 60204-1: 1997, Safety of machinery - Electrotechnicalaspects- Part 1: General requirements 2.9 IEC 60309-1: 1988, Plugs, socket-outlets, and couplers forindustrial purposes - Part 1: General requirements. IEC 60332-1: 1979, Tests on electric cables under fire conditions,- Part 1: Test on a single vertical insulated wire or cable. 2.11 IEC 60417M: 1985, Graphical Symbols for Use on Equipment- Index, Survey, and Single Sheets 2.12 IEC 60529: 1989, Degrees of protection provided byenclosures (IP Code). 2.13 IEC 60536: 1976, Classification of electrical and electronicequipment with regard to protection against electric shock. 2.14 IEC 60947-5-1: 1990, Low-voltage switchgear and controlgear- Part 5: Control circuit devices and switching elements - SectionOne - Electromechanical circuit devices. 2.15 IEC 60947-7-1: 1989, Low-voltage switchgear and controlgear- Part 7: Ancillary equipment, 2.16 ISO 3864: 1984, Safety Colors and Safety Signs 2.17 ANSI/UL 1682-Plugs, receptacles,, and Cable Connectors ofthe Pin and Sleeve Type 2.18 ANSI/UL 498- Attachment Plugs, Receptacles 2.21 IEEE 100 1992, Standard Dictionary of Electrical andElectronic Terms 2.22 ANSI/IEEE 315-1989, Graphical Symbols for Electrical andElectronics Diagrams 2.23 ANSI/NEMA FB 1-1988, Fittings, Cast Metal Boxes, andConduit Bodies for Conduit and Cable Assemblies 2.24 ANSI/NEMA ICS-2: 1988, Industrial Control Devices,Controllers, and Assemblies 2.25 ANSI/NFPA 70-1999, National Electrical Code 2.26 ANSI/UL 1063-1986, Standard for Safety Machine - ToolWires and Cables 2.27 ASTM B 8-1986, Standard for Concentric - Lay - StrandedCopper Conductors Hard, Medium-Hard, or Soft 2.28 ASTM B 33-1981 (R 1985), Tinned Soft or Annealed CopperWire for Electrical Purposes 2.29 ASTM B 174-1971 (R 1985), Specification for Bunch-Stranded Copper Conductors for Electrical Conductors 2.30 ASTM B 286-1989, Copper Conductors for Use in HookupWire for Electronic Equipment NOTE: A list of standards that may provide additionalinformation related to electrical equipment of industrial machinesis found in annex A - Bibliography.COMMITTEE STATEMENT: The committee understands thatthis is a work in progress and will be updated at the ROC andagain edited by staff before publication.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: A final editorial verification of references usedand not used must be made.

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(Log #3779- 11 - (Clause 3 [Clause 3]): Accept in Principle TCC NOTE: The TCC directs the committee to consider thecomments expressed in the voting. This action will be consideredby the committee as a public comment.SUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Modify Clause 3 - Definitions to reflectchanges in the use of normative terms.4 Proposal

3. Definitions

3.1 accessible (as applied to equipment): Admitting closeapproach; not guarded by locked doors, elevation, or othereffective means. [NFPA 70]

3.2 accessible, readily (readily accessible): Capable of beingreached quickly for operation, renewal, or inspections, withoutrequiring those to whom ready access is requisite to climb over orremove obstacles or to resort to portable ladders, etc. [NFPA 70]

3.3 actuator: The part of the actuating system to which an externalactuating force is applied. [IEV 441-15-22]


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NOTES—1 The actuator may take the form of a handle, knob, push-button,

roller, plunger, etc.2 There are some actuating means that do not require an external

actuating force but only an action.3 See also 3.74 “machine actuator.”

3.4 adjustable speed drives : An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included.

3.5 ambient temperature: The temperature of the air or othermedium where the equipment is to be used. [IEV 826-01-04]NOTE—Ambient air temperature as applied to an enclosure orhousing is the average temperature of the surrounding air thatcomes in contact with the enclosure or housing. Ambient airtemperature as applied to a component or device within theenclosure is the average temperature of the surrounding air thatcomes in contact with the component.

3.6 ampacity: The current, in amperes, that a conductor cancarry continuously under the conditions of use, without exceedingthe design limits for the temperature rating of the insulation, theconductor and the wire termination.

3.7 approved: Acceptable to the authority having jurisdiction.(NFPA 70)

NOTE : The National Fire Protection Association does not approve,inspect, or certify any installations, procedures, equipment, or materialsnor does it approve or evaluate testing laboratories. In determining theacceptability of installations or procedures, equipment, or materials, the“authority having jurisdiction” may base acceptance on compliance withNFPA or other appropriate standards. In the absence of such standards,said authority may requi re evidence of proper installation, procedure, oruse. The “authority having jurisdiction” may also refer to the listings orlabeling practices of an organization that is concerned with productevaluations and is thus in a position to determine compliance withappropriate standards for the current production of listed items.

3.8 attachment plug (plug cap) (plug): A device that, by insertionin a receptacle, establishes a connection between the conductorsof the attached flexible cord and the conductors connectedpermanently to the receptacle. [NFPA 70]

3.9 Authority Having Jurisdiction — The organization, office, orindividual responsible for approving equipment, an installation, ora procedure.NOTE: The phrase “authority having jurisdiction” is used in NFPAdocuments in a broad manner because jurisdictions and approvalagencies vary, as do their responsibilities. Where public safety isprimary, the authority having jurisdiction may be a federal, state,local, or other regional department or individual such as a firechief; fire marshal; chief of a fire prevention bureau, labordepartment, or health department; building official; electricalinspector; or others having statutory authority. For insurancepurposes, an insurance inspection department, rating bureau, orother insurance company representative may be the authorityhaving jurisdiction. In many circumstances, the property owner orhis or her designated agent assumes the role of the authorityhaving jurisdiction; at government installations, the commandingofficer or departmental official may be the authority havingjurisdiction.

3.10 barrier: A part providing protection against direct contactfrom any usual direction of access. [IEV 826-03-13.]

3.11 bonding (bonded): The permanent joining of metallic partsto form an electrically conductive path that will ensure electricalcontinuity and the capacity to conduct any current likely to beimposed. [NFPA 70]

Note: See “protective bonding circuit.”

3.12 branch circuit: The circuit conductor s between the finalovercurrent device protecting the circuit and the outlet(s). (NFPA70)

3.13 cable tray system: A unit or assembly of units or sections andassociated fittings forming a structural system used to securelyfasten or support cable s and raceways. [NFPA 70]

3.14 cable trunking system: A system of enclosures comprised of abase and a removable cover intended for the completesurrounding of insulated conductors, cables, and cords [IEV 826-06-04, modified]

Note: See “wireway.”

3.15 circuit breaker: A device designed to open and close acircuit by nonautomatic means and to open the circuitautomatically on a predetermined overcurrent without damage toitself when properly applied within its rating. [NFPA 70]

3.16 concurrent: Acting in conjunction; used to describe asituation wherein two or more control devices exist in an actuatedcondition at the same time (but not necessarily simultaneously).

3.17 conduit, intermediate metal: A listed steel raceway of circularcross-section with integral or associated couplings, connectors,and fittings approved for the installation of electrical conductorsand used with listed fittings to provide electrical continuity. [NFPA70]

3.18 conduit, rigid metal: Rigid metal conduit is a listed metalraceway of circular cross section with integral or associatedcouplings, approved for the installation of electrical conductorsand used with listed fittings to provide electrical continuity. [NFPA70]3.19 conduit, rigid nonmetallic: A type of conduit and fittings ofsuitable nonmetallic material that is resistant to moisture andchemical atmospheres, flame retardant, resistant to impact andcrushing, and resistant to distortion from heat or low temperaturesunder conditions likely to be encountered in service. [NFPA 70]

3.20 control circuit (of a machine): The circuit of a controlapparatus or system that carries the electric signals directing theperformance of the controller but does not carry the main powercurrent.Note: Power circuit protection can be provided by control shunt- tripping.

3.21 control circuit transformer: A voltage transformer utilized tosupply a voltage suitable for the operation of control devices.[IEEE 100]

3.22 control circuit voltage: The voltage utilized for the operationof control devices.

3.23 control device: A device connected into the control circuitand used for controlling the operation of the machine (e.g.position sensor, manual control switch, relay, magneticallyoperated valve). [IEC 60204–1]

3.24 controlled stop: The stopping of machine motion , whileretaining power to the machine actuators during the stoppingprocess.

3.25 controlgear: A general term covering switching devices andtheir combination with associated control, measuring, protective,and regulating equipment, also assemblies of such devices andequipment with associated interconnections, accessories,enclosures, and supporting structures, intended in principle forthe control of electrical energy - consuming equipment. [IEV 441-11-03]<Possible alternate term: control equipment: Operating elementssuch as relays, contactors, circuit breakers, switches, solenoids,brakes and similar types of components, intended to govern orperform a given function in the operation, including measuring,sensing, monitoring, protection, and regulation of machinery

3.26 controller: A device or group of devices that serves to govern,in some predetermined manner, the electric power delivered tothe apparatus to which it is connected. [NFPA 70]

3.27 cord(flexible):Flexible cords are constructed as described in,and listed for use in accordance with Article 400 of the NationalElectrical Code (NFPA 70). All conductors are stranded copper.


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3.28 device: A unit of an electrical system that is intended to carrybut not utilize electric energy. (NFPA 70)

3.29 digital: Operated by the use of discrete signals to representdata in the form of numbers or other characters.[IEC-60204-1]

3.30 direct contact: Contact of persons or livestock with live parts.[IEV 826-03-05]

3.31 disconnecting means: A device, or group of devices, or othermeans by which the conductors of a circuit can be disconnectedfrom their source of supply. [NFPA 70]

3.32 dry location: A location not normally subject to dampnessor wetness.Note: A lo cation classified as dry may be temporarily subject to dampnessor wetness, as in the case of a building under construction. [NFPA 70]

3.33 duct: An enclosed channel designed expressly for holdingand protecting electrical conductors, cables, and busbars.

NOTE—Conduits, cable trunking systems (see 3.10) andunderfloor channels are types of duct. See “raceway.”

3.34 dwelling unit: One or more rooms for the use of one ormore persons as a housekeeping unit with space for eating, living,and sleeping, and permanent provisions for cooking andsanitation. (NFPA 70)

3.35 earth: See “ground.”

3.36 electromechanical: Applied to any device in which electricalenergy is used to magnetically cause mechanical movement.

3.37 e lectrical operating area: A room or location for electricalequipment to which access is intended to be restricted to skilled orinstructed persons, by the opening of a door or the removal of abarrier without the use of a key or tool, and which is clearlymarked by appropriate warning signs.

3.38 electronic equipment: That part of the electrical equipmentcontaining circuitry mainly based on electronic devices andcomponents.

3.39 Emergency switching off: An emergency operation intendedto switch off the supply of electrical energy to all or a part of aninstallation where a risk of electric shock or another risk ofelectrical origin is involved.

3.40 enclosed electrical operating area: A room or location forelectrical equipment to which access is intended to be restricted toskilled or instructed persons by the opening of a door or theremoval of a barrier by the use of a key or tool and which is clearlymarked by appropriate warning signs.

3.41 enclosure: A surrounding case constructed to provide adegree of protection against incidental contact with the enclosedequipment and to provide a degree of protection to the enclosedequipment against specified environmental conditions.

3.42 energized: Electrically connected to a source of potentialdifference (NFPA 70).

3.43 equipment: A general term including material, fittings,devices, appliances, fixtures, apparatus, and the like used as partof, or in connection with, an electrical installation. NFPA 70

3.44 exposed (as applied to live parts): Capable of beinginadvertently touched or approached nearer than a safe distance bya person. It is applied to parts not suitably guarded, isolated, orinsulated. [NFPA 70]

3.45 failure [of equipment]: The termination of the ability of anitem to perform a required function.

NOTES—1 After failure the item has a fault.2 "Failure" is an event, as distinguished from "fault", which is a

state.

3 This concept as defined does not apply to items consisting ofsoftware only. [IEV 191-04-01]

3.46 fault: The state of an item characterized by inability toperform a required function, excluding the inability, duringpreventive maintenance or other planned actions, or due to lack ofexternal resources.

NOTE: A fault is often the result of a failure of the item itself, but mayexist without prior failure

[IEV 191-05-01]

3.47 feeder: All circuit conductors between the serviceequipment or the source of a separately derived system and thefinal branch-circuit overcurrent device. (NFPA 70)

3.48 flame retardant: So constructed or treated that it will notsupport flame. [IEEE 100]

3.49 ground: A conducting connection, whether intentional oaccidental, between an electrical circuit or equipment and theearth, or to some conducting body that serves in place of the earth[NFPA 70]

3.50 grounded: Connected to earth or to some conducting bodythat serves in place of the earth. [NFPA 70]

3.51 grounded conductor: A system or circuit conductor that isintentionally grounded. [NFPA 70]

3.52 grounding conductor: A conductor used to connectequipment or the grounded circuit of a wiring system to agrounding electrode or electrodes. [NFPA 70]

3.53 grounding conductor, equipment: The conductor used toconnect the noncurrent-carrying metal parts of equipment,raceways, and other enclosures to the system grounded conductor,the grounding electrode conductor, or both, at the serviceequipment or at the source of a separately derived system. [NFPA70]

3.54 grounding electrode conductor: The conductor used toconnect the grounding electrode to the equipment groundingconductor, to the grounded conductor, or to both, of the circuit atthe service equipment or at the source of a separately derivedsystem. [NFPA 70]

3.55 guard: Part of a machine specifically used to provideprotection by means of a physical barrier. Depending on itsconstruction, a guard may be called casing, cover, screen, door,enclosing guard. [ISO/TR 12100-1, 3.22, modified]

3.56 harm : physical injury or damage to health.

3.57 hazard: A source of possible injury or damage to health[ISO/TR 12100-1, 3.5, modified]

3.58 hazardous situation: a circumstance in which a person is

exposed to a hazard(s). the exposure can immediately or over a

long period of time have the potential to result in harm.

3.59 identified (as applied to equipment): Recognizable assuitable for the specific purpose, function, use, environment,application, etc., where described in a particular coderequirement. (See "equipment.")

NOTE—Suitability of equipment for a specific purpose,environment, or application may be determined by a qualifiedtesting laboratory, inspection agency, or other organizationconcerned with product evaluation. Such identification mayinclude labeling or listing. [NFPA 70]

3.60 indirect contact: Contact of persons exposed conductive partswhich have become live under fault conditions. [IEV 826-03-06]

3.61 industrial machine: A power-driven machine (or a group ofmachines working together in a coordinated manner), notportable by hand while working, that is used to process material bycutting, forming, pressure, electrical, thermal, or opticaltechniques, lamination, or a combination of these processes. It


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can include associated equipment used to transfer material ortooling (including fixtures), assemble/disassemble, inspect or test,or package. (The associated electrical equipment including thelogic controller(s) and associated software or logic together withthe machine actuators and sensors are considered as part of theindustrial machine.)

3.62 industrial manufacturing system: A systematic array of one ormore industrial machines that are not portable by hand and thatincludes any associated material handling, manipulating, gauging,measuring, or inspection equipment.

3.63 Input1 The terminals where current, voltage, power, or driving force

may be applied to a circuit or device;2 The state or sequence of states occurring on a specific input

channel;3 The device or collective set of devices used for bringing data into

another device.[IEC 60204–1]

3.64 in sight from, within sight from, within sight : Where thisstandard specifies that one equipment shall be "in sightfrom," "within sight from," or "within sight," etc., of anotherequipment, one of the equipments specified is to be visibleand not more than 50 ft (15.24 m) distant from the other.(NFPA 70)

3.65 inrush current (solenoid): The inrush current of a solenoidis the steady-state current taken from the line at rated voltage andfrequency with the plunger blocked in the rated maximum openposition.

3.66 inrush locked rotor current (motor): See “locked rotormotor current.”

3.67 (electrically) instructed person: A person adequately advisedor supervised by an electrically skilled person to enable him or herto perceive risks and to avoid hazards which electricity can create.[IEV 826-09-02, modified]

3.68 (electrically) skilled person: A person with relevant educationand experience to enable him or her to perceive risks and to avoidhazards which electricity can create. [IEV 826-09-01, modified]

3.69 interlock (for safeguarding): An arrangement thatinterconnects guard(s) or device(s) with the control system or allor part of the electrical energy distributed to the machine.

3.70 interrupting rating: The highest current at rated voltage that adevice is intended to interrupt under standard test conditions.

NOTE—Equipment intended to interrupt current at other thanfault levels may have its interrupting rating implied in otherratings, such as horsepower or locked motor current.

3.71 jogging (inching): The quickly repeated closure of the circuitto start a motor from rest for the purpose of accomplishing smallmovements of the driven machine.[IEEE 100]

3.72 listed: Equipment, materials, or services included in a listpublished by an organization that is acceptable to the authorityhaving jurisdiction and concerned with evaluation of products orservices, that maintains periodic inspection of production of listedequipment or materials or periodic evaluation of services, andwhose listing states that either the equipment, material, or servicesmeets identified standards or has been tested and found suitablefor a specified purpose. (NFPA 70)

NOTE—The means for identifying listed equipment may vary foreach organization concerned with product evaluation, some ofwhich do not recognize equipment as listed unless it is alsolabeled. Use of the system employed by the listing organizationallows the authority having jurisdiction to identify a listed product.

3.73 live part (as applied to being energized during normal use):A conductor or conductive part intended to be energized innormal use, including a neutral conductor, but, by convention,not a PEN conductor.NOTE—This term does not necessarily imply a risk of electricshock. [IEV 826-03-01]

3.74 live parts (as applied to exposure to an existing shockhazard): Electric conductors, busses, terminals, or componentsthat are uninsulated or exposed and a shock hazard exists.

3.75 locked rotor motor current: The steady-state current takenfrom the line with the rotor locked and with rated voltage (andrated frequency in the case of alternating-current motors) appliedto the motor. [IEEE 100]

3.76 machine actuator: A power mechanism used to effect motionof the machine.

3.77 marking: Signs or inscriptions for the identification of the typeof a component or device attached by the manufacturer of thecomponent or device.

3.78 neutral conductor (symbol N): A conductor connected to theneutral point of a system and capable of contributing to thetransmission of electrical energy. [IEV 826-01-03]

3.79 obstacle: A part preventing unintentional direct contact, butnot preventing direct contact by deliberate action. [IEV 826-03-14]

3.80 output:1. The terminals where current, voltage, power, or driving force

may be delivered by a circuit or device;2. The state or sequence of states occurring on a specific output

channel;3. The device or collective set of devices used for taking data out

of another device.

3.81 overcurrent: Any current in excess of the rated current of theequipment or the rated ampacity (current-carrying capacity) of theconductor. It may result from overload, short circuit, or electricalfault. [NFPA 70]

3.82 overload: Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that,when it persists for a sufficient length of time, would cause damageor dangerous overheating. A fault, such as a short circuit or aground fault, is not an overload. (See "overcurrent.") [NFPA 70]NOTE – Overload should not be used as a synonym for overcurrent.

3.83 plug/socket combination: A plug and socket-outlet, a cablecoupler, or an appliance coupler, in accordance with IEC 60309-1.

3.84 point of operation: The location in the (machine) where thematerial or workpiece is positioned and work is performed.

3.85 positive opening operation (of a contact element): Theachievement of contact separation as the direct result of a specifiedmovement of the switch actuator through non-resilient members(e.g. not dependent upon springs). [IEC 60947-5-1, chapter 3, 2.2]

3.86 power circuit: A circuit used for supplying power from thesupply network to units of equipment used for productiveoperation and to transformers supplying control circuits.

3.87 programmable electronic system (PES): A system based onone or more central processing units (CPUs), connected tosensors or actuators, or both, for the purpose of control omonitoring.

NOTE: The term PES includes all elements in the systemextending from sensors to other input devices via data highwayor other communication paths to the actuators or other outpudevices.

3.88 protective bonding circuit: The whole of the protectiveconductors and conductive parts used for protection againstelectric shock in the event of an insulation failure.See “bonding.”

3.89 protective conductor: A conductor required by somemeasures for protection against electric shock for electricallyconnecting any of the following parts:– exposed conductive parts;– extraneous conductive parts;– main earthing terminal. [IEV 826-04-05, modified]

3.90 qualified person: At a minimum, a qualified person shall betrained and knowledgeable of the construction and operation of


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equipment or a specific work method, and be trained to recognizeand avoid the electrical hazards that might be present with respectto that equipment or work method. Such persons shall also befamiliar with the proper use of special precautionary techniques,personal protective equipment, insulating and shielding materials,and insulated tools and test equipment. [NFPA 70E]See “(electrically) instructed person” and “(electrically) skilledperson.”

3.91 raceway: An enclosed channel of metal or nonmetallicmaterials designed expressly for holding wires, cables, or busbars,with additional functions as permitted in this standard. Racewaysinclude, but are not limited to, rigid metal conduit, rigidnonmetallic conduit, intermediate metal conduit, liquidtightflexible conduit, flexible metallic tubing, flexible metal conduit,electrical nonmetallic tubing, electrical metallic tubing, wireways,and busways.

3.92 receptacle: A contact device installed at the outlet for theconnection of a attachment plug. A single receptacle is a singlecontact device with no other contact device on the same yoke. Amultiple receptacle is two or more contact devices on the sameyoke. [NFPA 70]See “socket.”

3.93 redundancy: The application of more than one device orsystem, or part of a device or system, with the objective of ensuringthat in the event of one failing to perform its function another isavailable to perform that function .

3.94 reference designation: A distinctive code which serves toidentify an item in a diagram, list, chart, and on the equipment.

3.95 relative humidity: The ratio between the amount of watervapor in the gas at the time of measurement and the amount ofwater vapor that could be in the gas when condensation begins, ata given temperature. [IEEE 100]

3.96 risk: A combination of the probability and the degree ofpossible injury or damage to health in a hazardous situation.[ISO/TR 12100-1]

3.97 safe working procedure: A method of working that reducesrisk. [IEC 60204–1]

3.98 safeguard: A guard or protective device used as a safetymeasure to protect persons from a present or impending hazard.[IEC 60204–1]

3.99 safeguarding: Those safety measures consisting of the use ofspecific means called safeguards to protect persons from hazardsthat cannot reasonably be removed or are not sufficiently limitedby design.

3.100 safety distance: The distance between the pinch point orpoint-of-operation and the presence sensing safety device (PSSD)sensing field which ensures that the operator cannot reach thedanger point before the machine comes to a full stop.

3.101 safety function [safety measure ]: A means that eliminatesor reduces a hazard. [IEC 60204–1]

3.102 servicing level: Location on which persons normally standwhen operating or maintaining the electrical equipment.

3.103 shall: Indicates a mandatory requirement.

3.104 short-circuit current: An overcurrent resulting from a shortcircuit due to a fault or an incorrect connection in an electriccircuit. [IEV 441-11-07]

3.105 should : Indicates a recommendation or that which isadvised but not required.

3.106 (electrically) skilled person: A person with relevanteducation and experience to enable him or her to perceive risksand to avoid hazards which electricity can create. [IEV 826-09-01,modified]

3.107 socket – See “receptacle.”

3.108 supplier: An entity (e.g. manufacturer, contractor, installer,integrator) who provides equipment or services associated with themachine.

NOTE—The user may also act in the capacity of a supplier tohimself.

3.109 subassembly: An assembly of electrical devices connectedtogether which forms a simple functional unit in itself.

3.110 subplate: An internal metal surface separate from the wallsof an enclosure or controller on which various component parts ofthe controller are mounted and wired. [IEEE 100]

3.111 supplementary overcurrent protective device: A device usedwhere protection is required for lighting fixtures, appliances, andother equipment or for internal circuits and components oequipment. It shall not be used as a substitute for power circuiovercurrent devices in place of the power circuit protection.

3.1012 switching device: A device designed to make or break thecurrent in one or more electric circuits. [IEV 441-14-01.]

3.113 tap conductor: a conductor that has overcurrent protectionahead of its point of supply, that exceeds the value permitted forsimilar conductors that are protected as described elsewhere inthis standard.

3.114 terminal: A conductive part of a device provided forelectrical connection to circuits external to the device.

3.115 tight (suffix): So constructed that the specified material isexcluded under specified conditions. (ANSI/IEEE Standard No100)

3.116 uncontrolled stop: The stopping of machine motion byremoving power to the machine actuators, all brakes and/or othemechanical stopping devices being activated. [IEC 60204–1]

3.117 undervoltage protection: The effect of a device that operateson the reduction or failure of voltage, to cause and maintain theinterruption of power.NOTE—The principal objective of this device is to preventautomatic restarting of the equipment. Standard undervoltage orlow-voltage protection devices are not designed to become effectiveat any specific degree of voltage reduction.3.118 user: An entity who utilizes the machine and its associatedelectrical equipment.

3.119 variable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or rollershifting controllers are not included.

3.120 ventilated: Provided with a means to permit circulation ofair sufficient to remove excess heat, fumes, or vapors. [NFPA 70]

3.121 wet location: Installations underground or in concrete slabsor masonry in direct contact with the earth, and locations subjectto saturation with water or other liquids, such as vehicle washingareas, and locations exposed to weather and unprotected. [NFPA70]

3.122 wireway: A sheet-metal or flame retardant nonmetallictrough with hinged or removable covers for housing andprotecting electric wires and cable and in which conductors arelaid in place after the wireway has been installed as a completesystem. [NFPA 70]SUBSTANTIATION: 3.3 Same definition as in current standardexcept reference to IEV has been added 3.5 OLDTerm is no longer used <?> 3.5 Note has been added for clarity 3.7 Both the definition and note recommended here are NFPAofficial definitions taken from the Regulations GoverningCommittee Projects. This definition leaves the final decision ofwhat is acceptable and what is not acceptable up to the authorityhaving jurisdiction. 3.9 Both the definition and note provided here are NFPA officialdefinitions taken from the Regulations Governing CommitteeProjects. Since NFPA 79 is a voluntary standard in many cases,often times the question is asked: "Who is the authority havingjurisdiction (AHJ)." This definition will assist the user in makingthat determination.


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3.11 Same definition except for the note. 3.13 Term is used in the document 3.14 Term is used in the document 3.17 Use of definition from the NEC 3.18 Use of definition from the NEC 3.20 Note added to provide an example 3.22 Better expresses the opinion of the Committee 3.24 Better expresses the opinion of the Committee 3.25 Term is used in the docxument 3.27 The terms "cord" and "cable" are distinctively differentwiring methods. Having a definition for cords coordinates with thedifferent permitted uses in Clause 14. 3.32 The second sentence is more appropriate as a note. 3.33 Term is used in the document OLD 3.29 electric controller - Delete term is no longer used. 3.37 Term is used in the document 3.31 OLD electronic term is no longer used 3.39 Term is used in the document 3.40 Term is used in the document 3.41 Definition better reflects the opinion of the Committee 3.42The use of the NEC definition will eliminate any perceivedconflict. 3.43Editorial to bring it in line with the current NFPA 70 3.37 OLD Delete: exposed conductive part: This term introducesa complicated concept that generally applies to high voltagemobile machinery typically related to earth moving. These areengineering based concepts that require sophisticated analysis(Mathematical analysis of gradient voltage problems). Also, thisconcept is not specifically addressed in the NEC. Bonding plusquick acting overcurrent protection together are consideredsufficient to render these parts harmless. Neither this committee (nor the NEC panels) is aware of any accidents related to groundfault gradients during the occurrence of a short circuit for circuitsnot exceeding 600 volts. 3.49 This term is used in the documen 3.56 Term is used in the document 3.58 Term is used in the document 3.66 Term is used in the document 3.67 Term is used in the document 3.68 Term is used in the document 3.72 Term is used in the document. The definition is consistentwith the NEC. 3.73 The Committee felt that the IEV definition better fit the useof the term in the document. 3.74 The committee felt that the term was used in two differentways and hence required two definitiona 3.77 The term is used in the document 3.62 OLD The term is no longer used in the document 3.78 The term is used in the document 3.79 The term is used in the document 3.83 The term is used in the document 3.84The term is used in the document 3.86 The Committee felt that the NOTE was no longer necessary 3.88 The term is used in the document 3.88 The term is used in the document 3.90 The Committee felt that this definition from NFPA 70E wasmore approprate to this document 3.93 This term is used in the document 3.94 This term is used in the document 3.95 This term is used in the document 3.72 OLD This term is no longer used in the document 3.100 The term is used in the document 3.102 The term is used in the document 3.103 The term is used in the document 3.104 The term is used in the document 3.105 The term is used in the document 3.78 OLD The term is no longer used in the document 3.106 The term is used in the document 379 OLD The term is no longer used in the document 3.80 OLD The term is no longer used in the document 3,108 The term is used in the document 3.109 The term is used in the document 3.81 OLD The term is no longer used in the document 3.110 The term is used in the document 3.13 The term is used in the document 3.14 The term is used in the document 3.118 This term is used in the document 3.119 This term is used in the document.COMMITTEE ACTION: Accept in Principle.Modified to read as follows:3. Definitions

Note: Chapter 3, “Definitions” contains only those definitionsessential to the proper application of this Standard. It is notintended to include commonly defined general terms orcommonly defined technical terms from related codes andstandards. In general, only those terms that are used in two ormore places are defined. Other definitions are included in thearticle in which they are used. Spelling and definitions of generalwords and terms follow Webster’s Collegiate Dictionar y, 10th edition.

The terms in parenthesis, used throughout this standard are fromthe English version of IEC 60204-1, and are based on the OxfordEnglish dictionary.<<end note>>







3.4 adjustable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included.

3.5 ambient temperature: The temperature of the air or othermedium where the equipment is to be used. [IEV 826-01-04]

NOTE—Ambient air temperature as applied to an enclosure orhousing is the average temperature of the surrounding air thatcomes in contact with the enclosure or housing. Ambient airtemperature as applied to a component or device within theenclosure is the average temperature of the surrounding air thatcomes in contact with the component.

3.6 ampacity: The current, in amperes, that a conductor can carrycontinuously under the conditions of use, without exceeding thedesign limits for the temperature rating of the insulation, theconductor and the wire termination.

3.6 ampacity: The current, in amperes, that a conductor can carrycontinuously under the conditions of use without exceeding itstemperature rating. (NFPA 70)


NOTE: The National Fire Protection Association does notapprove, inspect, or certify any installations, procedures,equipment, or materials nor does it approve or evaluate testinglaboratories. In determining the acceptability of installations orprocedures, equipment, or materials, the “authority havingjurisdiction” may base acceptance on compliance with NFPA orother appropriate standards. In the absence of such standards,said authority may require evidence of proper installation,procedure, or use. The “authority having jurisdiction” may alsorefer to the listings or labeling practices of an organization that isconcerned with product evaluations and is thus in a position todetermine compliance with appropriate standards for the currentproduction of listed items.

3.8 attachment plug (plug cap) (plug): A device that, by insertionin a receptacle, establishes a connection between the conductorsof the attached flexible cord and the conductors connectedpermanently to the receptacle. [NFPA 70]

3.9 Authority Having Jurisdiction : The organization, office, orindividual responsible for approving equipment, an installation, ora procedure.


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NOTE: The phrase “authority having jurisdiction” is used in NFPAdocuments in a broad manner because jurisdictions and approvalagencies vary, as do their responsibilities. Where public safety isprimary, the authority having jurisdiction may be a federal, state,local, or other regional department or individual such as a firechief; fire marshal; chief of a fire prevention bureau, labordepartment, or health department; building official; electricalinspector; or others having statutory authority. For insurancepurposes, an insurance inspection department, rating bureau, orother insurance company representative may be the authorityhaving jurisdiction. In many circumstances, the property owner orhis or her designated agent assumes the role of the authorityhaving jurisdiction; at government installations, the commandingofficer or departmental official may be the authority havingjurisdiction.


3.10 Barrier. A physical obstruction that is intended to preventcontact with equipment or live parts or to prevent unauthorizedaccess to a work area. [NFPA 70E-2000]



3.12 branch circuit: The circuit conductors between the finalovercurrent device protecting the circuit and the outlet(s). (NFPA70)


3.14 cable trunking system: A system of enclosures comprised of abase and a removable cover intended for the completesurrounding of insulated conductors, cables, and cords [IEV 826-06-04, modified]


3.15 circuit breaker: A device designed to open and close a circuitby nonautomatic means and to open the circuit automatically on apredetermined overcurrent without damage to itself when properlyapplied within its rating. [NFPA 70]


3.17 conduit, intermediate metal: A listed steel raceway of circularcross-section with integral or associated couplings, connectors,and fittings approved for the installation of electrical conductorsand used with listed fittings to provide electrical continuity. [NFPA70]

3.18 conduit, rigid metal: Rigid metal conduit is a listed metalraceway of circular cross section with integral or associatedcouplings, approved for the installation of electrical conductorsand used with listed fittings to provide electrical continuity. [NFPA70]

3.19 conduit, rigid nonmetallic: A type of conduit and fittings ofsuitable nonmetallic material that is resistant to moisture andchemical atmospheres, flame retardant, resistant to impact andcrushing, and resistant to distortion from heat or low temperaturesunder conditions likely to be encountered in service. [NFPA 70]

3.20 control circuit (of a machine): The circuit of a controlapparatus or system that carries the electric signals directing theperformance of the controller but does not carry the main powercurrent.

Note: Power circuit protection can be provided by control shunt- tripping.

3.21 control circuit transformer: A voltage transformer utilized tosupply a voltage suitable for the operation of control devices.[IEEE 100]

3.22 control circuit voltage: The voltage utilized for the operationof control devices.3.23 control device: A device connected into the control circuitand used for controlling the operation of the machine (e.g.position sensor, manual control switch, relay, magneticallyoperated valve). [IEC 60204–1]


3.25 controlgear: A general term covering switching devices andtheir combination with associated control, measuring, protective,and regulating equipment, also assemblies of such devices andequipment with associated interconnections, accessories,enclosures, and supporting structures, intended in principle forthe control of electrical energy- consuming equipment. [IEV 441-11-03]<Possible alternate term: control equipment: Operating elementssuch as relays, contactors, circuit breakers, switches, solenoids,brakes and similar types of components, intended to govern orperform a given function in the operation, including measuring,sensing, monitoring, protection, and regulation of machinery

3.26 controller: A device or group of devices that serves to govern,in some predetermined manner, the electric power delivered tothe apparatus to which it is connected. [NFPA 70]

3.27 cord(flexible): Flexible cords are constructed as described in,and listed for use in accordance with Article 400 of the NationalElectrical Code (NFPA 70). All conductors are stranded copper.


3.29 digital: Operated by the use of discrete signals to representdata in the form of numbers or other characters. [IEC-60204-1]



3.32 dry location: A location not normally subject to dampness orwetness.

Note: A location classified as dry may be temporarily subject todampness or wetness, as in the case of a building underconstruction. [NFPA 70]

3.33 duct: An enclosed channel designed expressly for holdingand protecting electrical conductors, cables, and busbars.

NOTE: Conduits, cable trunking systems (see 3.10) andunderfloor channels are types of duct. See “raceway.”







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3.39 Emergency switching off: An emergency operation intendedto switch off the supply of electrical energy to all or a part of aninstallation where a risk of electric shock or another risk ofelectrical origin is involved.


3.41 enclosure: A surrounding case constructed to provide adegree of protection against incidental contact with the enclosedequipment and to provide a degree of protection to the enclosedequipment against specified environmental conditions.





NOTES—1 After failure the item has a fault.2 "Failure" is an event, as distinguished from "fault", which is a

state.3 This concept as defined does not apply to items consisting of

software only. [IEV 191-04-01]

3.46 fault: The state of an item characterized by inability toperform a required function, excluding the inability, duringpreventive maintenance or other planned actions, or due to lack ofexternal resources.

NOTE: A fault is often the result of a failure of the item itself, butmay exist without prior failure[IEV 191-05-01]

3.47 feeder: All circuit conductors between the service equipmentor the source of a separately derived system and the final branch-circuit overcurrent device. (NFPA 70)


3.49 ground: A conducting connection, whether intentional oraccidental, between an electrical circuit or equipment and theearth, or to some conducting body that serves in place of the earth.[NFPA 70]







3.56 harm: Physical injury or damage to health.

3.57 hazard: A source of possible injury or damage to health.[ISO/TR 12100-1, 3.5, modified]

3.58 hazardous condition situation: A circumstance in which aperson is exposed to a hazard(s). the exposure can immediately orover a long period of time have the potential to result in harm.

3.59 identified (as applied to equipment): Recognizable assuitable for the specific purpose, function, use, environment,application, etc., where described in a particular coderequirement. (See "equipment.")


3.60 indirect contact: Contact of persons with exposed conductiveparts which have become live under fault conditions. [IEV 826-03-06]

3.61 industrial machine: A power-driven machine (or a group ofmachines working together in a coordinated manner), notportable by hand while working, that is used to process material bycutting, forming, pressure, electrical, thermal, or opticaltechniques, lamination, or a combination of these processes. Itcan include associated equipment used to transfer material ortooling (including fixtures), assemble/disassemble, inspect or testor package. (The associated electrical equipment including thelogic controller(s) and associated software or logic together withthe machine actuators and sensors are considered as part of theindustrial machine.)


3.63 Input1 The terminals where current, voltage, power, or driving forcemay be applied to a circuit or device;2 The state or sequence of states occurring on a specific inputchannel;3 The device or collective set of devices used for bringing datainto another device. [IEC 60204–1]

3.64 In sight from, within sight from, within sight: Where thisstandard specifies that one equipment shall be "in sight from,""within sight from," or "within sight," etc., of another equipment,one of the equipments specified is to be visible and not more than50 ft (15.24 m) distant from the other. (NFPA 70)

3.65 inrush current (solenoid): The inrush current of a solenoid isthe steady-state current taken from the line at rated voltage andfrequency with the plunger blocked in the rated maximum openposition.

3.66 inrush locked rotor current (motor): See “locked rotor motorcurrent.”

3.67 (electrically) instructed person: A person adequately advisedor supervised by an electrically skilled person to enable him or herto perceive risks and to avoid hazards which electricity can create.[IEV 826-09-02, modified]



3.70 interrupting rating : The highest current at rated voltage that adevice is intended to interrupt under standard test conditions.


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NOTE—Equipment intended to interrupt current at other thanfault levels may have its interrupting rating implied in other ratings,such as horsepower or locked motor current.


3.72 Labeled: Equipment or materials to which has been attacheda label, symbol, or other identifying mark of an organization that isacceptable to the authority having jurisdiction and concerned withproduct evaluation, that maintains periodic inspection ofproduction of labeled equipment or materials, and by whoselabeling the manufacturer indicates compliance with appropriatestandards or performance in a specified manner. [NFPA 70]



3.73 live part (as applied to being energized during normal use):A conductor or conductive part intended to be energized innormal use, including a neutral conductor, but, by convention,not a PEN conductor.

NOTE—This term does not necessarily imply a risk of electricshock. [IEV 826-03-01]

3.74 live parts: Energized conductive components. [NFPA 70- 2002] (as applied to exposure to an existing shock hazard):Electric conductors, busses, terminals, or components that areuninsulated or exposed and a shock hazard exists.




3.78 neutral conductor (symbol N) : A conductor connected to theneutral point of a system and capable of contributing to thetransmission of electrical energy. [IEV 826-01-03]




channel;3. The device or collective set of devices used for taking data out

of another device.


3.82 overload: Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that,when it persists for a sufficient length of time, would cause damageor dangerous overheating. A fault, such as a short circuit or aground fault, is not an overload. (See "overcurrent.") [NFPA 70]

NOTE – Overload should not be used as a synonym forovercurrent.

3.83 Panel: An element of an electric controller consisting of aslab or plate on with various component parts of the controller aremounted or wired. [IEEE 100]





3.87 programmable electronic system (PES) : A system based onone or more central processing units (CPUs), connected tosensors or actuators, or both, for the purpose of control ormonitoring.

NOTE: The term “ programmable electronic system” PES includesall elements in the system extending from sensors to other inputdevices via data highways or other communication paths to theactuators or other output devices.



3.90 qualified person: At a minimum, a qualified person shall betrained and knowledgeable of the construction and operation ofequipment or a specific work method, and be trained to recognizeand avoid the electrical hazards that might be present with respectto that equipment or work method. Such persons shall also befamiliar with the proper use of special precautionary techniques,personal protective equipment, insulating and shielding materials,and insulated tools and test equipment. [NFPA 70E]See “(electrically) instructed person” and “(electrically) skilledperson.”

3.91 raceway: An enclosed channel of metal or nonmetallicmaterials designed expressly for holding wires, cables, or busbars,with additional functions as permitted in this standard. Racewaysinclude, but are not limited to, rigid metal conduit, rigidnonmetallic conduit, intermediate metal conduit, liquidtightflexible conduit, flexible metallic tubing, flexible metal conduit,electrical nonmetallic tubing, electrical metallic tubing, wireways,and busways.




3.95 relative humidity: The ratio between the amount of watervapor in the gas at the time of measurement and the amount of


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water vapor that could be in the gas when condensation begins, ata given temperature. [IEEE 100]




3.99 safeguarding: Those safety measures consisting of the use ofspecific means called safeguards to protect persons from hazardsthat cannot reasonably be removed or are not sufficiently limitedby design.


3.101 safety function [safety measure ]: A means that eliminatesor reduces a hazard. [IEC 60204–1]




3.105 should: Indicates a recommendation or that which isadvised but not required.


3.107 socket: See “receptacle.”





3.111 supplementary overcurrent protective device: A device usedwhere protection is required for lighting fixtures, appliances, andother equipment or for internal circuits and components ofequipment. It shall not be used as a substitute for power circuitovercurrent devices in place of the power circuit protection.


3.113 tap conductor: A conductor that has overcurrent protectionahead of its point of supply, that exceeds the value permitted forsimilar conductors that are protected as described elsewhere inthis standard.


3.115 tight (suffix): So constructed that the specified material isexcluded under specified conditions. (ANSI/IEEE Standard No.100)

3.116 uncontrolled stop: The stopping of machine motion byremoving power to the machine actuators, all brakes and/or othermechanical stopping devices being activated. [IEC 60204–1]

3.117 undervoltage protection: The effect of a device that operateson the reduction or failure of voltage, to cause and maintain theinterruption of power.

NOTE—The principal objective of this device is to preventautomatic restarting of the equipment. Standard undervoltage orlow-voltage protection devices are not designed to become effectiveat any specific degree of voltage reduction.

3.118 user: An entity who utilizes the machine and its associatedelectrical equipment.

3.119 variable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or rollershifting controllers are not included.


3.121 Voltage, Nominal. A nominal value assigned to a circuit orsystem for the purpose of conveniently designating its voltage class(e.g., 120/240 volts, 480Y/277 volts, 600 volts).The actual voltage at which a circuit operates can vary from thenominal within a range that permits satisfactory operation ofequipment.


3.122 wireway: A sheet-metal or flame retardant nonmetallictrough with hinged or removable covers for housing andprotecting electric wires and cable and in which conductors arelaid in place after the wireway has been installed as a completesystem. [NFPA 70]COMMITTEE STATEMENT: A new note effecting the entireClause 3 was added to clarify how the terminology is used instandard. Additionally, the following definitions were revised forthe following reasons: 3.6 Ampacity was revised to match the definition in the NEC. 3.10 Barrier was revised to correlate with the definition of barrieras presently exists in NFPA 70E-2000. 3.25 Controlgear was removed and replaced with the term"control equipment" to correlate with the use of the term in thedocument. 3.56 Harm was deleted since it is no longer used in thenormative text. 3.58 Hazardous situation was changed to "hazardous condition"to be consistent with the use of the term in the normative text. 3.60 The word "with" was added to the definition of IndirectContact for editorial purposes. 3.72 added the definition Labeled from the NEC and to agreewith Proposal 79-13 (Log #141). 3.78 Neutral conductor (symbol N). Deleted the symbol since itis not used in the document. 3.83 add the definition of "Panel" from IEEE 100 3.87 The acronym PES was deleted because it not commonlyunderstood. 3.121 Voltage, Nominal was added to clarify its meaning withinthe standard.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: I cannot accept the 2nd paragraph of the Notewhich was added during the ROP meeting. It is erroneous andmisleading. There are a number of terms which are followed byan alternate term or modifier (e.g. accessible (as applied toequipment)) which does not fit the 2nd paragraph. Also in thebody of the text there are alternate terms which do not appear assuch in the Oxford Dictionary (e.g. protective bondingconductor). I support deleting the note (or at least the 2nd


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paragraph) in favor of the addition to Foreword (see Proposal 79-7(Log #33).I would accept retaining the first paragraph if it was changed to anintroductory statement and not a note.COMMENT ON AFFIRMATIVE: DOBROWSKY: (1) The term "panel" and its definition shouldnot be added to this standard, or it should be modified. There isa conflict with the defined term "controller" and it does not appearto have the same meaning in Chapter 12. (2) Some of the definitions are for terms that are only used inparenthetical form (in this standard) which may only be anapproximation of the actual term used in this standard. If definitions for parenthetical terms are included in Chapter 3they may conflict with or be confused with the "primary" term usedin this standard. A solution may be to place the parentheticaldefinition in an annex, possibly Annex A, with an asterisk next tothe primary term in Chapter 3. The second paragraph of theintroductory note would also need to be modified accordingly. FREUDENBERG: If 79-8 and/or 79-9 are revised add definitionof "hazardous process material (HPM)" from Uniform BuildingCode. Text available upon request.

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(Log #CP1)79- 12 - (Chapter 3 Definitions (GOT)): Accept in PrincipleSUBMITTER: Technical Committee on Electrical Equipment ofIndustrial MachineryRECOMMENDATION: Adopt the preferred definitions from theNFPA Glossary of Terms for the following terms: Accessible (as applied to equipment) (preferred) NFPA 70 Admitting close approach; not guarded by locked doors,elevation, or other effective means. Accessible (as applied to equipment) (secondary) Admitting close approach: not guarded by locked doors,elevation, or other effective means. (See "Accessible, Readily.") Accessible, Readily. (Readily Accessible) (preferred) NFPA 70 Capable of being reached quickly for operation, renewal, orinspections, without requiring those to whom ready access isrequisite to climb over or remove obstacles or to resort to portableladders, etc. Accessible, Readily. (Readily Accessible) (secondary) Capable of being reached quickly for operation, renewal, orinspections, without requiring those to whom ready access isrequisite to climb over or remove obstacles or to resort to portableladders, chairs, etc. (See "Accessible.") Circuit Breaker (preferred) NFPA 70 A device designed to open and close a circuit by nonautomaticmeans and to open the circuit automatically on a predeterminedovercurrent without damage to itself when properly applied withinits rating. FPN: The automatic opening means can be integral, direct actingwith the circuit breaker, or remote from the circuit breaker. Circuit Breaker (secondary) A device designed to open and close a circuit by nonautomaticmeans and to open the circuit automatically on a predeterminedovercurrent without injury to itself when properly applied within itsrating. Controller (preferred) NFPA 70 A device or group of devices that serves to govern, in somepredetermined manner, the electric power delivered to theapparatus to which it is connected. Controller (secondary) A device or group of devices that serves to govern, in somepredetermined manner, the electric power delivered to theapparatus to which it is connected. For the purpose of thisstandard, a controller is any switch or device normally used to startand stop a motor by making and breaking the motor circuitcurrent. (NFPA 70.) Dwelling Unit (preferred) NFPA 101 A single unit, providing complete, independent living facilities forone or more persons, including permanent provisions for living,sleeping, eating, cooking, and sanitation. Dwelling Unit (secondary) One or more rooms for the use of one or more persons as ahousekeeping unit with space for eating, living, and sleeping, andpermanent provisions for cooking and sanitation. (NFPA 70.) Equipment (preferred) NFPA 820 A general term including material, fittings, devices, appliances,fixtures, apparatus, and so forth, used as part of, or in connectionwith, a mechanical, instrumentation, or electrical installation. Equipment (secondary)

A general term including material, fittings, devices, appliances,fixtures, apparatus, and the like used as a part of, or in connectionwith, an electrical installation. Exposed (as applied to live parts) (preferred) NFPA 70 Capable of being inadvertently touched or approached nearerthan a safe distance by a person. It is applied to parts that are notsuitably guarded, isolated, or insulated. Exposed (as applied to live parts) (secondary) Capable of being inadvertently touched or approached nearerthan a safe distance by a person. It is applied to parts not suitablyguarded, isolated, or insulated. (NFPA 70.) Feeder (preferred) NFPA 70 All circuit conductors between the service equipment, the sourceof a separately derived system, or other power supply source andthe final branch-circuit overcurrent device. Feeder (secondary) All circuit conductors between the service equipment or thesource of a separately derived system and the final branch-circuitovercurrent device. Interlock (preferred) NFPA 97 A device, or an arrangement of devices, in which the operation ofone part or one mechanism of the device or arrangement controlsthe operation of another part of another mechanism. Interlock (secondary) A device, or an arrangement of devices, in which the operation ofone part or one mechanism of the device or arrangement controlsthe operation of another mechanism. Interrupting Rating (preferred) NFPA 70 The highest current at rated voltage that a device is intended tointerrupt under standard test conditions. FPN: Equipment intended to interrupt current at other than faultlevels may have its interrupting rating implied in other ratings,such as horsepower or locked rotor current. Interrupting Rating (secondary) The highest current at rated voltage that a device is intended tointerrupt under standard test conditions. (FPN): Equipment intended to break current at other than faultlevels may have its interrupting rating implied in other ratings,such as horsepower or locked rotor current. Overcurrent (preferred) NFPA 70 Any current in excess of the rated current of equipment or theampacity of a conductor. It may result from overload, short circuitor ground fault. A current in excess of rating may be accommodated by certainequipment and conductors for a given set of conditions. Thereforethe rules for overcurrent protection are specific for particularsituations. Overcurrent (secondary) Any current in excess of the rated current of the equipment orthe rated ampacity of the conductor. It may result from overload,short circuit, or ground fault. (NFPA 70.) Overload (preferred) NFPA 70 Operation of equipment in excess of normal, full-load rating, orof a conductor in excess of rated ampacity that, when it persists fora sufficient length of time, would cause damage or dangerousoverheating. A fault, such as a short circuit or ground fault, is notan overload. Overload (secondary) Operation of equipment in excess of normal, full-load rating, orof a conductor in excess of rated ampacity that, when it persists fora sufficient length of time, would cause damage or dangerousoverheating. A fault, such as a short circuit or ground fault, is notan overload. (See "Overcurrent.") Qualified Person (preferred) NFPA 1500 A person who, by possession of a recognized degree, certificate,professional standing, or skill, and who, by knowledge, training,and experience, has demonstrated the ability to deal withproblems relating to a particular subject matter, work, or project. Qualified Person (secondary) One familiar with the construction and operation of theequipment and the hazards involved. Raceway (preferred) NFPA 70 An enclosed channel of metal or nonmetallic materials designedexpressly for holding wires, cables, or busbars, with additionalfunctions as permitted in this Code. Raceways include, but are notlimited to, rigid metal conduit, rigid nonmetallic conduit,intermediate metal conduit, liquidtight flexible conduit, flexiblemetallic tubing, flexible metal conduit, electrical nonmetallictubing, electrical metallic tubing, underfloor raceways, cellularconcrete floor raceways, cellular metal floor raceways, surfaceraceways, wireways, and busways. Raceway (secondary) An enclosed channel of metal or nonmetallic materials designedexpressly for holding wires, cables, or busbars, with additional


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functions as permitted in this standard. Raceways include, but arenot limited to, rigid metal conduit, rigid nonmetallic conduit,intermediate metal conduit, liquidtight flexible conduit, flexiblemetallic tubing, flexible metal conduit, electrical nonmetallictubing, electrical metallic tubing, surface raceways, wireways, andbusways. Receptacle (preferred) NFPA 70 A receptacle is a contact device installed at the outlet for theconnection of an attachment plug. A single receptacle is a singlecontact device with no other contact device on the same yoke. Amultiple receptacle is two or more contact devices on the sameyoke. Receptacle (secondary) A contact device installed at the outlet for the connection of asingle attachment plug. (NFPA 70.)SUBSTANTIATION: Adoption of preferred definitions will assistthe user by providing consistent meaning of defined termsthroughout the National Fire Codes.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-11 (Log #37) [Clause 3, Definitions]. The committee hasrevised Clause 3 to incorporate the preferred definitions wherethey are appropriate.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: See my Comment of Affirmative for Proposal 79-11 (Log #37). FREUDENBERG: If 79-8 and/or 79-9 are revised add definitionof "hazardous process material (HPM)" from Uniform BuildingCode. Text available upon request.

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(Log #141)79- 13 - (Chapter 3 labeled [Chapter 3 labeled]): Accept TCC NOTE: The TCC directs the committee to consider thecomments expressed in the voting. This action will be consideredby the committee as a public comment.SUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Add new text as follows: Add definition for "labeled" from NFPA 70 or NFPA officialdefinitions taken from the Regulations Governing CommitteeProjects.SUBSTANTIATION: Per my notes the TC79 committee hadvoted to add "labeled" as a defined term but inadvertently left"labeled" out of the latest draft of section 3. The term "labeled" is frequently used in the notes for thedefinitions of approved, identified and listed. This will align NFPA 79 definition for listed and relateddefinitions with NFPA 70, indicating listed is not necessarilylimited to the more commonly known practices of NRTL listed orUL listed. 3.7 approved: Acceptable to the authority having jurisdiction.(NFPA 70) NOTE: The National Fire Protection Association does notapprove, inspect, or certify any installations, procedures,equipment, or materials not does it approve or evaluate testinglaboratories. In determining the acceptability of installations orprocedures, equipment, or materials, the "authority havingjurisdiction" may base acceptance on compliance with NFPA orother appropriate standards. In the absence of such standards,said authority may require evidence of proper installation,procedure, or use. The "authority having jurisdiction" may alsorefer to the listings or labeling practices of an organization that isconcerned with product evaluations and is thus in a position todetermine compliance with appropriate standards for the currentproduction of listed items. Substantiation for definition 3.7 approved. Both the definitionand note recommended here are NFPA official definitions takenfrom the Regulations Governing Committee Projects. Thisdefinition leaves the final decision of what is acceptable and whatis not acceptable up to the authority having jurisdiction. 3.9 Authority Having Jurisdiction - the organization, office, orindividual responsible for approving equipment, an installation, ora procedure. NOTE: The phrase "authority having jurisdiction" is used inNFPA documents in a broad manner because jurisdictions andapproval agencies vary, as do their responsibilities. Where publicsafety is primary, the authority having jurisdiction may be a federal,state, local, or other regional department or individual such as a

fire chief; fire marshal; chief of a fire prevention bureau, labordepartment, or health department; building official; electricalinspector; or others having statutory authority. For insurancepurposes, an insurance inspection department, rating bureau, orother insurance company representative may be the authorityhaving jurisdiction. In many circumstances, the property owner orhis or her designated agent assumes the role of the authorityhaving jurisdiction; at government installation, the commandingofficer or departmental official may be the authority havingjurisdiction. Substantiation for definition 3.9 Authority having Jurisdiction.Both the definition and note provided here are NFPA officialdefinitions taken from the Regulations Governing CommitteeProjects. Since NFPA 79 is a voluntary standard in many cases,often times the question is asked: "Who is the authority havingjurisdiction (AHJ)." This definition will assist the user in makingthat determination. 3.59 identified (as applied to equipment): Recognizable assuitable for the specific purpose, function, use, environment,application, etc. where described in a particular coderequirement. (See "equipment.") NOTE - Suitability of equipment for a specific purpose,environment, or application may be determined by a qualifiedtesting laboratory, inspection agency, or other organizationconcerned with product evaluation. Such identification mayinclude labeling or listing. [NFPA 70] 3.72 listed: Equipment, materials, or services included in a listpublished by an organization that is acceptable to the authorityhaving jurisdiction and concerned with evaluation of products orservices, that maintains periodic inspection of production of listedequipment or materials or periodic evaluation of services, andwhose listing states that either the equipment, material, or servicesmeets identified standards or has been tested and found suitablefor specified purpose. (NFPA 70). NOTE - The means for identifying listed equipment may vary foreach organization concerned with product evaluation, some ofwhich do not recognize equipment as listed unless it is alsolabeled. Use of the system employed by the listing organizationallows the authority having jurisdiction to identify a listed product. Substantiation for definition 3.72 listed Term is used in thedocument. The definition is consistent with the NEC.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal modifies the Action on Proposal 79-11 (Log #37).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FISHER: The appropriate text is: Labeled. Equipment or materials to which has been attached alabel, symbol, or other identifying mark of an organization that isacceptable to the authority having jurisdiction and concerned withproduct evaluation, that maintains periodic inspection ofproduction of labeled equipment or materials, and by whoselabeling the manufacturer indicates compliance with appropriatestandards or performance in a specified manner. FREUDENBERG: The definition of labeled needs to beextracted from the NFPA Rules and included in NFPA79 tofacilitate a better understanding of listed and labeled.

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(Log #4979- 14 - (Chapter 3 electronic drive [Chapter 3 electronic drive ]):Accept in PartSUBMITTER: John J. Kowal, Webster, NYRECOMMENDATION: Revise text as follows: Remove definitions for adjustable speed drives and variable speeddrives and replace with new definition titled electronic drives. Thenew definition will include the same wording contained in the olddefinitions with just a title change. 3.4 adjustable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included. 3.119 variable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included.


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3.XXX electronic drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included. SUBSTANTIATION: This change will provide clarity for thepublic in the proposed NFPA 79-2002 standard. The proposedNFPA 79-2002 does not have a reference to either a variable speedor adjustable speed drive. There is a reference to electronic drivesin the proposed Section 11.4, titled Electronic Drives. Thisreference encompasses both of the previously mentioned drivetypes. Therefore the existing definition is used.COMMITTEE ACTION: Accept in Part. 1) Retain the definition of Adjustable Speed Drive. 2) Delete the definition of Variable Speed Drive in 3.119. 3) Do not accept the new definition of electronic drive.COMMITTEE STATEMENT: The committee accepts deleting thedefinition of Variable Speed Drive. The definition of AdjustableSpeed Drives was retained because it matches the definition usedin the NEC. The committee does not accept the proposeddefinition of Electronic Drive because it conflicts with the NEC.The committee understands that this proposal modifies theCommittee Action on Proposal 79-11 (Log #37) [Clause 3,Definitions]NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #50)79- 15 - (Chapter 3 inrush current (solonoid) [Chapter 3 inrushcurrent (solonoid)]): RejectSUBMITTER: John J. Kowal, Webster, NYRECOMMENDATION: Revise text as follows: 3.65 inrush current (solenoid): the inrush current of a solenoidis the steady state current taken from the line at rated voltage andfrequency with the plunger blocked in the rated maximum openposition. This current is several times greater than its holdingcurrent. If allowed to continue, by malfunction, with a constantpower source still connected to its coil, it will quickly overheat andburn out. SUBSTANTIATION: The existing text is not clear and does notdifferentiate from momentary inrush currents as a motor ortransformer exhibits on start-up (harmless), as the definition usedin this text for a solenoid. This change will enhance the user’s knowledge of these types ofdevices. It will allow for the increased safe and reliable use of theseproducts, providing the proper protection against overcurrents thatcan cause dangerous overheating and burnout.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The statement is not necessarilycorrrect in that certain types of solonoids do not fail under theseconditions (e.g. dc coils, pilot operated valves). In addition, thetext contains information that is better suited for inclusion in ahandbook.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: SANDERS: This material is more suitable for NFPA 70B"Recommended Practices for Electrical Maintenance". The submitter is urged to re-submit this information to thatTechnical Committee for consideration.

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(Log #154)79- 16 - (Chapter 3 safety control circuit [Chapter 3 safety controlcircuit]): Accept in PrincipleSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Add new text to read as follows: 3.X safety control circuit: The part of the control circuit thatincorporates the safety related actuators intended to guarantee theoperational safety of the machine (e.g. emergency stop button,light curtain, safety limit switch, two hand control, safety mat,safety pull cord, ...) into the control scheme of the machine.SUBSTANTIATION: No definition for new Sub Clause 9.1.5COMMITTEE ACTION: Accept in Principle. Revise the proposed definition to read as follows:

3.X safety control circuit: The part of the control circuit thatincorporates safety related components.COMMITTEE STATEMENT: The revised definition removed thelist of examples because the list is unnecessary and removed theterm guarantee since that term is not enforceable. The committeeunderstands that this proposal modifies the Action on Proposal 7911 (Log #37).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 20 NEGATIVE: 5 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: This term was to be added to provide adefinition for the proposed modification to new clause 9 (9.1.5,seq# 79–63 (Log #153). Since the Committee Action for Proposal79-63 (Log #153) is to reject the term no longer is being used andtherefore should be added to clause 3. In addition, the term usedthroughout the standard is safety function. FISHER: The definition is unnessary and is possibly misleading.Safety components can be applied in any circuit but just utilizing asafety component does not ensure a safety circuit. The acceptanceof this concept should be as part of an entire system as describedin the negative comment on 79-73 (Log #153) and 79-77. MONTEITH: I agree with the Explanation of Negative votes byMr. Fisher and Mr. Saunders. PADGET: I agree with Mr. Saunders ‘ Explanation of NegativeVote. SAUNDERS: See the Committee Action on Proposal 79-63 (Log#46), which was rejected, and therefore eliminated the need forthe new definition in Clause 3.COMMENT ON AFFIRMATIVE: DOBROWSKY: I am not opposed to adding the term but theproposed (revised) definition may be confusing. A safety controlcircuit may not necessarily be part of another control circuit. Thedefinition should be revised to remove the word "related". Theacceptance of Proposal 79-1 (Log #CP4) globally replaces "safetyrelated function" with "safety function". There may not be a needfor the definition based on Proposal 79-63 (Log #153) beingrejected. PILZ: This comment is in support of the committee action toaccept in principle to include a definition for safety control circuit However, I suggest changing the wording of 3.X as follows: 3.X Safety Circuit. The part of the control circuit thatincorporates the control devices intended to control the safetyfunction of the machine protecting personnel from mechanicalhazards. Substantiation: The suggested wording adds clarity to the user ofthe document; Historically, NFPA 79 was designed to protectagainst electrical hazards such as electrocution and fire. NFPA 79was not intended to provide guidance on how to protect againstmechanical hazards. However, through the inclusion of thefunctionality of the Emergency Stop, the scope of NFPA 79 hasbeen extended to cover protection against mechanical hazards aslong as they are electronically controllable. If the committeeacknowledges this fact and decides to incorporate the newlyproposed 9.1.5 which gives guidance of the design of such circuitrythe above mentioned definition is necessary to be incorporatedinto the standard. Also, the term Safety (Stop) Circuit is currentlyused in the ANSI/RIA 15-06 1999 edition ( See page 18, clause 6.12Robot system stopping circuits).

___________________(Log #51

79- 17 - (Chapter 3 solonoid [Chapter 3 solonoid]): RejectSUBMITTER: John J. Kowal, Webster, NYRECOMMENDATION: Add the following new definition toClause 3: 3.XXX solenoids: are electromechanical devices used to convertelectrical energy into mechanical work. There are three basictypes: pull-type, push-type, and rotary. Reference 3.65 Inrushcurrent (solenoid). SUBSTANTIATION: The requirements for the safe and reliableinstallation of these devices are not clear in the text of thisdocument. The purpose of this proposal is to clarify "solenoid(valve)" and "inrush current (solenoid)".COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposed definition isunnecessary since the term solonoid is commonly understood.The committee disagrees with the first line of the submitterssubstantiation. In addition, the second sentence containsinformation that is more properly suited for a handbook.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26


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VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________(Log #23)

79- 18 - (Clause 4 [Clause 17]): Accept in PrincipleSUBMITTER: Carl E. Padgett, Jr., Padgett Consulting/Rep. TheAssociation for Manufacturing Technology1RECOMMENDATION: Revise part of NFPA 79-1997 Clause 4"Diagrams, instruction and nameplates" and subclause 11.10"Warning marks." Issue as new Clause 17 "Markings, warning signsand referece designations."

17 Marking, warning signs and reference designations

17.1 General

17.1.1 The electrical equipment shall be marked with thesupplier's name, trademark, or other identifying symbol and,where required, with a certification mark.

17.1.2 Warning signs, nameplates, markings, and identificationplates shall be of sufficient durability to withstand the physicalenvironment involved.

17.2 Warning marking and signs

17.2.1 Enclosures that do not clearly show that they contain electricaldevices shall be marked with a black lightning flash on a yellowbackground within a black triangle, shaped in accordance with thegraphical symbol 60417-2-IEC-5036, the whole in accordance with signB.3.6 of ISO 3864:

Figure XX – Warning sign on enclosures

17.2.2 The warning sign shall be plainly visible on the enclosuredoor or cover.

17.2.3 It is permitted to omit this warning sign on:

– an enclosure equipped with a supply disconnecting device;– an operator–machine interface or control station;– a single device with its own enclosure (e.g. position sensor)

17.2.4 A warning marking shall be provided adjacent to thedisconnect operating handle(s) where the disconnect(s) that isinterlocked with the enclosure door does not deenergize allexposed live parts when the disconnect(s) is in the "open (off)"position.

17.2.5 Where an attachment plug is used as the disconnectingmeans, a warning marking shall be attached to the controlenclosure door or cover indicating that power shall bedisconnected from the equipment before the enclosure is opened.

17.2.6 Where the disconnecting means is remote from the controlenclosure, a warning marking shall be attached to the enclosuredoor or cover indicating that the power shall be disconnectedfrom the equipment before the enclosure is opened and that theenclosure is to be closed before the power is restored.

17.3 Function identification

Control devices, visual indicators, and displays used in the man- machine interface shall be clearly and durably marked with regardto their functions either on or adjacent to the unit.

Note 1: Such markings may be as agreed between the user and thesupplier of the equipment, see Annex B for additionalinformation.

Note 2: For further information on symbols, see IEC 60417 andISO 7000.

Note 3: Consideration should be given to the use of IEC symbolsfor pushbuttons (see Annex C for examples).

17.4 Machine nameplate data

17.4.1 Control equipment (e.g. controlgear assemblies) shall belegibly and durably marked in a way that it is plainly visible aftethe equipment is installed. A nameplate giving the followinginformation shall be attached to the enclosure:

– name or trademark of supplier;– certification mark, when required;– serial number, where applicable;– rated voltage, number of phases and frequency (if a.c.)

and full-load current for each supply– ampere rating of the largest motor or load;– short-circuit interrupting capacity of the machine

disconnecting means where provided as part of theequipment;

– the electrical diagram number(s) or the number of the indexto the electrical drawings.

17.4.2 The full-load current shown on the nameplate shall not beless than the full-load currents for all motors and other equipmenthat can be in operation at the same time under normal conditionof use. Where unusual loads or duty cycles , require oversizedconductors, the required capacity shall be included in the full-loadcurrent specified on the nameplate.

17.4.3 Where more than one incoming supply circuit is to beprovided, the nameplate shall state the above information for eachcircuit.

17.4.4 Where only a single motor or motor controller is used, themotor nameplate shall be permitted to serve as the electricalequipment nameplate where it is plainly visible.

17.4.5 Where overcurrent protection is provided in accordancewith 7.2.3., the machine shall be marked "overcurrent protectionprovided at machine supply terminals." A separate nameplate shallbe permitted to be used for this purpose.

17.5 Equipment marking and identification

17.5.1 Where equipment is removed from its original enclosure ois so placed that the manufacturer's identification plate is not easilyread, an additional identification plate shall be attached to themachine or enclosure.

17.5.2 Where a motor nameplate or connection diagram plate isnot visible, additional identification shall be provided where it canbe easily read.

17.5.3 Nameplates, identification plates, or warning markings shallnot be removed from the equipment.

17.5.4 All control panel devices and components shall be plainlyidentified with the same designation as shown on the diagram(s)This identification shall be adjacent to (not on) the device ocomponent.

Exception No. 1: Where the size or location of the devices makeindividual identification impractical, group identification shall be used.

Exception No. 2: This section shall not be required to apply to machineon which the equipment consists only of a single motor, motor controllerpushbutton station(s), and worklight(s).

17.5.5 All devices external to the control panel(s) shall beidentified by a nameplate with the same designation as shown onthe diagram(s) and mounted adjacent to (not on) the device.

Exception: Devices covered by 17.3

17.5.6 Terminations on multiconductor plugs and receptacleshall be plainly marked. The markings on the plug/receptaclesand on drawings shall correspond.

17.5.7 Where group protection as provided for in 7.2.10 is usedinformation specifying the short circuit protective device for eachgroup protected motor branch circuit shall be included with theequipment


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SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738.Historical Background

In March of 1998, the NFPA 79 committee prepared a statement ofwork. The major elements of the statement of work are:

Harmonization – Purpose

As the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation,and at the same time maintain the high standard of electricalmachine safety, the NFPA 79 committee has expressed theirdesire, through balloted vote, to harmonize NFPA 79 with IEC- 60204-1.

Importance of Issue – Harmonization

Today's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable,industrial machines originally produced for a foreign market mayquickly be transported to the domestic market. The reverse is alsotrue. Differing electrical standards add a large cost tomultinational manufacturers as they build and sometimes movemanufacturing facilities.

Harmonization – Objective

This work is necessary to accomplish the goal of allowing industryto economically build one industrial machine capable of passing adetailed electrical safety inspection using either IEC 60204-1 orNFPA 79 standard.

Both the NEC Technical Correlating Committee and the StandardsCouncil reviewed the statement of work in July of 1998. The TCCunanimously recommended the following action to the StandardsCouncil:

"The Technical Correlating Committee agrees with the efforts ofthe NFPA 79 committee to harmonize the technical requirementsof NFPA 79 and IEC 60204, where feasible and where in concertwith the NEC and its related codes and standards."

Result

The NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committeeformed 20 Task Groups. Each Task Group was assigned oneproposed new clause.

The Task Group compared NFPA-79-1997, Clause 4 with IEC60204-1 Clause 17. The Task Group presented its work to theentire committee on several occasions for review and comment.This proposal is a result of that work.

The Task Group proposes to renumber NFPA 79-1997 Clause 4 tocorrespond with IEC 60204-1 Clause 17. The task group proposesthe following changes to further improve usability. SUBSTANTIATION FOR NFPA 79-1997 REVISIONS TO PARTOF CLAUSE 4 AND SUBCLAUSE 11.10 17 Marking, warning signs and reference designations

Add the IEC 60204-1 Clause 17 heading to the proposedNFPA 79-2002.

Substantiation: The proposed NFPA 79-2002 Clause17 heading is added to harmonize with IEC 60204-1.

All subclause numbers in NFPA 79-2002 follow theIEC 60204-1 numbering sequence.

17.1 General

Add IEC 60204-1 subclause 17.1 heading to the proposedNFPA 79-2002.

Substantiation: The IEC subclause heading isadded for general information on marking, warningsigns and reference designations and to harmonizewith IEC 60204-1.

17.1.1

(a) Add the subclause number 17.1.1 to be in compliancewith the NFPA Manual of style.

(b) Dele te NFPA 79-1997 subclause 4.6 heading “MachineMarking” and paragraph.

(c) Add the IEC 60204-1 subclause 17.1 first paragraph:

The electrical equipment shall be marked with thesupplier's name, trademark, or other identifying symboland, where required, with a certification mark.

Substantiation: The NFPA 79-1997 subclause 4.6text is the same as the IEC 60204-1 subclause 17.1 firstparagraph except “and, where required, with acertification mark” is added at the end of subclause4.6 paragraph. This addition harmonizes NFPA 79with IEC 60204-1.

17.1.2


(b) Delete NFPA 79-1997 subclause 4.4 heading andparagraph.

(c) Add IEC 60204-1 subclause 17.1 second paragraph:

Warning signs, nameplates, markings, and identificationplates shall be of sufficient durability to withstand thephysical environment involved.

Substantiation: The NFPA 79-1997 subclause 4.4text is the same as the IEC 60204-1 subclause 17.1second paragraph except “Warning signs,” is added atthe beginning of subclause 4.4 paragraph. Thisaddition harmonizes NFPA 79 with IEC 60204-1.


Revise NFPA 79-1997 subclause 4.5 heading “Warningmarking” for the proposed NFPA 79-2002.

Substantiation: This revision combines NFPA 79-1997 subclause 4.5 Warning mark and IEC 60204-1subclause 17.2 Warning signs in order to harmonizewith IEC 60204-1.

17.2.1


(b) Delete the NFPA 79-1997 subclause 11.10 heading.

(c) Add the NFPA 79-1997 subclause 11.10 revised firstparagraph:

Enclosures that do not clearly show that they containelectrical devices shall be marked with a black lightningflash on a yellow background within a black triangle,shaped in accordance with the graphical symbol 60417-2-IEC-5036, the whole in accordance with sign B.3.6 ofISO 3864:


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Substantiation: The text is the same as NFPA 79-1997 subclause 11.10, except the IEC standardnumbers have been revised to harmonize with IEC60204-1.

(d) Revise the NFPA 79-1997 Figure 3 to Figure XX.17.2.2


(b) Add the NFPA 79-1997 subclause 11.10 third paragraphwithout changes.

17.2.3


(b) Add the NFPA 79-1997 subclause 11.10 second paragraphand bullets without changes.

17.2.4


(b) Add the NFPA 79-1997 subclause 4.5.1 paragraph withoutchanges.

17.2.5



17.2.6




(a) Add the NFPA 79-1997 subclause 4.9 heading.(b) Revise the NFPA 79-1997 subclause 4.9 paragraph and

note and add three notes as follows:

Control devices, visual indicators, and displays used inthe man-machine interface shall be clearly and durablymarked with regard to their functions either on oradjacent to the unit. Such markings may be as agreedbetween the user and the supplier of the equipment (seeannex B).

Note 1: Such markings may be as agreed between theuser and the supplier of the equipment, see Annex B foradditional information.

Note 2: For further information on symbols, see IEC60417 and ISO 7000.

Note 3: Consideration should be given to the use of IECsymbols for pushbuttons (see Annex C for examples).

Substantiation: The NFPA 79-1997 text was revisedin order to harmonize with IEC 60204-1.


Add the NFPA 79-1997 subclause 4.7 heading.

17.4.1


(b) Revise NFPA 79-1997 subclause 4.7.1 paragraph asfollows:

Control equipment (e.g. controlgear assemblies) shallbe legibly and durably marked in a way that it is plainlyvisible after the equipment is installed. A nameplategiving the following information shall be attached to theenclosure:– name or trademark of supplier;– certification mark, when required;– serial number, where applicable;

– rated voltage, number of phases and frequency(if a.c.), and full-load current for each supply– ampere rating of the largest motor or load;– short-circuit interrupting capacity of the

machine disconnecting means where providedas part of the equipment;

– the electrical diagram number(s) or thenumber of the index to the electrical drawings.

Substantiation: This is a combination of NFPA 791997 subclause 4.7.1 and IEC 60204-1 subclause 17.4first paragraph. The NFPA 79-1997 text was revised inorder to harmonize with IEC 60204-1.

17.4.2


(b) Add the NFPA 79-1997 subclause 4.7.2 paragraph withouchange.

17.4.3


(b) Add the NFPA 79-1997 subclause 4.7.1 last sentencewithout change.

17.4.4


(b) Add the NFPA 79-1997 subclause 4.7.1 exception as aparagraph without text change.

17.4.5




Add the NFPA 79-1997 subclause 4.8 heading.17.5.1



17.5.2



17.5.3



17.5.4


(b) Add the NFPA 79-1997 subclause 4.8.4 paragraph andexceptions without change.

17.5.5

(a) Add the subclause number 17.5.5 to be in compliance with theNFPA Manual of style.


(c) Revise the subclause number in the exception from “4.9” to“17.3.”

17.5.6



17.5.7


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(b) Add the NFPA 79-1997 subclause 4.8.7 paragraph.

(c) Change the subclause reference number from”8.5.4” to “7.2.10.” CLAUSE NUMBER CROSS REFERENCE --- NFPA 79-1997 ANDPROPOSED NFPA 79-2002

NFPA 79-1997 Proposed NFPA 79-2002

Clause Heading or Text Clause Heading or text 4.4 Markings 17.1.2 Paragraph 4.5 Warning marking 17.2 Warning markings and signs

Warning mark 17.2 Warning marking and signs First paragraph and symbol 17.2.1 paragraph and symbol Second paragraph and bullets 17.2.3 Paragraph and bullets

11.10

Third paragraph 17.2.2 Paragraph 4.5.1 Paragraph 17.2.4 Paragraph 4.5.2 Paragraph 17.2.5 Paragraph 4.5.3 Paragraph 17.2.6 Paragraph 4.6 Machine marking 17.1.1 Paragraph 4.7 Machine nameplate data 17.4.3 Machine nameplate data

Paragraph, except last sentence 17.4.1 Paragraph Last sentence of paragraph 17.4.3 Paragraph

4.7.1

Exception 17.4.4 Paragraph 4.7.2 Paragraph 17.4.2 Paragraph 4.7.3 Paragraph 17.4.5 Paragraph 4.8 Equipment marking and identification 17.5 Equipment and identification 4.8.1 Paragraph 17.5.1 Paragraph 4.8.2 Paragraph 17.5.2 Paragraph 4.8.3 Paragraph 17.5.3 Paragraph 4.8.4 Paragraph 17.5.4 Paragraph 4.8.5 Paragraph 17.5.5 Paragraph 4.8.6 Paragraph 17.5.6 Paragraph 4.8.7 Paragraph 17.5.7 Paragraph

Function identification Function identification 4.9 Paragraph and note

17.3 Paragraph and note

CLAUSE NUMBER CROSS REFERENCE --- PROPOSED NFPA 79-2002 AND NFPA 79-1997

Proposed NFPA 79-2002 NFPA 79-1997

Clause Heading or Text Clause Heading or Text 17 Marking, warning signs and reference designations 17.1 General 17.1.1 Paragraph 4.6 Machine marking 17.1.2 Paragraph 4.4 Markings

4.5 Warning marking 17.2 Warning marking and signs Warning mark

17.2.1 Paragraph First paragraph and symbol 17.2.2 Paragraph Third paragraph 17.2.3 Paragraph

11.10

Second paragraph and bullets 17.2.4 Paragraph 4.5.1 Paragraph 17.2.5 Paragraph 4.5.2 Paragraph 17.2.6 Paragraph 4.5.3 Paragraph

Function identification Function identification 17.3 Paragraph and note

4.9 Paragraph and note

17.4 Machine nameplate data 4.7 Machine nameplate data 17.4.1 Paragraph 4.7.1 Paragraph and exception 17.4.2 Paragraph 4.7.2 Paragraph 17.4.3 Paragraph 4.7.1 Last sentence of the first paragraph 17.4.4 Paragraph 4.7.1 Exception 17.4.5 Paragraph 4.7.3 Paragraph 17.5 Equipment marking and identification 4.8 Equipment marking and identification 17.5.1 Paragraph 4.8.1 Paragraph 17.5.2 Paragraph 4.8.2 Paragraph 17.5.3 Paragraph 4.8.3 Paragraph 17.5.4 Paragraph 4.8.4 Paragraph 17.5.5 Paragraph 4.8.5 Paragraph 17.5.6 Paragraph 4.8.6 Paragraph 17.5.7 Paragraph 4.8.7 Paragraph


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NFPA 79 CLAUSE 4 (PARTS) AND SUBCLAUSE 11.10 CROSS REFERENCE TO PROPOSED NFPA 79-2000

NFPA 79-1997 Proposed NFPA 79-2002 Comments

17 Marking, warning signs and referencedesignations

Add IEC 60204-1 Clause 17 heading.

17.1 General Add IEC 60204-1 subclause 17.1 heading.4.6 Machine markingThe machine shall be marked with the builder'sname, trademark, or other identificationsymbol.

17.1.1 The electrical equipment shall bemarked with the supplier's name, trademark, orother identifying symbol and, where required,with a certification mark.

The subclause 4.6 heading meaning isincluded in the Clause 17 heading.Revise the 4.6 paragraph and move toClause 17..

4.4 Markings Nameplates, markings, and identification platesshall be of sufficient durability to withstand theenvironment involved.

17.1.2 Warning signs, nameplates,markings, and identification plates shall be ofsufficient durability to withstand the physicalenvironment involved.

The subclause 4.4 heading meaning isincluded in the Clause 17 heading. Revisethe subclause 4.4 paragraph and move toClause 17.

4.5 Warning marking


Revised the subclause 4.5 heading andmove to Clause 17.

11.10 Warning mark

Enclosures that do not clearly show that they containelectrical devices shall be marked with a blacklightning flash on a yellow background within ablack triangle, shaped in accordance with thegraphical symbol 5036 of IEC 417M, the whole inaccordance with symbol 13 of ISO, 3864, as shownin Figure 3.

Figure 3 – Warning sign on enclosures

17.2.1 Enclosures that do not clearly showthat they contain electrical devices shall be markedwith a black lightning flash on a yellow backgroundwithin a black triangle, shaped in accordance withthe graphical symbol 60417-2-IEC-5036, the whole inaccordance with sign B.3.6 of ISO 3864:

Figure XX Warning sign on enclosures

Revise the subclause 11.10 heading andmove to Clause 17. Revised the subclause 11.10 referencestandards and move to Clause 17..

11.10 (third paragraph)

The warning sign shall be plainly visible on theenclosure door or cover.

17.2.2 The warning sign shall be plainlyvisible on the enclosure door or cover.

No change - Move subclause 11.10 thirdparagraph to Clause 17.

11.10 (second paragraph)It is permitted to omit this warning sign on:

– an enclosure equipped with a supplydisconnecting device;

– an operator–machine interface orcontrol station;

– a single device with its own enclosure(e.g. position sensor)

17.2.3 It is permitted to omit this warningsign on:

– an enclosure equipped with a supplydisconnecting device;

– an operator–machine interface orcontrol station;

– a single device with its own enclosure(e.g. position sensor)

No change – Move subclause 11.10second paragraph to Clause 17.

4.5.1 A warning marking shall be providedadjacent to the disconnect operating handle(s)where the disconnect(s) that is interlocked withthe enclosure door does not deenergize allexposed live parts when the disconnect(s) is inthe "open (off)" position.

17.2.4 A warning marking shall be providedadjacent to the disconnect operating handle(s)where the disconnect(s) that is interlocked withthe enclosure door does not deenergize allexposed live parts when the disconnect(s) is inthe "open (off)" position.

No change – Moved subclause 4.5.1 toClause 17.

4.5.2 Where an attachment plug is used as thedisconnecting means, a warning marking shallbe attached to the control enclosure door orcover indicating that power shall bedisconnected from the equipment before theenclosure is opened.

17.2.5 Where an attachment plug is used asthe disconnecting means, a warning markingshall be attached to the control enclosure dooror cover indicating that power shall bedisconnected from the equipment before theenclosure is opened.

No change – Moved subclause 4.5.2

4.5.3 Where the disconnecting means is remotefrom the control enclosure, a warning markingshall be attached to the enclosure door or coverindicating that the power shall be disconnectedfrom the equipment before the enclosure isopened and that the enclosure is to be closedbefore the power is restored.

17.2.6 Where the disconnecting means isremote from the control enclosure, a warningmarking shall be attached to the enclosure dooror cover indicating that the power shall bedisconnected from the equipment before theenclosure is opened and that the enclosure is tobe closed before the power is restored.

No change – Moved subclause 4.5.3 toClause 17.


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Each control station device (e.g. pushbutton,indicating light, selector switch) shall beidentified as to its function on or adjacent tothe device.

NOTE: Consideration shall be given to the useof IEC symbols for pushbuttons (see Annex Cfor examples


Control devices, visual indicators, and displaysused in the man-machine interface shall beclearly and durably marked with regard to theirfunctions either on or adjacent to the unit.

Note 1: Such markings may be as agreedbetween the user and the supplier of theequipment, see Annex B for additionalinformation.

Note 2: For further information on symbols,see IEC 60417 and ISO 7000.

Note 3: Consideration should be given to the use ofIEC symbols for pushbuttons (see Annex C forexamples).

Revise subclause 4.9 and move toClause 17.



No change – Move subclause 4.7 toClause 17.

4.7.1 A permanent nameplate listing themachine serial number, supply voltage, phase,frequency, full-load current, ampere rating ofthe largest motor or load, short-circuitinterrupting capacity of the machineovercurrent protective device where furnishedas part of the equipment, and the electricaldiagram number(s) or the number of the indexto the electrical diagrams (bill of material)shall be attached to the control equipmentenclosure or machine where plainly visible afterinstallation. Where more than one incomingsupply circuit is to be provided, the nameplateshall state the above information for eachcircuit.

Exception: Where only a single motor or motorcontroller is used, the motor nameplate shall bepermitted to serve as the electrical equipmentnameplate where it is plainly visible.

17.4.1 Control equipment (e.g. controlgearassemblies) shall be legibly and durably markedin a way that it is plainly visible after theequipment is installed. Wherever possible, anameplate giving the following informationshall be attached to the enclosure:

– name or trademark of supplier;– certification mark, when required;– serial number, where applicable;– rated voltage, number of phases and

frequency (if a.c.), and full-load currentfor each supply

– ampere rating of the largest motor;– short-circuit interrupting capacity of the

machine disconnecting means whereprovided as part of the equipment;

– the electrical diagram number(s) or thenumber of the index to the electricaldrawings.

Revise subclause 4.7.1 and move toClause 17. See subclause 17.4.3 for last sentence ofsubclause 4.7.1 and see subclause17.4.4 for subclause 4.7.1 exception.

4.7.2 The full-load current shown on thenameplate shall not be less than the full-loadcurrents for all motors and other equipmentthat can be in operation at the same time undernormal conditions of use. Where unusual loadsor duty cycles , require oversized conductors,the required capacity shall be included in thefull-load current specified on the nameplate.

17.4.2 The full-load current shown on thenameplate shall not be less than the full-loadcurrents for all motors and other equipmentthat can be in operation at the same time undernormal conditions of use. Where unusual loadsor duty cycles , require oversized conductors,the required capacity shall be included in thefull-load current specified on the nameplate.

No change – Move subclause 4.7.2 to Clause 17.

4.7.1 (last sentence)

Where more than one incoming supply circuitis to be provided, the nameplate shall state theabove information for each circuit.

17.4.3 Where more than one incomingsupply circuit is to be provided, the nameplateshall state the above information for eachcircuit.

No change – Move the last sentence ofsubclause 4.7.1 to Clause 17.

4.7.1 (exception) Exception: Where only a single motor or motorcontroller is used, the motor nameplate shall bepermitted to serve as the electrical equipmentnameplate where it is plainly visible.

17.4.4 Where only a single motor or motorcontroller is used, the motor nameplate shallbe permitted to serve as the electricalequipment nameplate where it is plainly visible.

Change subclause 17.4.4 exception to aparagraph and move to Clause 17.

4.7.3 Where overcurrent protection is providedin accordance with 8.2, the machine shall bemarked "overcurrent protection provided atmachine supply terminals." A separatenameplate shall be permitted to be used for thispurpose.

17.4.5 Where overcurrent protection isprovided in accordance with 7.2.3., themachine shall be marked "overcurrentprotection provided at machine supplyterminals." A separate nameplate shall bepermitted to be used for this purpose.

No change – Move subclause 4.7.3 to Clause 17.


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COMMITTEE ACTION: Accept in Principle. Revise to read as follows:17 Marking, and warning safety signs and reference designations

17.1 General

17.1.1 The electrical equipment shall be marked with thesupplier's name, trademark, or other identifying symbol and,where required, with a certification mark .

17.1.2 Warning Safety signs, nameplates, markings, andidentification plates shall be of sufficient durability to withstandthe physical environment involved.


17.2.1 Enclosures that do not clearly show that they contain electricaldevices shall be marked with a bla ck lightning flash on a yellowbackground within a black triangle, shaped in accordance with thegraphical symbol 60417-2-IEC-5036, the whole in accordance with signB.3.6 of ISO 3864:

Figure XX – Warning sign on enclosures

17.2.2 The warning sign shall be plainly visible on the enclosuredoor or cover.

17.2.3 It is shall be permitted to omit this warning sign on:

– an enclosure equipped with a supply disconnecting device;– an operator–machine interface or control station;– a single device with its own enclosure (e.g. position sensor)

17.2.4 A warning marking safety sign shall be provided adjacent tothe disconnect operating handle(s) where the disconnect(s) that isinterlocked with the enclosure door does not deenergize allexposed live parts when the disconnect(s) is in the "open (off)"position.

17.2.5 Where an attachment plug is used as the disconnectingmeans, a warning marking safety sign shall be attached to thecontrol enclosure door or cover indicating that power shall bedisconnected from the equipment before the enclosure is opened.



No change – Move subclause 4.8 toClause 17.

4.8.1 Where equipment is removed from itsoriginal enclosure or is so placed that themanufacturer's identification plate is not easilyread, an additional identification plate shall beattached to the machine or enclosure.

17.5.1 Where equipment is removed from itsoriginal enclosure or is so placed that themanufacturer's identification plate is no t easilyread, an additional identification plate shall beattached to the machine or enclosure.

No change – Move subclause 4.8.1 toClause 17.

4.8.2 Where a motor nameplate or connectiondiagram plate is not visible, additionalidentification shall be provided where it can beeasily read.

17.5.2 Where a motor nameplate orconnection diagram plate is not visible,additional identification shall be providedwhere it can be easily read.


4.8.3 Nameplates, identification plates, orwarning markings shall not be removed fromthe equipment.

17.5.3 Nameplates, identification plates, orwarning markings shall not be removed fromthe equipment.


4.8.4 All control panel devices andcomponents shall be plainly identified with thesame designation as shown on the diagram(s).This identification shall be adjacent to (not on)the device or component. Exception No. 1: Where the size or location of thedevices makes individual identification impractical,group identification shall be used.

Exception No. 2: This section need not apply tomachines on which the equipment consists only of asingle motor, motor controller, pushbuttonstation(s), and worklight(s).

17.5.4 All con trol panel devices andcomponents shall be plainly identified with thesame designation as shown on the diagram(s).This identification shall be adjacent to (not on)the device or component.

Exception No. 1: Where the size or location of thedevices makes individual identification impractical,group identification shall be used.

Exception No. 2: This section shall not be requiredto apply to machines on which the equipmentconsists only of a single motor, motor controller,pushbutton station(s), and worklight(s).

No change – Move subclause 4.8.4 andexceptions to Clause 17

4.8.5 All devices external to the controlpanel(s) shall be identified by a nameplate withthe same designation as shown on thediagram(s) and mounted adjacent to (not on)the device.

Exception: Devices covered by 4.9.

17.5.5 All devices external to the controlpanel(s) shall be identified by a nameplate withthe same designation as shown on thediagram(s) and mounted adjacent to (not on)the device.


No change except subclause number inthe exception – Move subclause 4.8.5 to Clause 17.

4.8.6 Terminations on multiconductor plugsand receptacles shall be plainly marked. Themarkings on the plug/receptacles and ondrawings shall correspond.

17.5.6 Terminations on multiconductorplugs and receptacles shall be plainly marked.The markings on the plug/receptacles and ondrawings shall correspond.


4.8.7 Where group protection as provided for in8.5.4 is used, information specifying the shortcircuit protective device for each groupprotected motor branch circuit shall beincluded with the equipment.

17.5.7 Where group protection as providedfor in 7.2.10 is used, information specifying theshort circuit protective device for each groupprotected motor branch circuit shall beincluded with the equipment



1497

17.2.6 Where the disconnecting means is remote from the controlenclosure, a warning marking safety sign shall be attached to theenclosure door or cover indicating that the power shall bedisconnected from the equipment before the enclosure is openedand that the enclosure shall is to be closed before the power isrestored.


Control devices, visual indicators, and displays used in the man- machine interface shall be clearly and durably marked with regardto their functions either on or adjacent to the unit.

Note 1: Such markings may be as agreed between the user and thesupplier of the equipment, see Annex B for additionalinformation.

Note 2: For further information on symbols, see IEC 60417 andISO 7000.

Note 3: Consideration should be given to the use of IEC symbolsfor pushbuttons (see Annex C for examples) .<<insert The existing Annex C header and the symbols c.3 , c.4, c.5and C.6 from annex C of NFPA 79-1997 here>>


17.4.1 Control equipment (e.g. controlgear assemblies) shall belegibly and durably marked in a way that it is plainly visible afterthe equipment is installed. A nameplate giving the followinginformation shall be attached to the enclosure:– name or trademark of supplier;– certification mark, when required;– serial number, where applicable;– rated voltage, number of phases and frequency (if a.c.),

and full-load current for each supply– ampere rating of the largest motor or load;– short-circuit interrupting capacity of the machine disconnecting

means where provided as part of the equipment; – the maximum ampere rating of the short-circuit and ground-

fault protective device, where provided; – the electrical diagram number(s) or the number of the index to

the electrical drawings.

17.4.2 The full-load current shown on the nameplate shall not beless than the full-load currents for all motors and other equipmentthat can be in operation at the same time under normal conditionsof use. Where unusual loads or duty cycles , require oversizedconductors, the required capacity shall be included in the full-loadcurrent specified on the nameplate.

17.4.3 Where more than one incoming supply circuit is to beprovided, the nameplate shall state the above information for eachcircuit.

17.4.4 Where only a single motor or motor controller is used, themotor nameplate shall be permitted to serve as the electricalequipment nameplate where it is plainly visible.

17.4.5 Where overcurrent protection is provided in accordancewith 7.2.3., the machine shall be marked "overcurrent protectionprovided at machine supply terminals." A separate nameplate shallbe permitted to be used for this purpose.


17.5.1 Where equipment is removed from its original enclosure oris so placed that the manufacturer's identification plate is not easilyread, an additional identification plate shall be attached to themachine or enclosure.

17.5.2 Where a motor nameplate or connection diagram plate isnot visible, additional identification shall be provided where it canbe easily read.

17.5.3 Nameplates, identification plates, or warning marking safetysign shall not be removed from the equipment.

17.5.4 All control panel devices and components shall be plainlyidentified with the same designation as shown on the diagram(s).

This identification shall be adjacent to (not on) the device orcomponent.

Exception No. 1: Where the size or location of the devices makesindividual identification impractical, group identification shall be used.

Exception No. 2: This section shall not be required to apply to machineson which the equipment consists only of a single motor, motor controller,pushbutton station(s), and worklight(s).

17.5.5 All devices external to the control panel(s) shall beidentified by a nameplate with the same designation as shown onthe diagram(s) and mounted adjacent to (not on) the device.


17.5.6 Terminations on multiconductor plugs and receptaclesshall be plainly marked. The markings on the plug/receptaclesand on drawings shall correspond.

17.5.7 Where group protection as provided for in 7.2.10 is used,information specifying the short circuit protective device for eachgroup protected motor branch circuit shall be included with theequipmentCOMMITTEE STATEMENT: The following changes are made tothe proposed text: 1) Title was changed because the reference to "referenceddesignations" does not exist in Clause 17. 2) Change text throughout to comply with the NFPA Manual ofstyle. 3) Change the term "waring sign" to "safety sign" throughout theclause for clarity. 4) In 17.2.6, editorially change "is to" to "shall" to comply withthe NFPA Manual of Style. 5) Note 3 was revised to place the reatin the NFPA 79-1997,Annex C symbols and place them here, in the body of Note 3. 6) In 17.4.1 Delete the parenthetical expression( e.g. controlgearassemblies) for consistancy within the documnet and because theterm "controlgear assemblies" was deleted from Clause 3 andClause 12. 7) In 17.4.1, delete the second bullet - "certification mark whererequired" because of document consistancy and this list is notexclusive. 8) The removal of the fifth bullet of 17.4.1 is because the short-circuit current rating of the machine is not necessarily the same asthe short-circuit current rating of the supply disconnecting means. 9) A new bullet was added to 17.4.1 to correlate with the NECsection, 670-3(a), first paragraph. 10) Replace the phrase "short-circuit interrupting capacity" with"short-circuit current rating" because the revised term is technicallycorrect and matches the product standards. 11) In 17.2.3 Replace "is" with "shall be" to conform with theNFPA Manual of Style. 12) In 17.3, Note 3, add symbols c.3 through c.6 to followexisting text including the introductory header because thecommittee believes it is worthwhile material. Remove theparanthetical reference for style. 13) In 17.5.3, change "warning marking" to "safety sign" for clarityand document consistancy.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FAUST: I am in agreement with most of the committee action.The following comments are directed at 17.4.1, specifically theinterrupting capacity data shown on a nameplate. The interrupting capacity of a piece of equipment is a necessaryparameter in determining the amount of fault current that can besafely tolerated by a piece of equipment. In a properlycoordinated electrical distribution scheme, the available faultcurrent is limited to a "safe level" by the facility that feeds theequipment. The "safe level" should be identified on the machinenameplate. This should be a requirement of the equipmentprovider since they are responsible for the construction of theequipment. The "safe level" IS NOT the AIC value of the main circuitbreaker. I can build any type of system and add a main circuitbreaker with a 250,000 AIC breaker upstream of the system eventhough it may only be able to withstand a fault current of 15,000AIC. Therefore the AIC value on the nameplate should be thewithstand capability of the equipment. NFPA 79 should directequipment manufactures to a "safe requirement".


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These concepts are applicable to a single motor unit as well as alarge complicated piece of equipment. If a fault cannot bemitigated by the equipment design then the design is unsafe. Thenameplate should require all of the necessary information to allowa determination on the appropriate electrical service requirements. The following bullet should be required on the nameplate: - short-circuit interrupting capacity of the machineCOMMENT ON AFFIRMATIVE: SAUNDERS: Do not agree with the committee action to deletethe fifth bullet of 17.4.1. The existing NEC requirement in Article 670-3(a) requires; "(a) Permanent Nameplate. A permanent nameplate that listssupply voltage, phase, frequency, full-load current, the maximumampere rating of the short-circuit and ground-fault protectivedevice, ampere rating of largest motor or load, short-circuitinterrupting capacity of the machine overcurrent-protective device,if furnished----" (underline added to highlight text) The text in NFPA 79-1997 and as proposed in the originalproposal for Clause 17 would require "short circuit interruptingcapacity of the machine disconnecting means where provided aspart of the equipment". The Committee action to change the test to "short circuit currentrating" should be accepted and the bullet should remain in thelist. This information applied on the machine nameplate is a betterstep in ensuring the coordination with supply system short circuitavailable currents and the capability of the "machine mounted"disconnect device then no label at all. This label does not addressthe issue of "the short circuit capability" of all the internal machinepower and control components which must be addressed as partof the equipment design, selection, testing and evaluation, that isrequired for the system. This problem is not addressed by theelimination of the nameplate requirement. WITHROW: COMMITTEE STATEMENT: 8) The removal ofthe fifth bullet of 17.4.1 is because the short-circuit current ratingof the machine is not necessarily the same as the short-circuitcurrent rating of the supply disconnecting means. 10) Replace the phrase "short-circuit interrupting capacity" with"short-circuit current rating" because the revised term is technicallycorrect and matches the product standards. REFERENCE: 1. NFPA 79-2002 17.4.1 (proposed sixth bullet deleted by item8): A nameplate giving the following information shall be attachedto the enclosure: - short-circuit interrupting capacity of the machine disconnectingmeans where provided as part of the equipment. 2. The source of subclause 17.4.1 sixth bullet is IEC 60204-1 andreplaces NFPA 79-1997 subclause 4.7.1. 3. NFPA 79-1997 subclause 4.7.1 reads "short-circuit interruptingcapacity of the machine overcurrent protective device wherefurnished as part of the equipment." 4. NFPA 70-1999 Article 670-3 (a) reads "short-circuitinterrupting capacity of the machine overcurrent-protective device,if furnished." 5. NFPA 70-2002 draft of Article 670-3 (a) reads "short-circuitinterrupting rating of the machine overcurrent-protective device, iffurnished." COMMENTS: Item 8: NFPA 70 Article 670-3 (a) states that thenameplate short-circuit interrupting rating is the machineovercurrent protective device and not the short-circuit interruptingrating of system. Therefore, this bullet was correct and should nothave been removed. When NFPA 70 Article 670-3 (a) is revised todefine the short-circuit interrupting rating as the system, the NFPA79 Committee should revise this subclause accordingly. Until theCode is revised NFPA 79 should follow the Code requirement forthis bullet. While it is true that "the short-circuit current rating of themachine is not necessarily the same as the short-circuit currentrating of the supply disconnecting means", the intent of NFPA 79-1997 and the Code is that the nameplate shall show the short-circuit interrupting rating of the machine overcurrent protectivedevice (disconnecting means), if furnished. When the machineuser requires specific information on the short-circuit interruptingrating of the machine system, the request should be made inAnnex B. A separate nameplate with the short-circuit interruptingrating of the machine system can be attached to the enclosure. Item 10: The Committee revised the above 17.4.1 bulletrequirement before it was deleted in item 8. The Committeereplaced the phrase "short-circuit interrupting capacity" with"short-circuit current rating" because the revised term is technicallycorrect and matches the product standards.

The term current rating may be technically correct but it does notmatch either the Code or NFPA 79-2002 definitions (see 3.70).NFPA 70-2002 draft of Article 670-3 (a) reads "short-circuitinterrupting rating" instead of "short-circuit current rating." RECOMMENDATION: The short-circuit interrupting rating ofthe machine overcurrent protective device should be listed on themachine nameplate. It is recommended that the deleted bullet in17.4.1 be added back with the following change: - short-circuit interrupting rating of the machine overcurrentprotective device, where furnished as part of the equipment

___________________

(Log #5379- 19 - (Clause 4 [Clause 18]): Accept in PrincipleSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to revise NFPA 79-1997Clause 4 "Diagrams, instuctions and nameplates" (through 4.3.4only) and issue as new Clause 18 "Technical Documentation" asfollows:18 Technical documentation

18.1 General

18.1.1 The information necessary for installation, operation,and maintenance of the electrical equipment of a machine shall besupplied in the form of drawings, diagrams, charts, tables, andinstructions as appropriate.

The information provided may vary with the complexity of the electricaequipment. For very simple equipment, the relevant inf ormation may bcontained in one document, provided this document shows all the deviceof the electrical equipment and enables the connections to the supplynetwork to be made.

18.1.2 The machinery supplier shall ensure that the technicaldocumentation specified in this clause is provided with eachmachine.

18.1.3 Technical documentation shall be permitted to besupplied in an agreed upon format.

18.2 Information to be providedThe following information shall be provided with the electricalequipment:

a) Clear, comprehensive description of the equipment,installation and mounting, and the connection to theelectrical supply(ies).

b) Electrical supply(ies) requirements.

c) Information on the physical environment (e.g. lighting,vibration, noise levels, atmospheric contaminants) whereappropriate.

d) Overview (block) diagram(s) where appropriate.

e) Schematic diagram(s).

f) Information (where appropriate) on:

1. Programming

2. Sequence of operation(s)

3. Frequency of inspection

4. Frequency and method of functional testing

5. Guidance on the adjustment, maintenance, andrepair, particularly of the protective devices andcircuits, and

6. Interconnection diagram

7. Panel layouts

8. Instruction and service manuals.


1499

g) A description (including interconnection diagrams) of thesafeguards interacting functions, and interlocking of guardswith potentially hazardous motions, particularly withinteracting installations.

h) A description of the safeguarding means and methodsprovided where the primary safeguards are suspended (e.g.manual programming, program verification).

i) Information for Safety Lockout Procedure (whereappropriate).

j) Explanation of unique terms.

k) Parts list and recommended spare parts list.

l) Maintenance instructions and adjustment procedures.

m) The following shall be furnished for reference only whereappropriate:

− Lubrication diagram− Pneumatic diagram− Hydraulic diagram− Miscellaneous system diagrams (e.g., coolant, refrigerant).

18.3 Requirements applicable to all documentation 18.3.1 The documents shall be prepared in accordance wi th therequirements of 18.4 through 18.10. 18.3.2 For referencing of the different documents, the suppliershall select one of the following methods: − each of the documents shall carry as a cross-reference the

document numbers of all other documents belonging to theelectrical equipment; or

− all documents shall be listed with document numbers andtitles in a drawing or document list.

The first method shall be used only where the documentationconsists of four or less documents

18.4 Basic information

The technical documentation shall contain, as a minimum,information on the following: – normal operating conditions of the electrical equipment

including the expected conditions of the electricalsupply, and where appropriate, the physicalenvironment;

– handling, transportation and storage;– inappropriate use(s) of the equipment.

That information may be presented as a separate document or aspart of the installation or operation documentation.

NOTE: The documentation should also contain, whereappropriate, information regarding load currents, peak startingcurrents and permitted voltage drops. That information should becontained in either the system or circuit diagram(s).

18.5 Installation diagram

18.5.1 The installation diagram shall provide all informationnecessary for the preliminary work of setting up the machine.

NOTE: In complex cases, it may be necessary to refer to theassembly drawings for details.

18.5.2 The specified position, type, and cross-sectional areas ofthe supply cables to be installed on site shall be clearly indicated.

18.5.3 The data necessary for choosing the type, characteristics,rated currents, and setting of the overcurrent protective device(s)

for the supply conductors to the electrical equipment of themachine shall be stated (see 7.2.2).

18.5.4 Where necessary, the size, purpose, and location of anyraceways (ducts) in the foundation that are to be provided by theuser shall be detailed (see annex B).

18.5.5 The size, type, and purpose of raceways (ducts), cabletrays, or cable supports between the machine and the associatedequipment that are to be provided by the user shall be detailed(see annex B).

18.5.6 Where necessary, the diagram shall indicate where spaceis required for the removal or servicing of the electricalequipment.

NOTE: Examples of installation diagrams can be found inIEC 61082-4.

18.5.7 In addition, where it is appropriate an interconnectiondiagram or table shall be provided. That diagram or table shallgive full information about all external connections. Where theelectrical equipment is intended to be operated from more thanone source of electrical supply, the interconnection diagram ortable shall indicate the modifications or interconnections requiredfor the use of each supply.

NOTE: Examples of interconnection diagrams/tables can befound in IEC 61082-3.

18.6 Block (system) diagrams and function diagrams

Where it is necessary to facilitate the understanding of theprinciples of operation, a system diagram shall be provided. Ablock diagram symbolically represents the electrical equipmenttogether with its functional interrelationships without necessarilyshowing all of the interconnections.

NOTE 1: Examples of block diagrams can be found in IEC 61082-1Section 2. Further rules and examples can be found in Section 3of IEC 61082-2.

NOTE 2: Function diagrams may be used as either part of, or inaddition to, the block diagram.

NOTE 3: Examples of function diagrams can be found in Section 2of IEC 61082-1 and in section 4 of IEC 61082-2.

18.7 C ircuit diagrams18.7.1 Diagrams, including machine schematics, of theelectrical system shall be provided and shall show the electricalcircuits on the machine and its associated electrical equipment.Any electrical symbols shall be in accordance with IEEE 315. Anyelectrical symbols not shown in IEEE 315 standards shall beseparately shown and described on the diagrams. The symbols andidentification of components and devices shall be consistentthroughout all documents and on the machine.

Exception: Wiring schematics shall not be required forcommercially available or field replaceable components.

18.7.2 Pertinent information such as motor horsepower, framesize, and speed shall be listed adjacent to its symbol.

NOTE: Examples of circuit diagrams can be found in IEC 61082-1and in section 5 of IEC 61082-2.

18.7.3 Where appropriate, a diagram showing the terminals forinterface connections shall be provided. That diagram may beused in conjunction with the circuit diagram(s) for simplification.The diagram should contain a reference to the detailed circuitdiagram of each unit shown.Switch symbols shall be shown on the electromechanical diagramswith all supplies turned off (e.g. electricity, air, water, lubricant)and with the machine and its electrical equipment in the normalstarting condition.

18.7.4 Conductors shall be identified in accordance with 14.2.

18.7.5 Circuits shall be shown in such a way as to facilitate theunderstanding of their function as well as maintenance and faultlocation. Characteristics relating to the function of the controldevices and components which are not evident from their symbolic


1500

representation shall be included on the diagrams adjacent to thesymbol or referenced to a note.18.7.6 Control circuit devices shall be shown between verticallines that represent control power wiring. The left vertical lineshall be the control circuits common and the right line shall bethe operating coils common, except where permitted by Clause 9design requirements. Control devices shall be shown on horizontallines (rungs) between the vertical lines. Parallel circuits shall beshown on separate horizontal lines directly adjacent to (above orbelow) the original circuit.

18.7.7 An interconnection diagram shall be provided on largesystems having a number of separate enclosures or controlstations. It shall provide full information about the externalconnections of all of the electrical equipment on the machine.

18.7.8 Interlock wiring diagrams shall include devices,functions, and conductors in the circuit where used.

18.7.9 Plug/receptacle pin identification shall be shown on thediagram(s).

18.8 Operating manual

18.8.1 The technical documentation shall contain an operatingmanual detailing proper procedures for set-up and use of theequipment. Particular attention should be given to the safetymeasures provided and to the improper methods of operation thatare anticipated.

18.8.2 Where the operation of the equipment can beprogrammed, detailed information on methods of programming,equipment required, program verification, and additional safetyprocedures (where required) shall be provided.

18.9 Maintenance manual

18.9.1 The technical documentation shall contain a maintenancemanual detailing proper procedures for adjustment, servicing andpreventive inspection, and repair.

NOTE: Recommendations on maintenance/service recordsshould be part of that manual.

18.9.2 Where methods for the verification of proper operationare provided (e.g. software testing programs), the use of thosemethods shall be detailed.

18.10 Parts list

18.10.1 The parts list shall comprise, as a minimum, informationnecessary for ordering spare or replacement parts (e.g.components, devices, software, test equipment, technicaldocumentation) required for preventive or corrective maintenanceincluding those that are recommended to be carried in stock bythe user of the equipment.

18.10.2 The parts list shall show for each item:– the reference designation used in the documentation– its type designation– the supplier and alternative sources where available– its general characteristics where appropriate.– the quantity of items with the same reference designation

SUBSTANTIATION:Historical BackgroundIn March of 1998, the NFPA 79 committee prepared a statement ofwork. The major elements of the statement of work are:Harmonization - PurposeAs the users and the manufacturers of industrial machines move towarda global manufacturing community, the need for a harmonized standardaffecting industrial machinery becomes an economic necessity. Generally,large users and manufacturers find regulations burdensome. However,multiple regulations as well as conflicting regulations are an economicdisincentive to global expansion. In order to ease the burden of differingregulation, and at the same time maintain the high standard of electricalmachine safety, the NFPA 79 committee has expressed their desire,through balloted vote, to harmonize NFPA 79 with IEC-60204-1.Importance of Issue - HarmonizationToday's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true. Differing

electrical standards add a large cost to multinational manufacturers asthey build and sometimes move manufacturing facilities.Harmonization - ObjectiveThis work is necessary to accomplish the goal of allowing industry toeconomically build one industrial machine capable of passing a detailedelectrical safety inspection using either IEC 60204-1 or NFPA 79standard.Both the NEC Technical Correlating Committee and the StandardsCouncil reviewed the statement of work in July of 1998. The TCCunanimously recommended the following action to the StandardsCouncil:"The Technical Correlating Committee agrees with the efforts of theNFPA 79 committee to harmonize the technical requirements of NFPA 79and IEC 60204, where feasible and where in concert with the NEC andits related codes and standards."ResultThe NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committeeformed 20 Task Groups. Each Task Group was assigned oneproposed new clause.The Task Group compared NFPA-79-1997, Clause X with IEC60204-1 Clause 18. The Task Group presented its work to the entirecommittee on several occasions for review and comment. Thisproposal is a result of that work.The Task Group proposes to renumber Clause X of NFPA 79-1997to correspond with IEC 60204-1. The task group proposes thefollowing changes to further improve useability:

18 Technical documentationProposal: Replace NFPA 79-1997 title “4 Diagrams, instructions,and nameplates” with “18 Technical Documentation”.

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this Clause heading was brought over intactfrom 60204-1. This new Clause 18 parallels the old Clause 4.

18.1 GeneralProposal: Add section. Add text as shown. Number section 18.1.

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this Clause heading was brought over intactfrom 60204-1. This new Clause 18 parallels the old Clause 4.1.

18.1.1Proposal: Add section. Add text as shown. Number section 18.1.1

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this text was brought over virtually intactfrom 60204-1. Minor text alterations were effected so as to addclarity, and create consistency with the rest of this document.

18.1.2Proposal: Reword first sentence of NFPA 79-1997, 4.2.1 as shown.Number section 18.1.2

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this text was brought over intact from 60204-1. The new text serves the same function as the first sentence ofNFPA-79 4.2.1


Substantiation: This section was added to permit electronic formatonly if it is agreed upon.

18.2 Information to be providedProposal: Add section. Add text as shown. Number section 18.2.

18.2a)Proposal: Add text as shown and number as 18.2a).

18.2b)Proposal: Add text as shown. Number section as 18.2b).

18.2c)Proposal: Add text as shown. Number section as 18.2c).

18.2d)Proposal: Add text as shown. Number section as 18.2d).

18.2e)Proposal: Add text as shown. Number section as 18.2e).


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18.2f)Proposal: Add text as shown. Number section as 18.2f).

18.2f)1Proposal: Reformat elements of NFPA 79-1997, 4.3.3 as shown andrenumber as 18.2f)1.

18.2f)2.Proposal: Reformat elements of NFPA 79-1997, 4.3.3 as shown andrenumber as 18.2f)2.

18.2f)3Proposal: Reformat elements of NFPA 79-1997, 4.3.5 a shown andrenumber as 18.2f)3.



18.2f)6Proposal: Move NFPA 79-1997, 4.1.1 sixth dash as shown andnumber as 18.2f)6.

18.2f)7Proposal: Move NFPA 79-1997, 4.1.1 fifth dash as shown andnumber as 18.2f)7.

18.2f)8Proposal: Move NFPA 79-1997, 4.1.1 ninth dash as shown andnumber as 18.2f)8.

18.2g)Proposal: Reword NFPA 79-1997, 4.2.7 and 4.2.8 as shown andrenumber as 18.2g).

18.2h).Proposal: Add text as shown. Number section as 18.2h).

18.2i)Proposal: Move NFPA 79-1997, 4.1.1 tenth dash as shown andnumber as 18.2i).

18.2j)Proposal: Reformat elements of NFPA 79-1997, 4.3.1 as shown andrenumber as 18.2j).

18.2k)Proposal: Reformat elements of NFPA 79-1997, 4.1.1 eight dash asshown and number as 18.2k).

18.2l)Proposal: Reformat elements of NFPA 79-1997, 4.3.1 as shown andnumber as 18.2l).

18.2m)Proposal: Move NFPA 79-1997, 4.1.2 as shown and number as18.2m).

Substantiation (applicable to all of 18.2): These provisions providecomprehensive requirements that are currently stated in NFPA79-1997, Clause 4 and provide information necessary for the propersite preparation, installation, operation and maintenance.

18.3 Requirements applicable to all documentationProposal: Add section. Add text as shown. Number section 18.3. 18.3.1Proposal: Add section. Add text as shown. Number section 18.3.1 18.3.2Proposal: Add section. Add text as shown. Number section 18.1.2 Substantiation (applicable to all of 18.3): Inclusion of thisrequirement serves to facilitate enhancements to safety relative toinstallations and maintenance and repair operations by providingpertinent information that might otherwise be omitted orneglected.

18.4 Basic information

Proposal: Add section. Add section. Add text as shown. Numbersection 18.4.

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this text was brought over intact from 60204-1 Clause 18.4). This text was included expressly for the purpose ofharmonization, and is comparable to existing text found in NFPA79 Clause 4.3.1.

18.5 Installation diagramProposal: Add section. Add text as shown. Number section 18.5.

18.5.1Proposal: Add section. Add text as shown. Number section 18.5.1.







Substantiation (applicable to all of 18.5) : In order to facilitate theharmonization of IEC 60204-1 and NFPA 79, this text was broughtover intact from 60204-1 Clause 18.2.c). This text was includedexpressly for the purpose of harmonization, and is comparable toexisting text found in NFPA 79 Clause 4.3.2.

18.6 Block (system) diagrams and function diagramsProposal: Add section. Add text as shown. Number section 18.6.

Substantiation: In order to facilitate the harmonization of IEC60204-1 and NFPA 79, this text was brought over intact from 60204-1 Clause 18.6. Minor text alterations were effected so as to addclarity, and create consistency with the rest of this document. Thistext was included expressly for the purpose of harmonization, andis comparable to existing text found in NFPA 79 Clause 4.3.3.

18.7 Circuit diagramsProposal: Add section. Add text as shown. Number section 18.7.

18.7.1Proposal: Move NFPA 79-1997, 4.2.1 first paragraph as shown.Number section 18.7.1. Add text as shown.

18.7.2Proposal: Move NFPA 79-1997, 4.2.1 second paragraph as shown.Number section 18.7.2.

18.7.3Proposal: Reword NFPA 79-1997, 4.2.4 as shown. Number section18.7.3.

18.7.4Proposal: Reword NFPA 79-1997, 4.2.5 as shown. Number section18.7.4.

18.7.5Proposal: Reword elements of NFPA 79-1997, 4.2.6 as shown.Number section 18.7.4.

18.7.6Proposal: Move elements of NFPA 79-1997, 4.2.6 as shown.Number section 18.7.6.

18.7.7Proposal: Move NFPA 79-1997, 4.2.7 as shown. Number section18.7.7.

18.7.8Proposal: Move NFPA 79-1997, 4.2.8 as shown. Number section18.7.8.


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18.7.9Proposal: Move NFPA 79-1997, 4.2.9 as shown. Number section18.7.9

Substantiation (applicable to all of 18.7) : This clause is primarilythe existing text found in NFPA 79 Clause 4.2 with a newintroductory sentence. The exception is necessary to permitmanufacturers protect their intellectual property rights.

18.8 Operating manualProposal: Add section. Add text as shown. Number section 18.8.



Substantiation (applicable to all of 18.8) : In order to facilitate theharmonization of IEC 60204-1 and NFPA 79, this text was broughtover from 60204-1 Clause 18.8. This text was included expressly forthe purpose of harmonization, and although not a verbatimrendition - it is substantially comparable to the existing text foundin NFPA 79 Clause 4.3.3.


Proposal: Add section. Add text as shown. Number section 18.9.18.9.1

Proposal: Add section. Add text as shown. Number section 18.9.1.


Substantiation (applicable to all of 18.9) : In order to facilitate theharmonization of IEC 60204-1 and NFPA 79, this text was broughtover from 60204-1 Clause 18.9. Minor text alterations were effectedso as to add clarity, and create consistency with the rest of thisdocument. This text was included expressly for the purpose ofharmonization, and although less comprehensive in nature - issubstantially comparable to existing text found in NFPA 79 Clause4.3.5.

18.10 Parts listProposal: Add section. Add text as shown. Number section 18.10.

18.10.1Proposal: Add section. Add text as shown. Number section18.10.1.

18.10.2Proposal: Add section. Add text as shown. Number section18.10.1.

Substantiation (applicable to all of 18.10): In order to facilitate theharmonization of IEC 60204-1 and NFPA 79, this text was broughtover intact from 60204-1 Clause 18.10. Minor text alterations wereeffected so as to add clarity, and create consistency with the rest ofthis document. This text was included expressly for the purpose ofharmonization, and although far more detailed in nature - iscomparable to existing text found in NFPA 79 Clause 4.3.4

CLAUSE NUMBERS: NFPA 79-1997 CROSS REF. TO PROPOSED NFPA 79-2002NFPA 79: -1997 Proposed NFPA 79: 2002

Clause 4 Heading (or topic) Clause 18 Heading (or topic)4 Diagrams, instructions, and nameplates 18 Technical documentation4.1 General 18.1 General

(not in NFPA 79-1997) 18.1.1 (The information necessary…)4.2.1 (Diagrams of the…) 18.1.2 (The machinery supplier…)

(not in NFPA 79-1997) 18.1.3 (Technical documentation…)(not in NFPA 79-1997) 18.2 Information to be provided(not in NFP)A 79-1997) 18.2a) (Clear, comprehensive…)

(not in NFP)A 79-1997) 18.2b) (Electrical supply(ies)…)(not in NFP)A 79-1997) 18.2c) (Information on the…)(not in NFPA 79-1997) 18.2d) (Overview (block)…)(not in NFPA 79-1997) 18.2e) (Schematic diagram(s)…)(not in NFPA 79-1997) 18.2f) (Information…)

4.3.3 (Information referring…) 18.2f)1 (Programming)4.3.3 (Information referring…) 18.2f)2 (Sequence of operation(s))4.3.5 (Maintenance and…) 18.2f)3 (Frequency of inspection)4.3.5 (Maintenance and…) 18.2f)4 (Frequency and method…)4.3.5 (Maintenance and…) 18.2f)5 (Guidance on the…)4.1.1 (The following…) 18.2f)6 (Interconnection diagram)4.1.1 (The following…) 18.2f)7 (Panel layouts)4.1.1 (The following…) 18.2f)8 (Instruction and…)4.1.1 (The following…) 18.2g) (A description…)

(not in NFPA 79-1997) 18.2h) (A description…)4.1.1 (The following…) 18.2i) (Information for…)4.3.1 (Information referring…) 18.2j) (Explanation of…)4.1.1 (The following…) 18.2k) (Parts list…)4.3.1 (Information referring…) 18.2l) (Maintenance…)4.1.2 (The following…) 18.2m) (The following…)4.2 Diagrams 18.3 Requirements applicable to all documentation

(not in NFPA 79-1997) 18.3.1 (The documents shall…)4.2.2 (A cross-referencing…) 18.3.2 (For referencing of…)4.3.1 (Information referring to…) 18.4 Basic information4.3.2 (The installation drawing(s)…) 18.5 Installation diagram4.3.2 (The installation drawing(s)…) 18.5.1 (The installation diagram)4.3.2 (The installation drawing(s)…) 18.5.2 (The specified position…)4.3.2 (The installation drawing(s)…) 18.5.3 (The data necessary…)4.3.2 (The installation drawing(s)…) 18.5.4 (Where necessary…)4.3.2 (The installation drawing(s)…) 18.5.5 (The size, type, and purpose…)4.3.2 (The installation drawing(s)…) 18.5.6 (Where necessary…)4.3.2 (The installation drawing(s)…) 18.5.7 (In addition…)4.3.3 (The description of…) 18.6 Block (system) diagrams and function diagrams


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COMMITTEE ACTION: Accept in Principle. Revise text as follows:18 Technical documentation

18.1 18.2 General

18.1.1 The information necessary for installation, operation, andmaintenance of the electrical equipment of a machine shall besupplied in the form of drawings, diagrams, charts, tables, andinstructions as appropriate.

The information provided may vary with the complexity of the electricalequipment. For very simple equipment, the relevant information may becontained in one document, provided this document shows all the devicesof the electrical equipment and enables the connections to the supplynetwork to be made.

18.1.2 The machinery supplier shall ensure that the technicaldocumentation specified in this clause is provided with eachmachine.

18.1.3 Technical documentation shall be permitted to be suppliedin an agreed upon format.

18.2 Information to be providedThe following information shall be provided with the electricalequipment:

a) g) Clear, comprehensive description of the equipment,installation and mounting, and the connection to theelectrical supply(ies).

b) h) Electrical supply circuit(s) (ies) requirements.

c)Information on the physical environment (e.g. lighting,vibration, noise levels, atmospheric contaminants) whereappropriate.

d) i) Overview (block) diagram(s) where appropriate.

e) j) Schematic diagram(s).

f) k) Information (where appropriate) on:

1. 9. Programming

2. 10. Sequence of operation(s)

3. 11. Frequency of inspection

4. 12. Frequency and method of functionaltesting

5. 13. Guidance on the adjustment,maintenance, and repair, particularly of theprotective devices and circuits, and

6. 14. Interconnection diagram

7. 15. Panel layouts

8. 16. Instruction and service manuals.9. physical environment (e.g. lighting, vibration, noise levels,atmospheric contaminants).

g) n) A description (including interconnection diagrams) ofthe safeguards , interacting functions, and interlocking ofguards with potentially hazardous motions , particularly withinteracting installations.

h) o) A description of the safeguarding means and methodsprovided where the primary safeguards are suspendedoverridden (e.g. manual programming, programverification).

i) p) Information for Safety Lockout Procedure (whereappropriate).

j) q) Explanation of unique terms.

k) r) Parts list and recommended spare parts list.

l) s) Maintenance instructions and adjustment procedures.

m) Reference information (where appropriate) on:m)The following shall be furnished for reference only where

appropriate:− Lubrication diagram− Pneumatic diagram− Hydraulic diagram− Miscellaneous system diagrams (e.g., coolant, refrigerant).

18.3 Requirements applicable to all documentation 18.3.1 The documents shall be prepared in accordance with therequirements of 18.4 through 18.10. 18.3.2 For referencing of the different documents, the suppliershall select one of the following methods: − each of the documents shall carry as a cross-reference the

document numbers of all other documents belonging to theelectrical equipment; or

− all documents shall be listed with document numbers andtitles in a drawing or document list.

The first method shall be used only where the documentationconsists of four or less documents

4.2 Diagrams 18.7 Circuit diagrams4.2.1 (Diagrams of the electrical system…) 18.7.1 (Diagrams, including machine schematics…)4.2.1 (Diagrams of the electrical system…) 18.7.2 (Pertinent information…)4.2.4 (Switch symbols shall…) 18.7.3 (Where appropriate…)4.2.5 (Directly connected conductors…) 18.7.4 (Conductors shall be identified…)4.2.6 (Circuits shall be shown…) 18.7.5 (Circuits shall be shown…)4.2.7 (An interconnection diagram…) 18.7.6 (An interconnection diagram…)4.2.8 (Interlock wiring diagrams…) 18.7.7 (Interlock wiring diagrams…)4.2.9 (Plug/receptacle pin…) 18.7.8 (Plug/receptacle pin…)4.3.3 (The description of…) 18.8 Operating manual4.3.3 (The description of…) 18.8.1 (The technical documentation…)4.3.3 (The description of…) 18.8.2 (Where the operation…)4.3.5 (Maintenance and service…) 18.9 Maintenance manual4.3.5 (Maintenance and service…) 18.9.1 (The technical documentation…)4.3.5 (Maintenance and service…) 18.9.2 (Where methods for…)4.3.4 (The parts list…) 18.10 Parts list4.3.4 (The parts list…) 18.10.1 (The parts list shall comprise…)4.3.4 (The parts list…) 18.10.2 (The parts list shall show…)


1504

18.3.3 Where appropriate, a table of contents shall appearprominently on the first sheet and shall refer to all major sectionsof the electrical drawings . <<this was added to correct an inadvertent omission from NFPA79-1997, 4.1.3.>> 18.4 Basic information

The technical documentation shall contain, as a minimum,information on the following: – normal operating conditions of the electrical equipment

including the expected conditions of the electricalsupply, and where appropriate, the physicalenvironment;

– handling, transportation and storage;– inappropriate use(s) of the equipment.

That information Th e technical documentation may shall bepermitted to be presented as a separate document or as part of theinstallation or operation documentation.

NOTE: The technical documentation should also contain, whereappropriate, information regarding load currents, peak startingcurrents and permitted voltage drops. That information should becontained in either the system or circuit diagram(s).

18.5 Installation diagram

18.5.1 The installation diagram shall provide all informationnecessary for the preliminary work of setting up the machine.

NOTE: In complex cases, it may be necessary to refer to theassembly drawings for details.

18.5.2 The specified position , type, and cross-sectional areas ofthe supply cables of the electrical supply to be installed on siteshall be clearly indicated.

18.5.3 The data necessary for choosing the type, characteristics,rated currents, and setting of the overcurrent protective device(s)for the supply circuit conductors to the electrical equipment of themachine shall be stated .Note: For further information regarding supply circuit conductors,(see 7.2.2).

18.5.4 Where necessary, the size, purpose, and location of anyraceways (ducts) in the foundation that are to be provided by theuser shall be detailed . Note: For r ecommendations concerning supplier agreements,(see annex B). .

18.5.5 The size, type, and purpose of raceways (ducts), cable trays,or cable supports between the machine and the associatedequipment that are to be provided by the user shall be detailed . Note: For recommendations concerning supplier agreements,(see annex B).

18.5.6 Where necessary, the diagram shall indicate where space isrequired for the removal or servicing of the electrical equipment.

NOTE: Examples of installation diagrams can be found inIEC 61082-4.

18.5.7 In addition, where it is appropriate an interconnectiondiagram or table shall be provided. That diagram or table shallgive full information about all external connections. Where theelectrical equipment is intended to be operated from more thanone source of electrical supply, the interconnection diagram ortable shall indicate the modifications or interconnections requiredfor the use of each supply.

NOTE: Examples of interconnection diagrams/tables can befound in IEC 61082-3.

18.6 18.8 Block (system) diagrams and functiondiagrams

Where it is necessary to facilitate the understanding of theprinciples of operation, a system diagram shall be provided. Ablock diagram symbolically represents the electrical equipment

together with its functional interrelationships without necessarilyshowing all of the interconnections.

NOTE 1: Examples of block diagrams can be found in IEC 61082-1Section 2. Further rules and examples can be found in Section 3of IEC 61082-2.

NOTE 2: Function diagrams may be used as either part of, or inaddition to, the block diagram.

NOTE 3: Examples of function diagrams can be found in Section 2of IEC 61082-1 and in section 4 of IEC 61082-2.

18.7 18.9 Circuit diagrams18.7.1 Diagrams, including machine schematics, of the electricalsystem shall be provided and shall show the electrical circuits onthe machine and its associated electrical equipment. Any electricalElectrical symbols shall be in accordance with IEEE 315 whereincluded therein . Any electrical symbols not shown included inIEEE 315 standards shall be separately shown and described on thediagrams. The symbols and identification of components anddevices shall be consistent throughout all documents and on themachine.

Exception: Wiring schematics shall not be required forcommercially available or field replaceable components.

18.7.2 Pertinent information such as motor horsepower, framesize, and speed shall be listed adjacent to its symbol.

NOTE: Examples of circuit diagrams can be found in IEC 61082-1and in section 5 of IEC 61082-2.

18.7.3 Where appropriate, a diagram showing the terminals forinterface connections shall be provided. That diagram may beused in conjunction with the circuit diagram(s) for simplification.The diagram should contain a reference to the detailed circuitdiagram of each unit shown.Switch symbols shall be shown on the electromechanical diagramswith all supplies turned off (e.g. electricity, air, water, lubricant)and with the machine and its electrical equipment in the normalstarting condition and at 20 degrees C (68 degrees F) ambient.Control setting s shall be shown on the drawing diagram . .

Note: The diagram showing the terminals for interfaceconnections may be used in conjunction with the circuitdiagram(s) for simplification. The diagram should contain areference to the detailed circuit diagram of each unit shown.

18.7.4 Conductors shall be identified in logical order inaccordance with 14.2.

18.7.5 Circuit characteristics

18.7.5.1 Circuits shall be shown in such a way as to facilitate theunderstanding of their function as well as maintenance and faultlocation. Characteristics relating to the function of the controldevices and components which are not evident from their symbolicrepresentation shall be included on the diagrams adjacent to thesymbol or referenced to a note.

18.7.5.2 A cross-referencing scheme shall be used in conjunctionwith each relay, output device, limit switch, and pressure switch sothat any contact associated with the device can be readily locatedon the diagrams.

18.7.6 Control circuit devices shall be shown between vertical linesthat represent control power wiring. The left vertical line shall bethe control circuits common and the right line shall be theoperating coils common, except where permitted by Clause 9design requirements. Control devices shall be shown on horizontallines (rungs) between the vertical lines. Parallel circuits shall beshown on separate horizontal lines directly adjacent to (above orbelow) the original circuit.

18.7.7 An interconnection diagram shall be provided on largesystems having a number of separate enclosures or controlstations. It shall provide full information about the externalconnections of all of the electrical equipment on the machine.


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18.7.8 Interlock wiring diagrams shall include devices, functions,and conductors in the circuit where used.

18.7.9 Plug/receptacle pin identification shall be shown on thediagram(s).

18.8 Operating manual

18.8.1 The technical documentation shall contain an operatingmanual detailing proper procedures for set-up and use of theequipment. Particular attention should be given to the safetymeasures provided and to the improper methods of operation thatare anticipated.

18.8.2 Where the operation of the equipment can beprogrammed, detailed information on methods of programming,equipment required, program verification, and additional safetyprocedures (where required) shall be provided.


18.9.1 The technical documentation shall contain a maintenancemanual detailing proper procedures for adjustment, servicing andpreventive inspection, and repair.

NOTE: Recommendations on maintenance/service recordsshould be part of that manual. Troubleshooting information andsuggestions for locating and replacing faulty components,suggested preventative maintenance schedules, and related datashould be included .

18.9.2 Where methods for the verification of proper operation areprovided (e.g. software testing programs), the use of thosemethods shall be detailed.

18.10 Parts list

18.10.1 The parts list shall comprise, as a minimum, informationnecessary for ordering spare or replacement parts (e.g.components, devices, software, test equipment, technicaldocumentation) required for preventive or corrective maintenanceincluding those that are recommended to be carried in stock bythe user of the equipment.

18.10.2 The parts list shall show for each item:– the reference designation used in the documentation– its type designation– the supplier and alternative sources where available– its general characteristics where appropriate.– the quantity of items with the same reference designation

COMMITTEE STATEMENT: 1) 18.2 was editorially revise andreorganized for clarity and document consistancy. 2) 18.3.3 was added to correct an inadvertent omission fromincluding the requirement stated in NFPA 79-1997, 4.1.3. 3) 18.4, 18.5.2, through 18.5.5, 18.7.1, and 18.7.3 were revised tocomply with the NFPA Manual of style and for clarity. 4) 18.7.3 was also revised to incorporate an inadvertent omissionfrom NFPA 79-1997, 4.2.4. 5) 18.7.5 was revised to correct an inadvertent omission fromNFPA 79-1997, 4.2.2. 6) 18.9.1, Note, was revised to correct an inadvertent omissionfrom NFPA 79-1997, 4.3.5, 3rd dash.

NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: (1) The first sentence of the second paragraphof 18.1.1 should be revised as follows: "The information providedmay shall be permitted to vary with the based on the complexity ofthe electrical equipment." Reason: Removes the word "may" and improves clarity. (2) Some of the Notes contain the word "should". I am not surethis is permitted especially if the notes will be located in Annex A. (3) Some of the Notes contain the word "may" which I believe isnot permitted.

___________________

(Log #11979- 20 - (4.2.1 [18.7.1]): AcceptSUBMITTER: Paul R. Warndorf, McLean, VARECOMMENDATION: Add to the rewrite of 1997 NFPA 79,Clause 4.2.1, that is the new Clause 18.7.1. Add the Note from NFPA 79, Clause 4.2.1 stating, "See Annex Dfor examples of electrical diagrams" to the new Clause 18.7.1.SUBSTANTIATION: The proposed revision maintains theelectrical drawings and reference to Annex D. The Note musthave been inadvertently left out since there is no substantiation forits removal.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal modifies the Action on Proposal 79-19 (Log #53),[Clause 18].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________(Log #118

79- 21 - (4.2.3 [18.7.5]): AcceptSUBMITTER: Paul R. Warndorf, McLean, VARECOMMENDATION: Add to the rewrite of 1997 NFPA 79,Clause 4.2.3, that is the new Clause 18.7.5. Add the Note from NFPA 79, Clause 4.2.3, stating, "See Annex Efor examples of devices and component designations" to the newClause 18.7.5.SUBSTANTIATION: The proposed revision maintains the deviceand component designations reference to Annex E. The Notemust have been inadvertently left out since there is nosubstantiation for its removal.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal modifies the Action on Proposal 79-19 (Log #53),[Clause 18].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________

(Log #9379- 22 - (4.3.6(New) [18.2(h)]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in rewrite of Clause 4, that is newClause 18 in 18.2, item h. Place the word "suspended" in parenthesis and before it add theword "overridden." The sentence would read: "...are overridden (suspended)...".SUBSTANTIATION: This proposed revision will provideclarification by adding the word customarily used in the U.S.,while retaining, in parenthesis, the word more frequently used inEurope.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-19 (Log #53), subclause 18.2(h), whichmeets the intent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________(Log #58

79- 23 - (4.7.2 (New) [17.4.1.1]): Reject TCC NOTE: The TCC directs the committee to consider thecomments expressed in the voting. This action will be consideredby the committee as a public comment.SUBMITTER: Wayman L. Withrow, Cincinnati IncorporatedRECOMMENDATION: Add the new proposed NFPA 79-2002subclause 17.4.1.1 after the bullets in subclause 17.4.1. 17.4.1.1 The value for the nameplate short-circuit interruptingcapacity shall be either: – the short-circuit interrupting capacity as specified on a circuitbreaker, or – the short-circuit interrupting capacity specified on a fuseddisconnect switch or accompanying literature. This value shall bethe no greater than the maximum specified by a nationallyrecognized testing laboratory for the disconnect switch and fusecombination.


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SUBSTANTIATION: This will help to eliminate the confusionwhere an Authority Having Jurisdiction interprets the short-circuitinterrupting capacity value as being the withstand rating of a standalone motor controller. Motor controller manufacturers and fusemanufacturers interrupt this value to be as specified in theproposal.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The nameplate rating is intendedfor the system and use of a single component ratings may beinappropriate.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 21 NEGATIVE: 4 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARVEY: The correct term is short-cirucit "current rating". Theterm is used the the NEC in Section 110-10 and in UL Standards.The term "interrupting capcity" is much broader and may beassigned several different definitions on a single switch or circuitbreaker. For example, the horsepower rating of a switch is an"interrupting capacity". PADGET: I agree with Mr. Garvey’s Explanation of NegativeVote. SANDERS: The committee’s action should be changed from"Reject" to "Accept in Principle". The submitter’s concern has been met by the committee actiontaken in Reference 79-18 Log 23 by changing "interruptingcapacity" to "current rating" in the bulleted text as confirmed bythe panel statement item 10. WITHROW: COMMITTEE STATEMENT: The nameplate ratingis intended for the system and use of a single component ratingmay be inappropriate. REFERENCE: 17.4.1 (NFPA 79-2002 ) A nameplate giving thefollowing information shall be attached to the enclosure: - short-circuit interrupting capacity of the machine disconnectingmeans where provided as part of the equipment. Note: This bullet was deleted by the Committee in proposal 79-18.17.4.1.1 (Proposal 79-23) The value for the nameplate short-circuitinterrupting capacity shall be either: – the short-circuit interrupting capacity as specified on a circuitbreaker, or – the short-circuit interrupting capacity specified on a fuseddisconnect switch or accompanying literature. This value shall bethe no greater than the maximum specified by a nationallyrecognized testing laboratory for the disconnect switch and fusecombination. Note: Proposed subclause 17.4.1.1 was rejected by theCommittee. COMMENTS: The Committee should first review the affirmativecomments by Wayman L. Withrow on proposal 79-18. 1. If the Committee rejects the affirmative comments in proposal79-18, reject this proposal. 2. If the Committee accepts the affirmative comments in proposal79-18, the deleted bullet will be added back into subclause 17.4.1and this proposal should be reconsidered. It is recommendedthat the original Log 58 proposal be revised as follows: 17.4.1.1 The value for the nameplate short-circuit interruptingrating of the machine overcurrent protective device, wherefurnished as part of the equipment shall be either: – the short-circuit interrupting rating as specified on a circuitbreaker, or – the short-circuit interrupting rating specified on a fuseddisconnect switch or accompanying literature. This value shall bethe no greater than the maximum specified by a nationallyrecognized testing laboratory for the disconnect switch and fusecombination.COMMENT ON AFFIRMATIVE: FREUDENBERG: There is a tremendous amount of confusionon interrupting capacity and the existing NFPA79 nameplaterequirements specifying a component rating on the systemnameplate have contributed to the confusion.

___________________

(Log #60)79- 24 - (Clause 5 [Clause 4]): Accept in PrincipleSUBMITTER: Lynn F. Saunders, General Motors CorporationRECOMMENDATION: Revise text as follows:4.1 General considerations

This chapter describes the general requirements and condi tionsfor the operation of the electrical equipment of the machine.

Note: A sample inquiry form is provided in Annex B foruse in facilitating an agreement between the supplier andthe user.<<end of note>>

The risks associated with the hazards relevant to the electricalequipment shall be assessed as part of the overall requirements forrisk assessment of the machine. This will determine theacceptable level of risk and necessary protective measures forpersons who can be exposed to these hazards, while stillmaintaining an acceptable level of performance of the machineand its equipment.

Note: Hazards can include, but are not limited to, thefollowing:

– failures or faults in the electrical equipmentresulting in the possibility of electrical shock orelectrical fire;

– failures or faults in control circuits (orcomponents and devices associated with thesecircuits) resulting in malfunctioning of themachine;

– disturbances or disruptions in power sources aswell as failures or faults in the power circuitsresulting in the malfunctioning of the machine;

– loss of continuity of circuits which depend uponsliding or rolling contacts , resulting in a failure ofa safety function;

– electrical disturbances (e.g. electromagnetic,electrostatic or radio interference) either from outsidethe electrical equipment or internally generated;

– stored energy (either electrical or mechanical);– audible noise at levels that cause health problems

to persons.

Safety measures are a combination of the measuresincorporated at the design stage and those measuresrequired to be implemented by the user.

Design and development should be the firstconsideration in the reduction of risks. Where this is notpossible, safeguarding should be considered.Safeguarding includes the use of safeguards , awarenessmeans, and safe working procedures. <<end of note>>

4.2 Electrical components and devices

Electrical components and devices shall be installed and usedassuming the operating conditions of ambient temperature,altitude, humidity, and supply voltage outlined in this chapter, andwithin their design ratings, taking into account any de-ratingstipulated by the component or device manufacturer.

4.3 Electrical supply

4.3.1 General The electrical equipment shall be designed to operate correctlywith the conditions of the supply: − as specified in 4.3.2, 4.3.3, or− as otherwise specified by the user, or− as specified by the supplier

Note: See Annex B.

4.3.2 A . C . supplies

Voltage Steady state voltage : 0.9 ... 1.1 ofnominal voltage.

Frequency 0.99 ... 1.01 of nominal frequencycontinuously; 0.98 ... 1.02 short time.

NOTE--The short time value may bespecified by the user (see annex B).

Harmonics Harmonic distortion not to exceed 10%of the total r.m.s. voltage between liveconductors for the sum of the 2 nd

through 5th harmonic. An additional2% of the total r.m.s. voltage between


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live conductors for the sum of the 6 th

through 30th harmonic is permissible.

Voltage unbalance Neither the voltage of the negativesequence component nor the voltage ofthe zero sequence component in 3 -phase supplies exceed s 2% of thepositive sequence component.

Voltage Impulses Not to exceed 1.5 ms in duration with arise/fall time between 500 ns and500ms and a peak value of not morethan 200% of the rated r.m.s. supplyvoltage value.

Voltage interruption Supply interrupted or at zero voltage fornot more than 3 ms at any random timein the supply cycle. There shall bemore than 1 s between successiveinterruptions.

Voltage dips Voltage dips shall not exceed 20% ofthe peak voltage of the supply for morethan 1 cycle. There shall be more than1 s between successive dips.

4.3.3 D . C . supplies

From batteries:

Voltage 0,85 ... 1,15 of nominal voltage . ;0,7 ... 1,2 of nominal voltage in the case of battery-operated vehicles.

Voltage interruption not exceeding 5 ms.

From converting equipment:

Voltage 0,9 ... 1,1 of nominal voltage.

Voltage interruption not exceeding 20 ms. Thereshall be more than 1 s betweensuccessive interruptions.

Ripple (peak-to-peak) does not exceed 0,15 of nominalvoltage.

4.4 Physical environment and operating conditions

4.4.1 General

The electrical equipment shall be suitable for use in the physicalenvironment and operating conditions specified in 4.4.2 to 4.4.8.When the physical environment or the operating conditions areoutside those specified, an agreement may be needed between thesupplier and the user (see annex B).

4.4.2 Electromagnetic compatibility (EMC)Note:The electrical interference's generated by the equipmentitself should not exceed levels specified in the relevantequipment standards and others dealing withelectromagnetic compatibility (EMC) levels. The levelsallowed should be determined for the specificapplication.

Generated interference signals can be kept to aminimum by:– suppression at the source by using capacitors,

inductors, diodes, Zener diodes, varistors, oractive devices, or a combination of these; or,

– screening of the equipment in a bondedelectrically conductive enclosure to providesegregation from other equipment.

Undesirable effects of electrostatic discharge, radiatedelectromagnetic energy, and supply conductor (mainsborne) interference should be avoided (e.g., use ofappropriate filters and time delays, choice of certainpower levels, suitable wiring types and practices).

The effects of interference on equipment can be reducedby:

– reference potential circuit or common connections:each common connection treated as a single circuitand connected to one of several central referencepoints which are connected to ground (wired toearth) by insulated conductors of large cross-sectionalarea;

– frame connections: in each piece of equipment allframe connections are to be taken to a common poinwith a conductor of large cross-sectional area (e.g.braided conductors, foil strips having a width muchgreater than the thickness) used between slides andenclosures; the connections to the frame to be ashort as possible;

– transmission of signals: electrostatic screenselectromagnetic shields, twisted conductors, andorientation (i.e., crossing cable runs at as near to 90degrees as practicable) as necessary to ensure that thelow level signal wiring is not affected by interferencefrom control or power cables, or running theconnections parallel to the ground plane as necessary

– separation of equipment: separating and/or shieldingsensitive equipment (e.g., units working with pulseand/or at low signal levels) from switching equipmen(e.g., electromagnetic relays, thyr istors); separation olow level signal wiring from control and power cables.

– European standards EN 50081, Electromagneticcompatibility – Generic emission standard, and EN50082, Electromagnetic compatibility – Genericimmunity standard, give general EMC emission andimmunity limits, or product standards (e.g. IEC 604391) that may supercede the generic EMC requirementsthat give more specific EMC requirements. <<end onote>>

4.4.3 Ambient operating temperature

Electrical equipment shall be capable of operating correctly in theintended ambient air temperature. The requirement for allelectrical equipment is correct operation between air temperaturesof + 5oC and + 40oC (41 degrees to 104 degrees F) . For very hotenvironments (e.g. hot climates, steel mills, paper mills) and forcold environments, extra requirements may be necessary (seeannex B).

4.4.4 Relative Humidity

The electrical equipment shall be capable of operating within arelative humidity range of 20-95 percent (noncondensing). Forextremely dry or moist environments, extra requirements may benecessary to prevent static discharge (see annex B).

Harmful effects of relative humidity outside the permitted rangeshall be avoided by proper design of the equipment or, wherenecessary, by proper additional measures (e.g. built-in heaters, airconditioners, humidifiers).

4.4.5 Altitude

Electrical equipment shall be capable of operating correctly aaltitudes up to 1 000 m (3300 ft) above mean sea level (see annexB).

4.4.6 Contaminants

Electrical equipment shall be adequately protected against theingress of solid bodies and liquids (see 12.3).

Equipment shall be suitable for the environment wherecontaminants (e.g. dust, acids, corrosive gases, salt) are present.

Note: See Annex B.

4.4.7 Non-ionizing radiationNote: Where equipment is subject to radiation (e.g.microwave, ultraviolet, lasers, X-rays), additional measuresshould be taken to avoid malfunctioning and accelerateddeterioration of the insulation. <<end of note>>

4.4.8 Vibration, shock, and bump


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Undesirable effects of vibration, shock, and bump (includingthose generated by the machine and its associated equipment andthose created by the physical environment) shall be avoided by theselection of suitable equipment, by mounting it away from themachine, or by the use of antivibration mountings.

4.5 Transportation and storage

The electrical equipment shall be designed to withstand storageand transportation temperatures within the range of –25 to 55°C(–13 to +131°F) and up to 65°C (149°F) for short periods notexceeding 24 hr. Suitable means shall be provided to preventdamage from excessive moisture, vibration, stress, and mechanicalshock during shipment. 4.6 Provisions for handling.

Heavy and bulky electrical equipment that has to be removed fromthe machine for transport, or that is independent of the machine,shall be provided with suitable means for handling by cranes orsimilar equipment. 4.7 Installation and operating conditionsThe electrical equipment shall be installed and operated inaccordance with the manufacturer's instructions. Any conditionsthat are outside the operating conditions specified in Clause 4 shall be permitted where acceptable to both the manufacturer anduser.SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738. 4.1 General. The added text introduces the concept of riskassessment for the design and evaluation of machinery andequipment. This assessment will determine the acceptable level ofrisk and necessary protective measures for persons who can beexposed to these hazards, while still maintaining an acceptablelevel of performance of the machine and its equipment. 4.2 Electrical components and devices 4.3 Electrical supply. 4.3.1 General. Add the "General" paragraph to provide andintroduction to the expanded section 4.3.2 A.C. Supplies. Added text provides and introduction to therevised Supply Voltage clauses for clarity and ease of use. Values inthe table reflect existing NFPA 79 requirements 4.3.3 D.C. Supplies. 4.4 Physical environment and operating conditions. 4.4.1 General. New heading added to provide a logical locationfor added paragraphs and requirements. Introduction paragraphadd for clarity

4.4.2 Electromagnetic compatibility (EMC). This section appearsas non-mandatory text in Appendix F.1 of NFPA 79. IEC 60204includes similar language as a "Note". The revised text will providea harmonization with the existing requirements in the IECstandards that electrical interference generated by the equipmentnot exceed levels specified in the relevant equipment standardsand others dealing with electromagnetic compatibility (EMC)levels. Existing non-mandatory language was retained by includingthe information in the Note. 4.4.3 Ambient operating temperature. Section heading utilizesexisting NFPA 79 wording. Requirements taken from SAE/IECbecause they are more inclusive e.g. excessive temperatureconditions, and provide reference to annex B. 4.4.4 Relative Humidity. Revised text is more comprehensivethan the existing NFPA 79 text and provides additional clarificationfor requirements 4.4.5 Altitude. Editorial revision for metric reference. Referenceadded to Annex B for clarification of requirement 4.4.6 Contaminants. The added text provides clarification ofrequirements for protection against contaminants 4.4.7 Non-ionizing radiation. This is nonmandatory as it existsin Annex to NFPA 79 and retained as nonmandatory text byincuding it in a note. 4.4.8 Vibration, shock, and bump. This is nonmandatory as itexists in Annex to NFPA 79 and should be moved to mandatorytext because the requirement ensures that harmful effects fromvibration are considered. "Should" replaced with "shall." NFPA 79text does not address agreements that may need to be establishedbetween parties in annex B. 4.5 Transportation and storage. 4.6 Provisions for handling. This is nonmandatory requirementas it exists in Annex to NFPA 79 and should be moved tomandatory text because the requirement ensures that provision forhandling are considered. "Should" replaced with "shall." 4.7 Installation and operating conditions. Editorial change toreference Clause 4.

NFPA 79: 1997 NFPA 79: 2002 (Proposed) Substantiation/Comments5 General operating conditions Clause 4 – General operating conditions Action: The Numbering for the

paragraphs will be changed tofollow the new table of contentsutilizing the basic outline of IEC60204-1 and the SAE HS1738document

5.1 General

This chapter describes the generalrequirements and conditions for the operationof the electrical equipment of the machine.

4.1 General considerations

This chapter describes the general requirementsand conditions for the operation of the electricalequipment of the machine.

Note: A sample inquiry form is provided inAnnex B for use in facilitating an agreementbetween the supplier and the user.<<end ofnote>>

Action: Use existing NFPA 79Paragraph and add proposed textfrom IEC 204 / SAE HS 1738document

Note added to include referenceto Annex B information

The risks associated with the hazards relevant tothe electrical equipment shall be assessed as partof the overall requirements for risk assessment ofthe machine. This will determine the acceptablelevel of risk and necessary protective measuresfor persons who can be exposed to thesehazards, while still maintaining an acceptablelevel of performance of the machine and itsequipment.


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NFPA 79: 1997 NFPA 79: 2002 (Proposed) Substantiation/CommentsNote: Hazards can include, but are not

limited to, the following:– failures or faults in the electrical

equipment resulting in the possibilityof electrical shock or electrical fire;

– failures or faults in control circuits (orcomponents and devices associatedwith these circuits) resulting inmalfunctioning of the machine;

– disturbances or disruptions in powersources as well as failures or faults inthe power circuits resulting in themalfunctioning of the machine;

– loss of continuity of circuits whichdepend upon sliding or rollingcontacts , resulting in a failure of asafety function;

– electrical disturbances (e.g.electromagnetic, electrostatic or radiointerference) either from outside theelectrical equipment or internallygenerated;

– stored energy (either electrical ormechanical);

– audible noise at levels that cause healthproblems to persons.

Safety measures are a combination ofthe measures incorporated at thedesign stage and those measuresrequired to be implemented by theuser.

Design and development should bethe first consideration in the reductionof risks. Where this is not possible,safeguarding should be considered.Safeguarding includes the use ofsafeguards , awareness means, and safeworking procedures. <<end of note>>


Electrical components and devices shall be used orinstalled assuming the operating conditions of ambienttemperature, altitude, humidity, an d supply voltageoutlined in this chapter, and within their designratings, taking into account any de-rating stipulated bythe component or device manufacturer.


Electrical components and devices shall be installed andused assuming the operating conditions of ambienttemperature, altitude, humidity, and supply voltageoutlined in this chapter, and within their design ratings,taking into account any de-rating stipulated by thecomponent or device manufacturer.


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5.7 Electrical supply 4.3 Electrical supply

The electrical equipment shall be designed to operatecorrectly under full load as well as no load with theconditions of the nominal supply as specified belowunless otherwise specified by the user.

4.3.1 General The electrical equipment shall be designed to operatecorrectly with the conditions of the supply: − as specified in 4.3.2, 4.3.3, or− as otherwise specified by the user, or− as specified by the supplier

Note: See Annex B.

Action: Add the "General" paragraphto provide and introduction to theexpanded section

5.7.1 AC supplies

Steady state voltageVoltage0.9 ... 1.1 of nominal voltageFrequency0.99 ... 1.01 of nominal frequency continuously0.98 ... 1.02 short time

Note: The short time va lue may be specified by theuser.HarmonicsHarmonic distortion not to exceed 10% of the totalrms voltage between live conductors for the sum of the2nd through 5th harmonic.

An additional 2% of the total rms voltage between liveconductors for the su m of the 6th through 30thharmonic is permissible.

Voltage unbalance (in 3-phase supplies)Neither the voltage of the negativesequencecomponent nor the voltage of the zerosequence component in 3-phase supplies exceeds 2%of the positive sequence component.

Voltage impulsesNot to exceed 1.5 ms in duration with a rise/fall timebetween 500 ns and 500ms and a peak value of notmore than 200% of the rated rms supply voltage value.

Voltage interruptionSupply interrupted or at zero voltage for not morethan 3 ms at any random time in the supply cycle.There shall be more than 1 sec between successiveinterruptions.

Voltage dipsVoltage dips shall not exceed 20% of the peak voltageof the supply for more than 1 cycle. There shall bemore than 1 sec between successive dips.

4.3.2 A.C . supplies

Voltage Steady state voltage : 0.9... 1.1 of nominal voltage.

Frequency 0.99 ... 1.01 of nominalfrequency continuously;0.98 ... 1.02 short time.

NOTE--The short timevalue may be specifiedby the user (see annexB).

Harmonics Harmonic distortion notto exceed 10% of thetotal r.m.s. voltagebetween live conductorsfor the sum of the 2nd

through 5 th harmonic.An additional 2% of thetotal r.m.s. voltagebetween live conductorsfor the sum of the 6th

through 30th harmonic ispermissible.

Voltage unbalance Neither the voltage ofthe negative sequencecomponent nor thevoltage of the zerosequence component in3 -phase suppliesexceed s 2% of thepositive sequencecomponent.

Voltage Impulses Not to excee d 1.5 ms induration with a rise/falltime between 500 ns and500ms and a peak valueof not more than 200%of the rated r.m.s.supply voltage value.

Voltage interruption Supply interrupted or atzero voltage for notmore than 3 ms at anyrandom time in thesupply cycle. There shallbe more than 1 sbetween successiveinterruptions.

Voltage dips Voltage dips shall not exceed 20% of thepeak voltage of the supplyfor more than 1 cycle.There shall be more than 1 sbetween successive dips.

Added text provides and introduction tothe revised Supply Voltage clauses for clarityand ease of use. Values in the table reflectexisting NFPA 79 requirements.>

The Section on Voltage Impulses wasadded to the SAE/IEC text. Thisrequirement appeared in both NFPA79 & 60204. No reason why it wasremoved from 60204 has been found


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5.7.2 DC supplies

From batteries

Voltage0.85 ... 1.15 of nominal voltage;0.7 ... 1.2 of nominal voltage in the case of battery-operated vehicles.

Voltage interruptionNot exceeding 5 msFrom converting equipment

Voltage0.9 ... 1.1 of nominal voltageVoltage interruptionNot exceeding 20 ms. There shall be more than 1 secbetween successive interruptions.

Ripple (peak-to-peak)Does not exceed 0.05 of nominal voltage.


From batteries:

Voltage 0,85 ... 1,15 ofnominalvoltage . ;

0,7 ... 1,2 of nominal voltage in the case ofbattery-operated vehicles.

Voltage interruption not exceeding 5ms.


Voltage 0,9 ... 1,1 ofnominal voltage.

Voltage interruption not exceeding20 ms. Thereshall be morethan 1 s betweensuccessiveinterruptions.

Ripple (peak-to-peak) does not exceed0,15 of nominalvoltage.

4.4 Physical environment and operatingconditions

Action: Add new Paragraph

4.4.1 General

The electrical equipment shall be suitable for use in thephysical environment and operating conditionsspecified in 4.4.2 to 4.4.8. When the physicalenvironment or the operating conditions are outsidethose specified, an agreement may be needed betweenthe supplier and the user (see annex B).

4.4.2 Electromagnetic compatibility (EMC)Note:The electrical interference's generated bythe equipment itself should not exceed levelsspecified in the relevant equipmentstandards and others d ealing withelectromagnetic compatibility (EMC) levels.The levels allowed should be determined forthe specific application.

Action: Revise NFPA Text from AnnexF.1 and add to document as a note –maintaining nonmandetory text

Generated interference signals can be keptto a minimum by:– suppression at the source by using

capacitors, inductors, diodes, Zenerdiodes, varistors, or active devices, ora combination of these; or,

– screening of the equipment in abonded electrically conductiveenclosure to provide segregationfrom other equipment.

Undesirable effects of electrostaticdischarge, radiated electromagnetic energy,and supply conductor (mains borne)interference should be avoided (e.g., use ofappropriate filters and time delays, choiceof certain power levels, suitable wiring typesand practices).


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The effects of interference on equipment can bereduced by:– reference potential circuit or common

connections: each common connection treatedas a single circuit and connected to one ofseveral central reference points which areconnected to ground (wired to earth) byinsulated conductors of large cross-sectionalarea;

– frame connections: in each piece of equipmentall frame connections are to be taken to acommon point with a conductor of large cross-sectional area (e.g., braided conductors, foilstrips having a width much greater than thethickness) used between slides and enclosures;the connections to the frame to be as short aspossible;

– transmission of signals: electrostatic screens ,electromagnetic shields, twisted conductors,and orientation (i.e., crossing cable runs at asnear to 90 degrees as practicable) as necessaryto ensure that the low level signal wiring is notaffected by interference from control or powercables, or running the connections parallel tothe ground plane as necessary;

– separation of equipment: separating and/orshielding sensitive equipment (e.g., unitsworking with pulses and/or at low signal levels)from switching equipment (e.g.,electromagnetic relays , thyristors); separationof low level signal wiring from control andpower cables.

– European standards EN 50081, Electromagneticcompatibility – Generic emission standard, andEN 50082, Electromagnetic compatibility –Generic immunity standard, give general EMCemission and immunity limits, or productstandards (e.g. IEC 60439-1) that maysupercede the generic EMC requirements. thatgive more specific EMC requirements. <<end ofnote>>

5.3 Ambient operating temperature

The electrical equipment shall be capable of operatingin an ambient temperature range of 5 to 40°C (41 to104°F) under no load to full load conditions.

4.4.3 Ambient operating temperature

Electrical equipment shall be capable of operatingcorrectly in the intended ambient air temperature. Therequirement for all electrical equipment is correct

operation between air temperatures of + 5oC and +

40oC (41 degrees to 104 degrees F) . For very hotenvironments (e.g. hot climates, steel mills, paper mills)and for cold environments, extra requirements may benecessary (see annex B).

Replace existing text with revised text

5.5 Relative humidity

The electrical equipment shall be capable of operatingwithin a relative humidity range of 20-95 percent(noncondensing).

4.4.4 Relative Humidity

The electrical equipment shall be capable of operatingwithin a relative humidity range of 20-95 percent(noncondensing). For extremely dry or moistenvironments, extra requirements may be necessary toprevent static discharge (see annex B).

Harmful effects of relative humidity outside thepermitted range shall be avoided by proper design ofthe equipment or, where necessary, by properadditional measures (e.g. built-in heaters, airconditioners, humidifiers).

5.4 Altitude

The electrical equipment shall be suitable foroperating correctly at altitudes up to 3300 ft (1000 m)above sea level.

4.4.5 Altitude

Electrical equipment shall be capable of operatingcorrectly at altitudes up to 1 000 m (3300 ft) abovemean sea level (see annex B).

Editorial revision – add reference toannex B


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COMMITTEE ACTION: Accept in Principle.Revise to read as follows:4 General Operating Conditions

4.1 General considerations

This chapter describes the general requirements and conditionsfor the operation of the electrical equipment of the machine.Note: A sample inquiry form is provided in Annex B for use infacilitating an agreement between the supplier and the user.<<endof note>>

The risks associated with the hazards relevant to the electricalequipment shall be assessed as part of the overall requirements forrisk assessment of the machine. This will determine theacceptable level of risk and necessary protective measures forpersons who can be exposed to these hazards, while stillmaintaining an acceptable level of performance of the machineand its equipment.

Note: Hazards can include, but are not limited to, the following:– failures or faults in the electrical equipment resulting in thepossibility of electrical shock or electrical fire;

– failures or faults in control circuits (or components and devicesassociated with these circuits) resulting in malfunctioning of themachine;– disturbances or disruptions in power sources as well as failuresor faults in the power circuits resulting in the malfunctioning ofthe machine;– loss of continuity of circuits which depend upon sliding orrolling contacts, resulting in a failure of a safety function;– electrical disturbances (e.g. electromagnetic, electrostatic or radiointerference) either from outside the electrical equipment or internallygenerated;

– stored energy (either electrical or mechanical);– audible noise at levels that cause health problems to persons.

Safety measures are a combination of the measures incorporated atthe design stage and those measures required to be implementedby the user.

Design and development should be the first consideration in thereduction of risks. Where this is not possible, safeguarding shouldbe considered. Safeguarding includes the use of safeguards , awareness means, and safe working procedures. <<end of note>>

4.4.6 Contaminants

Electrical equipment shall be adequately protectedagainst the ingress of solid bodies and liquids (see 12.3).

Equipment shall be suitable for the environment wherecontaminants (e.g. dust, acids, corrosive gases, salt) arepresent.

Note: See Annex B.

4.4.7 Non-ionizing radiationNote: Where equipment is subject to radiation(e.g., microwave, ultraviolet, lasers, X-rays),additional measures should be taken to avoidmalfunctioning and accelerated deterioration ofthe insulation. <<end of note>>

4.4.8 Vibration, shock, and bump

Undesirable effects of vibration, shock, and bump(including those generated by the machine and itsassociated equipment and those created by the physicalenvironment) shall be avoided by the selection ofsuitable equipment, by mounting it away from themachine, or by the use of antivibration mountings


The electrical equipment shall be designed towithstand storage and transportation temperatureswithin the range of –25 to 55°C (–13 to +131°F) and upto 65°C (149°F) for short periods not exceeding 24 hr.Suitable means shall be provided to prevent damagefrom excessive moisture, vibration, stress, andmechanical shock during shi pment.


The electrical equipment shall be designed to withstandstorage and transportation temperatures within therange of –25 to 55°C (–13 to +131°F) and up to 65°C(149°F) for short periods not exceeding 24 hr. Suitablemeans shall be provided to prevent damage fromexcessive moisture, vibration, stress, and mechanicalshock during shipment.

Test remains the same

4.6 Provisions for handling.

Heavy and bulky electrical equipment that has to beremoved from the machine for transport, or that isindependent of the machine, shall be provided withsuitable means for handling by cranes or similarequipment.

5.8 Installation and operating conditions

The electrical equipment shall be installed andoperated in accor dance with the manufacturer'sinstructions. Any conditions that are outside theoperating conditions specified in Clause 5 shall bepermitted where acceptable to both the manufacturerand user.

4.7 Installation and operating conditions

The electrical equipment shall be installed andoperated in accordance with the manufacturer'sinstructions. Any conditions that are outside theoperating conditions specified in Clause 4 shall bepermitted where acceptable to both the manufacturerand user.

Editorial Rvision


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4.2 Electrical components and devices. Electrical components anddevices shall be installed and used assuming the operatingconditions of ambient temperature, altitude, humidity, and supplyvoltage outlined in this chapter, and within their design ratings,taking into account any de-rating stipulated by the component ordevice manufacturer.

4.4 Electrical supply

4.3.1 General The electrical equipment shall be designed to operate correctlywith the conditions of the supply: − as specified in 4.3.2, 4.3.3, or− as otherwise specified by the user, or− as specified by the supplier

Note: See Annex B.

4.3.2 A . C . supplies

Voltage Steady state voltage : 0.9 ... 1.1 of nominal voltage.

Frequency 0.99 ... 1.01 of nominal frequency continuously; 0.98... 1.02 short time.

NOTE--The short time value may be specified by the user (seeannex B).

Harmonics Harmonic distortion not to exceed 10% of the totalr.m.s. voltage between live conductors for the sum of the 2nd

through 5th harmonic. An additional 2% of the total r.m.s. voltagebetween live conductors for the sum of the 6 th through 30thharmonic is permissible.

Voltage unbalance(in 3-phase supplies)Neither the voltage of the negative sequence component nor thevoltage of the zero sequence component in 3 -phase suppliesexceed s 2% of the positive sequence component.

Voltage Impulses Not to exceed 1.5 milliseconds in duration witha rise/fall time between 500 nanoseconds and 500 microseconds and a peak value of not more than 200% of the rated r.m.s. supplyvoltage value.

Voltage interruption Supply interrupted or at zero voltage for notmore than 3 ms at any random time in the supply cycle. Thereshall be more than 1 s between successive interruptions.

Voltage dips Voltage dips shall not exceed 20% of the peak voltageof the supply for more than 1 cycle. There shall be more than 1 sbetween successive dips.


From batteries:

Voltage 0.85 ... 1.15 of nominal voltage . ; 0.7 ... 1.2 of nominal voltage in the case of battery-operatedvehicles.

Voltage interruption not exceeding 5 ms.


Voltage 0.9 ... 1.1 of nominal voltage.

Voltage interruption not exceeding 20 ms. There shall be morethan 1 s between successive interruptions.

Ripple (peak-to-peak) does not exceed 0.05 of nominal voltage.

4.4 Physical environment and operating conditions

4.4.1 General. The electrical equipment shall be suitable for usein the physical environment and operating conditions specified in4.4.2 to 4.4.8 . The electrical equipment shall be suitable for use inthe physical environment and operating conditions specified in4.4.3 to 4.4.6 and 4.4.8. When the physical environment or the

operating conditions are outside those specified, an agreementmay be needed between the supplier and the user (see annex B).

4.4.2 Electromagnetic compatibility (EMC)

Note: The electrical interference's generated by the equipmentitself should not exceed levels specified in the relevant equipmentstandards and others dealing with electromagnetic compatibility(EMC) levels. The levels allowed should be determined for thespecific application.

Generated interference signals can be kept to a minimum by:– suppression at the source by using capacitors, inductors, diodesZener diodes, varistors, or active devices, or a combination ofthese; or,– screening of the equipment in a bonded electrically conductiveenclosure to provide segregation from other equipment.

Undesirable effects of electrostatic discharge, radiatedelectromagnetic energy, and supply conductor (mains borne)interference should be avoided (e.g., use of appropriate filters andtime delays, choice of certain power levels, suitable wiring typesand practices).

The effects of interference on equipment can be reduced by: – reference potential circuit or common connections: eachcommon connection treated as a single circuit and connected toone of several central reference points which are connected toground (wired to earth) by insulated conductors of large cross-sectional area;– frame connections: in each piece of equipment all frameconnections are to be taken to a common point with a conductorof large cross-sectional area (e.g., braided conductors, foil stripshaving a width much greater than the thickness) used betweenslides and enclosures; the connections to the frame to be as shortas possible;– transmission of signals: electrostatic screens, electromagneticshields, twisted conductors, and orientation (i.e., crossing cableruns at as near to 90 degrees as practicable) as necessary to ensurethat the low level signal wiring is not affected by interference fromcontrol or power cables, or running the connections parallel tothe ground plane as necessary;– separation of equipment: separating and/or shielding sensitiveequipment (e.g., units working with pulses and/or at low signallevels) from switching equipment (e.g., electromagnetic relays,thyristors); separation of low level signal wiring from control andpower cables.– European standards EN 50081, Electromagneticcompatibility – Generic emission standard, and EN 50082,Electromagnetic compatibility – Generic immunity standard, givegeneral EMC emission and immunity limits, or product standards(e.g. IEC 60439-1) that may supercede the generic EMCrequirements. that give more specific EMC requirements. <<end ofnote>>

4.4.3 Ambient operating temperature. Electrical equipment shallbe capable of operating correctly in the intended ambient airtemperature. The requirement for all electrical equipment iscorrect operation between air temperatures of + 5o C and + 40oC(41 degrees to 104 degrees F) . For very hot environments (e.g. hotclimates, steel mills, paper mills) and for cold environments, extrarequirements may be necessary.

Note: See annex B.

4.4.4 Relative Humidity. The electrical equipment shall becapable of operating within a relative humidity range of 20-95percent (noncondensing). For extremely dry or moistenvironments, extra requirements may be necessary to preventstatic discharge (see annex B).

Harmful effects of relative humidity outside the permitted rangeshall be avoided by proper design of the equipment or, wherenecessary, by proper additional measures (e.g. built-in heaters, airconditioners, humidifiers).

4.4.5 Altitude. Electrical equipment shall be capable of operatingcorrectly at altitudes up to 1 000 m (3300 ft) above mean sea level.

Note: See annex B.


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4.4.6 Contaminants. Electrical equipment shall be adequatelyprotected against the ingress of solid bodies and liquids (see 12.3).

Equipment shall be suitable for the environment wherecontaminants (e.g. dust, acids, corrosive gases, salt) are present.

Note: See Annex B.

4.4.7 Non-ionizing radiation

Note: Where equipment is subject to radiation (e.g., microwave,ultraviolet, lasers, X-rays), additional measures should be taken toavoid malfunctioning and accelerated deterioration of theinsulation. <<end of note>>

4.4.8 Vibration, shock, and bump. Undesirable effects ofvibration, shock, and bump (including those generated by themachine and its associated equipment and those created by thephysical environment) shall be avoided by the selection of suitableequipment, by mounting it away from the machine, or by the useof antivibration mountings.

4.5 Transportation and storage. The electrical equipment shall bedesigned to withstand storage and transportation temperatureswithin the range of –25 to 55°C (–13 to +131°F) and up to 65°C(149°F) for short periods not exceeding 24 hr. Suitable meansshall be provided to prevent damage from excessive moisture,vibration, stress, and mechanical shock during shipment.

4.6 Provisions for handling. Heavy and bulky electrical equipmentthat has to be removed from the machine for transport, or that isindependent of the machine, shall be provided with suitablemeans for handling by cranes or similar equipment.

4.7 Installation and operating conditions. The electricalequipment shall be installed and operated in accordance with themanufacturer's instructions. Any conditions that are outside theoperating conditions specified in Clause 4 shall be permittedwhere acceptable to both the manufacturer and user.COMMITTEE STATEMENT: 1) The second sentence of thesecond paragraph in 4.1 was deleted because it conflicted with theNFPA Manaul of Style, Section 2.2.3.2. In addition this provisionwould introduce concepts not presently in the NFPA 79 document. 2) Editorial corrections were made to conform with the NFPAManual of Style, for clarity, editorial consistancy, and to correctrevised cross references.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: BLOODGOOD: As noted at the ROP meeting, the 2ndparagraph together with the note are also found in the Forewordas non mandatory language. This addition to the Foreword wasmade at a previous committee with the intent of deleting it fromthe new clause 4. There is no information provided to the user ofthe standard as to how the risk assessment is to be conducted norhow risk reduction is to be conducted. DOBROWSKY: There are some requirements, which have beenincorporated into various chapters of this standard, that apply toall or multiple portions of a machine. These requirements, suchas working space, which is presently proposed for Chapter 12,"bridge" issues covered by more than one chapter. I believe thesetypes of requirements are more appropriately placed in Chapter 4,which would then apply in general to the entire machine.

___________________

(Log #68)79- 25 - (Clause 6 [Clause 6]): Accept in PrincipleSUBMITTER: John Freudenberg , TeradyneRECOMMENDATION: Revise wording as follows:6 Protection from Electric Shock.

6.1 General. The electrical equipment shall provide protection ofpersons from electrical shock both in normal operation andduring fault conditions.

6.2 Protection from electric shock during normal operation

6.2.1 Live parts operating at 50 volts rms ac or 60 volts dc or moreshall be guarded against accidental contact by an enclosure or

shall be encased in listed insulation (e.g. flexible cords or flexiblecables).

6.2.1.1 Protection by Insulation of Live Parts. Live parts protected

by insulation shall be completely covered with insulation

that can only be removed by destruction. Such insulation

shall be capable of withstanding the mechanical,

chemical, electrical, and thermal stresses to which it can

be subjected under normal operating conditions.

Paints, varnishes, lacquers, and similar products are inadequatefor protection against electric shock under normal operatingconditions.

6.2.2 Protection by Enclosures.

6.2.2.1 Direct Contact from outside an enclosure. Live parts shallbe located inside enclosures such that there cannot be any directcontact to live parts from the outside of an enclosure when usingthe test finger. The determination of the suitability of an enclosureas protection from electrical shock shall be determined by using atest finger as described in figure XX. The test finger is applied,without appreciable force, in every opening in the enclosure afterremoval of all parts of the enclosure that can be removed withoutthe use of a tool. (Figure shown on following page)

6.2.3 Enclosure InterlockingEnclosure interlocking as described in this subclause shall beprovided.

6.2.3.1 Each disconnecting means shall be mechanically orelectrically interlocked, or both, with the control enclosure doors.Interlocking shall be reactivated automatically when panel doorsare closed.

Exception No. 1: A disconnecting means used only formaintenance lighting circuits within control enclosures shall notbe required to be interlocked with the control enclosure. Themarking requirements of XXX shall apply.

Exception No. 2: Where an attachment plug is used as thedisconnecting means in accordance with XXX

Exception No. 3: A disconnecting means used for power supplycircuits within control enclosures to memory elements and theirsupport logic requiring power at all times to maintain the storageof information shall not be required to be interlocked with thecontrol enclosure doors. The marking requirements of XXX shallapply.

Exception No. 4: Where a remotely mounted disconnecting meansis permitted as per XXX Exception No. 2, (machines with amotor(s) totaling 2hp or less) interlocking shall not be requiredprovided that a tool is required to open the enclosure door and alabel is attached to the control enclosure warning of dangerousvoltage inside and advising disconnection of the power beforeopening.

Where the disconnecting means is not interlocked with theenclosure door in accordance with 6.2.2.1, per Exceptions 1, 2, 3and 4, the enclosure shall comply with 6.2.2.6.

6.2.3.2 Interlocking shall be provided to prevent closing of thedisconnecting means while the enclosure door is open, unless aninterlock is operated by deliberate action.

6.2.3.3 All doors on multiple-door enclosures shall be interlockedsimultaneously with the door that is interlocked with the maindisconnecting means.

6.2.3.4 Where there are two or more sources of power to theequipment or where there are two or more independentdisconnecting means, power wiring from each disconnectingmeans shall be run in separate conduit and shall not terminate inor pass through common junction boxes.


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Figure XX - Jointed test finger


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6.2.3.5 Any door(s) that permits access to live parts operating at50 volts rms or 60 volts dc or more shall be so interlocked that thedoor(s) cannot be opened unless all power is disconnected.

Exception No. 1: External interlocking circuits operating at lessthan 150 volts shall not be required to be disconnected providedthat the circuit conductors are identified with a yellow-coloredinsulation as described in XXX and a warning marking is attachedto the door in accordance with XXX.

Exception No. 2: It shall be permitted to provide means forqualified persons to gain access without removing power. Theinterlocking shall be reactivated automatically when the door(s) isclosed.

Exception No. 3: Where an attachment plug is used as thedisconnecting means and a warning marking is attached to thedoor in accordance with XXX.

Exception No. 4: Where the motor(s) on the machine totals twohorsepower or less, an external, noninterlocked disconnectingmeans shall be permitted provided that the disconnecting means isin sight from and readily accessible, the control enclosure door orcover is marked with a warning indicating that the power shall beremoved by the disconnecting means before the enclosure isopened, and further provided that a tool is required to open theenclosure.

6.2.3.6 Protection from Direct Contact inside an Enclosure.Requirements in this subclause are addressing equipment where aqualified (skilled) person, using appropriate work practices, needsto enter an enclosure not meeting the requirements of 6.2.2.1while the equipment is energized.

Note: The design objective is to minimize operations where aqualified (skilled) person must enter the enclosure while theequipment is energized.

All enclosures relied on to prevent contact with live parts operatingat 50 volts rms ac or 60 volts dc or more shall comply with at leastone of the following conditions:

a) the use of a key or tool is required for opening an enclosure.

b) disconnection of live parts inside the enclosure before theenclosure door is opened.

c) for opening an enclosure without the use of a key or a tool andwithout disconnection of live parts shall be possible only when alllive parts inside are separately enclosed or guarded such that therecannot be any direct contact to live parts with the test finger .

6.3 Protection by the use of PELV (protective extra low voltage)

6.3.1 General Requirements. The use of PELV (protective extra-low voltage) is to protect persons against electric shock fromindirect contact and limited area direct contact.

PELV circuits shall satisfy all of the following conditions:

a) the nominal voltage shall not exceed:– 30 V a.c. r.m.s. or 60 V ripple-free d.c. when the equipment isnormally used in dry locations and when large area contact of liveparts with the human body is not expected; or– 6 V a.c. r.m.s. or 15 V ripple-free d.c. in all other cases;

NOTE – Ripple-free is conventionally defined for a sinusoidalripple voltage as a ripple content of not more than 10 % r.m.s.

b) one side of the circuit or one point of the source of the supplyof that circuit shall be connected to the equipment grounding(protective bonding) circuit;live parts of PELV circuits shall be electrically separated from otherlive circuits. Electrical separation shall be not less than thatrequired between the primary and secondary circuits of a safetyisolating transformer.

Note: For additional information on isolating transformers, referto IEC 60742 and IEC 61558-1.

c) conductors of each PELV circuit shall be physically separatedfrom those of any other circuit. When this requirement isimpracticable, the insulation provisions of X.XX shall apply;

d) Attachment plugs and receptacles (plugs and socketcombinations) for a PELV circuit shall conform to the following:1) Attachment plugs (plugs) shall not be able to enter receptacles(socket-outlets) of other voltage systems;2) receptacles (socket-outlets) shall not admit plugs of othervoltage systems.

Where such circuits are used as control circuits, they shall alsofulfill the relevant requirements of Clause X

6.3.2 Sources for PELV. The source for PELV shall be one of thefollowing:– a safety isolating transformer;– a source of current providing a degree of safety equivalent to thatof the safety isolating transformer (e.g. a motor generator withwinding providing equivalent isolation);– an electrochemical source (e.g. a battery) or another sourceindependent of a higher voltage circuit (e.g. a diesel-drivengenerator);- a n i d e n t i f i e d e l e c t r o n i c p o w e r s u p p l y c o n f o r m i n g t o a p p r o p r i a t e s t a n d a r d s s p e c i f y i n g m e a s u r e s t o b e t a k e n t o e n s u r e t h a t , e v e n i n t h e c a s e o f a n i n t e r n a l f a u l t , t h e v o l t a g e a t t h e o u t g o i n g t e r m i n a l s c a n n o t e x c e e d t h e v a l u e s s p e c i f i e d i n 6 . X . X .

6.4 Protection Against Residual Voltages.

6.4.1 Live parts having a residual voltage greater than 60 volts aftethe supply has been disconnected shall be reduced to 60 volts oless within 5 seconds after disconnection of the supply voltage.

Exception 1: Exempted from this requirement are componentshaving a stored charge of 60 micro-coulombs or less.

Exception 2: Where such a provision would interfere with theproper functioning of the equipment, a durable warning noticedrawing attention to the hazard and stating the delay requiredbefore the enclosure may be entered shall be displayed at an easilyvisible location on or immediately adjacent to the enclosurecontaining the capacitance.

6.4.2 In the case of plugs or similar devices, the withdrawal owhich results in the exposure of conductors (e.g. pins), thedischarge time shall not exceed 1 second.

Exception 1: Exempted from this requirement are componentshaving a stored charge of 60 micro-coulombs or less.

Exception 2: Exempted from this requirement are conductorswhich are protected against direct contact

Exception 3: removable collectors on collector wires, conductorbars, or slip-ring assemblies which comply with X.X.X arepermitted.SUBSTANTIATION:Historical BackgroundIn March of 1998, the NFPA 79 committee prepared a statement ofwork. The major elements of the statement of work are:Harmonization - PurposeAs the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation, andat the same time maintain the high standard of electrical machinesafety, the NFPA 79 committee has expressed their desire, throughballoted vote, to harmonize NFPA 79 with IEC-60204-1.Importance of Issue - HarmonizationToday's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industriamachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true.Differing electrical standards add a large cost to multinationalmanufacturers as they build and sometimes move manufacturingfacilities.Harmonization - ObjectiveThis work is necessary to accomplish the goal of allowing industryto economically build one industrial machine capable of passing adetailed electrical safety inspection using either IEC 60204-1 orNFPA 79 standard.Both the NEC Technical Correlating Committee and the StandardsCouncil reviewed the statement of work in July of 1998. The TCC


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unanimously recommended the following action to the StandardsCouncil:"The Technical Correlating Committee agrees with the efforts ofthe NFPA 79 committee to harmonize the technical requirementsof NFPA 79 and IEC 60204, where feasible and where in concertwith the NEC and its related codes and standards."Result:The NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committeeformed 20 Task Groups. Each Task Group was assigned oneproposed new clause.The Task Group compared NFPA-79-1997, Clause 6 with IEC60204-1 Clause 6. The Task Group presented its work to the entirecommittee on several occasions for review and comment. Thisproposal is a result of that work.The Task Group proposes to renumber Clause 6 of NFPA 79-1997to correspond with IEC 60204-1. The task group proposes thefollowing changes to further improve usability.

Revise NFPA79:1997 clause 6 title

Replace “Safeguarding of personnel” with “Protection from electricshock”.

The proposed wording is intended to narrowly focus the scope ofclause 6 on “Protection from electric shock”. This new title isconsistent with all existing NFPA79:1997 clause 6 subclauses except6.5 which was deleted.Revise NFPA79:1997 clause 6.1 text.

Safeguarding and service have other meanings. Change"safeguarding" to "protection" and change "service" to "operation"consistent with the originalintent of NFPA79:1997 and proposed revised title.

Revise NFPA79:1997 clause 6.2 title..

Safeguarding and service have other meanings. Change"safeguarding" to "protection" and change "service" to "operation"consistent with the original intent of NFPA79:1997 and proposedrevised title.

Revise NFPA79:1997 clause 6.2.1 text.

Insert "operating at 50 volts rms ac or 60 volts dc or more" toseparate hazardous live parts and live parts, otherwise parts atsignal level and other live parts at potentials below 50 volts wouldhave to be protected the same as hazardous live parts at primaryvoltages and other voltages 50 volts or more.

Insert a new 6.2.1.1 text.

This proposed new wording provides more specific requirementsin support of original NFPA79:1997 clause 6.2.1 generalrequirement for “insulation that can only be removed bydestruction”.Insert a new 6.2.2 titleInsert a new 6.2.2.1 title and new text.

The UL test finger provides a simple consistent approach forinspecting all kinds of regular and irregular openings. The UL testfinger also addresses the appropriate recess for a live part behindthe opening where a test finger can be partially inserted. The testfinger is commonly used throughout USA and IEC standards forhousehold, computer, office, and other electrical equipmentstandards including some industrial standards such as UL508.Insert new Figure XX illustrating the dimensions of the test finger.Renumber NFPA79:1997 7.9 to 6.2.3 in the new committee draft ofNFPA79:2002Renumber NFPA79:1997 7.9.1 to 6.2.3.1 in the new committeedraft of NFPA79:2002

No changes to NFPA79:1997 7.9.1 text.Renumber NFPA79:1997 7.9.2 to 6.2.3.2 in the new committeedraft of NFPA79:2002

Delete "To prevent closing of the disconnecting means while thedoor is in the initial latch position or until the door hardware isfully engaged." This requirement does not reduce the probabilityof shock and was considered overly restrictive and impractical.Renumber NFPA79:1997 7.9.3 to 6.2.3.3 in the new committeedraft of NFPA79:2002

No changes to NFPA79:1997 7.9.3 text.

Renumber NFPA79:1997 7.9.4 to 6.2.3.4 in the new committeedraft of NFPA79:2002

No changes to NFPA79:1997 7.9.4 text.Renumber NFPA79:1997 11.8 to 6.2.3.5 in the new committeedraft of NFPA79:2002

No changes to NFPA79:1997 11.8 text. However, 11.8 applied onlyto control enclosures in the original NFPA79:1997 clause 11 and itnow applies to all enclosures in the proposed clause 6.Insert new clause 6.2.3.6 in the committee draft of NFPA79:2002

There are 4 exceptions to NFPA79:1997 7.9.1 (now proposed6.2.3.1) and 4 exceptions to NFPA79:1997 11.8 (now proposed6.2.3.5) that need a minimum requirement for protection againstelectric shock. The new 6.2.3.6 in the committee draft ofNFPA79:2002 will address minimum requirements for all otherconditions NOT excepted or not specifically included in theoriginal NFPA79:1997 text.

The NFPA79:1997 clause 6.3 text for PELV was extracted fromIEC204. The proposed text in new committee draft ofNFPA79:2002 clause 6.3.1 was extracted from IEC60204:1997. Theprimary justification for this changes are to maintain consistencybetween IEC60204 & NFPA79 on the conditions to satisfy PELV.

Summary:added ripple-free for dc voltagesadded max wet location voltages in item adeleted text in item bdeleted test in item crevised text in item drevised text in item erevised text in item frevised text in item g

Item b in the original NFPA79:1997 text was deleted because thelimitation of maximum current to 1 A ac or 0.2 A dc (30 VA) incase of failure (short circuit) has absolutely no relationship withthe maximum currents through the human body that can causeshock or burn injury. The limitation of maximum current forPELV is overly restrictive compared to limited power circuits andClass 2 circuits such that very few , if any, low voltage & low energycircuits satisfy PELV with this limitation of maximum current.

Insert new 6.3.2 from IEC60204 titled “Sources for PELV”

Revise NFPA:1997 6.4 text and renumber as 6.4.1.A voltage that reduces to 60 volts or less in 5 seconds would alsomeet 50 volts or less in 1 minute.

By harmonizing the level between NFPA79 and IEC60204 suppliersusers , evaluators and inspectors can perform one analysis or onecapacitor discharge test that is accepted worldwide.

Add new Exception 1 where stored energy from small capacitorsnot considered significant to electric shock (ex thousands of tinyprinted wiring board mounted capacitors.)

Add new Exception 2 where stored energy hazard cannot beeliminated by design and warning is appropriate.Insert new clause 6.4.2 in committee draft of NFPA79:2002

NFPA 79 :1997 does not address discharge at the pins of the plugfor cord-connected machines. The person is likely to be touchingthe bare pins of the plug immediately after disconnection from thereceptacle and "X" capacitors connected from phase to phase canbe discharged across the person's fingersDelete NFPA79: 1997 clause 6.5 including the text of clause of 6.5.1& 6.5.2

Safeguarding against other hazards (presumably other thanelectrical shock ) does not fit in clause 6 and possibly does not fitwithin the scope of the electrical standard for machines. Ifmechanical hazards are to be addressed in NFPA79 it wouldwarrant a dedicated clause to address mechanical hazardsproperly.


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Cross Reference between NFPA 79-1997 and proposed text

COMMITTEE ACTION: Accept in Principle. Revise text to read as follows:

6 Protection from Electric Shock

6.1 General. The electrical equipment shall provide protection ofpersons from electrical shock both in normal operation andduring fault conditions.

6.2 Protection from electric shock during normal operation. Liveparts operating at 50 volts rms ac or 60 volts dc or more shall beguarded against accidental contact by an enclosure or shall beencased in listed insulation a listed multiconductor cable orflexible cord . (e.g. flexible cords or flexible cables).

6.2.1 Protection by Insulation of Live Parts. Live parts protected by

insulation shall be completely covered with insulation that can

only be removed by destruction. Such insulation shall be capable

of withstanding the mechanical, chemical, electrical, and thermal

stresses to which it can be subjected under normal operating

conditions.

Paints, varnishes, lacquers, and similar products are inadequatefor protection against electric shock under normal operatingconditions.

6.2.2 Protection by Enclosures

6.2.2.1 Direct Contact from outside an enclosure. Live parts shallbe located inside enclosures such that there cannot be any directcontact to live parts from the outside of an enclosure when usingthe test finger. The determination of the suitability of an enclosureas protection from electrical shock shall be determined by using atest finger as described in figure XX. The test finger is shall beapplied, without appreciable force, in every opening in theenclosure after removal of all parts of the enclosure that can beremoved without the use of a tool. (Figure shown on following page)

6.2.3 Enclosure Interlocking. Enclosure interlocking as describedin this subclause shall be provided.

6.2.3.1 Each disconnecting means shall be mechanically orelectrically interlocked, or both, with the control enclosure doors.Interlocking shall be reactivated automatically when panel doorsare closed.

Exception No. 1: A disconnecting means used only formaintenance lighting circuits within control enclosures shall notbe required to be interlocked with the control enclosure. Themarking requirements of 17.2.4 shall apply.

Exception No. 2: Where an attachment plug is used as thedisconnecting means in accordance with 5.3.3.3.

Exception No. 3: A disconnecting means used for power supplycircuits within control enclosures to memory elements and theirsupport logic requiring power at all times to maintain the storageof information shall not be required to be interlocked with thecontrol enclosure doors. The marking requirements of 17.2.4 shallapply.

Exception No. 4: Where a remotely mounted disconnecting meansis permitted as per 5.3.1.3 Exception No. 2, (machines with amotor(s) totaling 2hp or less) interlocking shall not be requiredprovided that a tool is required to open the enclosure door and alabel is attached to the control enclosure warning of dangerousvoltage inside and advising disconnection of the power beforeopening. <<end of exception no. 4>>

Where the disconnecting means is not interlocked with theenclosure door in accordance with 6.2.3.1, per Exceptions 1, 2, 3and 4, the enclosure shall comply with 6.2.3.6.

6.2.3.2 Interlocking shall be provided to prevent closing of thedisconnecting means while the enclosure door is open, unless aninterlock is operated by deliberate action.

6.2.3.3 All doors on multiple-door enclosures shall be interlockedsimultaneously with the door that is interlocked with the maindisconnecting means.

6.2.3 Enclosure Interlocking. Enclosure interlocking as describedin this subclause shall be provided.

NFPA 79:1997 Proposed NFPA 79:2002Clause Heading Clause Heading6 Safeguarding of personnel 6 Protection from Electric Shock6.1 General 6.1 General6.2 Safeguarding against electric shock in

normal service6.2 Protection from electric shock during

normal operation6.2.1 6.2.1new 6.2.1.1 Protection by Insulation of Live Parts6.2.2 6.2.2 Protection by Enclosuresnew 6.2.2.1 Direct Contact from outside the enclosurenew Figure XX Test finger7.9 Interlocking 6.2.3 Enclosure Interlocking7.9.1 6.2.3.17.9.2 6.2.3.27.9.3 6.2.3.37.9.4 6.2.3.411.8 6.2.3.5new 6.2.3.6 Protection from Direct Contact inside an

Enclosure6.3 Protection by the use of PELV (protective

extra low voltage)6.3 Protection by the use of PELV (protective

extra low voltage)6.3.1 General requirements

new 6.3.2 Sources for PELV6.4 Protection Against Residual Voltages6.4 Safeguarding against electrical shock from

residual voltages 6.4.1new 6.4.26.5 Safeguarding against other hazards deleted6.5.1 deleted6.5.2 deleted


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Figure XX - Jointed test finger.


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6.2.3.1 Each disconnecting means mounted within or adjacent toa control enclosure that contains live parts operating at 50 voltsrms or 60 volts dc or more shall be mechanically or electricallyinterlocked, or both, with the control enclosure doors so thatnone of the doors can be opened unless the power isdisconnected. Interlocking shall be reactivated automatically whenall the doors are closed.

Exception No. 1: A disconnecting means used only formaintenance lighting circuits within control enclosures shall notbe required to be interlocked with the control enclosure. A safetysign shall be provided which meets the requirements of 17.2.5.

Exception No. 2: A disconnecting means used for power supplycircuits within control enclosures to memory elements and theirsupport logic requiring power at all times to maintain the storageof information shall not be required to be interlocked with thecontrol enclosure doors. A safety sign shall be provided whichmeets the requirements of 17.2.5.

6.2.3.1.1 Means shall be permitted to be provided for qualifiedpersons, using appropriate work practices, to gain access withoutremoving power. The interlocking means shall:

a) utilize a device or tool as specified by the manufacturer of theinterlock to allow qualified persons to defeat the interlock, and b) be reactivated automatically when the door(s) is closed, and

c) prevent closing of the disconnecting means while the enclosuredoor is open, unless an interlock is operated by deliberate action.

6.2.3.2 Where a qualified (skilled) person, using appropriate workpractices, need to enter an enclosure not having a disconnect, oneof the following conditions shall be met:

a) the use of a key or tool is required for opening the enclosure,or

b) an enclosure door shall be permitted to be opened without theuse of a key or a tool and without disconnection of live parts onlywhen all live parts inside are separately enclosed or guarded suchthat there cannot be any direct contact with live parts by a testfinger.

6.2.3.4 Where there are two or more sources of power to theequipment or where there are two or more independentdisconnecting means, power wiring from each disconnectingmeans shall be run in separate conduit raceway and shall notterminate in or pass through common junction boxes.

6.2.3.5 Any door(s) that permits access to live parts operating at50 volts rms or 60 volts dc or more shall be so interlocked that thedoor(s) cannot be opened unless all power is disconnected.

Exception No. 1: External interlocking circuits operating at lessthan 150 volts shall not be required to be disconnected providedthat the circuit conductors are identified with a yellow or orange -colored insulation as described in 14.2.4.1 and a warning markingis attached to the door in accordance with 17.2.4 .

Exception No. 2: It shall be permitted to provide means forqualified persons to gain access without removing power. Theinterlocking shall be reactivated automatically when the door(s) isclosed.

Exception No. 3: Where an attachment plug is used as thedisconnecting means and a warning marking is attached to thedoor in accordance with 17.2.5 .

Exception No. 4: Where the motor(s) on the machine totals twohorsepower or less, an external, noninterlocked disconnectingmeans shall be permitted provided that the disconnecting means isin sight from and readily accessible, the control enclosure door orcover is marked with a warning indicating that the power shall beremoved by the disconnecting means before the enclosure is

opened, and further provided that a tool is required to open theenclosure.

6.2.3.6 Protection from Direct Contact inside an Enclosure

Requirements in this subclause are addressing equipment where aqualified (skilled) person, using appropriate work practices, needsto enter an enclosure not meeting the requirements of 6.2.2.1while the equipment is energized.

Note: The design objective is to minimize operations where aqualified (skilled) person must enter the enclosure while theequipment is energized.

All enclosures relied on to prevent contact with live parts operatingat 50 volts rms ac or 60 volts dc or more shall comply with at leastone of the following conditions:

a) the use of a key or tool is required for opening an enclosure.

b) disconnection of live parts inside the enclosure before theenclosure door is opened.

c) for opening an enclosure without the use of a key or a tool andwithout disconnection of live parts shall be possible only when alllive parts inside are separately enclosed or guarded such that therecannot be any direct contact to live parts with the test finger .<<D fisher Friday actiom>>

6.3 Protection by the use of PELV (protective extra low voltage)

6.3.1 General requirementsThe use of PELV (protective extra-low voltage) is to protectpersons against electric shock from indirect contact and limitedarea direct contact.Where such c ircuits are used as control circuits, they shall alsofulfill the relevant requirements of Clause 5.

PELV circuits shall satisfy all of the following conditions:

a) the nominal voltage shall not exceed:– 30 V a.c. r.m.s. or 60 V ripple-free d.c. when the equipment isnormally used in dry locations and when large area contact of liveparts with the human body is not expected; or– 6 V a.c. r.m.s. or 15 V ripple-free d.c. in all other cases;

NOTE – Ripple-free is conventionally defined for a sinusoidalripple voltage as a ripple content of not more than 10% r.m.s.

b) one side of the circuit or one point of the source of the supplyof that circuit shall be connected to the equipment grounding(protective bonding) circuit;live parts of PELV circuits shall be electrically separated from otherlive circuits. Electrical separation shall be not less than thatrequired between the primary and secondary circuits of a safetyisolating transformer.

Note: For additional information on isolating transformers, referto IEC 60742 and IEC 61558-1.

c) conductors of each PELV circuit shall be physically separatedfrom those of any other circuit. When this requirement isimpracticable, the insulation provisions of 14.1.3 shall apply;

d) Attachment plugs and receptacles (plugs and socketcombinations) for a PELV circuit shall conform to the following:1) Attachment plugs (plugs) shall not be able to enter receptacles(socket-outlets) of other voltage systems;2) receptacles (socket-outlets) shall not admit plugs of othervoltage systems.

Where such circuits are used as control circuits, they shall alsofulfill the relevant requirements of Clause X

6.3.2 Sources for PELV. The source for PELV shall be one of thefollowing:

– a safety isolating transformer;– a source of current providing a degree of safety equivalent tothat of the safety isolating transformer (e.g. a motor generatorwith winding providing equivalent isolation);– an electrochemical source (e.g. a battery) or another sourceindependent of a higher voltage circuit (e.g. a diesel-drivengenerator);


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- an identified electronic power supply conforming toappropriate standards specifying measures to be taken to ensurethat, even in the case of an internal fault, the voltage at theoutgoing terminals cannot exceed the values specified in6.3.1(a) .

6.4 Protection Against Residual Voltages

6.4.1Live parts having a residual voltage greater than 60 volts after thesupply has been disconnected shall be reduced to 60 volts or lesswithin 5 seconds after disconnection of the supply voltage.

Exception 1 Exempted from this requirement are componentshaving a stored charge of 60 micro-coulombs or less.

Exception 2 Where such a provision would interfere with theproper functioning of the equipment, a durable warning noticedrawing attention to the hazard and stating the delay requiredbefore the enclosure may be entered shall be displayed at an easilyvisible location on or immediately adjacent to the enclosurecontaining the capacitance.

6.4.2 In the case of plugs or similar devices, the withdrawal of whichresults in the exposure of conductors (e.g. pins), the dischargetime shall not exceed 1 second.

Exception 1 Exempted from this requirement are componentshaving a stored charge of 60 micro-coulombs or less.

Exception 2 Exempted from this requirement are conductorswhich are protected against direct contact

Exception 3 removable collectors on collector wires, conductorbars, or slip-ring assemblies which comply with X.X.X arepermitted.<deleted for correlation>COMMITTEE STATEMENT: All cross references were updated toreflect current locations. In addition the following items furtherexplain the changes made to the initial proposal. 1) In 6.2, the phrase listed insulation was changed to a listedmulticonductor cable or flexible cord for clarity. The e.g.statement was removed because it no longer added clarity. 2) The word "is" 6.2.2.1 was change to "shall be" to comply withthe NFPA Manual of Style. 3) Section 6.2.3 was completely reorganized to assist in clarityand useability. 4) In 6.2.3.4 the term conduit was changed to raceway to be lessrestrictive and reflect current practice. 5) 6.3.1(d)(2), last sentence, was moved to 6.3.1, Generalbecause if is more appropriate at that location. 6) 6.4.2, Exception No. 3 was deleted for corelation with actiontaken on Clause 13.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: ANDERSON: The chapter material hierarchical arrangementand resultant numbering system shown in the proposal is still notclear [or consistent]. After reading the chapter with thecommittee's statement and consulting the MOS, I believe thechapter organization would be as outlined below. The numbersare only proposed to illustrate the chapter, section and subsectionsubject order for the titles. The numbered but untitled paragraphsand subparagraphs are not shown. 6 Protection from Electric shock 6.1 General 6.2 Protection from electric shock during normal operation 6.2.1 Protection by Insulation of Live Parts 6.2.2 Protection by Enclosures 6.2.3 Enclosure interlocking 6.3 Protection by the use of PELV (protective extra low voltage) 6.3.1 General requirements 6.3.2 Sources for PELV 6.4 Protection against residual voltages BLOODGOOD: I would be in favor of modifying this proposalbased on the proposal submitted by John Deam (seq #79–27 (Log#73) DOBROWSKY: (1) I am close to casting a negative vote on thisproposal.

(2) 6.2.2.1 The test finger and its related information belong inan annex. Much of the language is informational and containsterms such as "must" and "may" which are not permitted. Manymachines are built using listed enclosures and using a test finger isnot necessary. (3) 6.2.3 The interlocking requirements belong in eitherChapter 5 or Chapter 12 or the relevant portions in both. Therequirements need to be revised to describe features instead ofbeing written as work practices. (4) 6.3 This should be revised or deleted. Most of the provisionsare informational and do not describe where PELV circuits are tobe used. (5) 6.4 The exceptions need to be revised to improve clarity. FREUDENBERG:Annex or note related to Clause 6 and Clause 11Protection from electric shock and energy hazards for electroniccomputer and test equipment

The product standards applicable to listed electronic computerand test equipment permit personnel to touch live outputs fromand energized live parts within the following circuits provided noenergy (burn) hazard exists based on the following safetyprinciples for protection against electric shock. These safetyprinciples including associated definitions and requirements arenot incorporated in the text of NFPA79:

- bare live parts of SELV circuits ( low voltage circuits ),

- bare live parts supplied by power supplies with SELV outputs,

- bare live parts supplied by limited current circuits (forhazardous voltage circuits exceeding 60Vdc with limited currents),

- bare live parts supplied by TNV circuits under the conditionsspecified for circuits powered by the telecommunication network.

Note: SELV circuit requirements are not equivalent to PELVcircuit requirements.

Protection from electrical energy (burn) hazards for electroniccomputer and test equipment

There shall be no energy hazard in operator access areas.

Compliance is checked by means of the test finger figure in astraight position applied without appreciable force. It shall not bepossible to bridge with this test finger two bare parts, one of whichmay be an earthed conductive part, between which a hazardousenergy level exists.

Protection from electric shock and energy hazards forInformation Technology Equipment (ITE)

Protection from electric shock and energy hazards for electroniccomputer equipment within the scope of InformationTechnology Equipment (ITE) are typically listed to UL1950 in theUSA. UL1950 is also harmonized with EN60950 in Europe andharmonized with the national versions of IEC60950 in 45 othercountries so computers certified by qualified labs in othercountries have been evaluated to the same requirements forprotection from electric shock and energy hazards in UL1950.

Protection from electric shock and energy hazards for ElectronicTest and Mesurement Equipment

Protection from electric shock and energy hazards for electronictest equipment within the scope of Electronic Test andMeasurement Equipment are typically listed to UL3111 in the USA.UL3111 is also harmonized with EN61010-1in Europe and harmonized with the national versions of IEC61010-1 in 45 other countries so test equipment certified by qualified labsin other countries have been evaluated to the same requirementsfor protection from electric shock and energy hazards in UL3111.

Classification of Information Technology Equipment (ITE) andTest Equipment for protection from electric shock

Grounded equipment or circuits relying on basic insulationbetween primary and earth ground (Class I ), or

Ungrounded equipment or circuits relying on the equivalent todouble insulation (Class II), or


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Grounded or Ungrounded equipment or circuits powered by alow voltage supply circuit with SELV outputs (Class III)

NOTE Equipment containing ELV circuits or parts at hazardousvoltage is Class I or Class II. There are no requirements in this standard for protection against electric shock for Class IIIequipment.

Protection from electrical energy (burn) hazards for electroniccomputer and test equipment

Live parts of terminals and associated interconnecting secondarywiring supplied by power limited sources will by definitionmeet the energy limits of Class 2 per article XX of the NEC NFPA70.

Note: Class II per UL1950 is not the same as Class 2 per the NEC.Power Limited Circuits complying with UL1950also satisfy Class 2 per the NEC. To avoid confusion between ClassII and Class 2, these circuits are referred to as power limitedcircuits.

Limited power circuits

A mains-operated limited power source, or a battery-operatedlimited power source that is recharged fromthe mains while supplying the load, shall incorporate an isolatingtransformer.

A limited power source shall comply with one of the following:

the output is inherently limited in compliance with table 8; an impedance limits the output in compliance with table 8. If aPositive Temperature Coefficient device is used, it shall pass the tests specified in IEC 730-1, clauses 15 and 17, and IEC730-1, amendment 3, clauses J15 and J17; an overcurrent protective device is used and the output islimited in compliance with table 9; a regulating network limits the output in compliance with table8, both under normal operating conditions and after any single fault in the regulating network (open circuit or short-circuit); a regulating network limits the output in compliance with table8 under normal operating conditions and an overcurrent protective device limits the output in compliance with table 9after any single fault in the regulating network (open-circuit or short-circuit).

Where an overcurrent protective device is used, it shall be a fuse ora non-adjustable non-autoreset electromechanicaldevice.

Insert Table 8 and Table 9 from proposal #79-31, log# 158

Definitions from UL1950 and UL3111

The definitions for circuits & circuit characteristics , classes ofequipment , and types of insulation are necessary for a basicunderstanding of the overview in this Annex. For further detailson all of above, see UL1950 and UL3111.

1.2.4 Classes of equipment - Protection against electric shock

1.2.4.1 CLASS I EQUIPMENT

Equipment where protection against electric shock is achievedby: a.using basic insulation, and also b.providing a means of connecting to the protective earthingconductor in the building wiring those conductive parts that are otherwise capable of assuming hazardous voltages ifthe basic insulation fails. NOTE 1 Class I equipment may have parts with doubleinsulation or reinforced insulation, or parts operating in SELVcircuits. NOTE 2 For equipment intended for use with a power supplycord, this provision includes a protective earthing conductor aspart of the cord.

1.2.4.2 CLASS II EQUIPMENT

Equipment in which protection against electric shock does notrely on basic insulation only, but in which additional

safety precautions, such as double insulation or reinforcedinsulation, are provided, there being no reliance on either protective earthing or installation conditions. NOTE 1 This definition for Class II equipment differs from theterm Class II equipment as used in IEC 536. NOTE 2 Class II equipment may be of one of the followingtypes: equipment having a durable and substantially continuouselectrical enclosure of insulating material which envelops allconductive parts, with the exception of small parts, such asnameplates, screws and rivets, which are isolated from parts athazardous voltage by insulation at least equivalent to reinforcedinsulation; such equipment is called insulation-encased class IIequipment. equipment having a substantially continuous metallicelectrical enclosure, in which double or reinforced insulation isused throughout; such equipment is called metal-encased class IIequipment. equipment which is a combination of the above twotypes.

1.2.4.3 CLASS III EQUIPMENT

Equipment in which protection against electric shock reliesupon supply from SELV circuits and in which hazardous voltages are not generated.

1.2.8 Circuits and circuit characteristics

1.2.8.1 PRIMARY CIRCUIT An internal circuit which is directly connected to the externalsupply mains or other equivalent source (such as a motor-generator set) which supplies the electric power. Itincludes the primary windings of transformers, motors, other loading devices and the means of connection to the supplymains.

1.2.8.2 SECONDARY CIRCUIT A circuit which has no direct connection to primary power andderives its power from a transformer, convertor or equivalent isolation device, or from a battery.

1.2.8.3 HAZARDOUS VOLTAGE A voltage exceeding 42.4 V peak, or 60 V d.c., existing in acircuit which does not meet the requirements for either a limited current circuit; or a TNV circuit.

1.2.8.4 ELV CIRCUIT A secondary circuit with voltages between any two conductors ofthe ELV circuit, and between any one such conductor and earth, not exceeding 42.4 V peak, or 60 V d.c., undernormal operating conditions, which is separated from hazardous voltage by at least basic insulation, and which neithermeets all the requirements for an SELV circuit nor meets all of the requirements for a limited current circuit.

1.2.8.5 SELV CIRCUIT A secondary circuit which is so designed and protected thatunder normal and single fault conditions the voltages do not exceed a safe value. NOTE 1 The limiting value of voltage under normal operatingand single fault conditions are specified in 2.3. See also annex Vand table V.1. NOTE 2 This definition of an SELV circuit differs from the termSELV as used in IEC 364.

1.2.8.6 LIMITED CURRENT CIRCUIT A circuit which is so designed and protected that under bothnormal conditions and a likely fault condition the current which can be drawn is not hazardous. NOTE The limiting values are specified in 2.4.

1.2.8.7 HAZARDOUS ENERGY LEVEL A stored energy level of 20 J or more, or an available continuouspower level of 240 VA or more at a potential of 2 V or more.

1.2.8.8 TELECOMMUNICATION NETWORK VOLTAGE (TNV)CIRCUIT

A circuit in the equipment to which the accessible area ofcontact is limited and that is so designed and protected that under normal operating and single fault conditions, the voltagesdo not exceed specified limiting values.


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A TNV circuit is considered to be a secondary circuit in themeaning of this standard. NOTE The specified limiting values of voltages under normaloperating and single fault conditions are in 6.2.1.1. See also annexV. Requirements regarding accessiblilty for TNV circuits are in 6.2.2. TNV circuits are classified as TNV-1, TNV-2 and TNV-3 circuitsas defined in 1.2.8.9, 1.2.8.10, 1.2.8.11 and as shown in table V.1.

1.2.8.9 TNV-1 CIRCUIT

A TNV circuit: whose normal operating voltages do not exceed the limits foran SELV circuit under normal operating conditions. on which overvoltages from telecommunication networks arepossible.


A TNV circuit: whose normal operating voltages exceed the limits for anSELV circuit under normal operating conditions. which is not subject to overvoltages from telecommunicationnetworks.


A TNV circuit: whose normal operating voltages exceed the limits for anSELV circuit under normal operating conditions. on which overvoltages from telecommunication networks arepossible.

1.2.9 Types of Insulation

1.2.9.1 OPERATIONAL INSULATION

Insulation needed for the correct operation of the equipment. NOTE Operational insulation by definition does not protectagainst electric shock. It may however serve to minimize exposureto ignition and fire.

1.2.9.2 BASIC INSULATION

Insulation to provide basic protection against electric shock.

1.2.9.3 SUPPLEMENTARY INSULATION

Independent insulation applied in addition to basic insulationin order to ensure protection against electric shock in the event of a failure of the basic insulation.

1.2.9.4 DOUBLE INSULATION

Insulation comprising both basic insulation and supplementaryinsulation.

1.2.9.5 REINFORCED INSULATION

A single insulation system which provides a degree of protectionagainst electric shock equivalent to double insulation under the conditions specified in this standard. NOTE The term "insulation system" does not imply that theinsulation has to be in one homogeneous piece. It may compriseseveral layers which cannot be tested as supplementary or basic insulation.

1.2.9.6 WORKING VOLTAGE

The highest voltage to which the insulation under considerationis, or can be, subjected when the equipment is operating at its rated voltage under conditions of normal use. NOTE See 2.2.7.

(See figure on following page)

SAUNDERS: The revision of the definition of live parts from"Electric conductors, buses, terminals, or components that areuninsulated or exposed and a shock hazard exists" to "Energizedconductive components" alters the requirement found in 6.2significantly. Previously, only live parts that are uninsulated orexposed and a shock hazard exists, would be required to be

guarded against accidental contact by an enclosure. By revisingthe definition of live parts, clause 6.2 now requires all energizedconductive components to be guarded against accidental contactby the use of an enclosure. No substantiation has been submittedto indicate that this previous requirement should be changed.During the committee meeting, it was recognized that there mightbe sections where the change in definition may alter therequirements and that these issues should be addressed during thecomment stage. Recommendation: Revise 6.2 to read "Live parts operating at 50 volts rms ac or 60volts dc or more that are uninsulated or exposed and a shockhazard exists shall be guarded against accidental contact be anenclosure or shall be a listed multiconductor cable or flexiblecord".Revise 6.2.2.1 to read "Live parts that are uninsulated or exposedand a shock hazard exists shall be located inside enclosures suchthat there cannot be any direct contact to the parts…"Revise 6.2.3.1 to read "…that contains live parts operating at 50volts rms ac or 60 volts dc or more that are uninsulated or exposedand a shock hazard exists shall be mechanically or electricallyinterlocked…"Revise 6.2.3.2 b to read "…direct contact with live parts that areuninsulated or exposed and a shock hazard exists by a test finger."

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(Log #2979- 26 - (6.1 [6.1]): RejectSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Revise text in Section 6.1 to read asfollows: 6.1 General. Electrical equipment shall provide protection ofpersons from electrical shock hazards during both normaloperation and during fault conditions.SUBSTANTIATION: Recent studies have expanded the list ofelectrical hazards to also include arcflash. Numerous IEEE papersand testing have been published relating to designing systems toreduce the hazardous effects of arcflash. This will also align withthe existing requirements in NFPA 70 1999 National ElectricalCode Section 110-3(a)(6).COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee does not desire toexpand the requirements of Clause 6 to include other "electrical"hazards.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: This proposal should be accepted. Section 1.6describes this standard as providing "detailed information..." thatwill promote safety to life and property..." Enclosing live partsaccomplishes more than just protection from electrical shock. FREUDENBERG: Adding "burn / energy" to shock to the title ofclause 6 would require new requirements limiting available energyinside and outside the enclosure. This should be done. Inside theenclosure any live part exceeding 2 volts where the availablecurrent exceeds 240 VA ( example a live part at 5 volts dc with anavailable current of more than 250 amperes) when inadvertentlyshorted to another live part or ground by a chain, ring, watch,screwdriver or other conductive object may cause a burn hazardfrom hot or molten metal. Certainly any output terminal or wiringmethod exiting the enclosure should be limited to NEC Class 2.Also see comments on proposal # 79-31, log# 158. GARVEY: Electrical energy hazards other than shock should beaddressed by Clause 6. Testimony presented to the panel clearlyindicates that listed equipment is not intended to be switched onor off with the door open. The proposed text in Clause 6 permitsoperating the disconnect through the deliberate action of defeatingthe supply disconnect interlock. Clause 6 should address theconsequences of such action. Clause 7 does cover overcurrent protection. Clause 7 rules areintended to protect the building and occupants from the potentialfire hazard improperly protected equipment presents. The testproposed by Mr. Lottmann belongs in Clause 6.

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(Log #73)79- 27 - (6.2.1 [6.2.2]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in the rewrite of 1997 NFPA 79Clause 6, that is new Clause 6 in 6.2.2 as proposed below. Delete the first sentence in the proposed clause 6.2.2 and useinstead the wording of the current edition of NFPA 79 clause 6.2.1,but with the references to Clause 11 and Clause 12 of the NFPA79.6.2.1 deleted. Change the second and third sentences in the proposed newrewritten Clause 6.2.2 to the form of a Note. Simultaneouslychange the word "shall" in the first sentence of the newly proposedNote to "could."SUBSTANTIATION: The requirement for the use of a "testfinger" to establish the sufficiency of clearances internal toenclosures is mandated in neither the current NFPA 79, nor in thecurrent IEC 60204-1. In the other hand the use of such a devicecould be one of a number of ways to test this condition. Hencethis current proposal to provide such information in note form.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee agrees with thesubstantiation provided in Proposal 79-25 (Log #68) which statesthe following: The UL test finger provides a simple consistent approach forinspecting all kinds of regular and irregular openings. The UL testfinger also addresses the appropriate recess for a live part behindthe opening where a test finger can be partially inserted. The testfinger is commonly used throughout USA and IEC standards forhousehold, computer, office, and other electrical equipmentstandards including some industrial standards such as UL508. In addition, the submitter has failed to provide alternativerecognized methods for compliance with this clause.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 21 NEGATIVE: 4 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: See my Comment on Affirmative for Proposal79-25 (Log # 68). DOBROWSKY: The proposal should be accepted or accepted inprinciple. The use of a test finger is not necessary in manysituations and its provisions should be located in an annex. Noevidence of a problem has been demonstrated with the existingNFPA 79 or IEC 60204-1 requirements. See also my Comment onProposal 79-25 (Log #68). MONTEITH: I agree with the Explanation of Negative Vote ofMr. Dobrowsky. PADGET: I agree with Mr. Dobrowsky’s Explanation of NegativeVote.COMMENT ON AFFIRMATIVE: FREUDENBERG: Compliance may be determined by inspection,or where appropriate, use of the test finger.The size and shape ofthe test finger is described in exact detail such that thedetermination can usually be made without actually owning orapplying the test finger.

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(Log #21)79- 28 - (6.2.4 (New) [6.x.x]): RejectSUBMITTER: Gordon T. Davis , Moeller Electric Corp.RECOMMENDATION: Add new text: 6.2.4 The use of a key or a tool is necessary for access by a skilledor instructed person to carry out the operation for which it maynot be appropriate to disconnect the equipment. The supplydisconnecting means may be operated as needed while the door isopen. Examples of such operations are: replacement of fuse elements;replacement of plug-in devices or assemblies; resetting ofprotective devices; adjustment of devices settings; and fault findingand diagnostic testing. Live part on the inside of the door shall be protected againstunintentional direct contact by the backside of personnel’s hands.Live parts which are likely to be touched, when resetting oradjusting devices intended for such operations while equipment isstill connected, shall additionally be protected againstunintentional direct contact by the fingers of personnel’s hands. Protection against unintentional contact may be accomplished byone or more of the following methods: the use of insulatedcovering, such as thermal plastic, to shield live parts; theinstallation of devices not complying with the fingersafe

requirement a minimum of six (6) inches from the devicesintended to be adjusted or operated with the enclosure door openthe use of devices that comply with the back of hand or fingersaferequirement or both; and the use of other approved means.SUBSTANTIATION: The proposal reduces the potential ofshock hazard. Equipment users (SAE HS 1738), NRTLs (UL 508),AHJ (Calf. OSHA) now require some form of back of hand andfingersafe construction.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The recommended text is written ina manner more suited for a procedure or work practice.Nonmandatory language is not permitted in the body of thestandard. Disconnects are not tested for, nor are they intended for,operation with the door in the open position.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Service personnel should not be subjected toinadvertent contact or unexpected contact with live parts whileperforming typical service operations; specific touchproof or backof hand requirements do not take into account typical serviceoperations and the need to access specific areas inside theenclosure for servicing. It is also unrealistic to assume power willalways be disconnected for service and maintenance operationswhere live adjustments and measurements must be made, howevertouchproof & back of hand access limitations are too restrictiveinside the enclosure in some cases and not safe enough in othercases where the live parts are located immediately adjacent toother parts that must be adjusted while the equipment isenergized. SANDERS: This material is more suitable for NFPA 70B"Recommended Practices for Electrical Maintenance". The submitter is urged to re-submit this information to thatTechnical Committee for consideration.

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(Log #15679- 29 - ([6.x]): RejectSUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Add text to read as follows: X.0 Measuring Circuit Terminals X.1 Voltage and current measuring circuit terminals whichgenerate or accept voltages above 50V ac rms or 60Vdc arepermitted provided both of the following conditions are met: - the measuring circuit has sufficiently high impedance at theinterface to safely generate or accept the rated maximum workingvoltage or current; - the measuring circuit terminals are marked with the ratedmaximum working voltage or current as applicable adjacent to theterminals. Exception 1: Measuring input circuit terminals (connectors)which are dedicated only for connection to specific terminals ofother equipment need not be marked Exception 2: If there is insufficient space for markings adjacentto the measuring circuit terminals (as in multi-input equipment),it is permissible for the rated maximum working voltage or currentinformation to be located in the operating manual. Exception 3: Measuring circuit terminals provided by listed testand measurement equipment.SUBSTANTIATION: NFPA 79 needs to cease includingmeasuring circuits in the scope and in the annex or technicallyaddress the significant differences between "high impedance"measuring circuits and "low impedance" power circuits. Voltmeters commonly accept voltages up to 1000V or more. Insulation resistance (megohm) meters commonly generate500Vdc voltages for measuring purposes. Ground continuity testers commonly use a current injectionmethod of 10 amps, 25 amps or more. Dielectric withstand (hypot) testers commonly generated up to5000V ac or 5000V dc. Obviously these types of measuring terminals have been used fordecades and can be designed safely even though NFPA 79 does notaddress why or how and worse these terminals are currently unsafeaccording to the letter of NFPA 79. Additional concepts of current limited terminals and powerlimited terminals can be extracted from standards for test andmeasurement equipment if the 79 Technical Committee wants toadd more detail. For now the above is a good introduction.COMMITTEE ACTION: Reject.


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COMMITTEE STATEMENT: The current requirements of NFPA79 do not prohibit this practice provided that safety is assured bycompliance with 6.2.2.1. It is not the intent of this committee thatthese parts should be exposed live parts.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: NFPA 79 does not currently addressmeasuring terminals inside or outside the equipmentenclosure.When measuring circuits are measuring voltage orcurrent at the terminals, there is likely to be an alternateconnection to an source of AC or DC power. The probes, leads,terminals and circuits used for measuring are protected by the veryimpedance of the measuring circuits

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(Log #157)79- 30 - ([6.x]): RejectSUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Add text to read as follows: X.0 Limited Current Circuits - the steady-state current drawn through a non-inductive resistorof 2000 ohms connected between the measuring terminal and theequipment protective earthing terminal shall not exceed 0.7 mApeak a.c. or 2 mA d.c.SUBSTANTIATION: One method permitted to allow measuringterminal with hazardous voltage sources above 50Vdc and 60Vdcrequired for some forms of measurement is to be designing highimpedance limited current circuits.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee is unaware ofprovisions in Clause 6 that provide for the use of "limited currentcircuits" as a protective technique from electric shock.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26

VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: A fine print note explaining how protectionagainst shock by limited current circuits are used in UL1950 wouldbe very extremely helpful. See attachment submitted for proposal #79-25, log # 68.

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(Log #15879- 31 - ([6.x]): RejectSUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Add text to read as follows: X.0 Limited power terminals A limited power terminal shall comply with one of the following: - output is inherently limited in compliance with Table 8; - an impedance limits the output in compliance with Table 8; - a regular network limits the output in compliance with table 8,both under normal operating conditions and after any single faultint he regulating network (open circuit or short-circuit); - a regulating network limits the output in compliance with Table8, both under normal operating conditions and after any singlefault in the regulating network (open circuit or short-circuit); Table 8 Limits for inherently limited power sources Table 9 Limits for power sources for inherently limited (overcurrent protective device required)SUBSTANTIATION: Section 6 protection against shock hazarddoes not address protection against energy hazard. The NEC refers to Class 2 which is not harmonized. By usingPower limited terminals for measurement terminals operatingbelow 50V or 60Vdc will satisfy the NEC Class 2 and addressadditional concerns with energy and fire from measuringterminals.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee is unaware ofprovisions in Clause 6 that provide for the use of "limited powerterminals" as a protective technique from energy hazard.

Table 8 Limits for inhertently limited power sourcesOutput Voltage 1)

(U oc )Output current2)

(Isc )VA3)

V.a.c V d.c. A VxAup to 20 up to 20 up to 8.0 Up to 5 x Uoc

over 20 up to30

over 20 up to30

up to 8.0 up to 100

- over 30 up to60

up to 150/U oc up to 100

Conditions applicable to table 8 1. Uoc : Output voltage measured with the equipment connected to thesupply at rated input voltage and with all load circuits disconnected. Voltagesare for sinusoidal a.c. and ripple free d.c. For non-sinusoidal a.c. and d.c.with ripple greater than 10% peak, the peak voltage shall not exceed 42.4 V. 2. Isc : Maximum output current after 60 s of operation with any non-capacitive load, including short circuit. 3. VA: Maximum output VA with any load. Initial transients lasting lessthan 100 ms are ignored.

Table 9 Limits for power sources not inherently limited(overcurrent protective device required)

Output Voltage1)

(U oc )Output current2)

(Isc )VA3) Rated current value of

overcurrent protectivedevice4)

V a.c. V d.c A V x A Aup to 20 up to 20 up to 5.0

over 20 up to 30 over 20 up to 30 Up to 1000/Uoc up to 250 up to 100/U ocover 30 up to 60 up to 100/U oc

Conditions applicable to table 9 1. Uoc : Output voltage measured with the equipment connected to the supply at rated input voltage andwith all load circuits disconnected. Voltages are for sinusoidal a.c. and ripple free d.c. For non-sinusoidala.c. and for d.c. with ripple greater than 10% peak, the peak voltage shall not exceed 42.4 V. 2. Isc : Maximum output current after 60 s of operation with any non-capacitive load, including shortcircuit and with any overcurrent protective devices bypassed. 3. VA: Maximum output VA with any load and with overcurrent protective devices bypassed. Initialtransients lasting less than 100 ms are ignored. 4. The rated current values of overcurrent protective devices are based on fuses and circuit breakers thatbreak the circuit within 120 s with a current equal to 210 percent of the rated current value specified in the

b


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NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Limited power output terminals are absolutelynecessary to comply with NEC Class 2 power outputs. Limitedpower extracts the technical requirements for NEC Class 2 withoutusing the term "Class 2" to avoid confusion with "Class II" ininternational IEC documents.

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(Log #96)79- 32 - ([4.4.9]): Accept in Principle TCC NOTE: The TCC directs the committee to reconsider thepanel action text for 12.5.1.1 Exception 4 and either reword theaction or define IP 20 since it appears in mandatory text. Thisaction will be considered by the committee as a public comment.SUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: Add text to read as follows:4.4.9 Spaces About Control Cabinets and Compartments. Accessand working space for control cabinets and compartmentsoperating at 600 volts, nominal, or less to ground and likely torequire examination, adjustment, servicing, or maintenance whileenergized shall comply with the provisions of this cause. Sufficient access and working space shall be provided andmaintained about all control cabinets and compartments to permitready and safe operation and maintenance of such controlcabinets and compartments. 4.4.9.1 Working Space. The working space shall permit at least90 degree opening of control cabinet and compartment doors orhinged panels. 4.4.9.1.1 The depth of the working space in the direction ofaccess to live parts shall not be less than indicated in Table4.4.9.1.1. Distances shall be measured from the control cabinet orcompartment front or opening.

Table 4.4.9.1.1 Working Space DepthMinimum Clear Distance (ft)Nominal Voltageto Ground

Condition 1 Condition 2 Condition 3

0-150 3 3 3151-600 3 3 1/2 4

Notes:1. For SI units, 1 ft = 0.30.48 m.2. Where the conditions are as follows: Condition 1— Exposed live parts on one side and no live orgrounded parts on the other side of the working space, or exposedlive parts on both sides effectively guarded by insulating materials.Insulated wire or insulated busbars operating at not over 300 voltsto ground shall not be considered live parts. Condition 2 — Exposed live parts on one side and a groundedsurface on the other side. Concrete, brick, or tile walls shall beconsidered as grounded. Condition 3 — Exposed live parts on both sides of the workingspace (not guarded as provided in Condition 1) with the operatorbetween. Exception 1 – Working space shall not be required in back orsides of control cabinets or compartments, where there are norenewable or adjustable parts on the back or sides and where allconnections are accessible from locations other than the back orsides. Where rear access is required to work on de-energized partson the back of enclosed control cabinet and compartment, aminimum working space of 2 1/2 ft. (762 mm) horizontally shallbe provided. Exception 2 – By special permission working space clearancedepth 2 1/2 (762 mm) or less shall be permitted where alluninsulated parts are at a voltage no greater than 50 volts rms ac,or 60 volts dc. Exception 3 – Condition 2 working clearance depth shall bepermitted between control cabinets or compartments locatedacross the aisle from each other or across from non-machineryassociated switchgear, panelboards, or motor control centerswhere conditions of maintenance and supervision ensure thatwritten procedures have been adopted to prohibit the affectedequipment doors on both sides of the aisle from being open at thesame time and qualified persons who are authorized will servicethe installation.

Exception 4 – Condition 1 working clearance depth shall bepermitted where control cabinets or compartments are locatedacross the aisle from each other, or across from a groundedsurface, and all associated control cabinet or compartment devicesand equipment operating at greater than 50 volts rms ac, or 60volts dc are protected or rated IP20 or greater. Exception 5 – 2 1/2 ft (762 mm) working space clearance depthshall be permitted where all of the following conditions are met: 1 – the control cabinet or compartment is operating at not over150 volts line-to-line or line-to-ground 2 – the conditions of maintenance and supervision ensure thatonly qualified persons will service the installation 3 – the door(s) of the control cabinet or compartment open atleast 90 degrees or are removable. Exception 6 – By special permission working space clearancedepth less than 2 1/2 (762 mm) shall be permitted where all of thefollowing conditions are met: 1 – the control cabinet or compartment is operating at not over150 volts line-to-line or line-to-ground 2 – the conditions of maintenance and supervision ensure thatonly qualified persons will service the installation 3 – the control cabinet and compartment requires a tool to open 4 – where only diagnostic troubleshooting and testing on liveparts is involved 5 – the door(s) of the control cabinet and compartment open atleast 90 degrees or are removable.4.4.9.1.2 The width of the working space in front of controlcabinets and compartments shall be the width of the controlcabinet or compartment, or 2 1/2 ft. (762 mm), whichever isgreater.4.4.9.1.3 The working space height shall be clear and extend fromthe grade, floor, or platform to a height of 6 1/2 ft (1.98 m).Within the height requirements of this section, other equipmentassociated with the machine located above or below the controlcabinet or compartment shall be permitted to extend not morethan 6 in. (153 mm) beyond the front of the electrical controlcabinet or compartment.4.4.10 Access. At least one entrance of sufficient area shall beprovided to give access to the working space about controlcabinets or compartments.4.4.10.1 Working space required by Clause 4.4.9 shall not be usedfor storage. When normally enclosed live parts are exposed forinspection or servicing, the working space, if in a passageway orgeneral open space, shall be suitable guarded.SUBSTANTIATION:NFPA 70 Article 110-26 is generally referenced for the access andworking space clearance requirements relative to electricalequipment. Requirements equivalent to those found in Article110-26 can also be are found in NFPA 70E Clause 1-8.1, and inOSHA 1910.303(I) - both of which imported the requirementsfrom NFPA 70 Article 110-26. None of the renditions of Article110-26, however, provide the appropriate granularity of detail for,nor are they specifically tailored to, the application of the electricaequipment of industrial machinery. The applicability of Article 110-26 relative to specific electricalequipment is unclear and ambiguous, NFPA 70 Article 100 definesequipment as “a general term including material, fittings, devices,appliances, fixtures, apparatus, and the like used as a part of, or inconnection with, an electrical installation”. This very broaddefinition is narrowed in Article 110-26(a) to only equipment thatis “...likely to require examination, adjustment, servicing, ormaintenance.” Although the definition narrows, it is still a verybroad definition in an article that comes with very specificrequirements. To what electrical equipment types do thesespecific requirements apply? It is generally accepted that the electrical equipment reference inArticle 110-26 includes switch gear, panel boards, and motorcontrol centers. To some Article 110-26 electrical equipmentincludes all of those equipment types as well as junction boxes,convenience receptacles, limit switches, and everything in between.Others are certain that is not the intent of Article 110-26 to be sobroadly interpreted as to include convenience receptacles andlimit switches. The fact that such confusion exists confirms thegeneral ambiguity associated with applying the very specificrequirements of Article 110-26. Some working space clearance detail specific to the electricalequipment of industrial machinery is available in NFPA 70 Article670-5. That detail, however, does not provide completecomprehensive coverage for the electrical equipment of industrialmachinery in general. The purpose of this proposal is to clearly establish the access andworking space clearance requirements for the electrical controlcabinets and compartments of industrial machinery in onelocation, and to remove some of the ambiguities resulting from the


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application of Article 110-26. The baseline text of this proposalcomes from Article 110-26, and Article 670-5, with additions andrevision intended to facilitate this stated purpose. Substantiation for 4.4.9 Spaces About Control Cabinets andCompartments The baseline of this text is from NFPA 70 Article 110-26(a) andNFPA 70 Article 110-26. Sentence positioning and structure, aswell as minor text alterations, are effected to enhance clarity ofpurpose relative to the control cabinets and compartments ofindustrial machinery, and to create consistency with the rest of thisdocument. Substantiation for 4.4.9.1 Working Space This text is from NFPA Article 110-26(a)2. The positioning ofthis sentence is appropriate in this location as relative to it’sposition in Article 110-26(a)2 because the opening of a controlcabinet or compartment door requires working space in threeplanes (i.e. depth, width and height), not one (i.e. width). Thetext is better served when more appropriately placed and readilyfound. The sentence brought over from Article 110-26(a)2 was truncatedbecause an element of the sentence (i.e. “In all cases…”) ismeaningless, and serves no purpose relative to the control cabinetsand compartments of industrial machinery. Substantiation for 4.4.9.1.1 This text is from NFPA 70 Article 110-26(a)1. The tablereference is renumbered to create consistency with the rest of thisdocument. Substantiation for Table 4.4.9.1.1 Working Space Depth This table is from NFPA 70 Table 110-26(a). The table isrenumbered to create consistency with the rest of this document. Substantiation for notes to Table 4.4.9.1.1 Note 1: This heading and text is from NFPA 70 Table 110-26(a)Notes 1 without alteration. Note 2: This heading and text is from NFPA 70 Table 110-26(a)Notes 2 without alteration. Substantiation for Condition 1: This heading and text is from NFPA 70 Table 110-26(a) NotesCondition 1. The first sentence was truncated because an elementof the sentence (i.e. “…by suitable wood or other…”) appears toserve no current practices relative to the control cabinets andcompartments of industrial machinery. Substantiation for Condition 2: This heading and text is from NFPA 70 Table 110-26(a) NotesCondition 2 without alteration. Substantiation for Condition 3: This heading and text is from NFPA 70 Table 110-26(a) NotesCondition 3 without alteration. Substantiation for Exception 1: This exception is from NFPA 70 Article 110-26(a) Exception 1.Minor text alterations are effected to enhance clarity of purposerelative to the control cabinets and compartments of industrialmachinery, and to create consistency with the rest of thisdocument. Substantiation for Exception 2: This exception is from NFPA 70 Article 110-26(a) Exception 2.Minor text alterations are effected to enhance clarity of purposerelative to the control cabinets and compartments of industrialmachinery, and to create consistency with the rest of thisdocument. The identified AC voltage level is altered to maintain consistencywith the rest of this document. A specific depth of 2 1/2 ft or less is identified for controlcabinets and compartments containing non-hazardous voltages.The 2 1/2 baseline depth is comparable to the permissible depthestablished in Article 70 Article 670-5 for the higher voltage levelsand specified conditions identified. Based on the logic ofcomparable adequacy the 2 1/2 ft depth is specified here to reducethe ambiguity in Article 110-26 Exception 2 where no specificdepth is identified. Substantiation for Exception 3: This exception is from NFPA 70 Article 110-26(a) Exception 3,with the intent of the text extensively modified. In its original formArticle 110-26(a) Exception 3 deals with Condition 2 workingspace acceptable under the specified circumstances of Article 110-26(a) Exception 3, can be replicated in many industrialestablishments. This exception would allow working spaceclearance depth relief of 6 in. in those establishments, whilemaintaining a comparable level of safety prescribed in Article 110-26(a) Exception 3. Additional minor text alterations are effected to enhance clarityof purpose relative to the control cabinets and compartments ofindustrial machinery, and to create consistency with the rest of thisdocument.

Substantiation for Exception 4: This exception is new text that seeks to establish IP20 (i.e. “fingersafe”) or greater protected or rated devices and equipment as aneffective means of enhancing work place safety. As a precursor to this discussion several definitions must beestablished. Per NFPA 70 Article 100 Definitions: “Exposed. Capable of being inadvertently touched orapproached nearer than a safe distance by a person. It is appliedto parts that are not suitably guarded, isolated, or insulated.” “Live Parts. Electric conductors, buses, terminals, orcomponents that are uninsulated or exposed and a shock hazardexists.” Per International Electro-technical Commission (IEC)Publication 529 Degrees of Protection by Enclosures: “IP20. Protection against touch with the finger and medium-sizedforeign bodies greater than 12 mm in diameter with no protectionagainst water.” (“IP” stands for “ingress protection”. The first digitof an IP rating indicates the degree of protection relative to contactwith a foreign body. The second digit indicates the degree ofprotection relative to water. All IP ratings with a value greater than20 are more restrictive against contact with a foreign body andoffer greater protection against water.)Per the stated definitions devices and equipment protected orrated IP20 or greater do not constitute “exposed” “live parts”.Equipment protected or rated IP20 or greater satisfy UL 508Industrial Control Equipment, and IEC 529 “finger safe” criteria.Equipment protected or rated IP20 or greater is “suitably guarded”can be “safely approached”, and cannot be “inadvertentlytouched”. As such the same degree of workspace clearance depthfor totally exposed terminals and bus bars is not necessary fordevices and equipment protected or rated IP20 or grater.Equivalent safety is achieved by technology that is not currentlyaddressed by NFPA 70 generally, nor covered by Articles 110-26and 670-5 specifically.If a control cabinet or compartment for industrial machinerycontains only equipment protected or rated IP20 or greater itwould not contain any “exposed” “live parts”. With no “exposed”“live parts” NFPA 70 Table 110-26(a) is inapplicable. How thenshould working space clearance depth be ascertained? Theminimum working space clearance depth identified in Table 110-26(a) is 3 ft – therefore, as a baseline requirement, it would appearthat 3 ft would be appropriate. Further more, Table 110-26(a)Condition 1 (i.e. 3 ft working space clearance depth) can provideguidance – reference; “…exposed live parts on both sideseffectively guarded by suitable wood or other insulating materials.”Although not “exposed” “live parts”, the devices and equipmentprotected or rated IP29 or greater, by design, are “effectivelyguarded” with “insulating materials”. As such Condition 1provides further indication that 3 ft would constitute anappropriate working space clearance depth. Substantiation for Exception 5: This exception is from NFPA 70 Article 670-5. Format and minortext alterations are effected to enhance clarity of purpose relative tothe control cabinets and compartments of industrial machinery,and to create consistency with the rest of this document. Substantiation for Exception 6: This exception is from NFPA 70 Article 670-5 and Article 670-5Exception. Format and minor text alterations are effected toenhance clarity of purpose relative to the control cabinets andcompartments of industrial machinery, and to create consistencywith the rest of this document. Substantiation for 4.4.9.1.2: This text is from NFPA 70 Article 110-26(a)(2). Minor textalterations are effected to enhance clarity of purpose relative to thecontrol cabinets and compartments of industrial machinery, andto create consistency with the rest of this document. Substantiation for 4.4.9.1.3: This text is from NFPA 70 Article 110-26(a)(2). Minor textalterations are effected to enhance clarity of purpose relative to thecontrol cabinets and compartments of industrial machinery, andto create consistency with the rest of this document. Substantiation for 4.4.9.10 Access: This text is from NFPA 70 Article 110-26(c). Minor textalterations are effected to enhance clarity of purpose relative to thecontrol cabinets and compartments of industrial machinery, andto create consistency with the rest of this document. Substantiation for 4.4.10.1: This text is from NFPA Article 110-26(b). Minor text alterationsare effected to enhance clarity of purpose relative to the controlcabinets and compartments of industrial machinery, and to createconsistency with the rest of this document.


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COMMITTEE ACTION: Accept in Principle. 1) Delete from Proposal 79-84 (Log #54) [Clause 12] Sections12.5, 12.5.1 and 12.5.2. Retain 12.5.3 from Proposal 79-84 (Log#54). 2) Insert the proposed text from this proposal into a new 12.5and before 12.5.3 to read as follows:12.5 4.4.9 Spaces About Control Cabinets and Compartments. Access and working space for control cabinets and compartmentsoperating at 600 volts, nominal, or less to ground and likely torequire examination, adjustment, servicing, or maintenance whileenergized shall comply with the provisions of this cause. Sufficient access and working space shall be provided andmaintained about all control cabinets and compartments to permitready and safe operation and maintenance of such controlcabinets and compartments.12.5.1 4.4.9.1 Working Space. The working space shall permit atleast 90 degree opening of control cabinet and compartment doorsor hinged panels.12.5.1.1 4.4.9.1.1 The depth of the working space in the directionof access to live parts shall not be less than indicated in Table XX.Distances shall be measured from the control cabinet orcompartment front or opening.

Table XX Working Space DepthMinimum Clear Distance (ft)NominalVoltage toGround

Condition 1 Condition 2 Condition 3

0-150 3 3 3151-600 3 3 1/2 4

Notes:1. For SI units, 1 ft = 0.30.48 m.2. Where the conditions are as follows: Condition 1— Exposed live parts on one side and no live orgrounded parts on the other side of the working space, or exposedlive parts on both sides effectively guarded by insulating materials.Insulated wire or insulated busbars operating at not over 300 voltsto ground shall not be considered live parts. Condition 2 — Exposed live parts on one side and a groundedsurface on the other side. Concrete, brick, or tile walls shall beconsidered as grounded. Condition 3 — Exposed live parts on both sides of the workingspace (not guarded as provided in Condition 1) with the operatorbetween. Exception 1 – Working space shall not be required in back orsides of control cabinets or compartments, where there are norenewable or adjustable parts on the back or sides and where allconnections are accessible from locations other than the back orsides. Where rear access is required to work on de-energized partson the back of enclosed control cabinet and compartment, aminimum working space of 2 1/2 ft (762 mm) horizontally shall beprovided. Exception 2 – By special permission working space clearancedepth 2 1/2 (762 mm) or less shall be permitted where alluninsulated parts are at a voltage no greater than 50 volts rms ac,or 60 volts dc. Exception 3 – Condition 2 working clearance depth shall bepermitted between control cabinets or compartments locatedacross the aisle from each other or across from non-machineryassociated switchgear, panelboards, or motor control centerswhere conditions of maintenance and supervision ensure thatwritten procedures have been adopted to prohibit the affectedequipment doors on both sides of the aisle from being open at thesame time and qualified persons who are authorized will servicethe installation. Exception 4 – Condition 1 working clearance depth shall bepermitted where control cabinets or compartments are locatedacross the aisle from each other, or across from a groundedsurface, and all associated control cabinet or compartment devicesand equipment operating at greater than 50 volts rms ac, or 60volts dc are protected or rated IP20 or greater. Exception 5 – 2 1/2 ft (762 mm) working space clearance depthshall be permitted where all of the following conditions are met: 1 – the control cabinet or compartment is operating at not over150 volts line-to-line or line-to-ground 2 – the conditions of maintenance and supervision ensure thatonly qualified persons will service the installation 3 – the door(s) of the control cabinet or compartment open atleast 90 degrees or are removable.

Exception 6 – By special permission working space clearancedepth less than 2 1/2 (762 mm) shall be permitted where all of thefollowing conditions are met: 1 – the control cabinet or compartment is operating at not over150 volts line-to-line or line-to-ground 2 – the conditions of maintenance and supervision ensure thatonly qualified persons will service the installation 3 – the control cabinet and compartment requires a tool to open 4 – where only diagnostic troubleshooting and testing on liveparts is involved 5 – the door(s) of the control cabinet and compartment open atleast 90 degrees or are removable.12.5.1.2 4.4.9.1.2 The width of the working space in front ofcontrol cabinets and compartments shall be the width of thecontrol cabinet or compartment, or 2 1/2 ft (762 mm), whicheveris greater.12.5.1.3 4.4.9.1.3 The working space height shall be clear andextend from the grade, floor, or platform to a height of 6 1/2 ft(1.98 m). Within the height requirements of this section, otherequipment associated with the machine located above or belowthe control cabinet or compartment shall be permitted to extendnot more than 6 in. (153 mm) beyond the front of the electricalcontrol cabinet or compartment.12.5.2 4.4.10 Access. At least one entrance of sufficient area shallbe provided to give access to the working space about controlcabinets or compartments.12.5.2.1 4.4.10.1 Working space required by Clause 4.4.9 shall notbe used for storage. When normally enclosed live parts areexposed for inspection or servicing, the working space, if in apassageway or general open space, shall be suitable guarded.COMMITTEE STATEMENT: The committee agrees with thesubstantiation submitted for this proposal. However, the textproposed is better suited for Clause 12 "Control equipment:location, mounting, and enclosures" then Clause 4 - "Generaloperating conditions". The committee understands that the actionon this proposal modifies Proposal 79-84 (Log #54) [Clause 12].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: (1) I agree that access and working spaceshould be addressed in this standard but believe the requirementsbelong in Chapter 4 because they apply to more than controlequipment. See also my comment on Proposal 79-24 (Log #60). (2) 4.4.9.1.1 Exception No. 4. The issue of using "IP ratings"needs to be addressed but I am concerned about having differentrequirements than the NEC. Electrical shock is only one of thehazards that needs to be considered. These types of componentsare used on industrial machinery but they are also becomingcommon on building systems associated with premises wiring. Idon’t see a reason for having different requirements. Possibly ajoint task group comprised of members of NEC CMP-1 and NFPA79 could be formed to address this issue. GARVEY: Proposed Exception No. 3 is significantly differentfrom the NEC. The NEC Exception applies only to existinginstallations. Permitting a Condition 2 working clearance of 42-inches with written procedures may be appropriate in areplacement situation. It doesnot afford the same level ofprotection for the worker as the minimum 48-inches required byCondition 3 with over 150-volts to ground present. Proposed Exception No. 6 is unenforceable. It does not provideany minimum workspace depth. Proposed Exception No. 5 givesinstallers a reduced clearance to 30-inches with similar restrictionsProposed Exception No. 5 should be the bottom line. Proposed Exception No. 4 is new. It should be accepted. TheIP-20 level of protection is very restrictive and does provide anadditional safeguard for the worker.

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(Log #5979- 33 - (Clause 7 [Clause 5]): Accept in PrincipleSUBMITTER: David S. Fisher, Rockwell Automation/Rep. NEMARECOMMENDATION: Revise text as follows: 5 Incoming supply conductor terminations and devices fordisconnecting and removal of power

5.1 Incoming supply conductor terminations

5.1.1 Where practicable, the electrical equipment of amachine shall be connected to a single power supply. Where it is


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necessary to use another supply for certain parts of the equipment(e.g. electronic circuits, electromagnetic clutches), that supplyshall, as far as is practicable, be derived from devices (e.g.transformers, converters) forming part of the electrical equipmentof the machine.

5.1.2 Unless an attachment plug is provided with themachine for the connection to the supply (see 5.3.2 item f), thesupply conductors shall be contained in their own separateconduit or raceway and shall be terminated at the supplydisconnecting means.

5.1.3 Connections to guarded terminal blocks or otherdevices ahead of the disconnecting means for excepted circuitsaccording to 5.3.5 shall be permitted. Terminals for more thanone conductor shall be so identified .

5.1.4 Where a grounded conductor is used it shal l be clearlyindicated in the technical documentation of the machine, such asin the installation diagram and in the circuit diagram. A separateinsulated terminal shall be provided for the grounded conductor(see question 14 in annex B).

5.1.5 All terminals for the incoming supply connection shallbe legibly marked.

5.2 Grounding terminal.

A grounding terminal shall be provided for each incoming supplycircuit (see 8.2.1.2 for requirements).

5.3 Supply disconnecting (isolating) means

5.3.1 General

5.3.1.1 A supply disconnecting means shall be provided:– for each incoming supply circuit to a machine;– for the supply to a feeder system using collector wires,

collector bars, slip-ring assemblies, flexible cable systems(reeled, festooned), to a machine or a number ofmachines; and

– for each on-board power source (e.g. generator)

5.3.1.1.1 Each disconnecting means required by 5.3.1.1 shall belegibly marked to indicate its purpose. Where a machine issupplied by more than one source of supply, a marking shall beinstalled at each supply disconnect location denoting all otherdisconnects that supply a source of power to the machine.

5.3.1.2 The supply disconnecting means shall disconnect(isolate) the electrical equipment of the machine, including allcontrol circuits, from the supply when required (e.g. for work onthe machine, including the electrical equipment). Circuits thatare not required to be disconnected by the supply disconnectingmeans shall comply with 5.3.5.

5.3.1.3 The supply disco nnecting means shall be mountedwithin the control enclosure or immediately adjacent thereto.Where the disconnecting means is mounted external to the controlenclosure, a tool is required to open the control enclosure doorand a label shall be attached to that door warning of dangerousvoltage inside and advising disconnection of the power beforeopening.

Exception: Externally mounted disconnecting means supplyingmachines totaling 2 HP or less shall be permitted to be mounted up to 20feet away from the enclosure providing that the disconnecting means isin sight from, and readily accessible to the operator.

5.3.1.4 Wire bending space shall be provided for the supplydisconnecting means in accordance with NFPA 70, Section430.10(b) and accidental contact with the line side live parts shallbe inhibited. The supply conductors to the disconnecting meansshall be separated from other internal conductors by either:

a mounting the disconnect as near as practicable to thetop of the enclosure while dedicating sufficient spacebetween the top of the enclosure and the disconnect forthe supply conductors; or

b mounting the disconnect other than at the top of theenclosure and guarding its line side live parts againstaccidental contact, and by separating the supplyconductors from other internal conductors by the use ofa barrier.

5.3.1.5 There shall be no exposed live parts with thedisconnecting means in the open (off) position except thoseassociated with the circuits described in 5.3.5.

5.3.1.6 Where two or more disconnecting means are providedwithin the control enclosure for multiple supply circuits, they shallbe grouped in one location. Protective Interlocks for their correctoperation shall be provided where a hazardous condition odamage to the machine or to the work in progress can occur. 5.3.2 Type

The supply disconnecting device shall be one of the followingtypes:

a) a listed motor-circuit switch (switch disconnector) ratedin horsepower;

b) a listed molded case circuit breaker;c) a listed molded case switch;d) an instantaneous trip circuit breaker that is part of a

listed combination motor controller;e) a listed self-protected combination controller limited to

single motor applications;f) an attachment plug and receptacle (plug/socke

combination) for cord connection to motor loadtotaling 2 hp or less.

5.3.3 Requirements

5.3.3.1 Where the supply disconnecting device is one of thetypes listed in 5.3.2 items a-e it shall fulfill all of the followingrequirements:

− isolate the electrical equipment from the supply andhave one OFF (isolated) and one ON position only.Circuit-breakers are permitted to have a reset (tripped)position between OFF and ON;

− have an external operating means (e.g. handle)

Exception: Power operated switchgear need not be operablefrom outside the enclosure where there are other means to openit.

− be provided with a permanent means permitting it to belocked only in the open (OFF) (isolated) position (e.g.by padlocks). When so locked, remote as well as localclosing shall be prevented;

– disconnect all ungrounded conductors of its powersupply circuit simultaneously

– be rated for the application as follows:

a) The ampere rating shall be at least 115 percent othe sum of the full-load currents required for allequipment that may be in operation at the sametime under normal conditions of use;

b) Where rated in horsepower, the horsepower ratingshall be at least equal that which is defined byANSI/NFPA 70, Table 430–151B for a locked rotoequivalent equal to the largest sum resulting fromthe locked-rotor currents of any combination omotors which can be started simultaneously andthe full load currents of the remaining motor andnon-motor loads that can be operated at that time

c) The voltage rating shall be at least equal to thenominal supply voltage.

5.3.3.2 Where the supply disconnecting device is one of thetypes listed in 5.3.2 items a-e, the available fault current at thepoint of the supply to the machine shall not be greater than theshort-circuit rating of the disconnecting device.

5.3.3.3 When the supply disconnecting device is anattachment plug and receptacle (plug/socket combination), itshall fulfil the following requirements:

− have a load-break rating or be interlocked with aswitching device that is load-break rated, to interrupt the


1532

(locked rotor current) stalled current of the largestmotor together with the sum of the normal runningcurrents of the remaining motors and non-motor loadsthat can be operating at that time;

− be of such a type and be so installed as to preventunintended contact with live parts at any time evenduring insertion or removal of the connectors;

− have a first make, last break grounding (earthing)contact;

− where rated at more than 20 A have a retaining means toprevent unintended or accidental disconnection.

5.3.3.4 In addition, a switching device on the machine shallbe provided for switching the machine on and off.

5.3.4 Operating Handle

5.3.4.1 The center of the grip of the operating handle of thedisconnecting means, when in its highest position, shall be notmore than 6 ft 7 in. (2.0 m) above the floor. A permanentoperating platform, readily accessible by means of a permanentstair or ladder, shall be considered as the floor for the purpose ofthis requirement.

5.3.4.2 An operating handle of the disconnecting means shall:be readily accessible with doors in the open or closed position;

– be engaged with the operating mechanism of thedisconnecting means at all times;

– maintain the environmental rating of the enclosure.

5.3.5 Excepted circuits

5.3.5.1 The following circuits are not required to bedisconnected by the main supply disconnecting means:

− lighting circuits for lighting needed during maintenanceor repair;

− Attachment plugs and receptacles (plug and socketoutlets) for the exclusive connection of repair ormaintenance tools and equipment (e.g. hand drills, testequipment);

− undervoltage protection circuits that are only used forautomatic tripping in the event of supply failure;

− circuits supplying equipment that are required to remainenergized for satisfactory operation (e.g. temperaturecontrolled measuring devices, product (work inprogress) heaters, program storage devices).

5.3.5.2 A source of supply for excepted circuits shall complywith all of the fol lowing conditions:

− be a separate primary disconnecting means, isolatingtransformer, and secondary overcurrent protectionfurnished in an enclosure and mounted within thecontrol enclosure, adjacent to the main disconnectingmeans;

- have line side (of the supply disconnect) supplyconnections internal to the control enclosure that areseparate from and do not share a raceway with otherconductors, and that are encased in rigid or flexibleconduit if longer than 18 inches. :

5.3.5.3 The control interlocking circuits shall be capable ofbeing disconnected at the control panel from which they aresourced. 5.3.5.4 Where circuits are not disconnected by the mainsupply disconnecting means device:

− a permanent warning label(s) shall be appropriately

placed in proximity adjacent to the main supplydisconnecting device means indicating that it does notde-energize all exposed live parts when it is in the open ( ( off) (isolated) position;

− a corresponding statement shall be included inthe maintenance manual;

_- a permanent warning label shall be placed in proximityto each excepted circuit or the excepted circuit shall beseparated from other circuits or shall be identified bycolor (see 14.2.4)..

_<<need some work>> 5.4 Devices for switching off for prevention of unexpected

start-up

Devices for switching off for the prevention of unexpected start-upshall be provided (e.g. where, during maintenance, a start-up ofthe machine can create a hazard). Devices described in 5.3.2 mayfulfil l that function.

Such devices shall be appropriate and convenient for the intendeduse, shall be suitably placed, and readily identifiable (e.g. by adurable marking where necessary).

Means shall be provided to prevent unintentional, inadvertent,and/or mistaken closure of the disconnecting device (see also5.6).

When devices other than supply disconnecting devices inaccordance with 5.3.2 are used (e.g. a contactor switched off by acontrol circuit), such means for switching off are intended to beemployed only for situations that include:

_no significant dismantling of the machine;_adjustments requiring a relatively short time;_no work is being carried out on the electrical equipment

except when:_there is no hazard arising from electric shock (see

clause 6) and burn;_the switching off means cannot be negated by the work;_the work is of a minor nature (e.g. replacement of

plug-in devices without disturbing existing wiring).

5.4 .4 Means for removal of power for prevention ofunexpected start-up

5.4.1 Means for removal of power shall be provided whenprevention of unexpected start-up is required (e.g. duringmaintenance where the unexpected start-up of a machine cancreate a hazard). Such means shall be:

− appropriate for the intended use;− conveniently located;− readily identifiable, and− provided with permanent means for locking in

the “Off” position only. except as allowed in .5.6.

5.4.2 Removal of power can be accomplished by the use ofthe supply disconnecting means, additional devices conforming to5.3.2, or other means (e.g. a contactor switched off by a controlcircuit). 5.4.3 Where such other means are used, a single failure ofany of its components shall not result in an inadvertant inadvertent or unexpected start-up . and shall prevent reinitiation of themachine intil the system is reset or the fault is corrected. 5.4.4 Such other means shall be employed only forsituations that include:

− routine exchange of parts, fixtures and tools requiringno significant dismantling of the machine;

− work on the electrical equipment where all of thefollowing conditions exist:

• there is no hazard arising from electric shock (seeclause 6) and burn;

• the switching off means cannot be negated by thework;

• the work is of a minor nature (e.g. replacement oplug-in devices without disturbing existing wiring).


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5.5 5.5 Devices for disconnecting electrical equipment 5.5.1 Devices shall be provided for disconnecting (isolating)electrical equipment to enable work to be carried out without arisk from electric shock or burn.

5.5.2 The supply disconnecting device (see 5.3) shall bepermitted to fulfil l this requirement where there is no need forisolating individual portions of the electrical circuit.

5.5.3 However, where it is expected that it will be necessaryto work on the electrical equipment of separately operable parts ofa machine, a disconnecting means shall be permitted for theelectrical equipment of each such part of the machine requiringseparate isolation.

5.5.4 The following devices shall be permitted to fulfill thisisolating function:

devices described in 5.3.2;a manual motor controller suitable for motor disconnecting andcomplying with UL 508 where located on the load side of the lastshort circuit protective device (in the branch), and

− a redundantly monitored, remotely operated contactorisolating system incorporating control lockoutprovisions, and listed for isolation purposes.

5.5.5 Such devices shall be:

− readily accessible;− within sight of the part of the machine

requiring isolation;− readily identifiable, and− for other than attachment plugs, provided with

permanent means for locking in the “Off” position only.

To be placed in an annex:

FPN to 5.1.1: For large complex machinery comprising a numberof widely-spaced machines working together in acoordinated manner, there may be a need for more thanone incoming supply depending upon the site supplyarrangements (see 5.3.1).

SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738.

Historical Background



As the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation, andat the same time maintain the high standard of electrical machinesafety, the NFPA 79 committee has expressed their desire, throughballoted vote, to harmonize NFPA 79 with IEC-60204-1.


Today's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true.Differing electrical standards add a large cost to multinationalmanufacturers as they build and sometimes move manufacturingfacilities.





Result

The NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committeeformed 20 Task Groups. Each Task Group was assigned oneproposed new clause.

The Task Group compared NFPA-79-1997, Clause 7 with IEC60204-1 Clause 5. The Task Group presented its work to the entirecommittee on several occasions for review and comment. Thisproposal is a result of that work.

The Task Group proposes to renumber NFPA 79-1997 Clause 7 tocorrespond with IEC 60204-1 Clause 5. The task group proposesthe following changes to further improve usability.

SUBSTANTIATION FOR NFPA 79 1997 CLAUSE 7 REVISIONS

5 Incoming supply conductor terminations and devicesfor disconnecting and removal or power

Recommendation: Revise the NFPA 79 – 1997 Clause 7title “Supply circuit disconnecting means” toharmonize with the IEC Clause 5 heading.

Substantiation: The new heading better reflects thebreadth of this revised Clause 5.

5.1 Incoming supply conductor terminations

Recommendation: Add this new subclause heading.

Substantiation: This heading describes the subjectcovered.

5.1.1 Recommendation: Add new subclause paragraph.

Substantiation: This added material is appropriate forthe installation of larger machines where there couldbe options as to the use of multiple of incomingsupplies.

5.1.2 Recommendation: Add new subclause paragraphessentially incorporating the requirements of 7.6 ofNFPA 79 – 1997.

Substantiation: The new text contains the originalprovisions along with the additional provision thatdisallows the installation of line and load conductorsin the same conduit or raceway. This provision isintended to provide protection for maintenancepersonal who may come in contact with conductorsthat may remain energized with the disconnect in OFFposition due to insulation failure.


Substantiation: This subclause explicitly allows for thetapping off of the line side of the main disconnect forsupplying circuits that cannot be disconnected when itis opened.


Substantiation: This subclause provides requirementsfor the connection of a grounded conductor, whereused, and stipulates its appropriate documentation.


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Substantiation: This subclause requires the marking ofthe incoming supply connections.

5.2 Grounding terminal

Recommendation: Add this new subclause headingand the associated requirement.

Substantiation: This text anticipates the possibility ofmultiple incoming supplies and the necessity ofkeeping the respective equipment groundingconductors separate in order to provide theappropriate ground fault paths.

5.3 Supply disconnecting (isolating) means


Substantiation: This heading is very similar to theClause 7 heading in NFPA 79 - 1997 except that thistitle includes the parenthetical term “isolating” whichdenotes an implicit function in listed disconnects inthe US but helps to align with IEC text.

5.3.1 General


5.3.1.1 Recommendation: Add this new subclause paragraphwhich hierarchically covers the requirements of 7.1 ofNFPA 79 – 1997.

Substantiation: This subclause elaborates on the typesof supply/source for which disconnects are required.The second bullet has been added to recognize thespecialty applications involving overhead cranes,gantries and such equipment. The third bullet wasadded to clarify that if the source of power to themachine is generated on board, then a supplydisconnecting means shall be provided.

5.3.1.1.1Recommendation: Add this new subclause paragraphproviding marking requirements for machinessupplied from more than one source.

Substantiation. First sentence is required by the NECSection 110-22. In addition, the requirement foridentification for multiple sources of supply isnecessary for the safety of maintenance personnel thatmay be required to service the machine.

5.3.1.2 Recommendation: Add this new subclause paragraphwhich captures the requirements of 7.5 of NFPA 79 -1997 except for the stipulation to open all ungroundedconductors of an incoming supply. (Thatrequirement is covered by the new 5.3.3.1)

Substantiation: This subclause embodies the originalrequirements of 7.5 in NFPA 79 - 1997 but in adifferent organizational structure.

5.3.1.3 and 5.3.1.4Recommendation: Add these new subclauseparagraphs which capture the requirements of 7.8.1 ofNFPA 79 – 1997.

Substantiation: These subclauses embody the originalrequirements of 7.8.1 in NFPA 79 -1997 but in adifferent organizational structure. Existing ExceptionNo. 1 has been deleted from subclause 7.8.1 ofexisting NFPA 79-1997 because the requirement iscovered by the new requirement of subclause 5.3.1.4.

5.3.1.5 Recommendation: Add this new subclause paragraphwhich captures the requirements of 7.7 of NFPA 79 –1997.

Substantiation: This subclause embodies the originalrequirements of 7.7 in NFPA 79 - 1997 but in adifferent organizational structure.

5.3.1.6 Recommendation: Add this new subclause paragraphwhich captures the requirements of 7.8.2 of NFPA 79 –1997 and provides additional requirements regardingprotective interlocks

Substantiation: This subclause embodies the originalrequirements of 7.8.2 in NFPA 79 - 1997 but in adifferent organizational structure. In addition itrequires that protective interlocks be used where ahazardous condition or damage to the machine couldoccur if all supply disconnects were closed at the sametime.

5.3.2 Type

Recommendation: Add this subclause heading whichis identical to 7.2 of NFPA 79 - 1997 and the associatedrequirements herein embody those of 7.21 and 7.2.2 ofNFPA 79 - 1997.

Substantiation: This subclause enlarges the list of thepermitted types of devices to align with the NationalElectric Code. Item “e” has been added to the list ofpermissable supply disconnecting means with anadditional restriction limiting it to single motors. Thisis because these devices are in of themselves limited toa single motor machine application.

5.3.3 Requirements


Substantiation: This heading organizationally collectsall of the requirements associated with the types ofdisconnecting devices permitted in 5.3.2.

5.3.3.1 Recommendation: Add this new subclause paragraphwhich embodies all of the requirements of 7.3 and 7.4and some of the requirements of 7.5 and 7.10 of NFPA79 – 1997.

Substantiation: This subclause essentially embodiesthe referenced requirements NFPA 79 – 1997 either inwhole or in part.

5.3.3.2 Recommendation: Add this subclause paragraphwhich is a revision of the short-circuit rating languageof 7.3.2 in NFPA 79 – 1997.

Substantiation: The language for the short-circuitrating of the disconnecting device is revised such thatthe burden of conformance does not appear to beimplicitly placed upon the provider of the machinealone.

5.3.3.3 Recommendation: Add this subclause paragraphwhich embodies the requirements for the use of anattachment plug for disconnecting purposes, 7.11 ofNFPA 79 – 1997, with the exception of the 2 nd, 3 rd and5th listed items of 7.11.

Substantiation: This subclause appropriately coversthe requirements stated but does not cover thefollowing requirements excepted from 7.11:

– The supply voltage shall not exceed 150 toground.– DC shall not be used.– The attachment plug shall be single voltagerated.

These requirements were not included because theywere considered to be unnecessarily restrictive.

5.3.3.4 Recommendation: Add this subclause paragraph whichrequires the provision of a switching device on the machine toswitch the machine on and off where its disconnecting means isan attachment plug.

Substantiation: This subclause requires a means to readily turnthe machine on and off which is practically not possible with aremote attachment plug used as a disconnecting means.


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5.3.4 Operating handle

Recommendation: Add this subclause heading whichis identical to the heading of 7.10 of NFPA 79 – 1997.

5.3.4.1 Recommendation: Add this subclause paragraphwhich is identical to the requirements of 7.10.2 ofNFPA 79 – 1997.

5.3.4.2 Recommendation: Add this subclause paragraphwhich broadens the requirements of 7.10 of NFPA 79 -1997.

Substantiation: The first two requirements of thissubclause both ultimately mandate that the handle ofthe disconnecting device be in control of thedisconnecting device at all times regardless of theposition of the door. In practical terms, this meansthat having the handle of a rotary operateddisconnecting device mounted to the door, such thatit separates from the rest of the disconnect mechanismwhen the door is opened, does not meet therequirements of this subclause. The intent here is toprovide immediate operability of the disconnectingdevice and to have the provision for locking thedisconnecting device in the off position, independentof the door position. These requirements align withthose of SAE HS - 1738: 2001. The additionalrequirement stipulates that the handle of thedisconnecting device not compromise theenvironmental rating of the enclosure.


Recommendation: Add this subclause headingcovering the requirements for those circuits that neednot be disconnected by the supply disconnect.

5.3.5.1 Recommendation: Add this subclause paragraphlisting those circuits that are not required to bedisconnected by the supply disconnecting means.

Substantiation: This subclause consolidates the twotypes of circuits referenced in 7.9.1 of NFPA 79 - 1997with two other types of circuits which can beexempted from disconnection by the supplydisconnecting means.

5.3.5.2 Recommendation: Add this subclause paragraphproviding requirements for the source of supply forthose circuits excepted in 5.3.5.1 in this proposedrevision.

Substantiation: This subclause specifies requirementsessentially identical to those specified in 14.3.2 f) ofNFPA 79 - 1997 for the supply for those circuitsexcepted from the requirement to be disconnected bythe supply disconnecting means. It further specifiesrequirements for the connections between the“transformer-disconnect” supply and the line side ofthe main supply disconnect.

5.3.5.3 Recommendation: Add this subclause paragraphregarding the disconnection of interlocking controlcircuits which are excluded from the requirement tobe disconnected by the supply disconnect by 7.5(Exception) of NFPA 79 – 1997.

Substantiation: Subclause 7.5 of NFPA 79 - 1997 makesthese circuits “excluded” but does not define anymeans by which they are to be disconnected. Thissubclause requires that the interlocking control circuitbe disconnected by either the supply disconnect or the“transformer-disconnect” (as provided in 5.3.5.2) inthe sourcing panel.

5.3.5.4 Recommendation: Add this subclause paragraphregarding requirements, other than those relating todisconnection, for the “excepted circuits”.

Substantiation: This subclause includes requirementsfor the warning as stipulated in the “Exception” of 7.5of NFPA 79 – 1997. In addition it includesdocumentation requirements and requirements forseparation, labeling or identifying the exceptedcircuits by color. The color requirements of theproposed 14.2.4 reserve the colors YELLOW orORANGE for all conductors that remain energizedafter the main disconnect is opened (i.e. all exceptedcircuits).

5.4 Means for removal of power for prevention of unexpected start-up

Recommendation: Add this new subclause headingand its associated subclause paragraphs.

Substantiation: This subclause provides requirementsfor the use of means other than the disconnectingdevices permitted for use as a supply disconnectingmeans. It provides reliability requirements for the“other means” and, in addition, limits the kinds ofwork or activity permitted on the machine where suchother means are used.

5.5 Devices for disconnecting electrical equipment

Recommendation: Add this new subclause headingand its associated subclause paragraphs.

Substantiation: This subclause stipulates the types ofdisconnecting devices that are permitted to beemployed where it is necessary to separately isolateindividual parts of the machine electrical equipmentfor work on these parts while the remaining parts ofthe electrical equipment can be energized. Inaddition, application requirements are specified forthese additional disconnecting means.

NFPA 79-1997, 7.9.2, second bullet:

This subclause bullet has been deletedbecause there is no exclusive requirement forvault-type hardware either in NFPA 79-1997 orin the new proposals, therefore, there can beno requirement for an interlock function thatrequires a complimentary function (initiallatch) inherent to traditional vault-typehardware.

NFPA 79-1997, 7.11, second, third and fifth bullet:

These subclause bullets have been deletedbecause suitably identified devices havingvoltage ratings greater than 150 volts areavailable. The requirement for a single voltagerated device is overly restrictive. Additionally,a load break rating is now required for thesedevices according to this proposal in subclause5.3.3.3.

NFPA 79-1997, 7.9.4:This subclause has been deleted because therequirement for separate conduits andseparation of supply circuits is not applicableto load side machinery wiring any longer. Therequirement currently appeared in NFPA 79-1997, 7.9.4 which covers interlockingprovisions and is not applicable to incomingsupply conductor requirements. Additionally,14.1.3, Conductors of Different circuits,contains installation requirements forconductors of different circuits which mayoccupy the same raceway (ducts).


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CLAUSE NUMBER CROSS REFERENCE --- NFPA 79-1997 ANDPROPOSED NFPA 79-2002

COMMITTEE ACTION: Accept in Principle.Revise text as follows:5 Incoming supply circuit conductor terminations and devices fordisconnecting and removal of power

5.1 Incoming supply circuit conductor terminations

5.1.1 Where practicable, the electrical equipment of a machineshall be connected to a single power supply circuit . Where it isnecessary to use another supply circuit for certain parts of theequipment (e.g. electronic circuits, electromagnetic clutches), thatsupply circuit shall, as far as is practicable, be derived from devices(e.g. transformers, converters) forming part of the electricalequipment of the machine.

5.1.2 Unless an attachment plug is provided with the machine forthe connection to the supply (see 5.3.2 item f), the supplyconductors shall be contained in their own separate conduit orraceway and shall be terminated at the supply disconnectingmeans.

5.1.3 Connections to guarded terminal blocks or other devicesahead of the disconnecting means shall be permitted for exceptedcircuits according to 5.3.5 shall be permitted . Terminals for morethan one conductor shall be so identified .

5.1.4 Where a grounded conductor is used it shall be clearlyindicated in the technical documentation of the machine, such asin the installation diagram and in the circuit diagram. A separate


Clause Heading Clause Heading 7 Supply circuit disconnecting means 5 Incoming supply conductor terminations

and devices for disconnecting andswitching off

5.3.1 General 7.1

General requirements 5.3.1.1 paragraph

7.2 Type 7.2.1 7.2.2

paragraph paragraph

5.3.2 Type

7.3 7.3.1 7.3.2

Rating paragraph paragraph

5.3.3.1 Paragraph (5th listed item)

7.3.3 paragraph 5.3.3.2 7.2

Paragraph Overcurrent protection

7.4 Position indication 5.3.3.1 paragraph (1st listed item) 7.5 Supply conductors to be disconnected 5.3.3.1

5.3.1.1 5.3.1.2

paragraph (4th listed item) paragraph paragraph

7.6 Connection to supply lines 5.1.2 paragraph 7.7 Exposed live parts 5.3.1.5 paragraph 7.8 7.8.1

Mounting paragraph

5.3.1.3 5.3.1.4

paragraph paragraph

7.8.2 paragraph 5.3.1.6 paragraph 7.9 Interlocking 6.2.3 paragraph 7.9.1 paragraph 6.2.3.1 paragraph 7.9.1 Exception No. 1 5.3.5.1 & 5.3.5.2

5.3.5.4 paragraphs paragraph (1st listed item)

7.9.1 Exception No. 2 no equivalent (moved into the main requirements of5.3.5.4)

7.9.1 Exception No. 3 5.3.5.1 & 5.3.5.2 5.3.5.4

paragraphs paragraph (1st listed item)

7.9.1 Exception No. 4 5.3.1.3 paragraph 7.9.2 paragraph (1st listed item) 6.2.3.2 paragraph 7.9.2 Paragraph (2nd listed item) deleted 7.9.3 paragraph 12.1.4 paragraph 7.9.4 paragraph deleted

7.10 Operating handle 5.3.4 Operating handle 7.10.1 paragraph 5.3.4.2 paragraph (1st listed item) 7.10.2 paragraph 5.3.4.1 paragraph 7.10.3 paragraph 5.3.3.1 paragraph (3rd listed item) 7.10.4 paragraph 5.3.3.1 paragraph (1st listed item) 7.11 Attachment plug and receptacle (1 st listed

item) 5.3.2.f

7.11 2nd listed item delete 7.11 3rd listed item delete 7.11 4th listed item 5.3.3.3 paragraph (1st listed item) 7.11 5th listed item delete 7.11 6th listed item 5.3.3.3 paragraph (3rd listed item) 7.11 7th listed item 5.3.1.3 paragraph (Exception) 7.11 8th listed item 5.3.1.3 paragraph


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insulated terminal shall be provided for the grounded conductor(see question 14 in annex B).

5.1.5 All terminals for the incoming supply circuit connectionshall be legibly marked.

5.2 Grounding terminal.

A grounding terminal shall be provided for each incoming supplycircuit

Note : ( For additional information on the grounding terminal, see8.2.1.2 . for requirements).

5.3 Supply circuit disconnecting (isolating) means

5.3.1 General

5.3.1.1 A supply circuit disconnecting means shall be provided:– for each incoming supply circuit to a machine;– for the supply circuit to a feeder system using collector

wires, collector bars, slip-ring assemblies, flexible cablesystems (reeled, festooned), to a machine or a numberof machines; and

– for each on-board power source (e.g. generator)

5.3.1.1.1 Each disconnecting means required by 5.3.1.1 shall belegibly marked to indicate its purpose. Where a machine issupplied by more than one source of supply circuit , a markingshall be installed at each supply circuit disconnect locationdenoting the location of all other supply circuit disconnects . thatsupply a source of power to the machine.

5.3.1.2 The supply circuit disconnecting means shall disconnect(isolate) the electrical equipment of the machine, including allcontrol circuits, from the supply circuit when required (e.g. forwork on the machine, including the electrical equipment).Circuits that are not required to be disconnected by the supplycircuit disconnecting means shall comply with 5.3.5.

5.3.1.3 The supply circuit disconnecting means other thanattachment plugs and receptacles shall be mounted within thecontrol enclosure or immediately adjacent thereto.

Exception: Externally mounted supply circuit disconnecting means,whether interlocked or not interlocked with the control enclosure,supplying machines totaling 2 HP or less shall be permitted to bemounted up to 20 feet away from the enclosure providing that thedisconnecting means is in sight from, and readily accessible to theoperator.

Supply circuit disconnecting means mounted within or adjacent tothe control enclosure shall be interlocked with the controlenclosure in accordance with 6.2.3. Where the supply circuitdisconnecting means is not adjacent to the control enclosure, orwhere the supply disconnecting means is an attachment plug andreceptacle, a tool is required to open the control enclosure doorand a label shall be attached to that door warning of dangerousvoltage inside and advising disconnection of the power beforeopening.

5.3.1.4 Wire bending space shall be provided for the supply circuitdisconnecting means in accordance with NFPA 70, Section430.10(b) . and accidental Space shall be determined by maximumwire size of incoming lines or by maximum capacity of line lugs onthe disconnecting means. Accidental contact with the line side liveparts shall be inhibited. The supply circuit conductors to thedisconnecting means shall be separated from other internalconductors by either:

( a ) mounting the disconnect as near as practicable to thetop of the enclosure while dedicating sufficient spacebetween the top of the enclosure and the disconnect forthe supply circuit conductors; or

( b ) mounting the disconnect other than at the top of theenclosure and guarding its line side live parts againstaccidental contact, and by separating the supply circuit

conductors from other internal conductors by the use ofa barrier.

5.3.1.5 There shall be no exposed live parts with the disconnectingmeans in the open (off) position except those associated with thecircuits described in 5.3.5.

5.3.1.6 Where two or more disconnecting means are providedwithin the control enclosure for multiple supply circuits, they shallbe grouped in one location. Protective Interlocks for their correctoperation shall be provided where a hazardous condition ordamage to the machine or to the work in progress can occur. 5.3.2 Type

The supply circuit disconnecting device shall be one of thefollowing types:

a) a listed motor-circuit switch (switch disconnector) rated in horsepower;b) a listed molded case circuit breaker;c) a listed molded case switch;d) an instantaneous trip circuit breaker that is part of a listed

combination motor controller;e) a listed self-protected combination controller limited to single motor applications;f) an attachment plug and receptacle (plug/socket

combination) for cord connection to motor loadstotaling 2 hp or less.

5.3.3 Requirements 5.3.3.1 Where the supply circuit disconnecting device is one of thetypes listed in 5.3.2 items a-e it shall fulfill all of the followingrequirements:

− isolate the electrical equipment from the supply circuitand have one OFF (isolated) and one ON position only.Circuit-breakers are permitted to have a reset (tripped)position between OFF and ON;

− have an external operating means (e.g. handle)

Exception: Power operated switchgear need not be operable from outsidethe enclosure where there are other means to open it.

− be provided with a permanent means permitting it to belocked only in the open (OFF) (isolated) position (e.g. bypadlocks) independent of the door position . When solocked, remote as well as local closing shall be prevented;

– disconnect all ungrounded conductors of its power supplycircuit simultaneously

– be rated for the application as follows:a) The ampere rating shall be at least 115 percent of the sum of

the full-load currents required for all equipment that maybe in operation at the same time under normal conditionsof use;

b) Where rated in horsepower, the horsepower rating shall beat least equal that which is defined by ANSI/NFPA 70,Table 430–151B for a locked rotor equivalent equal to thelargest sum resulting from the locked-rotor currents of anycombination of motors which can be startedsimultaneously and the full load currents of the remainingmotor and non-motor loads that can be operated at thattime;

c) The voltage rating shall be at least equal to the nominalsupply circuit voltage.

be operable, by qualified persons, independent of the doorposition without the use of accessory tools or devices.

5.3.3.2 Where the supply circuit disconnecting device is one of thetypes listed in 5.3.2 items a-e, the available fault current at thepoint of the supply to the machine shall not be greater than theshort-circuit current rating of the disconnecting device.

5.3.3.3 When the supply circuit disconnecting device is anattachment plug and receptacle (plug/socket combination), itshall fulfil all of the following requirements:

− have a load-break rating or be interlocked with a switchingdevice that is load-break rated, to interrupt the (lockedrotor current) stalled current of the largest motor togetherwith the sum of the normal running currents of the


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remaining motors and non-motor loads that can beoperating at that time;

− be of such a type and be so installed as to preventunintended contact with live parts at any time even duringinsertion or removal of the connectors;

− have a first make, last break grounding (earthing) contact;− where rated at more than 20 A have a retaining means to

prevent unintended or accidental disconnection.− be located within sight from the operator station and

readily accessible.

5.3.3.4 In addition, a switching device on the machine shall beprovided for switching the machine on and off. 5.3.4 Operating Handle

5.3.4.1 The center of the grip of the operating handle of thedisconnecting means, when in its highest position, shall be notmore than 6 ft 7 in. (2.0 m) above the floor. A permanentoperating platform, readily accessible by means of a permanentstair or ladder, shall be considered as the floor for the purpose ofthis requirement.

5.3.4.2 An operating handle of the disconnecting means shall:_be readily accessible with doors in the open or closedposition;

– be engaged with the operating mechanism of thedisconnecting means at all times;

– maintain the environmental rating of the enclosure.not be restricted by the enclosure door when the door is inthe open position.


5.3.5.1 The following circuits are shall not be required to bedisconnected by the main supply circuit disconnecting means:

− lighting circuits for lighting needed during maintenance orrepair;

− Attachment plugs and receptacles (plug and socket outlets)for the exclusive connection of repair or maintenance toolsand equipment (e.g. hand drills, test equipment);

− undervoltage protection circuits that are only used forautomatic tripping in the event of supply circuit failure;

− circuits supplying equipment that are required to remainenergized for satisfactory operation (e.g. temperaturecontrolled measuring devices, product (work in progress)heaters, program storage devices).

5.3.5.2 A source of supply Supply circuits for excepted circuitsshall comply with all of the following conditions:

− be a separate primary disconnecting means, isolatingtransformer, and secondary overcurrent protectionfurnished in an enclosure and mounted within the controlenclosure, adjacent to the main disconnecting means;

- have line side (of the supply circuit disconnect) supply circuitconnections internal to the control enclosure that areseparate from and do not share a raceway with otherconductors, and that are encased in rigid or flexibleconduit if longer than 18 inches. :

5.3.5.3 The control interlocking circuits shall be capable of beingdisconnected at the control panel from which they are sourced. 5.3.5.4 Where circuits are not disconnected by the supply circuitdisconnecting means:

− a permanent warning label(s) shall be placed adjacent to

the supply circ u it disconnecting means indicating that itdoes not de-energize all exposed live parts when it is in theopen ( off) (isolated) position;

− a corresponding statement shall be included in themaintenance manual;

- a permanent warning label shall be placed in proximity toeach excepted circuit or the excepted circuit shall beseparated from other circuits or shall be identified by color

Note. ( For additional information on identification by color forother conductors , see 14.2.4 ) . .

5.4 Means for removal of power for prevention of unexpectedstart-up

5.4.1 Means for removal of power shall be provided whenprevention of unexpected start-up is required (e.g. duringmaintenance where the unexpected start-up of a machine cancreate a hazard). Such means shall be:

− appropriate for the intended use;− conveniently located;− readily identifiable, and− provided with permanent means for locking in the “Off”

position only.

5.4.2 Removal of power can be accomplished by the use of thesupply circuit disconnecting means, additional devices conformingto 5.3.2, or other means (e.g. a contactor switched off by a controlcircuit). 5.4.3 Where such other means are used, a single failure of any ofits components shall not result in an inadvertent or unexpectedstart-up. 5.4.4 Such other means shall be employed only for situations thatinclude:

− routine exchange of parts, fixtures and tools requiring nosignificant dismantling of the machine;

− work on the electrical equipment where all of the followingconditions exist:

• there is no hazard arising from electric shock (see clause 6and burn;

• the switching off means cannot be negated by the work;• the work is of a minor nature (e.g. replacement of plug-in

devices without disturbing existing wiring).

5.5 Devices for disconnecting electrical equipment 5.5.1 Devices shall be provided for disconnecting (isolating)electrical equipment to enable work to be carried out performedwithout a risk from electric shock or burn.

5.5.2 The supply circuit disconnecting device (see 5.3) shall bepermitted to fulfil l this requirement where there is no need forisolating individual portions of the electrical circuit . 5.5.3 However, where it is expected that it will be necessary towork on the electrical equipment of separately operable parts of amachine, a disconnecting means shall be permitted for theelectrical equipment of each such part of the machine requiringseparate isolation. 5.5.4 The following devices shall be permitted to fulfill thisisolating function:_devices described in 5.3.2;_a manual motor controller suitable for motor disconnecting andcomplying with UL 508 where located on the load side of the lastshort circuit protective device (in the branch), and_a redundantly monitored, remotely operated contactor isolatingsystem incorporating control lockout provisions, and listed forisolation purposes. 5.5.5 Such devices shall be:

− readily accessible;− within sight of the part of the machine requiring isolation;− readily identifiable, and− for other than attachment plugs, provided with

permanent means for locking in the “Off” position only.

To be placed in an annex:

FPN to 5.1.1: For large complex machinery comprising a numberof widely-spaced machines working together in acoordinated manner, there may be a need for more than


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one incoming supply circuit depending upon the sitesupply circuit arrangements (see 5.3.1).

COMMITTEE STATEMENT: 1) Add the word "circuit" after theword "supply" throughout Clause 5 where appropriate to clarifythat the term "supply" actually means "circuit supply." 2) Remove 5.1.2 since it is outside the scope of the document. 3) Move phrase "shall be permitted" to follow "disconnectingmeans" to improve clarity. 4) Editorially revise the first sentence of 5.1.3 to be consistentwith previous change to 5.1.2. 5) Revised note following 5.2 to be more user friendly. 6) The editorial revision to 5.3.1.3 adds clarity to therequirement. 7) Separate first sentence of 5.3.1.4 into two sentence for clarity. 8) Add a new bullet to 5.3.3.3 to include text inadvertentlyomitted text from NFPA 79-1997, sub clause 7.11. 9) Revise "are not required" to "shall not be required" in 5.3.5.1to comply with the NFPA Manual of Style. 10) In 5.3.5.4 and elsewhere make the note into completesentences to comply with the NFPA Manual of Style. 11) Change "carry out" to "performed" in 5.5.1. 12) NFPA 79-1997, 7.8.1, last sentence "Space shall bedetermined by maximum wire size of incoming lines or bymaximum capacity of line lugs on the disconnecting means" wasadded to 5.3.1.4 because it was an inadvertent omission. 13) In 5.5.3, delete the first instance of the phrase "… theelectrical equipment of …" This will clarify the intent of thesection. 14) Add a new bullet to 5.3.4.2 to clarify that access to theoperating handle should not be impeeded by the enclosure door.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DEFELICE: The wording of the fourth bullet item of 5.3.5.1"Excepted circuits" (see committee action) is vague and can easilybe misinterpreted to allow many or even all of the electricalcircuits of a machine to remain energized when the main supplycircuit disconnecting means is opened. The result is that the riskof injury when troubleshooting is greatly increased. In its present form, the fourth bullet item can lead to unsafeworking conditions for maintenance personnel and enforcementdifficulties for the authority having jurisdiction. This item shouldbe deleted or modified.COMMENT ON AFFIRMATIVE: ANDERSON: In the committee statement Point # 2 "Remove5.1.2 since it is outside the scope of the document" I believe thecommittee has inadvertently over looked the situation in which thesupply conductors are routed though the control enclosure to theincoming supply circuit conductor terminations, rather thandirectly in the top of the enclosure directly to the disconnectingdevices terminations. If the incoming supply cable is not isolatedin a separate conduit or raceway then it would become a powercircuit within the control cabinet that may remain energized whenthe cabinet's main disconnecting means is in the off position. Theincoming supply circuit is not included as an excepted circuit[5.3.5], and consistent provisions to identify the incoming supplycables as a potential hazard during maintenance work within thecabinet are not in place in the proposed standard. Keeping 5.1.2would provide a way to manage this hazard without placing anundue burden on the equipment manufacture because the wireway within the enclosure could be something as simple a apiece ofnon-metallic flex tubing. 5.1.2 Unless and attachment plug is provided with the machinefor the connection to the supply (see 5.3.2 item f), the supplyconductors shall be contained in their own separate conduit orraceway and shall be terminated at the supply disconnectingmeans. DOBROWSKY: 5.3.2 An exception should be added as follows: "Exception: Listed attachment plugs shall be permitted to beused in accordance with their ratings." Another option is to revise (f) as follows: "(f) an a listed attachment plug and receptacle (plug/socketcombination) for cord connection to motor loads totaling 2hp orless. Reason: Listed products are readily available that exceed 2hpratings and should be permitted to be used according to theirratings. FISHER: Through the door disconnect handles are presentlyapplied in many applications. NEMA feels that the committee hasadded requirements in the last bulleted item in 5.3.3.1 (- be

operable, by qualified persons, independent of the door positionwithout the use of accessory tools or devices) that were notsubstantiated in the proposal. MONTEITH: Clause 5.3.4.2 - It is confusing and leave openinterpretation to the type of disconnects that can be used.Proposal 79-39 (Log #122) suggests a clarification that could bereworded to state "a secondary handle attached to the shaft of thedisconnect device shall be permitted that can be operated whenthe door is in the open position provided it can be locked in theOFF (open) position when the door is open." PADGETT: Clause 5.3.4.2 It is confusing and leaves openinterpretation to the type of disconnects that can be used.Proposal 79-39 (Log #122) suggests a clarification that could bereworded to state "a secondary handle attached to the shaft of thedisconnect device shall be permitted that can be operated whenthe door is in the open position provided it can be locked in theOff (open) position when the door is open." WITHROW: COMMITTEE STATEMENT: 14) Add a new bulletto 5.3.4.2 to clarify that access to the operating handle should notbe impeded by the enclosure door. After adding the new bullet, the subclause reads as follows: 5.3.4.2 An operating handle of the disconnecting means shall: - be readily accessible with doors in the open or closed position; - maintain the environmental rating of the enclosure; - not be restricted by the enclosure door when the door is in theopen position. COMMENT: The third bullet is the Committee proposal andappears to be included in the first bullet. Clarify the intent of thethird bullet.

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(Log #3079- 34 - (7.2.1(b) [5.3.2]): AcceptSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Revise text as follows: b) a listed , branch circuit rated, molded case circuit breaker;SUBSTANTIATION: The added words will clarify for the publicthe use of UL489 branch rated rated circuit breakers versus UL1077supplementary protectors (circuit breakers). UL489 CircuitBreakers are tested and rated for branch circuit switching and canbe used for this purpose. UL1077 Supplementary protectors arenot tested and rated for branch circuit switching and cannot beused for this purpose. The devices are very similar in physicalappearance, thus leaving an opening for possible misapplication.The additional words will clarify, for the public, the proper deviceto select.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal modifies the Committee Action on Proposal 79-33(Log #59), in subclause 5.3.2(b). The committee understands thatthe remainder of 5.3.2 remains unchanged.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: ANDERSON: The attempt in using the "branch circuit rated"requirement is to clarify that supplementary protection devices arenot to be considered for use in a supply circuit, disconnectingapplications. The proposed modification is to add the term"branch circuit rated", however this "rated" requirement is notdirectly defined. Defined terminology needs to be found andapplied, e.g. " suitable for branch circuit over current protection".

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(Log #14279- 35 - (7.8.2 [5.3.1.6]): AcceptSUBMITTER: Wilson Benosa , Applied MaterialsRECOMMENDATION: Revise as follows: "Where two or more disconnecting means are provided withinthe control enclosure for multiple supply circuits, they shall begrouped in one location where practicable ."SUBSTANTIATION: Some semiconductor wafer manufacturingtools we build use external uninterruptible power supply (UPS)units (ranging from 15 to 30 amperes/120 or 208 volts.) For agiven tool, UPS ungrounded conductor/s are terminated in 1- or2-pole DIN rail-mounted circuit breaker within the controlenclosure. This circuit breaker serves as disconnect for the UPSsupply circuit. The disconnecting means for the normal power istypically a 400-600A 3-pole molded case circuit breaker. With twodisconnecting means that are extremely different in size, it is not


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practical to mount them in one location as required in thissubclause. Also, the two circuit breaker disconnects are notintended to be interlocked.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal modifies the Action on Proposal 79-33 (Log #59), insubclause 5.3.1.6. The committee understands that the remainderof 5.3.1.6 remains unchanged.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: The phrase "where practicable" is necessary inthis case.

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(Log #69)79- 36 - (7.9.5(New) [ 6.2.3]): Accept in Principle in PartSUBMITTER: Gordon T. Davis , Moeller Electric Corp.RECOMMENDATION: Add new text to read as follows: "A device or tool as specified by the manufacturer of the interlockmay permit skilled persons to defeat the interlock provided that - it is possible at all times while the interlock is defeated to openthe disconnecting means and - on closing the door the interlock is automatically restored. The operation of the disconnecting means shall only beperformed using tools or devices provided or specified by themanufacturer of the disconnecting means. For operators thatremain with the door when the door is open, a disconnectingmeans shall have a secondary operator provided or specified by themanufacturer."SUBSTANTIATION: This proposal is based on the wordingfound in IEC 60204-1. It sets a standard for the disconnectingmeans in panels in which work must be performed with the paneldoor open and the disconnecting means energized. It indicatesthat when the panel door is open, the disconnecting means mustbe operable and able to deenergize the assembly. Locking thedisconnecting means in the energized position with the door openwould be prohibited. It emphasizes that only skilled personnelshould work on any live equipment. The proposal specifically prohibits the unsafe practice of usingtools unspecified by the manufacturer with the disconnectingmeans. The proposal allows for presently available designs ofdisconnecting means and it gives the user a choice of devicesbased on risk assessment per ANSI B11.COMMITTEE ACTION: Accept in Principle in Part.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-25 (Log #68) [Clause 6] in 6.2.3.2. Thecommittee believes that this text meets the intent of the submitterin part and in principle. The word "may" was changed to shall be permitted to follow theNFPA Manual of Style. The term Qualified persons is a definedterm from Clause 3. The committee rejected the remainder of theproposed text because the language is more appropriate for a workpractice standard. The committee understands that all action fromthis proposal is already incorporated in Proposal 79-25 (Log #68)[Clause 6].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #74)79- 37 - (7.9.5 (New) [6.2.3.6]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in the rewrite of 1997 NFPA 79Clause 6, that is new Clause 6 in 6.2.3.6 as proposed below. Change in bullet (c) of the second paragraph the word "to"following the words "direct contact" to the word "with." Sentenceto read "...direct contact with live parts..." In the same sentence, delete the words "with the test finger"located at the end of the sentence.SUBSTANTIATION: The first change adds clarity to thesentence. The reference to the use of a test finger is too restrictive indenoting the only means of test.COMMITTEE ACTION: Reject.

COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-27 (Log #73).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Compliance may be determined by inspectionor where appropriate, use of the test finger.The size and shape ofthe test finger is described in exact detail such that thedetermination can usually be made without actually owning orapplying the test finger.

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(Log #7079- 38 - (7.9.5 Note (New) [5.3]): RejectSUBMITTER: Gordon T. Davis , Moeller Electric Corp.RECOMMENDATION: Add new Fine Print Note to read asfollows: "OSHA requires that each installation have suitable existent safetyprocedures for any work performed with panel door open."SUBSTANTIATION: Because of the dangers of work with thepanel door open there is a need for users to be reminded ofOSHA requirements. There is also a need for the authority havingjurisdiction to ascertain the existence of the safety procedures.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: OSHA regulations do notnecessarily apply to all locations where industrial machines areused. Users should refer to NFPA 70E for the correct applicationsof work practices.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: If this submitter referenced OSHA rather thenNFPA 70E maybe a fine print note saying "See NFPA 70E foradditional information on work practices".

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(Log #12279- 39 - (7.10.1 [5.3.4.2]): Accept in PrincipleSUBMITTER: Richard Graham, Bridgeport MachinesLimited/Rep. CECIMO (European Committee for Co-operation ofthe Machine Tool IndustriesRECOMMENDATION: Add the same wording as proposed by thecommittee in the new 5.3.4.2 and add the following: Note - The disconnect may have more than one operatinghandle. The main one that is fixed to the door and a secondaryone that is attached to the shaft of the disconnect device that canbe operated when the door is in the open position.SUBSTANTIATION: The secondary handle will indicate theposition of the contacts of the disconnect. The proposal will allowmanufacturers to develop a solution to the revised clause withoutmajor changes to the enclosure and disconnect switch that theproposal would demand if it remains unaltered.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-41 (Log #31) and 79-33 (Log #59).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KIIHR: See my Explanation of Negative on Proposal 79-41(Log #31). This proposal (79-39) was Accepted in Principle basedupon the Committee Action on 79-41. I am essentially votingagainst the acceptance of Proposal 79-41.COMMENT ON AFFIRMATIVE: MONTEITH: See my Comment on Affirmative for Proposal 79-33 (Log #59). PADGETT: See my Comment on Affirmative for Proposal 79-33(Log #59).

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(Log #12679- 40 - (7.10.1 [5.3.4.2]): Accept in PrincipleSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Revise text to read as follows:


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7.10.1 The operating handle of the disconnecting means shall bereadily accessible and in control of the disconnect at all times,irregardless of enclosure door being in the open position. SUBSTANTIATION: The concern is the ability to control thedisconnect switch to the open position (off) from the operatinghandle while the door is in the open position. Furthermore, toprevent the door hinge from being located on the same side of theenclosure as the operator handle creating a barrier between theenclosure opening and the switch while the door is opened. Theadded text addresses these concerns.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-41 (Log #31) and 79-33 (Log #59).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KIIHR: See my Explanation of Negative on Proposal 79-41 (Log#31). This proposal (79-40) was Accepted in Principle basedupon the Committee Action on 79-41. I am essentially votingagainst the acceptance of Proposal 79-41.

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(Log #31)79- 41 - (7.10.1 Exception [5.3.4.2]): Accept in PrincipleSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Add the following Exception to thebottom of proposed Section 5.3.4.2: Exception: A disconnect with a handle mounted on the paneldoor shall be considered to meet these requirements provided itcomplies with all the following: - an additional internal operating handle is supplied whichremains in contact with the switch operating mechanism at alltimes - the internal operating handle is lockable in the open (OFF)positionSUBSTANTIATION: This added exception will allow the use ofrotary disconnects with through the door handles only under theconditions stated in the exception. With this setup all therequirements are met in the proposed section 5.3.4.2 as follows:- With the door closed the external (door mounted handle) will beaccessible and with the door open the internal handle will beaccessible.- With the door closed the external (door mounted handle) will bein control of the operating mechanism of the switch and with thedoor open the internal handle will be in control of the operatingmechanism.- The environmental rating can be maintained with the externalhandle In addition the requirements of proposed NFPA 79-2002subclause 6.2.3.2 can be met:- With the lockable handle being locked out a deliberate actionwill be required to operate the disconnect- The switch is not operable until the door is fully closed. Theshaft has to be inserted a certain distance into the door mountedhandle before the switch is operable and this will only be achievedwhen the door is fully closed.COMMITTEE ACTION: Accept in Principle. 1. Delete the second listed item of 5.3.4.2, 2. Add another listed item to 5.3.3.1 with text as follows:"be operable, by qualified persons, independent of the doorposition without the use of accessory tools or devices", 3. Add the following text to the end of the first sentence of thethird listed item of 5.3.3.1: "independent of the door position".COMMITTEE STATEMENT: he action of this proposal hasalready been incorporated into Proposal 79-33 (Log #59) and thisaction meets the intent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KIIHR: I vote against the Accept in Principle of this proposal forthe following reasons: 1. I am strongly opposed to the removal of the second listed itemof 5.3.4.2, which states that "an operating handle of thedisconnecting means shall: - be engaged with the operatingmechanism of the disconnecting means at all times".

2. Of particular concern is the use of rotary, through the doortype disconnects. The use of these types of disconnects results inthe possibility of a serious, possibly even fatal, accident. Thepossible situation is one in which a service technician locks out themachine and begins to perform this task. Meanwhile, anothertechnician, opens the control enclosure door, thus removing thefirst technicians lock from the operating mechanism of thedisconnect. The machine could now potentially be restartedwithout the knowledge of the first technician, who assumes that themachine is still locked out. 3. The solution which was presented in the original proposal toalleviate this problem was to require a "a additional internaloperating handle which remains in contact with the switchoperating mechanism at all times". This solution was not includedas part of the Accept in Principle. 4. Therefore, the original substantiation for proposal 79-41which states "with the door closed the external (door mountedhandle) will be accessible and with the door open the internalhandle will be accessible" is no longer applicable. Without theinclusion of a requirement for this second handle, thesubstantiation given for this proposal, no longer supports itsacceptance.

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(Log #12379- 42 - (7.10 [5.3.4.2]): Accept in PrincipleSUBMITTER: Richard Graham, Bridgeport MachinesLimited/Rep. CECIMO (European Committee for Co-operation ofthe Machine Tool IndustriesRECOMMENDATION: Retain current text.SUBSTANTIATION: The proposal of the NFPA 79 committee inthe new 5.3.4.2 will result in many manufacturers having toredesign the electrical enclosure interlocking aspect of themachine at considerable cost. The new clause will reducedrastically the amount of rotary through the door disconnectdevices that could be used and that would still satisfy the proposedclause. The rotary through the door devices can be consideredstate of the art considering the amount of manufacturers usingthem as could be seen at recent trade fairs in the USA and Europe.These devices and their associated implementation have anexcellent track record. Forcing manufacturers to source either adifferent rotary or a new flange mount disconnect will add to thecost of every machine tool. I have never witnessed any supportingdata to rule the current practice unsafe.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-41 (Log #31) and 79-33 (Log #59).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KIIHR: See my Explanation of Negative on Proposal 79-41 (Log#31). This proposal (79-42) was Accepted in Principle basedupon the Committee Action on 79-41. I am essentially votingagainst the acceptance of Proposal 79-41.

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(Log #7279- 43 - (7.10.1 [5.3.4.2]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Delete from the rewrite of 1997 NFPA 79that is Clause 5, sub clause 5.3.4.2, the second bullet that reads "-be engaged with the ...".SUBSTANTIATION: There is no requirement for the provisionof the proposed second bullet in the current edition (1997) ofNFPA 79, or in the current edition (2000) of the InternationalStandard 60204-1 entitled Safety of Machinery - ElectricalEquipment of Machines. Nor does there appear to be credibleevidence that this provision would improve the safety of theindustrial machinery.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-41 (Log #31) and 79-33 (Log #59).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 Norman


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EXPLANATION OF NEGATIVE: KIIHR: See my Explanation of Negative on Proposal 79-41 (Log#31). This proposal (79-43) was Accepted in Priciple based uponthe Committee Action on 79-41. I am essentially voting against theacceptance of Proposal 79-41.

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(Log #45)79- 44 - (Clause 8 [new Clause 7]): Accept in PrincipleSUBMITTER: Jim Carroll , Nashville, TNRECOMMENDATION: Revise text as follows:

7 Protection of equipment

7.1 GeneralThis clause details the measures to be taken to protect equipmentagainst the effects of:

• overcurrent arising from a short circuit;• overload currents;• ground faults;• overvoltages due to lightning and switching

surges;• abnormal temperatures;• loss of or reduction in the supply voltage;• overspeed of machines/machine elements;• incorrect phase sequence

7.2 Overcurrent protection 7.2.1 General Overcurrent protection shall be provided where the current in amachine circuit can exceed either the rating of any component orthe current carrying capacity of the conductors, whichever is thelesser value. The ratings or settings to be used are detailed in7.2.10. 7.2.2 Supply conductors Unless otherwise specified by the user, the supplier of theelectrical equipment shall not be responsible for providing theovercurrent protective device for the supply conductors to theelectrical equipment. The supplier of the electrical equipment shall state on theinstallation diagram the data necessary for selecting thisovercurrent protective device (see 7.2.10 and 18.5) NOTE—The size and overcurrent protection of the supply conductors toa machine are covered by NFPA 70, Article 670. 7.2.3 Power circuits (feeder & branch circuits) Devices for detection and interruption of overcurrent, selected inaccordance with 7.2.10, shall be applied to each ungroundedphase conductor. 7.2.4 Control circuits A control circuit tapped from the load side of the branch-circuitshort-circuit and ground-fault protective device(s) and functioningto control the load(s) connected to that branch circuit shall beprotected against overcurrent in accordance with this subclause.Such a tapped control circuit shall not be considered to be abranch circuit and shall be permitted to be protected by either asupplementary or branch-circuit overcurrent protective device(s). 7.2.4.1 Conductor protection 7.2.4.1.1 Conductors larger than AWG No. 14 shall be protectedagainst overcurrent in accordance with their ampacities. See Table310-16 of NFPA70 for conductor ampacities. 7.2.4.1.2 Conductors sizes of AWG 18, 16, and 14 shall beconsidered as protected by an overcurrent device(s) of not morethan 20 amperes rating. 7.2.4.1.3 Conductors that do not extend beyond the controlcabinet enclosure shall be considered protected by the loadbranch-circuit short-circuit and ground-fault protective device(s)where the rating of the protective device(s) is not more than 400percent of the ampacity of the control circuit conductor forconductors AWG No. 14 and larger, or not more than 25 amperesfor AWG No. 18 and 40 amperes for AWG No. 16.

7.2.4.1.4 Conductors of AWG No. 14 and larger that extendbeyond the enclosure shall be considered protected by the loadbranch-circuit short-circuit and ground-fault protective device(s)where the rating of the protective device(s) is not more than 300percent of the ampacity of the control circuit conductors. 7.2.4.1.5 Conductors supplied by the secondary side of a single-phase transformer having a 2-wire (single-voltage) secondary shallbe considered protected by overcurrent protection provided on theprimary (supply) side of the transformer, provided this protectionis in accordance with 7.2.7 and does not exceed the valuedetermined by multiplying the secondary conductor ampacity bythe secondary-to-primary voltage ratio. Transformer secondaryconductors (other than 2-wire) are not considered to be protectedby the primary overcurrent protection. 7.2.4.1.6 Conductors of control circuits shall be consideredprotected by the motor branch-circuit short-circuit and ground-fault protective device(s) where the opening of the control circuitwould create a hazard as, for example, the control circuit of amagnetic chuck and the like. 7.2.5 Receptacle outlets and their associated conductors Overcurrent protection shall be provided for the circuits feedinggeneral purpose receptacle outlets intended primarily forsupplying power to maintenance equipment. Overcurrent protective devices shall be provided in theungrounded phase conductors of each circuit feeding receptacleoutlets. Overcurrent protection for these socket outlets shall notexceed 15 amps. 7.2.6 Lighting circuits Overcurrent protection for lighting branch circuits shall notexceed 15 amperes. 7.2.7 Transformers Transformers for Motor Control Circuits shall be protected inaccordance with NFPA70 Article 430-Part F; Transformers forother than Motor Control Circuits shall be protected inaccordance with NFPA70 Article 450-Part A. 7.2.8 Location of overcurrent protective devices An overcurrent protective device shall be located at the pointwhere the conductor to be protected is connected to the supplyexcept (a) Overcurrent protection at the supply shall not be required ifall of the following conditions are met:

− the current carrying capacity of the conductor s is at leastequal to that required for the load;

− each connecting conductor to the overcurrent protectivedevices is no longer than 3 m (9.9 ft.)and ;

− the conductor is suitably protected from physicaldamage;

− the conductor does not extend beyond the control panelenclosure;

− the conductor terminates in a splitter block, singlecircuit breaker or set of fuses.

(b) Overcurrent protection at the supply shall not be required ifall of the following conditions are met:

− the conductor has an ampacity of at least one-third(1/3) that of the conductor from which it is supplied;


− the conductor is not over 25 ft. (7.62 m) long and theconductor terminates in a single circuit breaker or set offuses.

7.2.9 Overcurrent protective devicesThe short-circuit interrupting rating shall be at least equal to theavailable fault current at the point of application. Where theshort-circuit current to an overcurrent protective device caninclude additional currents other than from the supply (e.g. frommotors, from power factor correction capacitors), these shall betaken into consideration.Class H fuses, and devices that will accept Class H fuses, shall notbe used.

7.2.10 Rating and setting of overcurrent protective devices


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7.2.10.1 Each motor controller and its associated wiring shall beprotected as an individual branch circuit by a short-circuitprotective device (SCPD) as specified by the controllermanufacturer. The maximum rating of the designated SCPD shallbe as shown in Table 1.Exception: Table 1 shall not apply to Design E motor circuits. Theprovisions of NFPA 70 shall be observed for Design E motor circuits.

7.2.10.2 Several motors each not exceeding 1 horsepower in ratingshall be permitted on a nominal 120-volt branch circuit protected at notover 20 amperes or a branch circuit of 600 volts, nominal, or less,protected at not over 15 amperes, where all of the following conditionsare met:

a. The full-load rating of each motor does not exceed 6amperes.

b. The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is notexceeded.

c. Individual overload protection conforms to 7.3.

Table 1 Fuse and circuit breaker selection: motor, motorbranch circuit, and motor controller

Maximum setting or rating1

(Fuse and circuit breaker)

Percentage of Full-Load Current

Fuse class with time delay3 Type 2 of ApplicationAC–2 AC–3 AC–4

RK–54 150 175 175RK–1 150 175 175J 150 175 225CC 150 300 300Instantaneous trip C/B5 800 800 800Inverse trip C/B6 150 250 250

NOTES (to Table 1):1. Where the values determined by Table 1 do not correspond to

the standard sizes or ratings, the next higher standard size,rating, or possible setting shall be permitted.

2) Types: --AC-2: Slip-ring motors starting, switching off, or all light-startingduty motors. --AC-3: Squirrel-cage motors; starting, switching off whilerunning, occasional inching, joging, or plugging but not to exceed5 operations per minute or 10 operations per 10 minutes. All wye-delta and two-step auto-transformer starting, or all mediumstarting duty motors. --AC-4: Squirrel-cage motors; starting, plugging, inching, jogging,or all heavy starting duty motors.

3) Where the rating of a time delay fuse (other than CC type)specified by the table is not sufficient for the starting of the motor,it shall be permitted to be increased but shall in no case bepermitted to exceed 225 percent. The rating of a time-delay ClassCC fuse shall be permitted to be increased but shall in no caseexceed 400 percent of the full-load current.

4) Class RK-5 fuses shall be used only with NEMA rated motorcontrollers.Exception: Motor controllers listed for use with RK5 fuses.

5) Magnetic only circuit breakers are limited to single motorapplications. These instantaneous trip circuit breakers shall onlybe used if they are adjustable, if part of a combination controllerhaving motor-running and also short-circuit and ground-faultprotection in each conductor, and if the combination is especiallyidentified for use, and it is installed per any instructions includedin its listing or labeling. Circuit breakers with adjustable tripsettings shall be set at the controller manufacturer'srecommendation, but not greater than 1300 percent of the motorfull-load current.

6) Where the rating of an inverse time circuit breaker specified inthe table is not sufficient for the starting current of the motor, itshall be permitted to be increased but in no case exceed: a. 400 percent for full-load currents of 100 amperes or less or

b. 300 percent for full-load currents greater than 100 amperes.NOTE: IEC 947-4 defines the terms Type 1 and Type 2 coordinatedprotection as follows: --Type 1 Protection: Under short-circuit conditions the contactoror starter may not be suitable for further use without repair orreplacement. -- Type 2 Protection: Under short-circuit conditions the contactoror starter shall be suitable for further use. The maximum allowable values in Table 1 do not guarantee Type2 protection. Type 2 protection is recommended for use inapplications where enhanced performance and reliability arerequired.

7.2.10.3 Where the branch-circuit and short-circuit and ground-fault protective device is selected not to exceed that allowed by7.2.10.1 for the motor of the smallest rating, two or more motorsor one or more motors and other load(s), with each motor havingindividual overload protection, shall be permitted to be connectedto a branch circuit where it can be determined that the branch-circuit short-circuit and ground-fault protective device will notopen under the most severe normal conditions of service thatmight be encountered.

7.2.10.4 Two or more motors and their control equipment shallbe permitted to be connected to a single branch-circuit whereshort-circuit and ground-fault protection is provided by a singleinverse-time circuit breaker or a single set of fuses, provided bothof the following conditions are met:

a) Each motor controller and overload device is listed (seeANSI/NFPA 70, Article 100, Listed) for group installation withspecified short-circuit current ratings.

NOTE: The short-circuit current rating includes: 1) The class and rating of the short-circuit protective device. 2) The maximum nominal application voltage. 3) The maximum available fault current.

b) The rating or setting of the overcurrent device does notexceed the values in Table 2 for the smallest conductor in thecircuit.

Table 2 – Relationship between conductor size and maximumrating or setting of short–circuit protective device for power

circuits

Conductor size(AWG)

Max. ratingNon-time delay fuse

or inverse timecircuit breaker in

Amperes

Time delay ordual element fuse

inAmperes

1412108643210

2/03/04/0

6080100150200250300350400500600700800

30405080100125150175200250300350400

7.2.11 Resistance heating branch circuit overcurrent protectionIf the branch circuit supplies a single nonmotor-operated loadrated at 16.7 amperes or more, the overcurrent device rating shallnot exceed 150 percent of the load rating.

Equipment employing resistance-type heating elements rated atmore than 48 amperes shall have the heating elements subdivided.Each subdivided load shall not exceed 48 amperes and shall beprotected at not more than 60 amperes.

EXCEPTIONA single sheath-type heating element requiringmore than 48 amperes shall be protected at not more than 125percent of the load where the element is integral with andenclosed within the machine housing.

The supplementary overcurrent protective devices shall be: (1)installed within or on the machinery or provided as a separate


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assembly; and (2) accessible but need not be readily accessible;and (3) suitable for branch-circuit protection.

The main conductors supplying these overcurrent protectivedevices shall be considered branch-circuit conductors.

7.3 Overload protection of motors

7.3.1 Overload Protection RequirementsOverload devices shall be provided to protect each motor, motorcontroller, and branch-circuit conductor against excessive heatingdue to motor overloads or failure to start.

Motor overload protection shall be provided as follows:11 Motors in accordance with NFPA 70, National Electrical

Code, Article 430, Part C.12 Adjustable speed drives (electronic drives) in

accordance with NFPA 70, National Electrical Code,Article 430-2.

7.3.2 ResettingResetting of the overload device shall not restart the motor.Exception: Where there is only a single motor of two horsepoweror less on the machine, an overload reset operator mounted onthe motor shall be permitted to restart the motor provided that thedistance between the overload reset operator and the machine startpushbutton operator is 12 in. (300 mm) or less, and a suitablewarning label is attached on or adjacent to the overload resetoperator.

7.3.3 Number of overloadsThe minimum number and location of running overcurrent unitsshall be determined from Table 3.

Table 3 – Running overcurrent units

Kind of motor Supply systems

Number and location ofovercurrent units (such astrip coils, relays, orthermal cutouts)

1–phase, ac ordc

2–wire, 1–phase ac ordc ungrounded

1 in either conductor

1–phase, ac ordc

2–wire, 1–phase ac ordc, one conductorgrounded

1 in ungroundedconductor

1–phase, ac ordc

3–wire, 1–phase ac ordc, grounded neutral

1 in either ungroundedconductor

3–phase, ac Any 3–phase * 3, one in each phase

* Exception: Unless protected by other approved means.

NOTE: For 2–phase power supply systems see ANSI NFPA 70,Section 430–37.

Sort-time rated motors or high-reversing duty motors that cannotbe adequately protected by external overload devices shall beprotected by a thermal device mounted in the motor and sensitiveto the temperature of the motor, or to both motor temperatureand current.

Motors that are an integral part of a refrigeration compressor ofthe hermetic or semihermetic type shall be protected per thecompressor manufacturer's recommendations.

7.4 Abnormal temperature protectionResistance heating or other circuits that are capable of attaining orcausing abnormal temperatures and therefore can cause ahazardous condition shall be provided with suitable detection toinitiate an appropriate control response. An example could be aresistance-heating circuit that is short-time rated or which loses itscooling medium.

2.2 Protection against supply interruption or voltagereduction and subsequent restoration

7.5.1 GeneralWhere a supply interruption or a voltage reduction can cause ahazardous condition, damage to the machine, or to the work inprogress, undervoltage protection shall be provided (e.g. to switchoff the machine) at a predetermined voltage level.

7.5.2 Undervoltage ProtectionWhere the operation of the machine can allow for an interruptionor a reduction of the voltage for a short time period, delayedundervoltage protection shall be permitted to be provided. Theoperation of the undervoltage device shall not impair theoperation of any stopping control of the machine.

7.5.3 RestartingUpon restoration of the voltage or upon switching on theincoming supply, automatic or unintentional restarting of themachine shall be prevented when such a restart can cause ahazardous condition.

Where only a part of the machine or of the group of machinesworking together in a coordinated manner is affected by thevoltage reduction or supply interruption, the undervoltageprotection shall initiate appropriate control responses to ensureco-ordination.

7.6 Motor overspeed protectionUnless the inherent characteristics of the motor or the controller,or both, are such as to limit the speed adequately, drive systemsmotors shall include protection against motor overspeed.

Overspeed protection means include, but are not necessarilylimited to, the following:

1. A mechanical overspeed device incorporated in the drive toremove armature voltage on motor overspeed.

2. An electrical overspeed detector that will remove armaturevoltage on motor overspeed.3. Field loss detection to remove armature voltage upon the lossof field current.4. Voltage-limiting speed-regulated drives that operate withconstant full field. In this case, protection is obtained individuallyfor the loss of field or tachometer feedback; however, protectionagainst simultaneous loss of field and tachometer is not provided.

Equipment overspeed protection:Where the safe operating speed of the equipment is less than thatof the drive motor, means shall be provided to limit the speed ofthe equipment

7.7 This section left intentionally blank

7.8 Phase sequence protectionWhere a phase loss or an incorrect phase sequence of the supplyvoltage can cause a hazardous condition or damage to themachine, protection shall be provided.

NOTEConditions of use which may lead to an incorrect phasesequence include:

- a machine transferred from one supply toanother;

- a mobile machine with a facility forconnection to an external power supply

7.9 Protection against overvoltages due to lightning and toswitching surges

7.9.1 Protective devices shall be permitted to be provided toprotect against the effects of overvoltages due to lightning or toswitching surges.

7.9.2 Where provided, devices for the suppression of overvoltagesdue to lightning shall be connected to the incoming terminals ofthe supply disconnecting device.

7.9.3 Where provided, devices for the suppression of overvoltagesdue to switching surges shall be connected across the terminals ofall equipment requiring such protection.

7.10 Power factor correction capacitors

7.10.1 Where capacitors are installed for motor power factorcorrection on circuits of 600 volts, nominal, and under,overcurrent protection for the conductors shall be provided. See7.2.1 and 7.2.10.

Each capacitor cell or capacitor bank shall be protected againstrupture of the individual cells. Protection included as a part of thecapacitor assembly shall be permitted.


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H7.10.2 Discharge of Stored EnergyCapacitors shall be provided with a means of discharging storedenergy.(a) Time of Discharge. The residual voltage of a capacitor shall bereduced to 50 volts, nominal, or less, within 1 minute after thecapacitor is disconnected from the source of supply.(b) Means of Discharge. The discharge circuit shall be eitherpermanently connected to the terminals of the capacitor orcapacitor bank, or provided with automatic means of connecting itto the terminals of the capacitor bank on removal of voltage fromthe line. Manual means of switching or connecting the dischargecircuit shall not be used.

HClause 7.10.2 is a copy of the text in NFPA 70 Section 460-6 andshould be shown as “extracted text”

SUBSTANTIATION:Substantiation for Clause 7 – NFPA79-2002

Historical Background.In March of 1998, the NFPA 79 committee prepared a statement ofwork. The major elements of the statement of work are:Harmonization - PurposeAs the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation, andat the same time maintain the high standard of electrical machinesafety, the NFPA 79 committee has expressed their desire, throughballoted vote, to harmonize NFPA 79 with IEC-60204-1.Importance of Issue - HarmonizationToday's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true.Differing electrical standards add a large cost to multinationalmanufacturers as they build and sometimes move manufacturingfacilities.Harmonization - ObjectiveThis work is necessary to accomplish the goal of allowing industryto economically build one industrial machine capable of passing adetailed electrical safety inspection using either IEC 60204-1 orNFPA 79 standard.Both the NEC Technical Correlating Committee and the StandardsCouncil reviewed the statement of work in July of 1998. The TCCunanimously recommended the following action to the StandardsCouncil:"The Technical Correlating Committee agrees with the efforts ofthe NFPA 79 committee to harmonize the technical requirementsof NFPA 79 and IEC 60204, where feasible and where in concertwith the NEC and its related codes and standards." ResultThe NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committeeformed 20 Task Groups. Each Task Group was assigned oneproposed new clause.The Task Group compared NFPA-79-1997, Clause 8 with IEC60204-1 Clause 7. The Task Group presented its work to the entirecommittee on several occasions for review and comment. Thisproposal is a result of that work.The Task Group proposes to renumber Clause 8 of NFPA 79-1997to correspond with IEC 60204-1. The task group proposes thefollowing changes to further improve usability.

These new reference numbers are used as the base in thissubstantiation for understanding the concept and substantiatedchanges.

Clause 7Recommendation: Revise the general heading of NFPA79-1997clause 8 from “Protection” to “Protection of Equipment”.

Substantiation: The change is an editorial change forharmonization.

Clause 7.1 GeneralRecommendation: A new sub-clause was created to provide abulleted list of the general topics addressed in Clause 7.

Substantiation: Editorially added a list clarifying content for theusers of the standard.

Clause 7.2 Overcurrent protectionRecommendation: Create a general header for grouping ofovercurrent protection requirementsSubstantiation: Editorial reorganization for user clarity.

Clause 7.2.1 GeneralRecommendation: Add a new sub-clause outlining the generalrequirements for location and ratings of overcurrent devices.

Substantiation: Although this is a new sub-clause the requirementswere implied in many section of NFPA79-1997 and is considerededitorial. The new statement is in agreement with the requirementsin NFPA70-1999.

Clause 7.2.2 Supply conductorsRecommendation: Restate clause 8.2 of NFPA 79-1997 withoutreference to figures.

Substantiation: This clause editorially restates the requirements inNFPA79-1997 clause 8.2 without references to figures withoutchange to the requirements.

Clause 7.2.3 Power circuitsRecommendation: Restate clause 8.3 of NFPA 79-1997 withoutreference to figures. A reference to the subclause outlining theselection of overcurrent devices (7.2.10) has been added.

Substantiation: This clause editorially restates the requirements inNFPA79-1997 clause 8.3 without references to figures. A referenceto the subclause outlining the selection of overcurrent devices(7.2.10) making the remaining subclauses in NFPA79-1997 clause8.3 unnecessary.

Clause 7.2.4 Control circuitsRecommendation: Utilize information currently shown as clause8.9.1 in NFPA79-1997.

Substantiation: Renumbered to conform to the new format.

Clause 7.2.4.1 Conductor ProtectionRecommendation: Utilize information currently shown as clause8.9.2 in NFPA79-1997.


Clause 7.2.4.1.1Recommendation: Utilize the information currently shown as8.9.2.1 in NFPA79-1997 with the exception that the reference toTable 11 has been replace with a reference to Table 310-16 in theNEC.

Substantiation: The modifications to the text were made to avoidduplication plus avoid discrepancies in case of change with theparent document. Table 11 has also been deleted from the newdocument since it is no longer referenced in the text.

Clause 7.2.4.1.2Recommendation: Utilize information currently in 8.9.2.2 ofNFPA79-1997.


Clause 7.2.4.1.3Recommendation: Utilize the information currently in 8.9.2.2Exception No. 1 of NFPA79-1997 with the exception that theinformation has been converted to positive text rather than anexception.

Substantiation: Renumbered to conform to the new format plusrevise to positive test to comply with the style manual.



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Substantiation: Renumbered to conform to the new format plusrevise to positive test to comply with the style manual.Clause 7.2.5 Receptacle outlets and their associated conductorsRecommendation: Incorporate into this subclause the overcurrentprotection requirements for receptacles currently addressed in14.2.3 and 14.2.4 of NFPA79-1997.

Substantiation: Renumbered to conform to the new format

Clause 7.2.6 Lighting circuitsRecommendation: Utilize the information currently in 8.10 ofNFPA79-1997.


Clause 7.2.7 TransformersRecommendation: Replace the information currently in 8.11,8.11.1, 8.11.2, 8.12, 8.12.1, 8.12.3, 8.12.4 and the associated tablesof NFPA79-1997 by this subclause which references the appropriatetransformer overcurrent protection clauses in the NationalElectrical Code.

Substantiation: This change is intended as editorial since therequirements were identical. The change eliminates duplication ofinformation plus avoids future conflicts if a change is made to theparent document.

Clause 7.2.8 Location of overcurrent protective devicesRecommendation: Utilize the information currently in 8.4 ofNFPA79-1997 with the exception that the information has beenmodified to turn the exceptions into positive text. Additionally thelanguage of the requirements have been correlated with thelanguage in the NEC in Section 240-21(b)(1) and (2).

Substantiation: Renumbered to conform to the new format plusrevise to positive test to comply with the style manual. In additionthe requirements have been aligned with the requirements in theNEC.Clause 7.2.9 Overcurrent protective devicesRecommendation: The short-circuit interrupting ratingrequirements currently contained 8.1.2, 8.1.3, and 8.1.4 ofNFPA79-1997 have been separated from the other requirements inthose sections and include here as a single statement.

Substantiation: The re-write is considered as editorial as all devicesshall be suitable for use at the point of application.

Clause 7.2.10 Rating and setting of overcurrent protective devicesRecommendation: Modify the heading currently in 8.5 of NFPA79-1997 to better reflect the information contained in this clause.

Substantiation: Modified wording for user clarity.

Clause 7.2.10.1Recommendation: Utilize the information currently in 8.5.1 ofNFPA79-1997 plus the referenced table is the same as Table 1 ofNFPA79-1997.


Clause 7.2.10.2Recommendation: Utilize the information currently in 8.5.2 ofNFPA79-1997


Clause 7.2.10.3Recommendation: Utilize the information currently in 8.5.3 ofNFPA79-1997


Clause 7.2.10.4Recommendation: Utilize the information currently in 8.5.4 ofNFPA79-1997 plus Table 2 of NFPA79-1997.


Clause 7.2.11 Resistance heating branch circuit overcurrentprotectionRecommendation: The heading of current 8.8 in NFPA79-1997 wasexpanded to clarify the requirements in this subclause wereovercurrent protection requirements. Additionally the requirementcurrently in 8.8.1, 8.8.2, 8.8.3, and 8.8.4 of NFPA79-1997 arecombined into a single clause.

Substantiation. Renumber to conform to the new format pluseditorial changes.

Clause 7.3 Overload protection of motorsRecommendation: The title of current 8.6 of NFPA79-1997 wasexpanded to clarify the intent is overcurrent protection.Substantiation: Added words for user clarity

Clause 7.3.1 Overload protection requirementsRecommendation: Utilize the information currently in 8.6.1 and8.15 of NFPA79-1997


7.3.2 ResettingRecommendation: Utilize the information currently in 8.6.2 ofNFPA 79-1997


7.3.3Recommendation: Utilize the information currently in 8.6.3 ofNFPA79-1997 plus the associated Table 3 in NFPA79-1997.


Clause 7.4 Abnormal temperature protectionRecommendation: Add new text for abnormal temperatures.

Substantiation: To recognize the hazards associated withunprotected heat sources, requirements have been addedrequiring those elements and circuits to be protected.

Clause 7.5 Protection against supply interruption or voltagereduction and subsequent restoration

Recommendation: In order to recognize and give requirements foradditional supply interruption hazards, the title of clause 8.14 inNFPA79-1997 is to be expanded to include supply interruptions inaddition to voltage reductions.

Substantiation: The title is modified for user clarity.

Clause 7.5.1Recommendation: Add a general statement to clarify therequirements in this clause.Substantiation: The text is added for user clarity in explanation ofthe clause contents.

Clause 7.5.2Recommendation: Utilize the language in subclause 8.14.1 ofNFPA79-1997 with editorial modifications.

Substantiation: The clause has been editorially modified toharmonize with international and global requirements. Theprotection requirements are the same.

Clause 7.5.3 RestartingRecommendation: Utilize the language in subclause 8.14.2 ofNFPA79-1997 with editorial modifications.

Substantiation: The clause has been editorially modified toharmonize with international and global requirements. Theprotection requirements are the same.


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Clause7.6 Motor overspeed protectionRecommendation: Utilize the requirements in subclause 8.16 and8.17 of NFPA79-1997 but combine into a single clause.

Substantiation: Renumbered to conform to the new format.Changes are editorial only.

Clause 7.8 Phase sequence protectionRecommendation: Add new text concerning phase sequenceprotection.

Substantiation: It is recognized there are personnel and equipmenthazards associated with improper phase sequence with someelectrical operations. This subclause is added to providerequirements to protect against such hazards.

Clause 7.9 Protection against overvoltages due to lightning and toswitching surges.Recommendation: Add this clause and its subclauses of 7.9.1,7.9.2 and 7.9.3

Substantiation: These requirements are non-mandatory but whereovervoltage protection is utilized requirements are added toindicate the location of proper connections.

Improper connection of these device may lead to the desiredprotection being negated. To protect against this hazard theserequirements were added.

Clause 7.10 Power factor correction capacitorsRecommendation: Add this clause and its subclauses of 7.10.1 and7.10.2.

Substantiation: These requirements are non-mandatory but wherepower factor correction capacitors are utilized requirements forproper connection are necessary.

Capacitors without proper overcurrent protection and a means todischarge stored energy may constitute a fire or shock hazard.Requirements are added for proper connection.

Recommendation: Delete existing figures 1 and 2 shown in Clause8 of NFPA 79-1997.

Substantiation: Due to the re-organization of the material in thisclause Figures 1 and 2 in Clause 8 of NFPA79-1997 are no longernecessary and have been omitted from the new text.

CLAUSE NUMBERS: NFPA 79-1997 VERSUS PROPOSED NFPA 79-2002


Clause Heading Clause Heading

8 Protection 7 Protection of Equipment

8.1 Machine Circuits

8.1.1

8.1.2 7.1, 7.2.1, 7.2.9

8.1.3 7.2.9

8.1.4. 7.2.9

Figure 1 One line representation of electricalsystem power distribution

Figure 2 One line representation of electrical systempower protection

8.2 Supply conductors and machine overcurrentprotection

7.2.2

8.3 Branch circuit overcurrent protection 7.2.3

8.3.1

8.3.2

8.3.3


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8.4 Location of protective devices 7.2.8

8.5 Motor branch circuits

8.5.1 7.2.10.1

Table 1 Fuse and circuit breaker selection: motor,motor branch circuit, and motor controller

8.5.2 7.2.10.2

8.5.3 7.2.10.3

8.5.4 7.2.10.4

Table 2 Relationship between conductor size andmaximum rating or short-circuit protectivedevice for power circuits

8.6 Motor overload 7.3 Overload protection of motors

8.6.1 7.3.1 Overload Protection Requirements

8.6.2 7.3.2 Resetting

8.6.3 7.3.3 Number of overloads

Table 3 Running overcurrent units

8.6.4

8.7 Motor overload, special duty 7.3

8.7.1 7.3

8.7.2 7.3

8.8 Resistance heating branch circuits 7.2.11

8.8.1 7.2.11

8.8.2 7..2.11

8.8.3 7.2.11

8.8.4 7.2.11

8.9 Control circuit conductors 7.2.4

8.9.1 General 7.2.4

8.9.2 Conductor protection 7.2.4.1 Conductor Protection

8.9.2.1 7.2.4.1.1

8.9.2.2 7.2.4.1.2

8.9.2.2 ExcNo 1

7.2.4.1.3

8.9.2.2 ExcNo 2

7.2.4.1.4

8.9.2.2 ExcNo 3

7.2.4.1.5

8.9.2.2 ExcNo 4

7.2.4.1.6

8.10 Lighting branch circuits 7.2.6

8.11 Power transformer 7.2.7

8.11.1 Primary 7.2.7

8.11.2 Primary and secondary 7.2.7


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COMMITTEE ACTION: Accept in Principle.Revise text as follows:

7 Protection of equipment

7.1 General. This clause details the measures to be taken toprotect equipment against the effects of:

• overcurrent arising from a short circuit;• overload currents;• ground faults;• overvoltages due to lightning and switching surges;• abnormal temperatures;• loss of or reduction in the supply voltage;• overspeed of machines/machine elements;• incorrect phase sequence

7.2 Overcurrent protection 7.2.1 General. Overcurrent protection shall be provided where thecurrent in a machine circuit can exceed either the rating of anycomponent or the current carrying capacity of the conductors,whichever is the lesser value. The ratings or settings to be used aredetailed in 7.2.10. Note: Figures 1 and 2 show typical circuits acceptable for theprotection of current-carrying and current-consuming electricalmachine components. Protective interlocks are not shown. <insert Figure 1 and Figure 2 from NFPA 79-1997 here> 7.2.2 Supply conductors Unless otherwise specified by the user, the supplier of theelectrical equipment shall not be responsible for providing theovercurrent protective device for the supply conductors to theelectrical equipment. The supplier of the electrical equipment shall state on theinstallation diagram the data necessary for selecting thisovercurrent protective device (see 7.2.10 and 18.5) NOTE—The size and overcurrent protection of the supply conductors toa machine are covered by NFPA 70, Article 670.

7.2.3 Power circuits (feeder & branch circuits) Devices for detection and interruption of overcurrent, selected inaccordance with 7.2.10, shall be applied to each ungroundedphase conductor. Conductors shall be protected againstovercurrent in accordance with their ampacities as specified in13.5 . 7.2.4 Control circuits. A control circuit tapped from the load sideof the branch-circuit short-circuit and ground-fault protectivedevice(s) and functioning to control the load(s) connected to thatbranch circuit shall be protected against overcurrent inaccordance with this subclause. Such a tapped control circuit shallnot be considered to be a branch circuit and shall be permitted tobe protected by either a supplementary or branch-circuitovercurrent protective device(s). 7.2.4.1 Conductor protection 7.2.4.1.1 Conductors larger than AWG No. 14 , other than flexiblecords and fixture wires, shall be protected against overcurrent inaccordance with their ampacities as specified in 13.5, unlessotherwise permitted in 7.2.4.1.2 through 7.2.4.1.6. See Table 310-16 of NFPA70 for conductor ampacities. 7.2.4.1.2 Conductors sizes of AWG 18, 16, and 14 shall beconsidered as protected by an overcurrent device(s) of not morethan 20 amperes rating. 7.2.4.1.3 Conductors that do not extend beyond the controlcabinet enclosure shall be considered protected by the loadbranch-circuit short-circuit and ground-fault protective device(s)where the rating of the protective device(s) is not more than 400percent of the ampacity of the control circuit conductor forconductors AWG No. 14 and larger, or not more than 25 amperesfor AWG No. 18 and 40 amperes for AWG No. 16. 7.2.4.1.4 Conductors of AWG No. 14 and larger that extendbeyond the enclosure shall be considered protected by the loadbranch-circuit short-circuit and ground-fault protective device(s)where the rating of the protective device(s) is not more than 300percent of the ampacity of the control circuit conductors. 7.2.4.1.5 Conductors supplied by the secondary side of a single-phase transformer having a 2-wire (single-voltage) secondary shallbe considered protected by overcurrent protection provided on the

8.12 Control circuit transformer 7.2.7

8.12.1 7.2.7

Table 4 Control transformer overcurrent protection 7.2.7

Table 5 Control transformer overcurrent protection 7.2.7

8.12.2 7.2.4, 7.2.7

8.12.3 7.2.7

8.12.4 7.2.7

8.13 Common overcurrent device 7.7 ?

8.14 Undervoltage protection 7.5 Protection against supply interruptionvoltage reduction and subsequentrestoration.

8.14.1 7.5.2 Undervoltage Protection

8.14.2 7.5.3 Restarting

8.14.3 7.5 --

8.15 Adjustable-speed drive system 7.3 Overload protection of motors

8.16 Motor overspeed protection 7.6

8.17 Equipment overspeed protection 7.6


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primary (supply) side of the transformer, provided this protectionis in accordance with 7.2.7 and does not exceed the valuedetermined by multiplying the secondary conductor ampacity bythe secondary-to-primary voltage ratio. Transformer secondaryconductors (other than 2-wire) are not considered to be protectedby the primary overcurrent protection. 7.2.4.1.6 Conductors of control circuits shall be consideredprotected by the motor branch-circuit short-circuit and ground-fault protective device(s) where the opening of the control circuitwould create a hazard as, for example, the control circuit of amagnetic chuck and the like. 7.2.5 Receptacle (socket) outlets and their associated conductors Overcurrent protection shall be provided for the circuits feedinggeneral purpose receptacle (socket) outlets intended primarily forsupplying power to maintenance equipment. Overcurrent protective devices shall be provided in theungrounded phase conductors of each circuit feeding receptacle(socket) outlets. Overcurrent protection for these receptacle( socket ) outlets shall not exceed 15 amps. 7.2.6 Lighting circuits. Overcurrent protection for lighting branchcircuits shall not exceed 15 amperes. 7.2.7 Transformers. Transformers for Motor Control Circuits shallbe protected in accordance with NFPA70 Article 430-Part F;Transformers for other than Motor Control Circuits shall beprotected in accordance with NFPA70 Article 450-Part A. 7.2.8 Location of overcurrent protective devices. An overcurrentprotective device shall be located at the point where the conductorto be protected is connected to the supply except (a) Overcurrent protection at the supply shall not be required ifall of the following conditions are met:

− the current carrying capacity of the conductor s is at leastequal to that required for the load;

− each connecting conductor to the overcurrent protectivedevices is no longer than 3 m (9.9 ft.)and ;


− the conductor does not extend beyond the control panelenclosure;

− the conductor terminates in a splitter block, singlebranch circuit rated circuit breaker or set of fuses.

(b) Overcurrent protection at the supply shall not be required ifall of the following conditions are met:

− the conductor has an ampacity of at least one-third(1/3) that of the conductor from which it is supplied;


− the conductor is not over 25 ft. (7.62 m) long and theconductor terminates in a single circuit breaker or set offuses.

7.2.9 Overcurrent protective devices. The short-circuit interruptingrating shall be at least equal to the available fault current at thepoint of application. Where the short-circuit current to anovercurrent protective device can include additional currents otherthan from the supply (e.g. from motors, from power factorcorrection capacitors), these shall be taken into consideration.Class H fuses, and devices that will accept Class H fuses, shall notbe used.

7.2.10 Rating and setting of overcurrent protective devices

7.2.10.1 Each motor controller and its associated wiring shall beprotected as an individual branch circuit by a short-circuitprotective device (SCPD) as specified by the controllermanufacturer. The maximum rating of the designated SCPD shallbe as shown in Table 1.Exception: Table 1 shall not apply to Design E motor circuits. Theprovisions of NFPA 70 shall be observed for Design E motor circuits.

7.2.10.2 Several motors each not exceeding 1 horsepower in rating shallbe permitted on a nominal 120-volt branch cir cuit protected at not over

20 amperes or a branch circuit of 600 volts, nominal, or less, protectedat not over 15 amperes, where all of the following conditions are met:

a. The full-load rating of each motor does not exceed 6amperes.

b. The rating of the branch-circuit short-circuit and groundfault protective device marked on any of the controllers is noexceeded.

c. Individual overload protection conforms to 7.3.

Table 1

Fuse and circuit breaker selection: motor, motor branch circuitand motor controller

Maximum setting or rating1

(Fuse and circuit breaker)

Percentage of Full-LoadCurrent

Fuse class with time delay 3 Type 2 of ApplicationAC–2 AC–3 AC–4

RK–54 150 175 175RK–1 150 175 175J 150 175 225CC 150 300 300Instantaneous trip C/B5 800 800 800Inverse trip C/B6 150 250 250

NOTES (to Table 1):2. Where the values determined by Table 1 do not correspond tothe standard sizes or ratings, the next higher standard size,rating, or possible setting shall be permitted.

2) Types: --AC-2: Slip-ring motors starting, switching off, or all light-starting duty motors. --AC-3: Squirrel-cage motors; starting, switching off whilerunning, occasional inching, joging, or plugging but not toexceed 5 operations per minute or 10 operations per 10minutes. All wye-delta and two-step auto-transformer starting, orall medium starting duty motors. --AC-4: Squirrel-cage motors; starting, plugging, inching,jogging, or all heavy starting duty motors.

3) Where the rating of a time delay fuse (other than CC type)specified by the table is not sufficient for the starting of themotor, it shall be permitted to be increased but shall in no casebe permitted to exceed 225 percent. The rating of a time-delayClass CC fuse shall be permitted to be increased but shall in nocase exceed 400 percent of the full-load current.

4) Class RK-5 fuses shall be used only with NEMA rated motorcontrollers.Exception: Motor controllers listed for use with RK5 fuses.

5) Magnetic only circuit breakers are limited to single motorapplications. These instantaneous trip circuit breakers shall onlybe used if they are adjustable, if part of a combinationcontroller having motor-running and also short-circuit andground-fault protection in each conductor, and if thecombination is especially identified for use, and it is installedper any instructions included in its listing or labeling. Circuitbreakers with adjustable trip settings shall be set at thecontroller manufacturer's recommendation, but not greater than1300 percent of the motor full-load current.

6) Where the rating of an inverse time circuit breaker specifiedin the table is not sufficient for the starting current of the motorit shall be permitted to be increased but in no case exceed: a. 400 percent for full-load currents of 100 amperes or less or b. 300 percent for full-load currents greater than 100 amperes.NOTE: IEC 947-4 defines the terms Type 1 and Type 2coordinated protection as follows: --Type 1 Protection: Under short-circuit conditions thecontactor or starter may not be suitable for further use withoutrepair or replacement. -- Type 2 Protection: Under short-circuit conditions thecontactor or starter shall be suitable for further use. The maximum allowable values in Table 1 do not guaranteeType 2 protection. Type 2 protection is recommended for use in


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applications where enhanced performance and reliability arerequired.

7.2.10.3 Where the branch-circuit and short-circuit and ground-fault protective device is selected not to exceed that allowed by7.2.10.1 for the motor of the smallest rating, two or more motorsor one or more motors and other load(s), with each motor havingindividual overload protection, shall be permitted to be connectedto a branch circuit where it can be determined that the branch-circuit short-circuit and ground-fault protective device will notopen under the most severe normal conditions of service thatmight be encountered.

7.2.10.4 Two or more motors and their control equipment shallbe permitted to be connected to a single branch-circuit whereshort-circuit and ground-fault protection is provided by a singleinverse-time circuit breaker or a single set of fuses, provided bothof the following conditions are met:

a) Each motor controller and overload device is listed (seeANSI/NFPA 70, Article 100, Listed) for group installation withspecified short-circuit current ratings.NOTE: The short-circuit current rating includes: 1) The class and rating of the short-circuit protective device. 2) The maximum nominal application voltage. 3) The maximum available fault current.

b) The rating or setting of the overcurrent device does not exceedthe values in Table 2 for the smallest conductor in the circuit.

Table 2 – Relationship between conductor size and maximumrating or setting of short–circuit protective device for power

circuits

Conductor size(AWG)

Max. ratingNon-time delay fuseor inverse timecircuit breaker inAmperes

Time delay or dualelement fuseinAmperes

14121086432102/03/04/0

6080100150200250300350400500600700800

30405080100125150175200250300350400

7.2.11 Resistance heating branch circuit overcurrent protection. Ifthe branch circuit supplies a single nonmotor-operated load ratedat 16.7 amperes or more, the overcurrent device rating shall notexceed 150 percent of the load rating.

Equipment employing resistance-type heating elements rated atmore than 48 amperes shall have the heating elements subdivided.Each subdivided load shall not exceed 48 amperes and shall beprotected at not more than 60 amperes.

EXCEPTIONA single sheath-type heating element requiringmore than 48 amperes shall be protected at not more than 125percent of the load where the element is integral with andenclosed within the machine housing.

The supplementary overcurrent protective devices shall be: (1)installed within or on the machinery or provided as a separateassembly; and (2) accessible but need not be readily accessible;and (3) suitable for branch-circuit protection.

The main conductors supplying these overcurrent protectivedevices shall be considered branch-circuit conductors.

7.2.12 Programmable electronic system power supply inputovercurrent protection

Programmable electronic system power supply inputs shall beprotected by overcurrent protective devices either externally orinternally. The overcurrent protection size or rating shall be inaccordance with the manufacturer’s instructions.

7.2.13 Control devices. Pushbuttons, selector switches, sensorsand limit switches shall in no case be connected to a circuit ratedlarger than 10 amperes. <<sensors was added to include additional pilot devices>>7.2.14 Common overcurrent device. The use of the sameovercurrent device to provide the protection called for in 7.2.4,7.2.6, and 7.2.7 shall be permitted.

7.3 Overload protection of motors

7.3.1 Overload Protection Requirements. Overload devices shallbe provided to protect each motor, motor controller, and branch-circuit conductor against excessive heating due to motor overloadsor failure to start.

Motor overload protection shall be provided as follows: (a) Motors in accordance with NFPA 70, National ElectricalCode, Article 430, Part C. (b) Adjustable speed drives (electronic drives) in accordancewith NFPA 70, National Electrical Code, Article 430-2.

7.3.2 Resetting. Resetting of the overload device shall not restartthe motor.

Exception: Where there is only a single motor of two horsepoweror less on the machine, an overload reset operator mounted onthe motor shall be permitted to restart the motor provided that thedistance between the overload reset operator and the machine startpushbutton operator is 12 in. (300 mm) or less, and a suitablewarning label is attached on or adjacent to the overload resetoperator.

7.3.3 Number of overloads. The minimum number and locationof running overcurrent units shall be determined from Table 3.

Table 3 – Running overcurrent unitsz

Supply systems

Number and locationof overcurrent units(such as trip coils,relays, or thermalcutouts)

1–phase, ac ordc

2–wire, 1–phase ac ordc ungrounded

1 in either conductor

1–phase, ac ordc

2–wire, 1–phase ac ordc, one conductorgrounded

1 in ungroundedconductor

1–phase, ac ordc

3–wire, 1–phase ac ordc, grounded neutral

1 in either ungroundedconductor

3–phase, ac Any 3–phase * 3, one in each phase

* Exception: Unless protected by other approved means.

NOTE: For 2–phase power supply systems see ANSI NFPA 70,Section 430–37.

Short-time rated motors or high-reversing duty motors that cannotbe adequately protected by external overload devices shall beprotected by a thermal device mounted in the motor and sensitiveto the temperature of the motor, or to both motor temperatureand current.

Motors that are an integral part of a refrigeration compressor ofthe hermetic or semihermetic type shall be protected per thecompressor manufacturer's recommendations.

7.4 Abnormal temperature protection. Resistance heating or othercircuits that are capable of attaining or causing abnormaltemperatures and therefore can cause a hazardous condition shallbe provided with suitable detection to initiate an appropriatecontrol response. An example could be a resistance-heatingcircuit that is short-time rated or which loses its cooling medium.

2.3 Protection against supply interruption or voltagereduction and subsequent restoration


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7.5.1 General. Where a supply interruption or a voltage reductioncan cause a hazardous condition, damage to the machine, or tothe work in progress, undervoltage protection shall be provided(e.g. to switch off the machine) at a predetermined voltage level.

7.5.2 Undervoltage Protection. Where the operation of themachine can allow for an interruption or a reduction of thevoltage for a short time period, delayed undervoltage protectionshall be permitted to be provided. The operation of theundervoltage device shall not impair the operation of any stoppingcontrol of the machine.

7.5.3 Restarting. Upon restoration of the voltage or upon switchingon the incoming supply, automatic or unintentional restarting ofthe machine shall be prevented when such a restart can cause ahazardous condition.

Where only a part of the machine or of the group of machinesworking together in a coordinated manner is affected by thevoltage reduction or supply interruption, the undervoltageprotection shall initiate appropriate control responses to ensureco-ordination.

7.6 Motor Overspeed protection

7.6.1 Motor overspeed protection. Unless the inherentcharacteristics of the motor or the controller, or both, are such asto limit the speed adequately, drive systems motors shall includeprotection against motor overspeed.

Note: Overspeed protection means include, but are not necessarilylimited to, the following:1. A mechanical overspeed device incorporated in the drive toremove armature voltage on upon motor overspeed.2. An electrical overspeed detector that will remove armaturevoltage on upon motor overspeed.3. Field loss detection to remove armature voltage upon the lossof field current.4. Voltage-limiting speed-regulated drives that operate withconstant full field. In this case, protection is obtained individuallyfor the loss of field or tachometer feedback; however, protectionagainst simultaneous loss of field and tachometer is not provided.<<end of note>>

7.6.2 Equipment Overspeed Protection. Where the safe operatingspeed of the equipment is less than that of the drive motor, meansshall be provided to limit the speed of the equipment

7.7 This section left intentionally blank

7.8 Phase sequence protection. Where a phase loss or an incorrectphase sequence of the supply voltage can cause a hazardouscondition or damage to the machine, protection shall be provided.

NOTEConditions of use which may lead to an incorrect phasesequence include: - a machine transferred from one supply to another; - a mobile machine with a facility for connection to an externalpower supply

7.9 Protection against overvoltages due to lightning and toswitching surges

7.9.1 Protective devices shall be permitted to be provided toprotect against the effects of overvoltages due to lightning or toswitching surges.

7.9.2 Where provided, devices for the suppression of overvoltagesdue to lightning shall be connected to the incoming terminals ofthe supply disconnecting device.

7.9.3 Where provided, devices for the suppression of overvoltagesdue to switching surges shall be connected across the terminals ofall equipment requiring such protection.

7.10 Power factor correction capacitors

7.10.1 Where capacitors are installed for motor power factorcorrection on circuits of 600 volts, nominal, and under,overcurrent protection for the conductors shall be provided. See7.2.1 and 7.2.10.

Each capacitor cell or capacitor bank shall be protected againstrupture of the individual cells. Protection included as a part of thecapacitor assembly shall be permitted.

7.10.2 (extracted text) Discharge of Stored Energy. Capacitorsshall be provided with a means of discharging stored energy.

(a) Time of Discharge. The residual voltage of a capacitor shall bereduced to 50 volts, nominal, or less, within 1 minute after thecapacitor is disconnected from the source of supply.(b) Means of Discharge. The discharge circuit shall be eitherpermanently connected to the terminals of the capacitor orcapacitor bank, or provided with automatic means of connecting itto the terminals of the capacitor bank on upon removal of voltagefrom the line. Manual means of switching or connecting thedischarge circuit shall not be used. <<end of extracted text>><<Clause 7.10.2 is a copy of the text in NFPA 70 Section 460-6 andshould be shown as “extracted text”>>COMMITTEE STATEMENT: 1) In 7.2.1, insert Figure 1 andFigure 2 from NFPA 79-1997. The committee does not agree thatthe reorganization of Clause 7 requires the deletion of Figures 1and 2. The committee desires that staff update the column 2references in both figures to reflect the new numbering of theproposed document. 2) In 7.2.3, make a correction to delete the cross reference andthen add a new sentence to clarify the intent of the committee. 3) Editorially correct 7.2.4.1, 7.2.5, 7.6, and 7.10.2(b) to addclarity, have consistancy with Chapter 3, and follow the manual ofstyle. 4) This was the correction of an inadvertent omission to includeNFPA 79-1997, 8.3.1. as the new 7.2.12. 5) This was the correction of an inadvertent omission to includeNFPA 79-1997, 8.3.3. as the new 7.2.13. 6) This corrects an inadvertent omission to include NFPA 79-1997, 8.13, but the committee editorially corrects the requirementfor clarity in 7.2.14.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DEFELICE: We believe that the rating of the overcurrent devicepermitted by 7.2.4.1.2 for protection of a AWG 18 copperconductor is unacceptable. While we acknowledge that the resultsof laboratory testing has shown that AWG 18 wire can be protectedby a 20 amp overcurrent device, our field experience indicatesquite the opposite. Insulations typically found on AWG 18 wirevary greatly, and in our experience many have proven to beinadequate to withstand the current levels over the durationrequired to clear some faults. We believe that 15 amps in anacceptable value. Similarly, the allowable levels for conductor protection found in7.2.4.1.3 for AWG 18 wire (25 amps) are excessive. Fieldexperience indicates that a maximum value of 15 amps doesprovide adequate protection of the conductor.COMMENT ON AFFIRMATIVE: DOBROWSKY: The following should be added to Section 7.2.9: 240.85 Applications. A circuit breaker with a straight voltagerating, such as 240V or 480V, shall be permitted to be applied in acircuit in which the nominal voltage between any two conductorsdoes not exceed the circuit breaker’s voltage rating. A two-polecircuit breaker shall not be used for protecting a 3-phase, corner-grounded delta circuit unless the circuit breaker is marked 1ø-3 øto indicate such suitability. A circuit breaker with a slash rating,such as 120/240V or 480Y/277V, shall be permitted to be appliedin a solidly grounded circuit where the nominal voltage of anyconductor to ground does not exceed the lower of the two valuesof the circuit breaker’s voltage rating and the nominal voltagebetween any two conductors does not exceed the higher value ofthe circuit breaker’s voltage rating. (ROP 10-65) FPN Note : Proper application of molded case circuit breakerson 3-phase systems, other than solidly grounded wye, particularlyon corner grounded delta systems, considers the circuit breakers’individual pole interrupting capability. Reason: To provide requirements for equipment used onindustrial machinery. The present text does not address theproper selection relative to voltage ratings. This requirement wastaken from the NEC 240.85. Possibly changing the term "circuitbreaker" to "equipment" or "overcurrent devices" would allow thisrequirement to apply to other products.

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(Log #97)79- 45 - ([7.2.10.1]): RejectSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to add new text to NFPA79-1997 as additional content for the newly proposed Clause 7which was reconciled with EN 60204-1 by Technical Committee onElectrical Equipment of Industrial Machinery action. Add text to read as follows: 7.2.10.1 Exception 1: Table 1 shall not apply to design E motors circuits.The provisions of NFPA 70 shall be observed for Design E motorcircuits. Exception 2: Provisions of 13.6.1 Exceptions 1 and 2 shall applyas specified.SUBSTANTIATION: Substantiation for 7.2.10.1 Exception 1: A new Exception 2 is added causing the existing Exception to benumbered Exception 1. Substantiation for 7.2.10.1 Exception 2: This exception will reconcile Table 1 with the provisions of theproposed 13.6.1 Exceptions 1 and 2.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This clause deals primarily withcontroller protection. There is no need to add this exception asthe smaller conductors and protection are already permitted inClause 13.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #75)79- 46 - (8.1.1 [7.2.1]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify rewritten new Clause 7.2.1 thatwas NFPA 79-1997, Clause 8.1.1. To the first sentence of rewritten proposed Clause 7.2.1, add thewords "in the circuit" immediately after the words "component"and "Conductors." Sentence to read "...of any component in thecircuit or the current carrying capacity of the conductors in thecircuit..." Delete the second sentence of the rewritten proposed Clause7.2.1. Retain 1997 NFPA 79 Clause 8.1.1 as a second paragraph in newrewritten Clause 7.2.1. Retain current NFPA 79 Figures 1 and 2.SUBSTANTIATION: Each recommended change will add clarityto the intent of the clause, and will thereby add to the potentialsafety of the installed equipment. The deletion of the secondsentence is required since the reference to 7.2.10 addresses motorcircuits and does not address other type machine circuits.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands thatthis proposal amends the Action on Proposal 79-44 (Log #45)[Clause 7].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #76)79- 47 - (8.3 [7.2.3]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Delete in rewrite of 1997 NFPA 79 Clause8 that is proposed new Clause 7 as follows. In proposed clause 7.2.3 delete the parenthetical part of the title.SUBSTANTIATION: The reference to 7.2.10 in the sentence ofproposed clause 7.2.3 applies to power (motor) circuits only, notfeeder and branch circuits.COMMITTEE ACTION: Accept.

COMMITTEE STATEMENT: The committee understands that theaction of this proposal modifies the Action on Proposal 79-44 (Log#45) [Clause 7]/NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #7779- 48 - (8.3 [7.2.3]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: In proposed clause 7.2.3 delete thereference to 7.2.10. Sentence to read: "Devices for detection and interruption of overcurrent shall beapplied to each ungrounded phase conductor."SUBSTANTIATION: The reference to 7.2.10 in the sentence ofproposed clause 7.2.3 applies to power (motor) circuits only, notfeeder and branch circuits.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-44 (Log #45).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #8779- 49 - (8.3.1 [11.2.5 (New)]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Add to proposed rewrite of NFPA 79,Clause 20, that is the new Clause 11, a sub clause (11.2.5) insertingthe wording of NFPA 79, clause 8.3.1 except eliminate "(PES)".SUBSTANTIATION: It is appropriate, as viewed in NFPA 79, torequire or make sure, that the inputs to the power supplies ofprogrammable electronic systems have some form of overcurrentprotection.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-44 (Log #45) since it meets the intent ofthe submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: SAUNDERS: I do not agree with the action to eliminate theacronym (PES). It is in the existing text in NFPA 79 and thedefinition of the term is in this section and refers to a term that iscommonly used in industry.

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(Log #3279- 50 - (8.4 Exception No. 2 [7.2.8]): AcceptSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Revise text as follows: Remove splitter block from proposed text and add branch circuitrated before circuit breakers. - the conductor terminates in a splitter block branch circuit rated circuit breaker or set of fuses.SUBSTANTIATION: The allowance of a splitter block for aproper termination point could lead to possibly overloading thetap feeding the splitter block. When the tap is first installed andsized it will be sized per the existing load requirements. Thepossibility exists, with the use of splitter blocks, to add circuits onto the tap in the future and overloading the tap, since it was sizedto the original load requirements. Allowing the use of only circuitbreakers and fuses would provide the proper protection of the tapeven if additional taps are added on in the future.


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Also the way the current text is written, it would allow theconnection of wire without any overcurrent protection. Thecurrent wording could allow wire to be installed that would not beprotected against short circuits or overloads. See the example givenbelow. Whenever the cable fed directly from the line-side overcurrentprotective device is sized smaller than the device, it is considered atap. If that tap conductor ends in a splitter block, smallerconductors will be connected on the load side of the splitterblock. Those are therefor taps, too. That means that we aretapping a tap, which is never allowed. The added words "branch circuit rated" will clarify for the publicthe use of UL489 branch rated circuit breakers versus UL1077supplementary protectors (circuit breakers). UL489 CircuitBreakers are tested and rated for branch circuit protection and canbe used for this purpose. UL1077 Supplementary protectors arenot tested and rated for branch circuit protection and cannot beused for this purpose. The devices are very similar in physicalappearance, thus leaving an opening for possible misapplication.The additional words will clarify, for the public, the proper deviceto select.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: This action from this proposal hasbeen incorporated into Proposal 79-44 (Log #45), in 7.2.8(a),bullet 5.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARVEY: The submitter is correct. The text proposed by Mr.Lottmann does not prohibit the use of splitter blocks. It clarifiesthat a single tap from the splitter block is consistent with industrypractice and should be allowed by the Code. By requiring the tapterminate in a branch-circuit circuit breaker or branch-circuitrated fuses, multiple taps from the splitter block are prohibited.COMMENT ON AFFIRMATIVE: ANDERSON: The attempt in using the "branch circuit rated"requirement is to clarify that supplementary protection devices arenot to be considered for use in a supply circuit, disconnectingapplications. The proposed modification is to add the term"branch circuit rated", however this "rated" requirement is notdirectly defined. Defined terminology needs to be found andapplied, e.g. " suitable for branch circuit over current protection". DOBROWSKY: The phrase "branch circuit rated" should also beinserted before "set of fuses". Reason: The proposal wording can be interpreted as requiringbranch circuit rated circuit breakers but allowing fuses that arenote branch circuit rated.

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(Log #13)79- 51 - (8.4.1(New) [7.2.2]): RejectSUBMITTER: Richard H. Geister , SCR ElectricRECOMMENDATION: Add new text to read as follows: "Propose that (Control) Panel Wiring, for line supply side of fuseblocks, wire be installed if mounted vertical at top of fuse block.Load wired at bottom of fuse block. If fuse block is mounthorizontal line supply to left. Load wired to right side of fuseblock."SUBSTANTIATION: I have myself seen and done pulled fuse fora motor (safety from electrical shock) think that the bottom orright side of the fuse block is dead. Only to find that it is not andthe live side is connected to the bottom or right of the fuse block.Knowing that in all cases one should check for voltage beforeworking on any system.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: There is no evidence that thischange will improve the safety of machines. Good work practices,such as checking for voltage before working in equipment is theappropriate safe method.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: The proposal should be accepted in principleand revised as follows: "The top terminal of cartridge type fuseholders shall beconnected to the line (supply) conductors where fuseholders aremounted so that the fuses are in a vertical position. Exception: Fuseholders that are marked to indicate the line andload side shall be permitted to have supply connections at thebottom." Reason: Providing a convention will inherently reduce the risk ofinjury and improve consistency. If this is not feasible the markingshould not be a major inconvenience. GARVEY: The panel should accept the principal of thesubmitter’s argument. Fuseholder enclosures should be mountedin a vertical position. This requirement is found in NEC 240-33.When an electrician removes a cartridge fuse, the motion of thearm and the body is away from the fuseholder and out of theenclosure. Mount the fuseholder horizontally and the motion istowards or into the enclosure. This is a safety hazard. Acceptedpractice is to supply the top of the overcurrent device. Listedproducts such as panelboards, motor control centers, andindustrial control panels utilize this construction. NFPA 79 shouldnot permit deviations from this practice. PADGET: I agree with Mr. Dobrowsky’s Explanation of NegativeVote.COMMENT ON AFFIRMATIVE: ANDERSON: Good work practices, such as checking for voltagebefore working in equipment is the appropriate safe method.However having equipment laid out in a consistent pattern is easierto service. Where as a fuse block's function doesn't depend onestablishing a load and a line side some devices such as circuitbreakers and fused switches with an interrupt rating generally do. If looking at molded case circuit breakers [not those used inpanel boards], and use the generally agreed man-machine interfaceactuating principles of up and to the right is the closed or "on"position, then the line side terminals would be at either the top orthe right side and the load terminals would be down or to the left.[Which is a different arrangement that was proposed in therejected proposal #13.] NFPA 79 1997 edition in 7.8.1 implies a top location for theincoming feed or line side but stop short of directly suggesting orrequiring the top to be the feeder circuit location. Base on missedexpectations of the feed verses the load connection locations onequipment supplied by various machine manufacturers, I wouldsuggest that some direct preference or, requirement for thelocation of the line and load terminals on circuit interruptingdevices including disconnect switches, fuses and circuit breakers beincluded by the committee in the NFPA79 2002 edition.

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(Log #161)79- 52 - (8.5.1 Table1 [7.2.10.1 Table1]): AcceptSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Revise Table 1 by adding the followingrows to the table and add another title in column 1 to what isshown below.

Fuse class nontime delaty

AC-2 AC-3 AC-4

R 300 300 300J 300 300 300CC 300 300 300T 300 300 300

Also revise note 3 to read as follows: 3) Where the rating of a time delay fuse (other than CC type)specified by the table is not sufficient for the starting of the motor,it shall be permitted to be increased but shall in no case bepermitted to exceed 225 percent. The rating of a time-delay ClassCC fuse and non time delay Class CC, J, or T shall be permitted tobe increased but shall in no case exceed 400 percent of the full-load current.SUBSTANTIATION: The addition of these fuse types will alignwith the requirements currently existing in the National ElectricalCode® Article 430.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on Proposal 79-44 (Log #45).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #8a)79- 53 - (8.5.4 [7.3]): RejectSUBMITTER: Endel Mell, Husky Injection Molding Systems Ltd.RECOMMENDATION: Revise the wording to cover one motor,together with other equipment such as resistive heating elements,etc.SUBSTANTIATION: NFPA 70 has clauses that cover singlemotor, grouped motor, and combination load applications. NFPA79 does not.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposal does not comply withthe Regulations Governing Committee projects, Section 4.3.3(c)since the submitter has not provided the specific recommendedtext.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #79)79- 54 - (8.6 Title [7.3 Title]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Change title of clause 7.3 in proposed newclause 7 to "Overload protection of motors and drives."SUBSTANTIATION: The proposed content of clause 7.3addresses overload protection for both drives and motors, not justmotors.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposed title change is notconsistant with the text of the clause. Drive manufacturers shouldbe consulted for proper selection of overcurrent protection.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #47)79- 55 - (8.6 [7.3.1]): RejectSUBMITTER: John J. Kowal, Webster, NYRECOMMENDATION: Revise text as follows: Move parentheses from electronic drives to adjustable speeddrives. Move electronic drive in front of adjustable speed drives. 7.3.1 Overload Protection Requirements. Overload devices shallbe provided to protect each motor, motor controller, and branch-circuit conductor against excessive heating due to motor overloadsor failure to start. Motor overload protection shall be provided as follows: Motors in accordance with NFPA 70, National Electrical Code,Article 430, Part C.Electronic drives (Adjustable speed drives) (electronic drives) inaccordance with NFPA 70, National Electrical Code, Article 430-2.


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SUBSTANTIATION: This change will provide clarity for thepublic in the proposed NFPA 79-2002 standard. This change willmatch up with the proposed Section 11.4, titled Electronic Drives,and move the reference to electronic drives which covers morethan just adjustable speed drives.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The current language in NFPA 70 is"adjustable speed drives". See Section 430-2 of the 1999 NEC.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #80)79- 56 - (8.6.4 [7.3.1]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in rewritten Clause 7.3.1 thatreplaces 1997 NFPA 79, Clause 8.6.4. In the first paragraph of proposed new clause 7.3.1 add "anddrive" after the initial word "Motor." Sentence to read: "...protect each motor and drive, motor controller...". In the second paragraph of proposed new clause 7.3.1 add "anddrive" after the initial word "Motor." Sentence to read: "Motor and drive overload...".SUBSTANTIATION: The proposed new clause addresses thesubject of overload protection for both motors and drives, not justmotors.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Drive protection is not specificallycovered in Part C of Article 430, of the 1999 NEC. Drivemanufacturers should be consulted for proper selection ofovercurrent protection.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #48)79- 57 - (8.8 (New) [7.2]): RejectSUBMITTER: John J. Kowal, Webster, NYRECOMMENDATION: Add the following new subclause to clause7: 7.2.XX Solenoids. Overcurrent protection for solenoids shall besupplied by a branch circuit overcurrent protective device sized at150 percent of the hold-in current rating. SUBSTANTIATION: There are no provisions in either NFPA 79or NFPA 70 that refer to the safe operation of these devices underovercurrent conditions. The solenoid is rated by coil voltage, pullin force, stroke, and power dissipation. The inrush current of anopen solenoid is several times greater than the holding currentwhen the solenoid is closed or seated. A solenoid, in its blockedopen position, with a constant power source, will quickly overheatand burn out. When unprotected solenoids are unable to becompletely seated, a hazardous condition and potential fire hazardcan be created by the breakdown of the insulation of the coil wire.Although low impedance wire does exist, resulting in some coilsopening safely under a sustained overcurrent condition, this is byfar not representative of the majority of the products manufacturedtoday.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee is not convinced thatmandatory individual overcurrent protection is warranted for allsolonoids. The manufactures instructions should be reviewed toensure that proper overcurrent protection is provided.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: I am not convinced that 150 percent is thecorrect value but some level of protection needs to be specified inthis standard.

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(Log #95)79- 58 - (Z.8.8 (New) [7.2]): RejectSUBMITTER: Steven D. Taplin, G.W. Lisk Co. Inc.RECOMMENDATION: Add text to read as follows: AC Solenoids: are electromechanical devices which producework, such as motors. They exhibit the same current drawfeatures. A solenoid has inrush and hold amps which directlyrelates to a motor with its start and run amp values.SUBSTANTIATION: AC solenoids when not allowed to shiftproduce a condition as a motor when in a "locked rotor" mode. Ifa solenoid is not fuse directly (150 percent hold amp value) itcould exceed the thermal withstand rating of the magnet wire.This will lead to overheating leading to burn out failure.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-57 (Log #48). The submitter has notprovided for specific direction for placement of the text accordingto the Regulations Governing Committee Projects, Section 4-3.3.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #62)79- 59 - (8.9 [7.2.4]): RejectSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Add text as follows: "Switch-off in case of short to ground after 0,5 sec at the latest."SUBSTANTIATION: Current NFPA definitions do not sufficientlyprotect against short to ground.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The time current characteristics ofovercurrent protective devices are included in the productstandards and product evaluations. The placement of theproposed text is not clear. The change is not properlysubstantiated. The practices in both NFPA 79 and NFPA 70 doprotect against shorts to ground.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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79- 60 - (8.9.2.1 [7.2.4.1.1]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify rewritten clause 7.2.4.1.1 to 1997NFPA 79 Clause 8.9.2.1. For the second sentence of proposed clause 7.2.4.1 use thesecond sentence of current NFPA 79 clause 8.9.2.1.SUBSTANTIATION: It is preferable that Table 11 of the newrewritten NFPA 79 (which was derived from NEC Table 310-16) beused since it is in the standard and to avoid references to otherstandards that may not be readily available.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-44 (Log #45) [Clause 7].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #4)79- 61 - (8.12.3 [7.2.7]): RejectSUBMITTER: Steven Duritt, Empire Abrasive Equipment Co.RECOMMENDATION: Revise as follows: "8.12.3 Where multiple overcurrent protective devices are used toprotect individual branch circuits, and the sum of the currentratings of these the overload protective devices which areconnected to simultaneously energized loads exceeds the currentallowed in Table 5...".SUBSTANTIATION: I utilize 500 VA through 5 KVA industrialcontrol transformers and apply 8.11.1 for primary overcurrentprotection. Due to coordination of the branch circuits connectedto the secondary, the current total is not exceeded. Since theenergized branch circuit loads at any instant do not exceed the


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values in Table 5, there should be no need for an additional "singleoverload protective device."COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Primary protection of a transformer(even if sized such that secondary transformer protection is notneeded) does not necessarily protect conductors on the secondaryside of a transformer.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #46)79- 62 - (Clause 9 [Clasuse 9]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise text to read as follows:9. Control circuits and control functions

9.1 Control circuits

9.1.1 Control circuit supply

9.1.1.1 Control transformers shall be used for supplying the controlcircuits. Control circuits shall not be derived fromautotransformers.

9.1.1.2 Where dc control circuits are connected to the equipmentgrounding (protective bonding) circuit (see 8.2.1); they shall besupplied from a separate winding of the ac control circuittransformer or by another control circuit transformer or a listed dcpower supply.

9.1.1.3 Transformers shall not be required if the supply voltagedoes not exceed 120 volts ac and the available short circuit currentdoes not exceed 1,000 amps RMS.

9.1.1.4 The source of supply for all control circuits shall be takenfrom the load side of the main disconnecting means.

EXCEPTION—Power supply to memory elements and their support logicrequiring power at all times to maintain the storage of information shallbe permitted to be taken from the line side of the main disconnectingmeans or other power source.

9.1.1.5 The marking requirements of subclause 17.2.4, Warningsigns, shall apply.

9.1.2 Control circuit voltages

9.1.2.1 AC control circuit voltages

The nominal voltage shall not exceed 120 volts AC single phase.

EXCEPTION 1: Other voltages shall be permitted, where necessary, forthe operation of electronic, precision, static, or devices used in the controlcircuit.

EXCEPTION 2: Any electromechanical magnetic device having aninrush current exceeding 20 amperes at 120 volts shall be permitted to beenergized at line voltage through contactor or relay contacts. Thecontactor or relay contacts shall break both sides of the line voltage circuitto the magnetic device. The relay coil shall be connected to the controlcircuit.

9.1.2.2 DC control circuit voltages

Direct-current (dc) control voltage shall be 250 volts or less.

9.1.3 Protection

Control circuits shall be provided with overcurrent protection inaccordance with Clause 7.

9.1.4 Connection of control circuit devices

9.1.4.1 All operating coils of electromechanical magnetic devicesand indicator lamps (or transformer primary windings forindicator lamps) shall be directly connected to the same side of thecontrol circuit. All control circuit contacts shall be connectedbetween the coil and the other side of the control circuit.

Exception No. 1: Overload relay contacts where the wiring to thesecontacts does not extend beyond the control enclosure.

Exception No. 2: Contacts of multi-pole control circuit switching devicesthat simultaneously open both sides of the control circuit.

Exception No. 3: Ground test switching device contacts in ungroundedcontrol circuits.

Exception No. 4: Solenoid test switching device contacts in ungroundedcircuits.

Exception No. 5: Coils or contacts used in electronic control circuitswhere the wiring to these coils or contacts does not extend beyond thecontrol enclosure.

Exception No. 6: "Run" push-buttons for two-hand operation, such asfor presses having ground detection circuits and overcurrent protectionin each conductor.

9.1.4.2 Contacts shall not be connected in parallel to increaseampacity.

9.2 Control functions

9.2.1 Start functions

Start functions shall operate by energizing the relevant circuit.

9.2.2 Stop functions

There are three categories of stops as follows:(a) Category 0: stopping by immediate removal of power to the

machine actuators (i.e. an uncontrolled stop - see 3.113).(b) Category 1: a controlled stop (see 3.24) with power to the

machine actuators available to achieve the stop and thenremoval of power when the stop is achieved.

(b) Category 2: a controlled stop with power left available to themachine actuators.

NOTE—With the exception of emergency stop (see 9.2.5.4), anddepending upon the risk assessment, removal of power may beaccomplished by the use of either electromechanical or solid-statecomponents.

9.2.3 Operating modes

9.2.3.1 Each machine shall be permitted to have one or moreoperating modes (e.g., automatic, manual, normal and bypass)determined by the type of machine and its application.

9.2.3.2 When hazardous conditions results from mode selection,such selection shall be prevented from occurring (e.g. keyoperated switch, access code). Mode selection by itself shall notinitiate machine operation. A separate action by the operator shallbe required.

9.2.3.3 Safeguarding means shall remain effective for all operatingmodes. (See 9.2.4 for suspension of safeguards under specialconditions).

9.2.3.4 Indication of the selected operating mode shall be provided(e.g. position of mode selector, provision of indicating light, visualdisplay indication).

9.2.4 Overriding of safeguards

Where it is necessary to temporarily override one or moresafeguards a mode selection device or means capable of beingsecured (e.g. locked) in the desired mode shall be provided toprevent automatic operation. In addition, one or more of thefollowing measures should be provided:

(1) Initiation of motion by a hold-to-run or other control device(2) A portable controls station (e.g. pendant) with an

emergency stop device, and where appropriate, an enablingdevice. Where a portable station is used, motion shall onlybe initiated from that station.

(3) Limiting the speed or the power of motion(4) Limiting the range of motion


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9.2.5 Operation

9.2.5.1 General

9.2.5.1.1 The necessary interlocks (see 9.3) shall be provided forsafe operation.

9.2.5.1.2 Measures shall be taken to prevent movement of themachine in an unintended manner after any stopping of themachine (e.g. locked-off condition, power supply fault, batteryreplacement, lost signal condition with cable-less control).

9.2.5.2 Start

9.2.5.2.1 The start of an operation shall be possible only where allof the safeguards are in place and functional except for conditionsas described in 9.2.4.

9.2.5.2.2 On those machines where safeguards cannot be appliedfor certain operations, manual control of such operations shall beby hold-to-run controls, together with enabling devices,

9.2.5.2.3 Interlocks shall be provided to ensure correct sequentialstarting.

9.2.5.2.4 On machines requiring the use of more than one controlstation to initiate a start:

(a) Each control station shall have a separate manually actuatedstart control device.

(b) All required conditions for machine operation shall be met.(c) All start control devices shall be in the released (off)

position before a start operation is permitted.(d) All start control devices shall be actuated concurrently (see

3.6).

9.2.5.3 Stop

9.2.5.3.1 Each machine shall be equipped with a category 0 stop.

9.2.5.3.2 Category 0, category 1 and/or category 2 stops shall beprovided where indicated by an analysis of the risk assessment andthe functional requirements of the machine (see 4.1). Category 0and category 1 stops shall be operational regardless of operatingmodes (see 9.2.3) and category 0 shall take priority. Stop functionsshall override related start functions (see 9.2.5.2).

9.2.5.3.3 Where required, provisions to connect protective devicesand interlocks shall be provided. Where applicable, the stopfunction shall signal the logic of the control system that such acondition exists. The reset of the stop function shall not initiateany hazardous conditions.

9.2.5.4 Emergency operations (emergency stop, emergencyswitching off)

9.2.5.4.1 General

This standard specifies the requirements for the emergency stopand emergency switching off functions, each of which are, in thisstandard, initiated by a single human action. Emergency switchingoff is an emergency operation intended to switch off the supply ofelectrical energy to all or a part of an installation where a risk ofelectric shock or another risk of electrical origin is involved. Forother safety related stop functions see 11.3.4.

9.2.5.4.2 Emergency stop

9.2.5.4.2.1 In addition to the requirements for stop (see 9.2.5.3),the emergency stop has the following requirements:

(a) It shall override all other functions and operations in allmodes.

(b) Power to the machine actuators which causes a hazardouscondition(s) shall be removed as quickly as possiblewithout creating other hazards (e.g. by the provision ofmechanical means of stopping requiring no external power,by reverse current braking for a category 1 stop).

(c) Reset of an emergency stop circuit shall not initiate a restart.

9.2.5.4.2.2 Where required provisions to connect additionalemergency stop devices shall be provided (see 10.7 for therequirements of emergency stop devices).

9.2.5.4.2.3 The emergency stop shall function as either a category 0or a category 1 stop (see 9.2.2). The choice of the category of theemergency stop shall be determined by the risk assessment of themachine.

9.2.5.4.2.4 Where a category 0 stop is used for the emergency stopfunction, it shall have hardwired electromechanical components.

Exception: An electronic logic system that complies with 11.3.3 shall bepermitted. The final removal of power shall be accomplished by means ofelectromechanical components.

9.2.5.4.2.5 Where a category 0 or a category 1 stops is used for theemergency stop function, final removal of power to the machineactuators shall be ensured and shall be by means ofelectromechanical components.

9.2.5.4.3 Emergency switching off

9.2.5.4.3.1 Emergency switching off shall be permitted where:

(1) Protection against direct contact (e.g. with collector wires,collector bars, slip-ring assemblies, control-gear inelectrical operating areas) is achieved only by placing out ofreach or by obstacles (see 6.2.5) or;

(2) There is the possibility of other hazards or damage causedby electricity.

9.2.5.4.3.2 Emergency switching off is accomplished bydisconnecting the incoming supply of the machine effecting acategory 0 stop. When the machine cannot tolerate the category 0stop, it shall be necessary to provide other protection, for exampleagainst direct contact so that emergency switching off is notnecessary.

9.2.5.5 Hold-to-run controls

9.2.5.5.1 Hold-to-run controls [e.g., jog, inch functions] shallrequire continuous actuation of the control device(s) to achieveoperation.

9.2.5.5.2 JOG or INCH functions shall operate only in theMANUAL mode. MANUAL reverse shall be considered a JOGfunction.

9.2.5.6 Two-hand control

All two-hand controls shall have the following features:

(a) The provision of two control devices requiring theconcurrent actuation by both hands:

(b) It shall be necessary to actuate the control devices within acertain time limit of each other (see annex B).

(c) Where the time limit of less than or equal to 0.5 seconds isexceeded, both control devices shall be released beforeoperation is initiated.

(d) The control devices shall require continuous actuationduring the hazardous conditions.

(e) Machine operation shall cease upon the release of eithercontrol device when hazardous conditions are still presentand;

(f) Require of the release of both control-devices, before themachine operation is reinitiated.

9.2.5.7 Enabling device

9.2.5.7.1 An enabling device is an additional manually operatedcontrol device used in conjunction with a start control and which,when continuously actuated, allows a machine to function.

9.2.5.7.2 When an enabling device is provided as a part of a system,it shall be designed to allow motion when actuated in one positiononly. In any other position motion shall be stopped.

9.2.5.7.3 Enabling device shall have the following features:(1) Be connected to a category 0 or a category 1 stop (see 9.2.2)(2) Be designed to ergonomic principles(3) For two-position types:

a. Position 1: off-function of the switch (actuator is notoperated)

b. Position 2: enabling function (actuator is operated)


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(4) For three-position types:a. Position 1: off-function of the switch (actuator is not

operated)b. Position 2: enabling function (actuator is operated in its

mid position)c. Position 3: off-function (actuator is operated past its mid

position)d. A three-position enabling device shall require manual

operation to reach “position 3”.

9.2.5.7.4 When returning from position 3 to position 2, the functionshall not be enabled.

9.2.5.7.5 An enabling device shall automatically return to its “off-function” when its actuator is not manually held in the enablingposition.

9.2.6 Combined start and stop controls

A push-button and other devices that alternately start and stopmotion shall only be used for secondary functions where nohazardous condition arises when they are operated.

9.2.7 Cable-less control functions

9.2.7.1 General

9.2.7.1.1 Means shall be provided to remove or disconnect thepower supply of the operator control station.

9.2.7.1.2 Means (e.g. key operated switch access code) shall beprovided, as necessary, to prevent unauthorized use of the operatorcontrol station.

9.2.7.1.3 Each operator control station shall carry an unambiguousindication of which machine(s) are intended to be controlled bythat operator control station.

9.2.7.2 Control limitation

9.2.7.2.1 Measures shall be taken to ensure that control commands:

(1) Affect only the intended machine(2) Affect only the intended functions

9.2.7.2.2 Measures shall be taken to prevent the machine fromresponding to signals other than those from the intended operatorcontrol station(s).

9.2.7.2.3 Means shall be provided so that the machine shall only becontrolled from operator control stations in one or morepredetermined zones or locations.

9.2.7.3 Stop

9.2.7.3.1 Operator control stations shall include a separate andclearly identifiable means to initiate the stop function of themachine or of all the motions that causes a hazardous condition.The actuating means to initiate this stop function shall not bemarked or labeled as an emergency stop device, even though thestop function initiated on the machine results in an emergency stopfunction.

9.2.7.3.2 A machine having safety-critical functions and which areequipped with cable-less control shall have a means ofautomatically initiating the stopping of the machine and preventingthe initiation of potentially hazardous motions, in the followingsituations:

(a) When a stop signal is received.(b) When a fault is detected in the system.(c) When a valid signal has not been detected within a specified

period of time (see annex B).

NOTEA valid signal also includes the signal that confirmscommunication is established and maintained.

9.2.7.4 Serial data communication

In a machine where the control of safety critical functions relies onserial data transfer, correct communications shall be ensured by

using an error detection method that is able to cope with up tothree error bits in any command sequence. The safety capability ofthe serial data communication system shall be certified by anationally recognized testing laboratory to have the same degree ofsafety capability as hardware based components installed inaccordance with this standard [NFPA 79].

NOTEOne way to determine applicable error detection methodsis to refer to IEC 60870-5-l: 1990, “Telecontrol equipment andsystems. Part 5:Transmission protocols - Section One:Transmission frame formats”.

9.2.7.5 Use of more than one operator control station

Where a machine has more than one operator control station,measures shall be taken to ensure that only one control stationshall be enabled at a given time. Indication of which operatorcontrol station is in control of the machine shall be provided atlocations where necessary for the safety requirements of themachine.

Exception: A stop command from any one of the control stations shall beeffective where necessary for the safety requirements of the machine.

9.2.7.6 Battery-powered operator control stations

A variation in the battery voltage shall not cause a hazardouscondition. If one or more potentially hazardous motions arecontrolled using a battery-powered operator control station, a clearindication shall be given to warn the operator when a variation inbattery voltage exceeds specified limits. Under thosecircumstances, the operator control station shall remain functionallong enough to put the machine into a non-hazardous condition.

9.3 Protective interlocks

9.3.1 Re-Closing or resetting of an interlocking safeguard

The re-closing or resetting of an interlocking safeguard shall notinitiate machine motion or operation where that results in ahazardous condition.

9.3.2 Overtravel limits

Where a machine overtravel cause a hazardous condition, aposition sensor or limit switch shall be provided to initiate controlaction.

9.3.3 Operation of auxiliary functions

9.3.3.1 Appropriate devices (e.g. pressure sensors) shall check thecorrect operation of the auxiliary functions.

9.3.3.2 Where the non-operation of a motor or device for anauxiliary function (e.g. lubrication, coolant, swarf removal) causesa hazardous condition, cause damage to the machine, or to thework in progress, interlocking shall be provided.

9.3.4 Interlocks between different operations and for contrarymotions

9.3.4.1 All contactors, relays, and other control devices whichcontrol elements of the machine that cause a hazardous conditionwhen actuated at the same time (e.g. those which initiate contrarymotion), shall be interlocked against incorrect operation.

9.3.4.2 Reversing contactors (i.e. those controlling the direction ofa motor) shall be interlocked in such a way that in normal serviceno short circuit shall occur when switching. This shall includeboth mechanical and electrical interlocking.

9.3.4.3 Where for safety or for continuous operation, certainfunctions on the machine are required to be interrelated,coordination shall be ensured by interlocks. For a group ofmachines working together in a coordinated manner and havingmore than one controller, provision shall be made to coordinatethe operations of the controllers as necessary.

9.3.4.4 Where a failure of a mechanical brake actuator results in thebrake being applied when the associated machine actuator isenergized and a hazardous situation results, interlocks shall beprovided to switch off the machine actuator.


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9.3.5 Reverse current braking

9.3.5.1 Where reverse current braking is used on motor, effectivemeasures shall be taken to prevent the motor starting in theopposite direction at the end of braking where this reversal willcause a hazardous condition or damage to the machine or to thework in progress. For this purpose, the use of a device operatingexclusively as a function of time shall not be allowed.

9.3.5.2 Control circuits shall be arranged so that rotation of amotor shaft, manually or otherwise, shall not result in a hazardouscondition.

9.4 Control functions in the event of failure

9.4.1 General requirements

Where failures or disturbances in the electrical equipment cause ahazardous condition or damage to the machine or the work inprogress, measures shall be taken to minimize the probability ofthe occurrence of such failures or disturbances . The requiredmeasures and the extent to which they are implemented, eitherindividually or in combination, depend on the safety requirementsassociated with the respective application (see 4.1)

Note 1 Measures to reduce these risks include but are not limitedto:

(1) Protective devices on the machine (e.g. interlock guards,trip devices)

(2) Protective interlocking of the electrical circuit(3) Use of proven circuit techniques and components (see

9.4.2.1)(4) Provisions of partial or complete redundancy (see 9.4.2.2)

or diversity (see 9.4.2.3)(5) Provision for functional tests (see 9.4.2.4)

In general, only single failures are to be regarded. In the event ofhigher levels of risk, it may be necessary to ensure that more thanone failure cannot result in a hazardous condition.

Note 2 Measures to minimize risk in the event of failure

Note 2.1 Use of proven circuit techniques and components

These measures include but are not limited to:(1) Bonding of control circuits for operational purposes (see

9.4.3.1)(2) One terminal of the control device (i.e. the operating coil)

connected to the bonded conductor and all switchingelements (e.g. contacts) connected to the non-earthed(grounded) side of the control supply (see 9.1.4)

(3) Stopping by de-energizing (see 9.2.2)(4) Switching of all live conductors to the device being

controlled (see 9.4.3.1)(5) Use of switching devices having positive opening operation

(see IEC 947-5-1)(6) Circuit design to reduce the possibility of failures causing

undesirable operations

Note 2.2 Provisions for redundancy

By providing partial or complete redundancy it is possible tominimize the probability that one single failure in the electricalcircuit can result in a hazardous condition. Redundancy can beeffective in normal operation (i.e. on-line redundancy) or designedas special circuits that take over the protective function (i.e. off-lineredundancy) only where the operating function fails.

Where off-line redundancy that is not active during normaloperation is used, suitable measures shall be taken to ensure thatthese control circuits are available when required.

Note 2.3 Use of diversity

The use of control circuits having different principles of operationor differing types of devices may reduce the probability of faultsand failures giving rise to hazards. Examples include:

(1) The combination of normally open and normally closedcontacts operated by interlocking guards

(2) The use of different types of control circuit components inthe circuit

(3) The combination of electromechanical and electroniccircuits in redundant configurations

(4) The combination of electrical and non-electrical systems(e.g. mechanical, hydraulic, pneumatic) may perform theredundant function and provide the diversity.

Note 2.4 Functional tests

Functional tests shall be permitted to be carried out automatically,by the control system, or manually by inspection or tests at start-upand at predetermined intervals, or a combination as appropriate(see also 18.2 and 19.7).

9.4.2 Protection against unintended operation due to ground(earth) faults and voltage interruptions

9.4.2.1 Ground (earth) faultsGround (earth) faults on any control circuit shall not causeunintentional starting, potentially hazardous motions, or preventstopping of the machine. Grounded control circuits shall be inaccordance with 8.2 and 8.3. Ungrounded control circuits shall beprovided with an insulation-monitoring device that either indicatesa ground (earth) fault or interrupts the circuit automatically after aground (earth) fault.

9.4.2.2 Voltage interruptions

9.4.2.2.1 The requirements detailed in 7.5 shall apply.

9.4.2.2.2 Where a memory is used, its functioning in the event ofpower failure shall be ensured (e.g. by using a non-volatilememory) where such loss of memory can result in a hazardouscondition.SUBSTANTIATION:

Historical Background.


Harmonization - PurposeAs the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation, andat the same time maintain the high standard of electrical machinesafety, the NFPA 79 committee has expressed their desire, throughballoted vote, to harmonize NFPA 79 with IEC-60204-1.Importance of Issue - HarmonizationToday's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true.Differing electrical standards add a large cost to multinationalmanufacturers as they build and sometimes move manufacturingfacilities.

Harmonization - ObjectiveThis work is necessary to accomplish the goal of allowing industryto economically build one industrial machine capable of passing adetailed electrical safety inspection using either IEC 60204-1 orNFPA 79 standard.



Result

The NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committee formed20 Task Groups. Each Task Group was assigned one proposed newclause.


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The Task Group for Clause 9 consisted of Bill Anderson, DaveFisher, Dick Bromstad and Thomas Pilz. The Task Groupcompared NFPA-79-1997, Clause 9 with IEC 60204-1 Clause 9. TheTask Group presented its work to the entire committee on severaloccasions for review and comment. This proposal is a result ofthat work.

The Task Group proposes to renumber Clause 9 of NFPA 79-1997to correspond with IEC 60204-1. The task group proposes thefollowing changes to further improve usability.

Substantiation for NFPA 79-2002 Chapter 9 Control circuits andcontrol functions

9

Recommendation: Replace NFPA 79 1997 Editions Clause “9Control circuits” with “Chapter 9 Control circuits and controlfunctions”Substantiation: Represents the material in Chapte r 9 that includesboth circuits and functions. Editorial addition to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

9.1

Recommendation: Relocate NFPA 79 1997 Edition 9 title “ Controlcircuits” to 9.1.Substantiation: Chapter 9 is divided into 4 sections 1 Controlcircuits, 2 Control functions, 3 Protective interlocks, and 4 Controlfunctions in the event of failure. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.1.1

Recommendation: Add title “ Control circuit supply”Substantiation: Section 9.1 is divided into 4 subsections 1 Controlcircuit supply, 2 Control circuit voltages, 3 Protection, and 4Connection of control circuit devices. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.1.1.1

Recommendation: NFPA 79 1997 Edition 9.2.1 supply isolationrequirement is moved to this paragraph and voltage limitation toparagraph 9.1.2.1Substantiation: The word “control” was added to the original IECtext to clarify the type and application of the transformer. Note thisis also a proposed change to IEC. In order to ensure derivedcircuits are isolated, auto-transformers are not permitted. Editorial changes to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

9.1.1.2

Recommendation: Add new text to reflect current technology.Substantiation: Added requirements that reflect current NorthAmerican practices.

9.1.1.3

Recommendation: Add new text to reflect current technology.Substantiation: The requirements thus far, recognize that controlcircuits generally consist of equipment that has little or no faultwithstand rating. The use of a control transformer is generallyspecified to establish a lower control voltage and to limit theavailable fault current. This paragraph establishes when a controltransformer may not be required based on an acceptable voltageand reduced available fault being present.

9.1.1.4

Recommendation: Relocate NFPA 79 1997 Edition , 9.1 “Source ofcontrol power” paragraph and exception to 9.1.1.4 and exceptionwith marking requirement contained in 9.1.1.5Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.1.1.5

Recommendation: Add marking requirements from NFPA 79 1997Edition 4.5.1Substantiation: Editorial addition to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition. Actualmarking requirement from NFPA79:1997 4.5.1 [ now found in17.2].

9.1.2

Recommendation : Relocate NFPA 79 1997 Edition , 9.2 “Controlcircuit voltages” to 9.1.2Substantiation: Section 9.1 is divided into 4 subsections 1 Controlcircuit supply, 2 Control circuit voltages, 3 Protection, and 4Connection of control circuit devices. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.1.2.1

Recommendation: NFPA 79 1997 Edition 9.2.1, voltage limitation,and exceptions 1 and 3 are moved to this paragraph and exceptions1 and 2: and, supply isolation requirement from NFPA 79 1997Edition 9.2.1, to paragraph 9.1.1.1Substantiation: Editorial move to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition. Note:NFPA 79 1997 Edition, 9.2.1 Exception No. 2 requirements movedto Clause 6.4

9.1.2.2

Recommendation: NFPA 79 1997 Edition , 9.2.2 moved to thisparagraph, exception is deletedSubstantiation: Revised NFPA 79-1997, 9.2.2 requirement byremoving the exception. The proposer is unaware of any need fordc control voltage to exceed 250 volt in machine control circuits

9.1.3

Recommendation: Add title “ Protection” and paragraph point tochapter 7 “protection of equipment”Substantiation: Section 9.1 is divided into 4 subsections 1 Controlcircuit supply, 2 Control circuit voltages, 3 Protection , and 4Connection of control circuit devices. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.1.4Recommendation: Relocate NFPA 79 1997 Edition 9.4 title“Connection of control circuit devices” to 9.1.4Substantiation: Section 9.1 is divided into 4 subsections 1 Controlcircuit supply, 2 Control circuit voltages, 3 Protection, and 4Connection of control circuit devices. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition

9.1.4.1

Recommendation: Relocate NFPA 79 1997 Edition 9.4.1 andexceptions to 9.1.4.1Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.1.4.2

Recommendation: Relocate NFPA 79 1997 Edition 9.4.2 to 9.1.4.2Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2

Recommendation; Relocate NFPA 79 1997 Edition 9.5 title“Control functions” to 9.2


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Substantiation: Chapter 9 is divided into 4 sections 1 Controlcircuits, 2 Control functions, 3 Protective interlocks, and 4 Controlfunctions in the event of failure. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.2.1

Recommendation: Relocate NFPA79 1997 Edition 9.5.1 “ Startfunctions” to 9.2.1.Substantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

9.2.2

Recommendation: Relocate NFPA79 1997 Edition 9.5.2 firstparagraph to 9.2.2 and the second paragraph to 9.2.5.3.1 and9.2.5.3.2, add note to recognize new technology now availableSubstantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to he lp organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

9.2.3

Recommendation: Relocate NFPA79 1997 Edition 9.8 “ Operatingmodes” to 9.2.3.Substantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

9.2.3.1

Recommendation: Relocate NFPA 79 1997 Edition , 9.8.1 to 9.2.3.1Substantiation: Examples added for clarity. Editorial relocationand addition to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

9.2.3.2

Recommendation: Relocate NFPA 79 1997 Edition , 9.8.2 to 9.2.3.2Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.3.3

Recommendation: Relocate NFPA 79 1997 Edition , 9.8.3 to 9.2.3.3Substantiation: Parenthetical information added for ease of use.Editorial relocation and addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

9.2.3.4

Recommendation: Add additional indication requirement, currentpractice.Substantiation: The additional requirement requires some visualindication of the machines operating mode, which enhances safeoperation of the machinery.

9.2.4

Recommendation: Relocate NFPA79 1997 Edition 9.15 “ Overridingof safeguards” to 9.2.4.Substantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure and

Manual of Style for NFPA Technical Committee Documents 2000Edition.

9.2.5

Recommendation: Relocate NFPA79 1997 Edition 9.6 title “Operation” to 9.2.5.Substantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

9.2.5.1

Recommendation: Add title “ General”Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1General, 2 Start, 3 Stop, 4 Emergency operations, 5 Hold to runcontrols, 6 Two-hand control, and 7 Enabling device. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.This sub-subsection, “General”, is used to consolidate informationthat applies to all the parts of the Subsection 9.2.5 into one area forclarity

9.2.5.1.1

Recommendation: Restate interlock requirement that is also inStart 9.2.5.2.3 and Stop 9.2.5.3.3 for clarity.Substantiation: Added as a general requirement for clarity. Thischange will help to make clear the interlock requirements apply toall of the operation sub sections. Editorial change to NFPA 791997 Edition material location following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition

9.2.5.1.2

Recommendation; Add text; requiring that machine operationalcontrols include some method to prevent unintentional movement.Substantiation: Supports the OSHA requirements in 1910.147; thecontrol of hazardous energy

9.2.5.2

Recommendation: Relocate NFPA79 1997 Edition 9.6.1 title “ Start”to 9.2.5.2.Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1General, 2 Start, 3 Stop, 4 Emergency operations, 5 Hold to runcontrols, 6 Two-hand control, and 7 Enabling device. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

9.2.5.2.1

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.1 1st

paragraph first sentence information moved to 9.2.5.2.1Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.2.2

Recommendation: Added textSubstantiation: There is no comparable NFPA 79-1997requirement. This text is comparable with the requirements of, andto harmonize with, IEC 60204-1, Clause 9. The requirement forhold to run controls on machines, where it is impracticable toprovide conventional safeguards, will enhance safe operation of themachinery. In addition, there may be specific machine operatingconditions that require hold to run controls to ensure properoperation.

9.2.5.2.3


paragraph second sentence information moved to 9.2.5.2.3Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.


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9.2.5.2.4


paragraph moved to 9.2.5.2.4Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.3

Recommendation: Relocate NFPA79 1997 Edition 9.6.2 title “ Stop”to 9.2.5.3.Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1General, 2 Start, 3 Stop, 4 Emergency operations, 5 Hold to runcontrols, 6 Two-hand control, and 7 Enabling device. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

9.2.5.3.1

Recommendation: Relocate requirement from NFPA 79-1997,9.5.2, last paragraph 1st sentence to 9.2.5.3.1.Substantiation: This requirement currently appears in NFPA 79-1997, 9.5.2, last paragraph. It has been separated out to add clarityand to align with the IEC 60204-1 structure; also to reflectconsistency in stop circuit, function and operation requirement

9.2.5.3.2

Recommendation: Relocate requirements and edit text from NFPA79-1997 Edition, 9.5.2 last paragraph to 9.2.5.3.2Substantiation: This requirement currently appears in NFPA 79-1997, 9.5.2, last paragraph. It has been separated out to add clarityand to align with the IEC 60204-1 structure.

9.2.5.3.3

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.2 2ndparagraph to 9.2.5.3.3Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.4

Recommendation: Add title “ Emergency operations (emergencystop, emergency switching off)”Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1General, 2 Start, 3 Stop, 4 Emergency operations, 5 Hold to runcontrols, 6 Two-hand control, and 7 Enabling device. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

9.2.5.4.1

Recommendation: Add title “ General” and textSubstantiation: Sub-subsection 9.2.5.4 is divided into 3 (sub) sub-subsections 1 General, 2 Emergency stop, and 3 Emergencyswitching off. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.This (sub)sub-subsection, “General”, is used to consolidateinformation that applies to all the parts of the sub-subsection9.2.5.4 into one area for clarity

9.2.5.4.2

Recommendation: Relocate NFPA79 1997 Edition 9.6.3 title “Emergency stop” to 9.2.5.4.2.Substantiation: Sub-subsection 9.2.5.4 is divided into 3 (sub) sub-subsections 1 General, 2 Emergency stop, and 3 Emergencyswitching off. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.4.2.1


paragraph requirement moved to 9.2.5.4.2.1Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.4.2.2

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.3 2nd


9.2.5.4.2.3

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.3 3rd

paragraph requirement moved to 9.2.5.4.2.3 with editorialclarificationSubstantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.4.2.4

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.3 4th

paragraph 1st sentence requirement moved to 9.2.5.4.2.4. ReplacedNFPA 79 1997 Edition, 9.6.3 4th paragraph 2nd sentence requirementwith added exception to allow for new technology.Substantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition. Thenew technology in the exception is currently available from severalvendors and approved for use by recognized third parties.

9.2.5.4.2.5

Recommendation: Relocate NFPA 79 1997 Edition, 9.6.3, 5th


9.2.5.4.3

Recommendation: Add title “ Emergency switching off”Substantiation: Sub-subsection 9.2.5.4 is divided into 3 (sub) sub-subsections 1 General, 2 Emergency stop, and 3 Emergencyswitching off. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

9.2.5.4.3.1

Recommendation: Add modified IEC text to permit Emergencyswitch offSubstantiation: The proposer understands that emergencyswitching off is a practice recognized and used throughout anumber of machinery sectors. This additional subclause includesprovisions for the implementation of this practice. Some industrieshave implemented this practice to permit an emergency responsefor non-motion hazards. Clause three has been revised to includea definition of emergency switching off.

9.2.5.4.3.2

Recommendation: Add modified IEC text to clarify how Emergencyswitch off can be accomplished and when Emergency switch off isnot necessarySubstantiation: The proposer understands that emergencyswitching off is a practice recognized and used throughout anumber of machinery sectors. This additional paragraph includesexamples of how and to do the implementation of this practice.Some industries have implemented this practice to permit anemergency response for non-motion hazards. Clause three hasbeen revised to include a definition of emergency switching off.

9.2.5.5

Recommendation: Relocate NFPA 79 1997 Edition, 9.7 title “Hold-to-run controls”, to 9.2.5.5Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1General, 2 Start, 3 Stop, 4 Emergency operations, 5 Hold to runcontrols, 6 Two-hand control, and 7 Enabling device. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.


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9.2.5.5.1

Recommendation: Relocate NFPA 79 1997 Edition, 9.7.1requirement to 9.2.5.5.1 text edited for claritySubstantiation: Editorial clarification and relocation to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.2.5.5.2

Recommendation: Relocate NFPA 79 1997 Edition, 9.7.2requirement to 9.2.5.5.2 text edited for claritySubstantiation: Editorial clarification and relocation to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

9.2.5.6

Recommendation: Relocate NFPA79 1997 Edition 9.14, title “Two-hand control circuits” and modified text to 9.2.5.6 Substantiation: Subsection 9.2.5, is divided into 7 sub-subsections 1Start functions, 2 Stop functions, 3 Operating modes, 4 Overridingof safeguards, 5 Operation, 6 Two-hand control, and 7 Enablingdevice. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.The requirement of two hand control have been modified bydeleting permission to utilize Type 1 and 2 control because thecircuitry is conventionally not suitable for applications that requireanti-tie-down features. Text has been changed to combine therequirements for Types 1, 2 and 3 into one provision and thuseliminate the type designations.

9.2.5.7

Recommendation: Add title “ Enabling device”Substantiation: Subsection 9.2.5 is divided into 7 sub-subsections 1Start functions, 2 Stop functions, 3 Operating modes, 4 Overridingof safeguards, 5 Operation, 6 Two-hand control, and 7 Enablingdevice. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New text added for Proposed NFPA 79-2002 9.2.5.7 “enablingdevice”, because it provides additional methods for personnelprotection than the present NFPA 79-1997 provides

9.2.5.7.1

Recommendation: Add definition and description of an enablingdeviceSubstantiation: The proposer understands that use of an enablingdevice is a practice recognized and used throughout a number ofmachinery sectors. This additional subclause includes adescription of such device

9.2.5.7.2

Recommendation: Add restriction for safe operation of anenabling device representing current practiceSubstantiation: The proposer understands that use of an enablingdevice is a practice recognized and used throughout a number ofmachinery sectors.

9.2.5.7.3

Recommendation: Add the design features of an enabling devicerepresenting current practiceSubstantiation: The proposer understands that use of an enablingdevice is a practice recognized and used throughout a number ofmachinery sectors.

9.2.5.7.4

Recommendation: Add restriction for safe operation of anenabling device representing current practiceSubstantiation: The proposer understands that use of an enablingdevice is a practice recognized and used throughout a number ofmachinery sectors.

9.2.5.7.5

Recommendation: Add restriction for safe operation of anenabling device representing current practiceSubstantiation: The proposer understands that use of an enablingdevice is a practice recognized and used throughout a number ofmachinery sectors. This “enabling device” is a type of additionalheld switch that is connected in series with the usual momentary“start” push button. This enabling (similar to an “arming” switch?)device prevents the casual/unintentional starting of the machine.An enabling device is not required for all systems. When one isprovided, the guidelines shown must be followed. No conflictexists with NFPA79

9.2.6

Recommendation: Add title “ Combined start and stop controls ”and textSubstantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.New text added for Proposed NFPA 79-2002 9.2.6 “Combined startand stop controls” was added because it prevents use of “push-push”, alternate action a push button as the primary start device.

9.2.7

Recommendation: Add title “ Cable-less control functions”Substantiation: Section 9.2 is divided into 7 subsections 1 Startfunctions, 2 Stop functions, 3 Operating modes, 4 Overriding ofsafeguards, 5 Operation, 6 Combined start and stop controls, and 7Cable-less control functions. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.New subsection from IEC 60204-1 1997 Edition 9.2.7 for ProposedNFPA 79-2002 9.2.7 “Cable-less control functions” was added withminor clarifying editorial changes to provided requirements thatrecognize the current practice for cable-less control applications.Radio-modem controls are used on a regular basis for control overa long distance, such as for decentralized sewage pumping stations.

9.2.7.19.2.7.1.1 though 9.2.7.1.3

Recommendation: Add title “ General” and IEC 60204-1 1997Edition 9.2.7.1 textSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection, “General”, is used to consolidate informationthat applies to all the parts of the Subsection 9.2.7 into one area forclarity

9.2.7.29.2.7.2.1 though 9.2.7.2.3

Recommendation: Add title “ Control limitation” and IEC 60204-11997 Edition 9.2.7.2 textSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection, “Control limitations”, is used to consolidateinformation about unique functional requirements that presentthemselves in cable-less controls [when used] verses the hard wiredportion of a machine’s control systems


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9.2.7.39.2.7.3.1 though 9.2.7.3.2

Recommendation: Add title “ Stop” and IEC 60204-1 1997 Edition9.2.7.3 textSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection, “Stop”, is used to consolidate informationabout unique requirements for the stop function that presentthemselves in cable-less controls [when used] verses the hard wiredportion of a machine’s control systems

9.2.7.4

Recommendation: Add title “ Serial data communication” and IEC60204-1 1997 Edition 9.2.7.4 text with minor clarifying editorialchanges and noteSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection paragraph, “Serial data communication”, isused present the requirements for serial data links and the specialcapabilities required when used in machines for safety criticalcontrol applications. This control situation is relatively new butseen in some current machine applications.

9.2.7.5

Recommendation: Add title “ Use of more than one operatorcontrol station” and IEC 60204-1 1997 Edition 9.2.7.5 text andexception with minor clarifying editorial changesSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection paragraph, “Use of more than one operatorcontrol station”, presents the requirements for the situation wheremultiple operator control stations may exist. This control situationis relatively new but seen in some current machine applications.

9.2.7.6

Recommendation: Add title “ Battery powered operator controlstations” and IEC 60204-1 1997 Edition 9.2.7.6 textSubstantiation: Subsection 9.2.7 is divided into 6 sub-subsections 1General, 2 Control limitation, 3 Stop, 4 Serial data communication,5 Use of more than one operator control station, 6 Battery-powered operator controls. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.This sub-subsection paragraph, “Battery powered operator controlstations”, presents the requirements when portable operatorcontrol stations may exist. This control situation is in somecurrent machine applications in warehouses and material handlingsituations.

9.3

Recommendation; Add title “ Protective interlocks”Substantiation: Chapter 9 is divided into 4 sections 1 Controlcircuits, 2 Control functions, 3 Protective interlocks, and 4 Controlfunctions in the event of failure. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.Guarding and interlocking application requirement are generallyfound in other equipment standards and legal requirements [e.g.ANSI B11 series and OHSA regulations such as CFR 29 ChapterXVII 1910.217 “Mechanical power presses”]. The text in this partof Chapter 9 to proposed NFPA 79-2002 Edition is added tosupport the execution of the needed guarding and interlockingfunction requirements from those standards and regulations.

9.3.1

Recommendation: Add title “ Re-closing or resetting of aninterlocking safeguard” and IEC 60204-1 1997 Edition 9.3.1 textSubstantiation: Section 9.3 is divided into 5 subsections 1 Re-closing of resetting of an interlocking safeguard, 2 Over-travellimits, 3 Operation of auxiliary functions, 4 Interlocks betweendifferent operations and for contrary motions, 5 Reverse currentbraking. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New text added for Proposed NFPA 79-2002 9.3.1 “Re-closing orresetting of an interlocking safeguard” was added because providesrequirements for application of safeguards interlock when they areused.

9.3.2

Recommendation: Add title “ Over-travel limits” and IEC 60204-11997 Edition 9.3.2 textSubstantiation: Section 9.3 is divided into 5 subsections 1 Re-closing of resetting of an interlocking safeguard, 2 Over-travellimits, 3 Operation of auxiliary functions, 4 Interlocks betweendifferent operations and for contrary motions, 5 Reverse currentbraking. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New text added for Proposed NFPA 79-2002 9.3.2 “Over travellimits” was added because provides requirements for application ofover travel limits when they are used.

9.3.39.3.3.1

Recommendation: Revise existing NFPA 9-1997 9.9 title “Feedinterlocked with spindle drive” to “Operation of auxiliaryfunctions” and add IEC 60204-1 1997 Edition 9.3.3, 1st paragraphtextSubstantiation: Section 9.3 is divided into 5 subsections 1 Re-closing of resetting of an interlocking safeguard, 2 Over-travellimits, 3 Operation of auxiliary functions, 4 Interlocks betweendifferent operations and for contrary motions, 5 Reverse currentbraking. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New text, added for Proposed NFPA 79-2002 9.3.3 “Operation ofauxiliary functions” to extend interlocking for spindle drive toauxiliary functions

9.3.3.2

Recommendation: And add IEC 60204-1 1997 Edition 9.3.3, 2nd

paragraph textSubstantiation: Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.New text, was added for Proposed NFPA 79-2002 9.3.3.2 providesrequirements of interlocking where the failure of a motor cancause hazardous condition or damage to the machine.

9.3.49.3.4.1 through 9.3.4.4

Recommendation: Revise existing NFPA 9-1997 9.11 title “Motorcontactors and starters” and existing NFPA 9-1997 9.12 title “Relaysand solenoids” to “ Interlocks between different operations and forcontrary motions” and add IEC 60204-1 1997 Edition 9.3.4 textSubstantiation: Section 9.3 is divided into 5 subsections 1 Re-closing of resetting of an interlocking safeguard, 2 Over-travellimits, 3 Operation of auxiliary functions, 4 Interlocks betweendifferent operations and for contrary motions, 5 Reverse currentbraking. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New title and text, more than existing NFPA 9-1997 9.11 and 9.12embodied and extended in Proposed NFPA 79-2002 9.3.4“interlocks between different operations and for contrary motions”

9.3.59.3.5.1 and 9.3.5.2

Recommendation: Add IEC 60204-1 1997 Edition 9.3.5 title,“Reverse current braking”, and text


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Substantiation: Section 9.3 is divided into 5 subsections 1 Re-closing of resetting of an interlocking safeguard, 2 Over-travellimits, 3 Operation of auxiliary functions, 4 Interlocks betweendifferent operations and for contrary motions, 5 Reverse currentbraking. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.New text added for Proposed NFPA 79-2002 9.3.5 “Reverse currentbraking” was added because provides requirements reflectingpresent practices.

9.4

Recommendation; Add title “ Control functions in the event offailure” to 9.4Substantiation: Chapter 9 is divided into 4 sections 1 Controlcircuits, 2 Control functions, 3 Protective interlocks, and 4 Controlfunctions in the event of failure. Editorial addition to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.New text added for Proposed NFPA 79-2002 9.4 “Control functionsin the event of failure” was added because provides requirementsfor application when the failure of control circuit must not resultin maloperation of the machine.

9.4.1

Recommendation: Add title, “ General requirements” and text withminor clarifying editorial changes from IEC 60204-1 1997 Edition9.4.1 1st paragraph. Text with minor clarifying editorial changesfrom IEC 60204-1 1997 Edition 9.4.1, 2 nd paragraph and all of 9.4.2“Measures to minimize risk in the event of failure” will be moved toa note.Substantiation: Section 9.4 is divided into 2 subsections 1 Generalrequirements, 2 Protection against unintended operation due toground (earth) faults and voltage interruptions. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.This sub-subsection, “General requirements”, is used toconsolidate information that applies to all the parts of the Section9.4 into one area for clarity.The text with minor clarifying editorial changes from IEC 60204-11997 Edition 9.4.1, 2 nd paragraph and all of 9.4.2 “Measures tominimize risk in the event of failure” is considered valuableguidance to be considered in control system design, though notenforceable, should be retained in a note form.

9.4.2

Recommendation: Add title, “ Protection against unintendedoperation due to ground (earth) faults and voltage interruptions”from IEC 60204-1 1997 Edition 9.4.3 with added USA words groundfor “earthed”Substantiation: Section 9.4 is divided into 2 subsections 1 Generalrequirements, 2 Protection against unintended operation due toground (earth) faults and voltage interruptions. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

9.4.2.1

Recommendation: Add title, “ Ground (earth) faults” with minorclarifying editorial changes from IEC 60204-1 1997 Edition 9.4.3.1,and relocate NFPA 79 1997 Edition 9.3 2 nd sentence with additionaltext . Relocate NFPA 79 1997 Edition 9.3 1 st sentence to 8.3 Controlcircuits “Control circuits shall be permitted to be grounded orungrounded.”Substantiation: Subsection 9.4.2 is divided into 2 sub-subsections 1“Ground (earth) faults”, 2 “Voltage interruptions”. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.The added text is to clarify the coordination of control circuitground (earth) requirements with additional requirements withinthis standard and provide additional requirements specific togrounded and ungrounded control circuits.

9.4.2.29.4.2.2.1 and 9.4.2.2

Recommendation: Add title, “ Voltage interruptions” and text fromIEC 60204-1 1997 Edition 9.4.3.2.Substantiation: Subsection 9.4.2 is divided into 2 sub-subsections 1“Ground (earth) faults”, 2 “Voltage interruptions”. Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.The added text is to clarify the coordination of control circuitground (earth) requirements with additional requirements withinthis standard and provide additional requirements specific togrounded and ungrounded control circuits.New text added for Proposed NFPA 79-2002 9.4.2.2 “Voltageinterruptions” was added because provides requirements forapplication when voltage interruption can result in hazardouscondition.

NFPA 79 1997 Edition, 9.2.1 Exception No. 2

Recommendation:, NFPA 79 1997 Edition 9.2.1 Exception No. 2 toproposed NFPA 79 2003 Edition 6.4 titled “ Protection by the useof PELV”Substantiation: Editorial relocation of topic to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

NFPA 79 1997 Edition, 9.2.2 Exception

Recommendation: NFPA 79 1997 Edition , 9.2.2 exception isdeletedSubstantiation: Revised NFPA 79-1997, 9.2.2 requirement byremoving the exception. The proposer is unaware of any need fordc control voltage to exceed 250 volt in machine control circuits

NFPA 79 1997 Edition, 9.3 “Grounding of control circuits”, 1st

sentence

Recommendation:, Relocate NFPA 79 1997 Edition 9.3 1 st sentenceto 8.3 Control circuits “Control circuits shall be permitted to begrounded or ungrounded.”Substantiation: Editorial relocation of topic to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

NFPA 79 1997 Edition 9.10 “Machinery door interlocking”

Recommendation: Drop, NFPA 79 1997 Edition 9.10 title “Machinery door interlocking” and text from proposed NFPA 792002 Edition.Substantiation: NFPA 79 1997 Edition 9.10 “ Machinery doorinterlocking” address the mechanical issues surrounding machineguarding, and which guards need to be interlocked, and the natureof the interlock. The mechanical issue of door interlocking isbeyond the stated purpose of NFPA 79 1997 Edition 1.2, and can befound in the relevant machinery safety standards. Section 9.3addressed the electrical control requirements in support of themechanically determined interlocks

NFPA 79 1997 Edition 9.13

Recommendation: Drop, NFPA 79 1997 Edition 9.13 title, “ Setupmode” and text from proposed NFPA 79 2002 Edition. NFPA 791997 Edition , 9.13, requirements are in 9,2,4 “Overriding ofsafeguards” with additional requirements in 9.2.5.3 “ Stop” and9.2.5.7 “Enabling device”Substantiation: Current practice in proposed 9.2.4 “Overriding ofsafeguards “ and 9.2.5.3 “Stop “ and 9.2.5.7 “Enabling device “represent a more comprehensive approach to the required Setupmode function. Editorial relocation of topic to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

Attachment C: NFPA 79 1997 Edition to NFPA 79 2002 CrossReferenceCLAUSE NUMBERS: NFPA 79-1997 Clause 9 VERSUSPROPOSED NFPA 79-2002 Chapter 9

Clauses in Substantiation are in numerical order, Last Paragraph9.4.2.2.2


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NFPA 79: 1997 Proposed NFPA 79: 2002

Clause Heading Section/Paragraph

Heading

9 Control circuits 9.1 Control circuits9.1 Source of control power 9.1.1.4

Exception 9.1.1.4 Exception9.2 Control circuit voltages 9.1.2 Control circuit voltages9.2.1 9.1.2.1 AC control circuit voltages

Exception No.1: 9.1.2.1 Exception No. 1Exception No.2: moved Covered in 6.4Exception No.3: 9.1.2.1 Exception No 2

9.2.2 9.1.2.2 DC control circuit voltagesException 9.1.2.2 Exception

9.3 Grounding of control circuits elsewhere provisions elsewhere see 8.3 & 9.4.2.19.4 Connection of control devices 9.1.4 Connection of control devices9.4.1 9.1.4.1

Exception No.1: 9.1.4.1 Exception No.1:Exception No.2: 9.1.4.1 Exception No.2:Exception No.3: 9.1.4.1 Exception No.3:Exception No.4: 9.1.4.1 Exception No.4:Exception No.5: 9.1.4.1 Exception No.5:Exception No.6: 9.1.4.1 Exception No.6:

9.4.2 9.1.4.29.5 Control functions 9.2 Control functions9.5.1 Start functions 9.2.1 Start functions9.5.2 Stop functions 9.2.2 Stop functions Note: Stop function requirement also

covered in 9.2.5 “Operation” & 9.2.5.3 “Stop”9.6 Operation 9.2.5 Operation9.6.1 Start 9.2.5.2 Start9.6.2 Stop 9.2.5.3 Stop9.6.3 Emergency stop 9.2.5.4.2 Emergency stop9.7 Hold to run circuits 9.2.5.5 Hold-to-run controls9.7.1 9.2.5.59.7.2 9.2.5.5.19.8 Operating modes 9.2.3 Operating modes9.8.1 9.2.3.19.8.2 9.2.3.29.8.3 9.2.3.39.9 Feed interlocked with spindle drive 9.3.3 Operation of auxiliary functions9.10 Machinery door interlocking dropped Not carried forward not in NFPA79 Purpose Statement.9.11 Motor contactors and starters 9.3.4.29.12 Relays and solenoids 9.3.4.29.13 Setup mode dropped Essentially part in 9.2.4, 9.2.5.3.3 and 9.2.5.79.14 Two-hand control circuits 9.2.5.6 Two-hand control9.15 Overriding of safeguards 9.2.4 Suspension of safeguards


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Proposed new Table of content

Chapter Section

SubsectionSub-subsection

Sub-sub-subsection

9 Control circuits and control functions

9.1 Control Circuits

9.1.1 Control circuit supply9.1.2 Control circuit voltages9.1.3 Protection9.1.4 Connection of control circuit devices

9.2 Control functions

9.2.1 Start functions9.2.2 Stop functions9.2.3 Operating modes9.2.4 Overriding of safeguards9.2.5 Operation

9.2.5.1 General9.2.5.2 Start9.2.5.3 Stop9.2.5.4 Emergency operations

(emergency stop, emergency switch off)

9.2.5.4.1 General9.2.5.4.2 Emergency Stop9.2.5.4.3 Emergency

switch off

9.2.5.5 Hold-to-run controls9.2.5.6 Two-hand control9.2.5.7 Enabling device

9.2.6 Combined start and stop controls9.2.7 Cable-less control functions

9.2.7.1 General9.2.7.2 Control limitation9.2.7.3 Stop9.2.7.4 Serial data communication9.2.7.5 Use of more than one operator

control station9.2.7.6 Battery-powered operator

control stations

9.3 Protective interlocks

9.3.1 Re-Closing of resetting of an interlockingsafeguard

9.3.2 Overtravel limits9.3.3 Operation of auxiliary functions9.3.4 Interlocks between different operations and

for contrary motions9.3.5 Reverse current braking

9.4 Control functions in the event of failure

9.4.1 General requirements9.4.2 Protection against unintended operation due

to ground (earth) faults and voltage interruptions

9.4.2.1 Ground (earth) faults9.4.2.2 Voltage interruptions

COMMITTEE ACTION: Accept in Principle.Revise text to read as follows:8 Grounding.

8.1 General. This clause provides for grounding, bonding andgrounded conductor requirements.

Note: The terms protective earthing conductor, protective bondingconductor, protective conductor, neutral, and earth are used inother countries.

8.1.1 Connections. Grounded conductors shall not be connectedto the equipment grounding (protective) circuit, except for, atseparately derived systems.

8.2 Equipment grounding (protective bonding) circuit.

8.2.1 Grounding system. The equipment grounding (protectivebonding) circuit consists of:(1) The equipment grounding (PE) terminal(s);(2) The conductive structural parts of the electrical equipment andthe machine;(3) The equipment grounding (protective) conductors andequipment bonding jumpers

All parts of the equipment grounding (protective bonding) circuitshall be capable of withstanding the highest thermal andmechanical stress that can be caused by fault currentswhich could flow in that part of the circuit.

All exposed conductive parts of the electrical equipment and themachine(s) shall be connected to the equipment grounding(protective bonding) circuit.

Exception: Small parts such as screws, rivets and nameplates thatare not likely to become energized shall not be required to begrounded.

8.2.1.1 Equipment grounding. The machine and all exposed,noncurrent-carrying conductive parts, material, and equipmentlikely to be energized shall be effectively grounded. Whereelectrical devices are mounted on metal mounting panels that arelocated within nonmetallic enclosures, the metal mounting panelsshall be effectively grounded.

8.2.1.2 Equipment grounding terminal.

(1) For each incoming supply circuit , an equipment grounding(external protective ) conductor terminal shall be provided in thevicinity of the associated phase conductor terminals.

(2) All of the items in 8.2.1.1 shall be interconnected to thisterminal.

(3) The terminal shall accommodate an equipment groundingconductor sized in accordance with Table XX.

Note: The minimum cross sectional area of the external protectivecopper conductor may be required to be larger for IECapplications. See Table 1, IEC 60204-1 for these requirements.

8.2.1.2.1 Equipment grounding terminal marking.

The equipment grounding terminal shall be identified with theword "GROUND," the letters "GND" or "GRD," the letter "G," bycoloring the terminal GREEN or the following symbol. In additionto the required marking, the letters PE shall also be permitted toidentify this terminal.

NOTE: Some other standards require the letters PE for theconnection to the external protective earthing system.


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Exception: Where an attachment plug and receptacle are used asthe disconnecting means, 5.3.3.3 shall apply.

8.2.2 Equipment grounding (protective) conductors and bondingjumpers.

Equipment grounding (protective) conductors and bondingjumpers shall be identified in accordance with 14.2.2.

8.2.2.1 Conductors used for grounding and bonding purposes shallbe copper. Stipulations on stranding and flexing as outlined in thisstandard shall apply.

8.2.2.2 Equipment grounding conductors and bonding jumpersshall be insulated, covered, or bare and shall be protected againstphysical damage.

8.2.2.3 Equipment grounding conductors and bonding jumpers ofthe wire type shall not be smaller than shown in Table XX.Equipment grounding conductors and bonding jumpers of thewire type shall not be smaller than shown in Table XX, but shallnot be required to be larger than the circuit conductors supplyingthe equipment.

8.2.2.3.1 (2) It shall be permitted to use machine members orstructural parts of the electrical equipment in the equipmentgrounding circuit provided that the cross-sectional area of theseparts is at least electrically equivalent to the minimum cross-sectional area of the copper conductor required. <<this was noteto table but was moved here according to Log #81>>

Table XX — Minimum Size of equipment groundingconductors and bonding jumpers

Column “A,” AmperesRating or setting ofautomatic overcurrentdevice in circuit ahead ofthe equipment

Copper Conductor Size, AWGor kcmil

10 16 or 1815 14, 16, or 1820 12, 14, 16, or 1830 1040 1060 10100 8200 6300 4400 3500 2600 1800 01000 2/01200 3/01600 4/02000 2502500 3503000 4004000 5005000 7006000 800

* Permitted only in multiconductor cable whereconnected to portable or pendant equipment.

(1) Column "A" indicates the maximum rating or setting of theovercurrent device in the circuit ahead of the equipment.

(2) It shall be permitted to use machine members or structuralparts of the electrical equipment in the equipment groundingcircuit provided that the cross-sectional area of these parts is atleast electrically equivalent to the minimum cross-sectional area ofthe copper conductor required. <<moved to precede tableaccording to Log #81>>

8.2.3 Continuity of the equipment grounding (protective bonding)circuit.

8.2.3.1 The continuity of the equipment grounding (protectivebonding) circuit shall be ensured by effective connections throughconductors or structural members.

8.2.3.2 Removing a device shall not interrupt the continuity of theequipment grounding (protective) circuit.

8.2.3.3 Bonding of equipment with bolts or other identified meansshall be permitted where paint and dirt are removed from the jointsurfaces or where the bonded members are effectively penetrated.

8.2.3.4 Moving machine parts, other than accessories orattachments, having metal-to-metal bearing surfaces shall beconsidered as bonded. Sliding parts separated by a nonconductivefluid under pressure shall not be considered as bonded.

8.2.3.5 Raceways, wireways, and cable trays shall not be used asequipment grounding or bonding conductors.

8.2.3.6 Doors or Covers.

(1) Where electrical devices are mounted on conductive doors orcovers, an equipment (protective) bonding jumper shall beinstalled.

(2) An equipment (protective) bonding jumper shall connect theconductive door or cover to the equipment enclosure or to an equipmentgrounding (protective bonding) terminal within the enclosure.

8.2.3.7 Portable, pendant, and resilient-mounted equipment shallbe bonded by separate conductors. Where multiconductor cable isused, the bonding conductor shall be included as one conductorof the cable.

8.2.3.8 Where equipment grounding conductors are subject tophysical damage they shall be protected or be monitored to ensurecontinuity.

8.2.4 Exclusion of switching devices. The equipment grounding(protective) circuit shall not contain any switches or overcurrentprotective devices. Links or plugs in the grounding circuit shall bepermitted if properly labeled or interlocked with the controlcircuits.

8.2.7 Equipment grounding (protective) conductor connectingpoints.

(1) All equipment grounding (protective) conductors shall beterminated in accordance with 14.1.1. The equipment grounding(protective) conductor connecting points shall have no otherfunction.

(2) The equipment grounding conductor connecting points, otherthan the equipment grounding terminal, shall beidentified by a green color or by use of the symbol thatappears in 8.2.1.2.1.

Note: The letters PE or the bicolor green and yellow is used insome countries.

8.3 Control circuits. Control circuits shall be permitted to begrounded or ungrounded. Where grounding is provided, that sideof the circuit common to the coils shall be grounded at the controltransformer if alternating current or at the power supply terminal ifdirect current. Where grounding is not provided, an insulationmonitoring system shall be utilized as described in 9.4.2.1.Ungrounded control circuits shall be provided with an insulation- monitoring device that either indicates a ground (earth) fault orinterrupts the circuit automatically after a ground (earth) fault.

Exception No. 1: Exposed control circuits as permitted by 6.4 6.3 shall begrounded.

Exception No. 2: Overload relay contacts shall be permitted to beconnected between the coil and the grounded conductor where theconductors between such contacts and coils of magnetic devices do notextend beyond the control enclosure.

Exception No. 3: NFPA 70, Article 725, Class 2, low voltage circuitsshall not require insulation monitoring.

8.5 Lighting circuits.

8.5.1 One conductor of all machine lighting and maintenancelighting circuits shall be grounded. The grounded conductor(s)shall be identified in accordance with 14.2, Identification ofconductors.


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8.5.2 Where the lighting circuit is supplied by a separate isolationtransformer, the grounding shall occur at the transformer. Wherethe equipment maintenance lighting circuit is supplied directlyfrom the plant lighting circuit, the grounding shall occur at thegrounding terminal.

8.5.3 The grounded conductor, where run to a screw-shelllampholder, shall be connected to the screw-shell.COMMITTEE STATEMENT: Revision to the proposed text wereas follows: 1) In Section 9.1.1.4, revise "main disconnecting means" to"supply disconnecting means" and add the word "circuit" after theword supply for editorial consistency. 2) In 9.2.2(a) and (b), make theeditorial corrections such aschange e.g. to i.e. and delete see x.xx in (a) and (b). Also, correctsecond (b) to a (c). 3) In 9.2.3.2, change the first word "when" to "where" and correctresult 4) In 9.2.3.3, insert the word "Note" before (see). Change theword "suspension" to "overriding." 5) In 9.2.4, change should to shall in the second sentence toComply with the NFPA Manual of Style. 6) n 9.2.5.1.1 and 9.2.5.2.4(d),delete the parentheticalexpression. 7) In 9.2.5.3.2, replace and/or with and. 8) Globally throughout Clause 9, delete all "(see x.xxx)" 9) In 9.2.5.4.1, delete last sentence since it is unnecessary. 10) In 9.2.5.4.2.1, change the word "has" to "shall have" in thefirst sentence. 11) In 9.2.5.4.2.2, editorially revise the sentence to read asfollows: "Where required, provisions to connect additionalemergency stop devices shall be provided in accordance with 10.7." 12) In 9.2.5.4.2.4, insert the word "only" before the word"hardwired" since there was no substantiation to delete the wordonly 13) In 9.2.5.4.3.2, change the word "is" to the word "shall be" andinsert the word "circuit" after the word "supply" in the firstsentence. 14) In 9.2.5.7.1, add "as used in this clause is defined as" forclarity and allows the verb is. 15) In 9.2.6, change "pushbutton" to "Pushbuttons" and deletethe word "a". Editorial 16) In 9.2.7.3.2, change "having" to "that has" and delete theword "and" after the word "functions. 17) In 9.3.4.2, revise sentence for clarity. 18) In 9.4.2, revise title for clarity. 19) Delete 9.4.2.2 since it is already covered in 11.3.2 and 7.5. 20) In 9.4.1, Notes 2.2 and 2.4, replace the word shall with theword "may". 21) Due to an inadvertent omission, add the last sentence to9.2.5.3.2 "Stop function shall operate by deenergizing that relevantcircuit and shall override related start functions." taken fromNFPA 79-1997, 9.5.2 22) Due to an inadvertent omission, Insert a new secondsentence in 9.2.5.5.2 to read as follows: "The prevention of RUNor AUTOMATIC operation during JOG or INCH shall beaccomplished by an operator interface and a separate JOG orINCH selection method." taken from 1997 NFPA 79-1997, 9.7.2.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE:ANDERSON: In the committee statement point # 7 " In 9.2.5.3.2,replace and/or with and was not immediately seen as feasiblewithout loosing the original meaning and failing that attempt theand/or was to remain. I look for this to be a point of clarificationat the ROC meeting. In the committee statement point # 9 "In 9.2.5.4.1, delete lastsentence since it is unnecessary", I would argue that the lastsentence should remain as it is pointing to another place in thestandard where control functions, "additional safety related stops",are described. Chapter 9 title is Control circuits and controlfunctions, Chapter 11 title is Electronic equipment, it may not beobvious from the index that Chapter 11 also contains additionalsafety related stop control functions. Since one of Chapter 9's maintopics is "control functions", and additional direct treatment of themain topic is outside the chapter, for good reason, reference to theadditional location is preferable to that of repeating the remotelylocated material. 9.2.5.4.1 General This standard specifies the requirements for the emergency stopand emergency switching off functions, each of which is, in thisstandard, initiated by a single human action. Emergency switching

off is an emergency operation intended to switch off the supply ofelectrical energy to all or a part of an installation where a risk ofelectric shock or another risk of electrical origin is involved. Forother safety related stop functions see 11.3.4. In the committee statement point #14 "In 9.2.5.7.1, add 'as usedin this clause is defined as ' for clarity and uses the verb is." Thecorrected 9.2.5.7.1 should actually include additional commas anditalicizing [see my comment to proposal 138] and read: 9.2.5.7.1 An enabling device, as used in this chapter, is defined asan additional manually operated control device used inconjunction with a start control and which, when continuouslyactuated, allows a machine to junction. In the committee statement point #15 "In .2.6, change'pushbutton' to 'Pushbuttons' and delete the word 'a'. Editorial".My notes indict that the referral to a single pushbutton wasintended and was the intent of when the requirement in 9.2.6 wasoperative with respect to a pushbutton. I believe the agreed text for9.2.6 is: 9.2.6 Combined start and stop controls. A single pushbutton andother devices that alternately start and stop motion shall only beused for secondary functions where no hazardous condition ariseswhen they are operated. In the committee statement point #16 "In 9.2.7.3.2, change'having' to ' than has ' and delete the word 'and' after the word'functions'." Deleting the word "and", changes the meaning of thesentence to nonsense because in fact the machine is equipped withthe "cable-less control", and has the "safety-critical functions". The"function" is not a part of the group of physical things, e.g.machine, cable-less control. From Webster's Collegiate Dictionary, 10th edition: functions[noun] " the action for which a person or thing is specially fittedor used or for which a thing exists: PURPOSE" or [intransitiveverb] " to carry on a function or be in action: OPERATE" Making sense from the committee statement by dropping thesuggested "and" and adding commas and keeping noun verbagreement, 9.2.7.3.1 should read as follows: 9.2.7.3.2 A machine, that has safety-critical functions, and that isequipped with cable-less control shall have a means ofautomatically initiating the stopping of the machine and preventingthe initiation of potentially hazardous motions, in the followingsituations:(a) When a stop signal is received.(b) When a fault is detected in the system.(c) When a valid signal has not been detected within aspecified period of time (see annex B for the agreed timespecification) Note - A valid signal also includes the signal that confirmcommunication is established and maintained In the committee statement point #18 "In 9.4.2, revise title forclarity." My notes show that this proposed point was rejected. Theproposal would have deleted " and voltage interruptions from thetitle of 9.4.2 on the basis it was covered in chapters 11 and 7. Infact the title of Chapter 9 is "Control circuits and control functions"subsection 9.4.2 deals with the control function aspect of ground(earth) faults and voltage interruptions. These particular topicsare not dealt with else where in the standard. In the committee statement point #19 "Delete 9.4.2.2 since it isalready covered in 11.32 and 7.5" Again my notes show that thisproposed point was rejected. The proposal would have deletedsub subsection 9.4.2.2 Voltage interruptions, on the basis it wascovered in chapters 11 and 7. In fact the title of Chapter 9 is"Control circuits and control functions" sub subsection 9.4.2.2deals with the control function aspect of voltage interruptions.These particular topics are not dealt with else where in thestandard. Subsection 11.32 deals with "Memory Retention andProtection"; one aspect of that topic involves voltage interruption.Chapter 7's title is Protection of equipment and section 7.5 title isProtection against supply interruption or voltage reduction andsubsequent restoration. Neither chapter 11 nor chapter 7 dealswith "control function". Note: Changes from log #84, 86 are included in the committeeaction for log 46. In the committee statement the changes from log # 85 wereinadvertently not brought forward to the committee action for log46, also please see log 85 [which is accepted] in which subsection9.4.1 is modified to read: 9.4.1 General requirements. Where failures or disturbances inthe electrical equipment can cause a hazardous condition ordamage to the machine or the work in progress, measures shall betaken to minimize the probability of the occurrence of such failuresor disturbances. The required measures and the extent, to whichthey are implemented, either individually or in combination,


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depend on the safety requirements associated with the respectiveapplication. In the committee statement the changes from log # 147 wereinadvertently not brought forward to the committee action for log46, also please see log 147 [which is accepted] in which subsubsection 9.4.2.1 is modified to read: 9.4.2.1 Ground (earth) faults. Ground (earth) faults on anycontrol circuit shall not cause unintentional starting, potentiallyhazardous motions, or prevent stopping of the machine. Groundedcontrol circuits shall be in accordance with 8.2 and 8.3.Ungrounded control circuits shall be provided with an insulation-monitoring device that either indicates a ground (earth) fault orinterrupts the circuit automatically after a ground (earth) fault . Arestart of the machine with a detected earth fault shall beprevented. In the committee statement the changes from log # 152 wereinadvertently not brought forward to the committee action for log46, also please see log 152 [which is accepted in part] in which subsubsection 9.2.3.2 is modified to read: 9.2.3.2 When Where hazardous conditions results result frommode selection, such inadvertent selection shall be prevented fromoccurring (e.g. key operated switch, access code). Modeselection by itself shall not initiate machine operation. A separateaction by the operator shall be required. In the committee statement the changes from log # 151 wereinadvertently not brought forward to the committee action for log46, also please see log 151 [which is shown as accepted witheditorial revision of "should" to "shall" in the proposed revision][also note: the log #151 accept does not show the committeestatement #5 for log 46, but is shown below]. Log 151 thus showssubsection 9.2.4 is modified to read: 9.2.4 Overriding of safeguards. Where it is necessary totemporarily override one or more safeguards a mode selectiondevice or means capable of being secured (e.g. locked) in thedesired mode shall be provided to prevent automatic operation.The control circuit for the suspension of a safeguard shall have thesame safety requirements as the suspended safeguard itself . Inaddition, one or more of the following measures should shall shallbe permitted to be provided: (1) Initiation of motion by a hold-to-run or other control device (2) A portable controls station (e.g. pendant) with an emergencystop device, and where appropriate, an enabling device. Where aportable station is used, motion shall only be initiated from thatstation. (3) Limiting the speed or the power of motion (4) Limiting the range of motion In the committee statement the changes from log # 150 and #171and #12 were inadvertently not brought forward to the committeeaction for log 46, also please see log 150 and 171 and 12 [which isaccepted, 12 accepted in principle] in which the exception toparagraph 9.2.5.4.2.4 is modified to read: 9.2.5.4.2.4 Where a category 0 stop is used for the emergency stopfunction, it shall have hardwired electromechanical components. Exception: An electronic logic (hardware or software) system aswell as the communication network of link that complies with11.3.3 11.3.4 and is listed for category 0 emergency stop function shall be permitted. The final removal of power shall beaccomplished by means of electromechanical components. In the committee statement the addition from log # 116 wasinadvertently not brought forward to the committee action for log46, also please see log 1116 [which is accepted in principle] inwhich subsection 9.3.6 is added to read: 9.3.6 Protective interlock. Where doors are interlocked, in theinterlocking devices shall be listed safety switches to prevent theoperation of the equipment when the doors are open In the committee statement the changes from log # 163 wereinadvertently not brought forward to the committee action for log46, also please see log 163 [which is accepted] in which Note 1 ofsubsection 9.4.1 is modified to read: Note 1 Measures to reduce those risks from failures ordisturbances in the electrical equipment that could cause ahazardous condition or damage to the machine or to the work inprogress include but are not limited to:(1) Protective devices on the machine (e.g. interlock guards,trip devices)(2) Protective interlocking of the electrical circuit(3) Use of proven circuit techniques and components (seenote 2.1)(4) Provisions of partial or complete redundancy (see note2.2) or diversity (see note 2.3)(5) Provisions for functional tests (see note 2.4)

BLOODGOOD: The exception to clause 9.2.5.4.2.4 permitting anelectronic logic system as an emergency stop should not beincluded if Proposal for 79-77 (Log #12) and 79-47 (Log #155) aredefeated. In the case that those log numbers are defeated theexception in this clause should be eliminated. FISHER: The exception to clause 9.2.5.4.2.4 permitting anelectronic logic system as an emergency stop should not beincluded if 79-73 (Log #155) and 79-77 (Log #12) are defeated. Inthe case that those log numbers are defeated the exception in thisclause should be eliminated. MONTEITH: Clause 9.3.2 This clause is vague and open tointerpretation. It is recommended that a “Note” be provided thatstates “Note: A hazardous condition and the use of a positionsensor (e.g. proximity switch, position comparator) or limit switchis determined through the overall requirements for risk assessmentof the machine as stated in 4.1.2. PADGETT: Clause 9.3.2 This clause is vague and open tointerpretation. It is recommended that a “Note” be provided thatstates “Note: A hazardous condition and the use of a positionsensor (e.g. proximity switch, position comparator) or limit switchis determined through the overall requirements for risk assessmentof the machine as stated in 4.1.2. PILZ: This comment is in support of the committee action toaccept in principle the work done in clause 9. I do want to point out that 9.2.5.4.2.1 is int he need of anadditional requirement. Proposal: Add the following wording to the committee proposal. 9.2.5.4.2.1(D) The emergency stop shall be incorporated into theSafety Circuit, where it can not be directly incorporated into thepower circuit. Substantiation: Safety lies in the design of the control, not in thechoice of the control technology. The committee acknowledgesthis by allowing an exception for programmable technology to beused in e-stop circuitry, thus allowing the advance oft ehtechnology to take place. However, the committee also decided togive guidance in Chapter 11 on how this technology needs to bedesigned in order to be admissible. By including this newparagraph D into 9.2.5.4.2.1, which points the user of the standardto the newly introduced wording of 9.5.1 the committee would givethe additional guidance on the design of the emergency stopcircuit. Like the wording of clause 11.3.4 in Chapter 11, the wording of9.5.1 is so selected that it points the user of the standard towardscontrol components that have been designed to be used in controlcircuits that need to be available at all times or in case of a failureof the control itself inform the personnel that a fault exists by eithershutting down the equipment or not allowing restart after a regularshut down. The user of the standard is pointed towards a riskassessment as guidance for the design of the safety circuit. Thistogether with the guidance given in Chapter 9.4 give the user ofNFPA 79 2002 a more comprehensive tool to design a safemachine. To undermine the importance this newly suggested paragraph Ihave included a power point presentation that demonstrates that ahardwired design of an e-stop circuit can be unsafe. Only whenincorporated into a safety circuit the desired protection can beachieved. Please see presentation titled En 60204 US. SAUNDERS: The addition to 9.2.5.3.2 in the committee actionthat requires all stop functions to operate by "deenergizing therelevant circuit" would eliminate the use of many category 1 and 2stops, since many of these stops achieve the stop withoutdeenergizing the circuit. Recommendation: Delete "shall operate by deenergizing thatrelevant circuit and" from the last sentence of 9.2.5.3.2.

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(Log #153)79- 63 - ([9.1.5]): RejectSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Add new text to read as follows: 9.1.5 Safety Control Circuit. The increase of the risk of failure insafety control circuits through additional control components shallbe limited by using only fail to safe components, independent ofthe risk of the machine. The performance of the safety relatedcontrol circuitry may be assessed in a risk assessment. (e.g. EN 954-1 or ANSI/RIA 15-06. ANSI B11 TR3.)SUBSTANTIATION: Wording used in EN 954-1 necessary toensure that control circuits do not carry an operational hazard inthemselves. IEC 60204 itself has no section to cover theperformance of safety circuitry. This is done in EN 954-1. In orderto achieve conformity with IEC 60204 I suggest this wording.


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COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The notion of a safety control circuithas not been established by the industry and is not recognized by aUS standard. It is also not recognized in IEC 60204-1. The term"safety control circuit" is not defined and is not in UL508.Introduction of new terms like "fail safe components" withoutdefinitions or a product standard with which to List the productwill cause confusion.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Suggest using the last sentence as a fine printnote "For additional information on the performance of the safetyrelated control circuitry see EN 954-1, ANSI/RIA 15-06 or ANSIB11 TR3." PILZ: I disagree with the committee action to reject the proposal.I suggest to change the vote into "Accept in Principle" with themodified wording as follows: 9.1.5 Safety Circuit. The probability of failure of the powercircuit shall not be increased through additional controlcomponents implemented in the safety circuit. The additionalfault probability in the safety circuit shall be limited independent ofthe risk of the machine by using control components that are sodesigned that if they fail do not prevent the stopping action and donot allow for a restart until the fault has been cleared. The design of the safety circuitry shall be assessed in a riskassessment. Note: EN 954-1 or ANSI/RIA 15-06. or ANSI B11 TR3. can beused for guidance at the Risk Assessment. Substantiation: The committee reference of UL 508 does notapply here. The Safety Circuit addresses the control of mechanicalmachine hazards and not electrical shock or fire hazards as UL 508does. Today many customers are asking for copies of the riskassessment before taking delivery of the machine. Also, it iscommon practice in the Automotive and Exporting Industry toincorporate safety circuits into the control circuit in order tocomply with IEC 60204-1 in combination with EN 954-1. The wording used in EN 954-1 is necessary to ensure that safetycircuits do not carry a hazard in themselves. IEC 60204 itself hasno section to cover the performance of safety circuitry. This isdone in EN 954-1. In order to achieve conformity with IEC 60204 Isuggest to include this wording into NFPA 79 due to the lack ofsupporting sub standards to NFPA 79 as EN 954-1 is to EN 60204-1. When it comes to protection of personnel from mechanicalhazards the human relies on the safeguards to be operating asintended. This includes the function of the emergency stop that issupposed to be available at all times. The control circuit thatincorporates these actuators therefore has to be designed so that itis detecting a single fault in the circuit itself as well as still beingable to perform the shut down function even so the fault is present.Therefore, the concept of the safety circuit is introduced to NFPA79 with a new definition in 3.9.5.1 is necessary to give the userguidance on how to design such circuitry. Test houses such asTUV product Services or TUV Rheinland, which are accredited inthe US and are currently in the process of being listed as a NRTLby OSHA, have developed test methods to certify the compliance ofcomponents/products with EN 60204-1. Since it is the objective ofthis group to harmonize the NFPA 79 document with EN 60204-1.These test procedures can be applied to list components/productsagainst the US Safety Standard, NFPA 79, 2002 edition, whichwould then be acceptable for use in the design of safety circuitry.The circuitry itself would not be required to be certified if suchlisted components are used. Last but not least it needs to bementioned that paragraph 4.1 acknowledges the risk ofmalfunctioning of the machine and the loss of safety function as aresult of faults or failures in the control circuit resulting inexposure of humans to mechanical hazards of the machine. Byintroducing the concept of safety circuits as suggested in theproposal the risk of loss of the safety function can be reducedsignificantly. By pointing the user towards a risk assessment for thedesign of the safety circuit the user is given a tool to determine thecomplexity needed for the design of the safety circuit. In the notethe user is guided towards American as well as Internationalstandards describing a method for conducting such a riskassessment as well as performance criteria for the safety circuitdesign.

To undermine the importance of this newly suggested paragraph,I have included a power point presentation that demonstrates thata hardwired design of an e-stop circuit can be unsafe. Only whenincorporated into a safety circuit the desired protection can beachieved. Note: Supporting Material is available for review at NFPAHeadquarters.COMMENT ON AFFIRMATIVE: DOBROWSKY: It appears by accepting Proposal 79-16 (Log#154) in principle there is a definition. See also my comment onProposal 79-16 (Log #154).

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(Log #149)79- 64 - ([9.3.4.5]): RejectSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Add new text to read as follows: 9.3.4.5 Locking safety gates preventing access to coasting downmoving parts shall only be unlocked when the non hazard status ofthe accessible area is detected. The detection system must have thesame safety capability as the safeguarding of the area.SUBSTANTIATION: The unlocking of safety gate to the access ofa hazardous area must be prevented with the same level of safety asthe shut down of the machine when opening the gate. See also EN1088 page 12.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This proposal introduces a conceptthat is outside the scope of NFPA 79. The requirement forelectrical interlocking of gates that provide access to mechanicalhazards is beyond the scope of NFPA 79. The requirement fordetermining the types of electrical devices to be used forinterlocking is within the scope of NFPA 79.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 21 NEGATIVE: 4 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: If the requirement for determining the types ofelectrical devices used for interlocking are within the scope , thenthe requirement for determining the types of electrical devices usedfor latching a cover or door can also be included. Wheremechanical hazards are beyond the scope of NFPA79 , shouldn'tthere be a fine print note to point where the designer should go forinformation. GARVEY: I agree with the proposed text and substantiation. Themethod under which safety gates are interlocked should beaddressed by this standard. PILZ: I disagree with the committee action to reject the proposal.I suggest to change the vote into "Accept in Principle" with themodified wording as follows: 9.3.4.5 Locking safety gates preventing access to coasting downmoving parts shall only be unlocked when the non-hazard status ofthe accessible area is reached or detected. The detection systemshall be designed in compliance with the requirements of the safetycircuit safeguarding the area. Substantiation: The protection against mechanical hazards iswithin the scope of the standard, as long as the hazard iselectrically controllable. Therefore, the committee justificationdoes not hold. Would the statement be correct, the entireparagraph 9.2 would have to be eliminated since it deals witht hecontrol of the mechanical apparatus of the machine and itshazards. The newly added wording will provide additionalguidance to the user of the document on designing a safermachine. SALZENSTEIN: This worthwhile recommendation is certainlywithin the scope of NFPA 79, just as emergency stops, doorinterlocks, safety switches, etc. are. This is a valuable addition to79-2002.

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(Log #84)79- 65 - (9.1.2 [9.3.4.2]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Include the wording of Clause 9.12. as thelast sentence of proposed new clause 9.3.4.2.SUBSTANTIATION: Retention of the wording of Clause 9.12 isneeded to insure that interlocking of relays and solenoids is alsoincluded in the new requirements.


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COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies 79-62 (Log #46) [Clause 9] by adding a newsecond sentence to 9.3.4.2.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #86)79- 66 - (Clause 9 [9.4.1]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify rewrite of 1997 NFPA 79, Clause 9that is new Clause 9 in 9.4.1, Note 2.2 and Note 2.4. In the second paragraph of Note 2.2, change the word "shall" to"should." In the first sentence of 2.4, change the words "shall be permittedto" to "may."SUBSTANTIATION: Both changes correct for mandatorylanguage placed in a note by deleting the words "shall" and "shallbe permitted."COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies 79-62 (Log #46) [Clause 9].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #85)79- 67 - ([9.4.1]): Accept TCC NOTE: The Technical Correlating Committee directs thatthe Panel clarify the Panel Action on this Proposal and correlatethis action with the action on proposal 79-82 (Log #163). Thisaction will be considered by the Panel as a Public Comment.SUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify rewrite of 1997 NFPA 79, Clause 9that is new Clause 9 in 9.4.1. Add in the first paragraph, first sentence, the word "can" betweenthe words "equipment" and "cause." Sentence to read: "..electrical equipment can cause a ...". Move the second sentence of the rewrite 9.4.1. to Note 1 andmake it the first sentence of the note and delete the word"required" from the sentence.SUBSTANTIATION: The word "can" is in IEC text of 9.4.1. andmust have been mistakenly not included, therefore, reinsert theword. The second sentence of the paragraph is not mandatory,therefore, it should be a note. Moving the sentence to the firstsentence of Note 1 provides a logical introduction to this note.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies 79-62 (Log #46) [Clause 46].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #66)79- 68 - (9.3.1(New) [9.4.2.1]): Accept in PrincipleSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Revise text as follows: "Ground-free control circuits are permitted only with earthleakage monitor."SUBSTANTIATION: Ground-free without earth leakage monitoris not a protection against malfunction due to short to ground.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: The proposal [Ground-free controlcircuits are permitted only with earth leakage monitor.], isaddressed in 9.4.2.1 "Ground (earth) faults", and 8.3 "(Grounding)Control Circuits". See Committee Action on Proposal 79-62 (Log#46). The committee believes that this action meets the intent ofthe submitter.

NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #147)79- 69 - (9.3.1(New) [9.4.2.1]): AcceptSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: OLD 9.4.2.1 Ground (earth) faults Ground (earth) faults on any control circuit shall not causeunintentional starting, potentially hazardous motions, or preventstopping of the machine. Grounded control circuits shall be inaccordance with 8.2 and 8.3. Ungrounded control circuits shall beprovided with an insulation monitoring device that either indicatesa ground (earth) fault or interrupts the circuit automatically after aground (earth) fault... NEW 9.4.2.1 Ground (earth) faults Ground (earth) faults on any control circuit shall not causeunintentional starting, potentially hazardous motions, or preventstopping of the machine. Grounded control circuits shall be inaccordance with 8.2 and 8.3. Ungrounded control circuits shall beprovided with an insulation-monitoring device that either indicateda ground (earth) fault or interrupts the circuit automatically after aground (earth) fault. A restart of the machine with a detectedearth fault shall be prevented.SUBSTANTIATION: Preventing operation of machines in a faultystatus with concern that an accumulation of faults will result in aloss of the safety function. This means that the machine can finishthe shift with a detected earth fault. Start up at next shift however isonly possible if the earth fault has been corrected. The event of aearth fault does not necessarily lead to the immediate shut down ofthe equipment. Only a "safety fault" shall have the immediate shutdown effect.COMMITTEE ACTION: Accept.The committee understands that the only change initiated by thisaccept action is to add a new last sentence to 9.4.2.1 to read asfollows: "A restart of the machine with a detected earth fault shall beprevented."COMMITTEE STATEMENT: The committee understands that thisAction modifies Proposal 79-62 (Log #46).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: SAUNDERS: The addition of prevention of restart of machinewith a detected earth fault in 9.4.2.1 can add considerable costboth in application and operation of machines using ungroundedcontrol circuits. Properly designed equipment should not result ina hazardous condition occurring due to the occurrence of aground in the control circuit. It has been a standard practice foryears to indicate the existence of a ground and allow the user todetermine whether the machine can continue to run safely with theground. No substantiation has been provided to indicate thathazardous conditions occur on machines designed applying provensafety principles of guarding and control reliable safety circuits toinsure malfunction of the machine due to grounds in the controlcircuit does not result in a hazardous condition. Recommendation: Delete the last sentence from 9.4.2.1 "A restartof the machine with a detected earth fault shall be prevented".

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79- 70 - ([9.2.3.2]): Accept in PartSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: OLD 9.2.3.2 When hazardous conditions results from mode selection,such selection shall be prevented from occurring (e.g. key operatedswitch, access code). Mode selection by itself shall not initiatemachine operation. A separate action by the operator shall berequired. New 9.2.3.2 Operation mode switches must have the same safetyrequirements as the control elements used in the most hazardousselectable operation mode of the machine, assessed in a riskassessment. When hazardous conditions results from modeselection, inadvertent selection shall be prevented from occurring(e.g. key operated switch, access code). Mode selection by itselfshall not initiate machine operation. A separate action by theoperator shall be required.


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SUBSTANTIATION: A selection of the wrong operation mode bya system fault can lead to a hazardous condition, therefore theoperation mode selection must be treated like the highestselectable hazardous mode. Therefore, a touch screen is not anacceptable device for a mode select switch. This would lead therequirement of the extensive hardwired circuit for this applicationad absurdum. Change "such selection" to inadvertent, since it canbe possible that the selected mode is dangerous. However, thedanger in that mode cannot be avoided by the design of themachine. The operator who is aware of the hazard however canhandle the danger, provided he knows that the dangerous mode isactivated. Therefore, the hazard is not the danger that comes fromthe operation mode of the machine but from the inadvertent switchto the dangerous mode.COMMITTEE ACTION: Accept in Part. Revise text as follows: 9.2.3.2 Operation mode switches must have the same safetyrequirements as the control elements used in the most hazardousselectable operation mode of the machine, assessed in a riskassessment. When Where hazardous conditions results result frommode selection, inadvertent selection shall be prevented fromoccurring (e.g. key operated switch, access code). Mode selectionby itself shall not initiate machine operation. A separate action bythe operator shall be required.COMMITTEE STATEMENT: The committee disagrees with thefirst three sentences of the substantiation because protectionequivelant to that of a key operated switch or access code can beprovided via a Man Machine Interface or a touch screen. Theoperation mode switches are judged to a different standard makingequivelant protection difficult to determine. The committee understands that this action is alreadyincorporated in Proposal 79-62 (Log #46) [Clause 9].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: PILZ: This comment is in support of the committee action toaccept in principle to include a definition for safety control circuit. However, I suggest adding the following sentence to the wordingsuggested by the committee. "... not initiate machine operation. The mode selection switchtherefore shall be incorporated into the safety circuit of themachine ..." Substantiation: The added sentence gives additional guidancetowards the design of a safe machine. A selection of the wrongoperation mode by a system fault can lead to a hazardouscondition, therefore the operation mode selection must be treatedlike the highest selectable hazardous mode. This requires theincorporation of the mode selection switch into the safety circuit. SAUNDERS: The first sentence of the revised text in theCommittee action should also be deleted. If the requirements ofthe second and third sentences are followed, the hazardouscondition indicated in the first sentence will never occur, thereforethe sentence is unnecessary.

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(Log #151)79- 71 - ([9.2.4]): AcceptSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Old 9.2.4 Overriding of safeguards Where it is necessary to temporarily override one or moresafeguards a mode selection device or means capable of beingsecured (e.g. locked) in the desired mode shall be provided toprevent automatic operation. In addition, one or more of thefollowing measures should be provided: (1) Initiation of motion by a hold to run or other control device (2) A portable controls station (e.g. pendant) with an emergencystop device, and where appreciate, an enabling device. Where aportable station is used, motion shall only be initiated from thatstation. (3) Limiting the speed or the power of motion (4) Limiting the range of motion New 9.2.4 Where it is necessary to temporarily override one or moresafeguards a mode selection device or means capable of beingsecured (e.g. locked) in the desired mode shall be provided toprevent automatic operation. The control circuit for thesuspension of a safeguard shall have the same safety requirements

as the suspended safeguard itself. In addition, one or more of thefollowing measures should be provided: (1) Initiation of motion by a hold-to-run or other control device (2) A portable controls station (e.g. pendant) with an emergencystop device, and where appropriate, an enabling device. Where aportable station is used, motion shall only be initiated from thatstation. (3) Limiting the speed or the power of motion (4) Limiting the range of motion.SUBSTANTIATION: A system fault in the suspension of thesafeguard can lead to hazardous condition, therefore thesuspension system must be treated like the suspended device itself.COMMITTEE ACTION: Accept. Editorially revise "should" to "shall" in the proposed revision.COMMITTEE STATEMENT: The committee understands that thisproposal will modify Proposal 79-62 (Log #46) [Clause 9].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: PADGET: I agree with Mr.Bloodgood’s Explanation of NegativeVote on Proposal 79-77 (Log 12). SAUNDERS: The change to require "the same safetyrequirements" has been rejected in several other proposals of thissame nature as "introducing a concept outside the scope of NFPA79" (see Committee Statement for Proposal 79-64 (Log #149). Thecommittee action to change the "should" to "shall" is acceptable tomatch the existing paragraph 9.15 in NFPA 79 – 1997.COMMENT ON AFFIRMATIVE: DEFELICE: The second sentence of the proposed languageshould be modified as follows: "The control circuit for the suspension of a safeguard shall havethe same safety requirements provide the same level of safety as thesuspended safeguard itself." Interpretation of the "same safety requirements" is difficult; as itmay be thought to require total component redundancy. Webelieve that the proposed change meets the submitter's intent whileproviding clarity to the reader.

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(Log #150)79- 72 - ([9.2.5.4.2.4]): AcceptSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Revise text as follows: 9.2.5.4.2.4 Where a category 0 stop is used for the emergency stopfunction, it shall have hardwired electromechanical components. Exception: An electronic logic system that complies with 11.3.4shall be permitted. The final removal of power shall beaccomplished by means of electromechanical components.SUBSTANTIATION: Correction of sub-clause reference. 11.3.4not 11.3.3 covers safety related functions of programmable systems.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies 79-62 (Log #46), section 9.2.5.4.2.2 by onlycorrecting the crossreference change from 11.3.3 to 11.3.4.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: See my Explanation of Negative for Proposal 79-77 (Log #12).

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(Log #155)79- 73 - (9.6 [11.3.4]): Accept in PrincipleSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Old 11.3.4 Use in Safety-related Functions Software and firmware based controllers used in place ofhardware based components with safety related devices shall: (a) Be designed such that nay singe safety related component orfirmware failure shall: (1) Lead to the shutdown of the system in a safe state, and (2) prevent subsequent operation until the component failurehas been corrected: Note: Firmware is the executive control program in a non volatileinternal storage mode and is not changeable by the user.


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(b) Supply the same degree of safety achieved by usinghardwired/hardware components. Note: For example, this degree of safety may be achieved by usingmicroprocessor redundancy, microprocessor diversity, and selfchecking; (c) Be listed to an approved standard for safety related functionssuch as IEC 61508, UL 991, UL 1998, or VDE 0801. New 11.3.4 Use in Safety-related Functions Software and firmware-based controllers used in place ofhardware based components with safety-related devices shall: (a) Be designed such that any singe safety related component orfirmware failure shall: (1) Lead to the shutdown of the system in a safe state, and (2) prevent subsequent operation until the component failurehas been corrected: Note: Firmware is the executive control program in a non-volatileinternal storage mode and is not changeable by the user. (b) Supply the same degree of safety achieved by usinghardwired/hardware components. Note: For example, this degree of safety may be achieved by usingmicroprocessor redundancy, microprocessor diversity, and selfchecking; (c) A safety PLC shall incorporate at least one passive, selfmonitored electromechanical device as back to ensure a linedisconnect in case of a failure of the solid state components (d) Be listed to an approved standard for safety-related functionssuch as IEC 61508, UL 991, UL 1998, or VDE 0801.SUBSTANTIATION: NFPA 79-1997 Paragraph 9 Section 9.6.3Emergency Stop states: "Where a category 0 stop is used for theemergency stop function, it shall have only hardwiredelectromechanical components. In addition, its operation shallnot depend on electronic logic (hardware or software) or thetransmission of commands over a communications network orlink" This statement constitutes a problem. The state of the art insafety technology today is using electronic logic to monitor theredundancy of the safety relays in a safety relay module such as forexample a PNOZ X3. Also light curtain controllers rely uponredundant microprocessor in conjunction with firmware to processthe signals from the light beam to the actuator. However, thewording of NFPA does not allow for those widely used componentsto be used in E-stop category 0 circuits. In addition, there areprogrammable safety systems on the market that have beenapproved by a third party in Europe to be suitable for the use insafety applications several years ago. The wording of NFPA 79however does not allow the American manufacturers to benefitfrom this cost saving technology; even so it meets the intent ofNFPA 79. In combination with the revised wording in clause 9,Paragraph 9.2.5.4.2.4, this sub-clause therefore covers a subject notpresently in NFPA 79-1997. This text is somewhat comparable withthe requirements from RIA and addresses the new technology inrobotics used in industrial machinery. IEC 61508, UL 991, UL 1998and VDE 0801 are the only published standard known to thecommittee that may be used for listing of Safety-related function. An additional requirements for a safety PLC should be theincorporation of at least one passive, self monitoredelectromechanical device into the safety PLC as back up in case ofa failure of the solid state components to ensure a line disconnect.COMMITTEE ACTION: Accept in Principle. 1) In Section 11.3.4 of Proposal 79-155 (Log #25), add a new (c)to read as follows: "(c) incorporate at least one passive, self monitoredelectromechanical device as back up to ensure a line disconnect incase of a failure of the solid state components" 2) Renumber existing from (c) to new (d).COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on Proposal 79-155 (Log #25)[Clause 11].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: See my Explanation of Negative for Proposal 79-77 (Log #12). FISHER: There may be occasions where it is advantageous toemploy electronic or programmable components in critical orsafety related control circuits and it is known that there are personscapable of designing safety related control systems that employ theuse of electronic or programmable components. It is imperative tounderstand that when we use words such as "integrity" or "safety"within the context of a control system we are talking about system

attributes. In order for the system to have a certain level of integritythere may be a need to have components with special capabilitiesor attributes. However, the use of components with specialcapabilities or attributes in a system will not assure that the systemachieves the intended or required integrity. The safety relatedcontrol system integrity is primarily a function of the system design. The focus of this proposal is on the components, and not on thesystem, with the final requirement for the component being thirdparty certification. There are many components certified for use assafety components by adding redundancy into the devices. The missing link is not the component with special capabilities orattributes. Rather, the missing link is an approved applicationstandard to guide the development of safety related control systemsincorporating electronic or programmable components. Suchstandards are under development but will not be ready within thenext year or two. UL 1998, mentioned in the substantiation, is notthat application standard as noted in the following excerpts fromits Preface and Scope: (Preface) "The requirements in UL 1998 are applicable whenused in conjunction with an application-specific standard thatcontains requirements for safety-related functions implementedusing software. UL 1998 does not apply to software inprogrammable components used in general purpose applicationswhen the risks for the end-application cannot be identified." (Scope) "1.1 These requirements apply to non-networkedembedded microprocessor software whose failure is capable ofresulting in a risk of fire, electric shock, or injury to persons. 1.4 These requirements are intended to supplement applicableproduct or component standards and requirements, and are notintended to serve as the whole basis for investigating the risk of fire,electric shock, or injury to persons." In short, this standard is neither a product standard nor a safetyrelated system application standard. It is a software standard. Itcannot substitute for what we described as the missing link. Without an appropriate application standard to which systemcompliance can be required, providing allowance in this standardfor this kind of system would require provision of all the necessaryrequirements in this standard. This would appear to be andunrealistically ambitious task at this time. Certainly, suchrequirements would need to be much more comprehensive than"no single failure shall..." and "shall supply the same degree ofsafety achieved by using hardwired/hardware components".Therefore, this proposal should be rejected. PADGET: I agree with Mr. Fisher’s Explanation of NegativeVote.COMMENT ON AFFIRMATIVE: FREUDENBERG: Software and firmware based controllersmeeting these stringent requirements can be more reliable thanhardware based components. Verification will be too complex fordetermination for many inspectors, therefore, listed safety relatedfunctions were deemed appropriate.

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(Log #88)79- 74 - (9.6.3 [11.3.4(a)(3)]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Add to proposed rewrite of Clause 20, thatis new Clause 11 in 11.3.4. Add line "(a.3)" that reads "prevent unintended start up ofequipment upon correction of the failure." Then at the end of the line identified as "(a.2)" change the periodto a comma and add the word "and".SUBSTANTIATION: This additional requirement is needed toprevent harm to personnel or damage to equipment.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the action on Proposal 79-155 (Log #25) [Clause11].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________(Log #89)

79- 75 - (9.6.3 [11.3.4(d)]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Add to proposed rewrite of Clause 20, thatis new Clause 11 in 11.3.4. Add a new paragraph stating "Software and firmware-basedcontrollers shall not be used for Category 0 emergency stopfunctions and shall comply with 9.2.5.4.2.


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SUBSTANTIATION: This additional requirement is needed sinceneither the current version 2000 of IEC 60204-1, nor the currentversion 1997 of NFPA 79 allow the use of electronic logic systems tocontrol a category 0 emergency stop function. The use of suchsystems for use in the stop function of last resort is yet to beendorsed by many designers and users alike. Nor does thereappear to be credible evidence that recognized third partiesapprove this provision for this specific purpose.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-77 (Log #12)NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #171)79- 76 - (9.6.3 [9.2.5.4.2.4]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the following paragraph (9.2.5.4.2.4Exception) 9.2.5.4.2.4 Where a category 0 stop is used for the emergency stopfunction, it shall have hardwired electromechanical components. Exception: An electronic logic system that complies with 11.3.3 4 shall be permitted. The final removal of power shall beaccomplished by means of electromechanical components.SUBSTANTIATION: The requirement is covered in NFPA 79proposed 2002 Edition 11.3.4 Use in Safety - related functions. Thereference number was shifted in final version of Clause 11.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-72 (Log #150).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: See my Explanation of Negative for Proposal 79-77 (Log #12).

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(Log #12)79- 77 - (9.6.3, 9-x.x (New) [9.2.5.4.2]): Accept in PrincipleSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Revise text as follows: "Where a Category 0 stop is used for the emergency stop function,it shall have only be designed with hardwired electromechanicalcomponents. In addition, its operation shall not depend onelectronic logic (hardware or software) or the transmission ofcommands over a communications network or link or anelectronic logic (hardware, software, communications network)that complies with Section 9.X.X." New Section 9.X.X. Safety-related software and firmware-basedcontrollers and communication networks. "Safety-related software and firmware-based controllers andcommunication networks used in place of hardware-basedcomponents with safety-related or hazard control devices shall: (a) Be designed such that any single safety component failure ofthe software and firmware-based controller or communicationnetwork shall: (1) Lead to the shutdown of the system in a safe state, and (2) Prevent subsequent automatic automatic operation until thecomponent failure has been corrected; NOTE: Firmware is that executive control program codeprovided by the manufacturer of the component in a nonvolatileinternal storage mode and is not changeable by the user. (b) Supply the same degree of safety achieved by usinghardwired/hardware components. For example, this degree ofsafety may be achieved by using microprocessor redundancy,microprocessor diversity, and self-checking; (c) Be certified by a Nationally Recognized Testing Laboratory(NRTL) to an approved standard applicable for safety devices." (Note: UL is a NRTL; the applicable standard is UL 1998.)SUBSTANTIATION: NFPA 79, Paragraph 9, Section 9.6.3,Emergency Stop, states: "Where a Category 0 stop is used for theemergency stop function, it shall have only hardwiredelectromechanical components. In addition, its operation shallnot depend on electronic logic (hardware or software) or thetransmission of commands over a communications network orlink."

This statement constitutes a problem. The state of the art insafety technology today is using electronic logic to monitor theredundancy of the safety relays in a safety relay module such as, forexample, a PNOZ X3. Also, light curtain controllers rely uponredundant microprocessor in conjunction with firmware to processthe signals from the light beam to the actuator. However, thewording of NFPA does not allow for those widely used componentsto be used in E-stop Category 0 circuits. In addition, there areprogrammable safety systems on the market that have beenapproved by a third party in Europe to be suitable for the use insafety applications several years ago. The wording in NFPA 79,however, does not allow the American manufacturers to benefitfrom this cost saving technology; even though it meets the intent ofNFPA 79. I therefore suggest the above change in NFPA 79, Paragraph 9,Section 9.6.3, Emergency Stop. Note: Supporting material is available for review at NFPAHeadquarters.COMMITTEE ACTION: Accept in Principle. Revise the Exception of 9.2.5.4.2.4 to read as follows: Exception: An electronic logic (hardware or software) system aswell as the communication network or link that complies with11.3.4 and is listed for category 0 emergency stop function, shall bepermitted. The final removal of power shall be accomplished bymeans of electromechanical components.COMMITTEE STATEMENT: The revised exception providesguidance for the proper use of new technology that is becomingState-of-the-Art in the industry. The committee understands that theonly action taken to this section was to revise the exception. Thecommittee understands that this proposal modifies the CommitteeAction on Proposal 79-62 (Log #46).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: BLOODGOOD: Proposals 79-77 (Log #12), 79-76 (Log #25), 79-72 (Log #150), 79-73 (Log #155), 79-76 (Log #171) I disapprove ofthe Committee Action on 79-77 (Log #12 & 79-76 (Log #171)particularly 79-77 (Log #12) as this is an attempt to redefineCategory 0. Also, there are communication standards whichpreclude the transmission of an Emergency Stop Command overthe network (e.g. ISO 9506 – MMS). It is noted that when‘Category 0’ was created it was done with the understanding thatthere are cases where programmable electronic devices andcommunication networks were not suitable for emergency stop nomatter what precautions or design requirements were taken.In seq # 79–73 (Log #155) what is meant by line disconnect? Tome it implies that the entire control is disconnected from thesupply. Not normally a good idea. Also there is no provision forthis in IEC 60204–1.I support the NEMA reasoning for the rejection of these proposals.I prefer the modifications to 11.3.4 made by the Committee exceptthat the Heading ‘Use in safety–related functions’ should bechanged to ‘Use in safety functions’ (See CP4). Same for 11.3.4(c).Also there is a discrepancy between the Committee Action onProposal 79-77 (Log #12) and 79-72 (Log #150). FISHER: See my Explanation of Negative Vote on Proposal 79-73(Log #155). PADGET: I agree with Mr. Bloodgood’s Explanation of NegativeVote.

___________________(Log #22)

79- 78 - (9.6.3.1 [ 9.2.5.4.2]): RejectSUBMITTER: Gordon T. Davis , Moeller Electric Corp.RECOMMENDATION: New 9.6.3.1 The safety related parts of anemergency stop circuit shall be so designed that a single fault inany of these parts does not lead to the loss of the safety function.SUBSTANTIATION: A fault tolerant emergency stop circuit addsa degree of additional safety to this critical safety circuit.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposed requirement isnormally associated with applications when the risk assessment hasidentified the need to have safety related parts in accordance withthe requirements of EN954 category 3 or 4. This requirement for allapplications is unduly restrictive and may in fact not provideadditional safety.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #116)79- 79 - (9.10 [9.3.6]): Accept in PrincipleSUBMITTER: Pat Hodge, Visteon CorpRECOMMENDATION: Provided that 9.10 "Machinery doorinterlocking" is retained from NFPA 79 1997 edition, revise text asfollows: "Hinged or sliding doors providing ready access to compartmentscontaining belts, gears, or other moving parts that may exposehazardous conditions shall be interlocked through limit switches orother means listed safety switches to prevent operation of theequipment when the doors are not closed. The requirements formachinery door interlocking shall be in accordance with therequirements of the applicable machinery safety standard(s). (e.g.,ANSI B-11 series)."SUBSTANTIATION: Current industry practice has been to refrainfrom the use of limit switches for safety guarding due to ease inwhich the switch can be defeated. Listed safety switches aregenerally used instead.COMMITTEE ACTION: Accept in Principle. Revise text to read: 9.3.6 Protective Interlock. Where doors are interlocked, theinterlocking devices shall be listed safety switches to prevent theoperation of the equipment when the doors are open.COMMITTEE STATEMENT: The requirement for electricalinterlocking of doors that provide access to mechanical hazards isbeyond the scope of NFPA 79. The requirement for determiningthe types of electrical devices to be used for interlocking is withinthe scope of NFPA 79. The committee understands that thisproposal modifies the Action on Proposal 79-62 (Log #46).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DEFELICE: The wording as revised by the committee's actionremoves the requirement for interlocking doors which provideprotection against mechanical hazards; yet the source of power forthese mechanical hazards most often an electric motor, whosecontrol is under the scope of NFPA 79. We believe that thepresence of this requirement in NFPA 79 for many years hasworked well to prevent injuries to both machine operators andmaintenance personnel. In the interest of safety, we are of the opinion that therequirements for door interlocking found in the current version ofNFPA 79 (1997) should be retained in the next edition of thestandard. SAUNDERS: "Listed safety switches" are not clearly defines in USindustry standards. All doors where interlocks are provided maynot be of the type previously described in 9.10 of NFPA 79 – 1997(i.e. Control enclosure door interlock, etc.).

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(Log #117)79- 80 - (9.10 [9.3.6]): RejectSUBMITTER: Pat Hodge, Visteon CorpRECOMMENDATION: Retain existing text paragraph 9.10"Machinery door interlocking" from NFPA 79 1997 edition andplace in NFPA 79 2002 edition as 9.3.6 under "Protectiveinterlocks".SUBSTANTIATION: This requirement is essential to assure thesafety of production & maintenance personnel. It still permitsOEM’s the option to provide "fixed" guarding, by the use of boltsor other such means, which would require the use of tools anddeliberate action to remove. "Fixed " guarding would not requireinterlocked switches to detect door closure.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-79 (Log #116).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DROBNICK: I vote negative for the reasons stated in the first twoparagraphs of the substantiation. I request that the committeereconsiders Proposal 79-80 (Log #117) with the following revisions: Strike original proposal to retain entire 9.10 from NFPA 79 1997edition. Revise existing 9.10 paragraph as follows and include it inthe 2002 edition as 9.3.6 under "Protective interlocks."

Hinged or sliding doors providing access to moving parts shall beinterlocked to prevent the operation of the equipment when thedoors are opened. Substantiation: This requirement is essential to assure the safetyof production and maintenance personnel. It still permits OEM’sthe option to provide "fixed" guarding, by the use of bolts or othersuch means, which would require the use of tools and deliberateaction to remove. "Fixed" guarding would not require interlockedswitches to detect door closure. I believe that any hinged or sliding door which allows access tomoving parts during equipment operation poses a safety hazard topersonnel. Therefore, it becomes the responsibility of theengineering community to ensure that safeguards are in place toprevent such hazards. Furthermore, since equipment safety fallsunder the scope of NFPA 79, any requirements which enhance andpromote personnel safety should be included in that document. Removed the phrase "through limit switches or other means" toreflect the Committee Action on Proposal 79-79 (Log #116), statingthe requirement of Listed Safety Switches when used for guarddoors. The requirement does not need to be re-stated in Proposal79-80 (Log #117). The word "ready" and phrase "compartments containing belts,gears, or other" were removed to clarify the intent to protect againstexposure to moving parts. Removed the phrase "that may expose hazardous conditions" toclarify intent and follow definitions in Chapter 3. (Only defineshazard and hazardous situations) Replaced "not closed" with "opened" for clarity. Removed last sentence. This is too vague and does not mandatecompliance with a specific standard. It only lists an example whichwould move to the back of the document as a note. Does not aidin clarifying the intent of the requirement. Not original material. Source 9.10 of NFPA 79, 1997 edition.

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(Log #1)79- 81 - (9.14 Exception (New) [9.2.5.6]): Accept in PrincipleSUBMITTER: David Mullins, DAC VisionRECOMMENDATION: Add an Exception to Section 9.14 to readas follows: Exception: On automated machinery which runs continuous orrepeated cycles, dual start buttons may be used which initiate thebeginning of a run which do not require continuous operation ofboth buttons for extended periods of time, for the purposepreventing confusion or mis-operation of other buttons on thecontrol panel, provided all other safeguards are in place.SUBSTANTIATION: As automation is becoming more prevalentin manufacturing and industry, machines are being made whichrun continuously for extended production runs. To require anoperator to be present to hold two buttons defeats the purpose ofsuch automation. The intent here, is to cause the operator tointentionally operate both buttons to start the cycle, as opposed tooperating a button such as collect open while observing the worksof the machine during setup or maintenance operations.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committe Action on Proposal79-62 (Log #46), in subclause 9.2.5.6(d), which meets the intent ofthe submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #163)79- 82 - (9.16 (New) [9.4.1 Note 1]): Accept TCC NOTE: The Technical Correlating Committee directs thatthe Panel clarify the Panel Action on this Proposal and correlatethis action with the action on proposal 79-67 (Log #85). Thisaction will be considered by the Panel as a Public Comment.SUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Editorial correction to existing proposedtext, not a new proposed requirement. Revise the following proposed paragraph (9.4.1 Note 1): 9.4.1 General requirements. Where failures or disturbances in the electrical equipment cause ahazardous condition or damage to the machine or the work inprogress, measures shall be taken to minimize the probability ofthe occurrence of such failures or disturbances. The requiredmeasures, and the extent to which they are implemented, either


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individually or in combination, depend on the safety requirementsassociated with the respective application (see 4.1). Note 1: Measures to reduce these risks include but are not limitedto: To read as follows: Note 1: Measures to reduce these risks from failures ordisturbances in the electrical equipment that cause a hazardouscondition or damage to the machine or the work in progress include but are not limited to:SUBSTANTIATION: When the material was moved from the textto a note and with the fact that the new format will place the notein a remote location in the document, the connection with thepronoun "these" beams became completely unclear. The proposalrepeats the original referred language in place of "these" in Note 1.COMMITTEE ACTION: Accept.In Note 1 of 9.4.1 of Proposal 79-62 (Log #46), editorially correctthe phrase "...that cause..." to "...that could cause...".COMMITTEE STATEMENT: The committee understands that thisproposal only modifies the note 1 of 9.4.1 in Proposal 79-62 (Log#46) [Clause 9].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #148)79- 83 - (9.16 (New) [9.4.1 (Note)]): RejectSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Old Note 2.3 Use of diversity The use of control circuits having different principles ofoperation or differing types of devices may reduce the probabilityof faults and failures giving rise to hazards. Examples include: (1) The combination of normally open and normally closedcontacts operated by interlocking guards (2) The use of different types of control circuit components inthe circuit (3) The combination of electromechanical and electroniccircuits in redundant configurations (4) The combination of electrical and non-electrical systems(e.g. mechanical, hydraulic, pneumatic) may perform theredundant function and provide the diversity. New Note 2.3 Use of diversity The use of control circuits having different principles ofoperation or differing types of devices may reduce the probabilityof faults and failures giving rise to hazards. Examples include: (1) The combination of normally open and normally closedcontacts operated by interlocking guards, while only the normallyopen contact shall be operated when the safe guard is in the closedposition. (2) The use of different types of control circuit components inthe circuit (3) The combination of electromechanical and electroniccircuits in redundant configurations (4) The combination of electrical and non-electrical systems(e.g. mechanical, hydraulic, pneumatic) may perform theredundant function and provide the diversity.SUBSTANTIATION: Wording changed to reduce the possibilityof misinterpretation. See EN 1088 picture.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Unfortunately the terms normallyopen and normally closed are ambiguous at best when applying toguard door-interlocking devices. The normally position for a safetycontact in a guard door switch is when the guard is in the closed orsafe position. In other devices the normal position is as found onthe shelf (without power). The additional proposed phrase addsno additional clarity to the situation.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARVEY: I agree with the substantiation. The added textclarifies the intent of the requirement and gives specific guidanceto the designer. PILZ: I disagree with the committee action to reject the proposal.I suggest changing the committee action to "accept". Substantiation: I disagree with the statement of the committeethat the terms normally open and normally closed are ambiguous.

It is commonly understood that devices are incorporated intocircuitry schematic in the de-enrgized mode as found on the shelf.This is where the terms normally open and normally closedoriginate. To bring conformity into the circuitry drawings. Everyelectrician knows this when reading a circuit diagram. Whenincorporated into a safety gate the normally open contact isactuated when the gate is closed. This means that the normalposition of the contact during the operation of the machine is inthe energized state and not in the de-energized state as drawn intothe circuits. In order to point this out to the user of NFPA 79, thenew wording was added. To me the committee statement issubstantiation for the inclusion of the wording rather than to rejectit, which in turn suggests the conclusion that the added wordingshould be accepted.

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(Log #54)79- 84 - (Clause 11 [Clause 12]): Accept in PrincipleSUBMITTER: Dick Bromstad, Commonwealth SystemsRECOMMENDATION: 12 Control equipment: location, mounting, and enclosures12. 1 General requirements

12.1.1. All control equipment shall be located and mounted so asto facilitate:Its accessibility and maintenance;Its protection against the external influences or conditions underwhich it is intended to operate;Operation and maintenance of the machine and its associatedequipment.12.1.2. For minimum construction requirements, see UL 508 &U.L. 50 for metallic and nonmetallic enclosures.12.1.3. The depth of the enclosure or compartment including doors orcovers shall not be less than the maximum depth of the enclosedequipment plus the required electrical clearances.12.1.4. Any door(s) that permits access to live parts shall comply with6.3.2.5.12.2 Location and mounting12.2.1 Accessibility and maintenance12.2.1.1. All items of control equipment shall be placed andoriented so that they can be identified without moving them or thewiring. Where practicable, items that require checking for correctoperation or that are liable to need replacement, those actionsshall be possible without dismantling other equipment or parts ofthe machine (except opening doors or removing covers).Terminals not associated with control equipment shall alsoconform to these requirements.12.2.1.2. Exposed, nonarcing, bare, live parts within an enclosureor compartment shall have an air space of not less than 13mm (1/2inch) between them and the uninsulated walls of the enclosure orcompartment, including conduit fittings. The air space foruninsulated covers or doors of the enclosure shall be not less than25 mm (1inch). Where barriers between metal enclosures orcompartments and arcing parts are required, they shall be of flame-retardant, noncarbonizing insulating materials.12.2.1.3. All control equipmen t shall be mounted so as to facilitateits operation and maintenance. Where a special tool is necessaryto remove a device, such a tool shall be supplied.Note: Where access is required for regular maintenance oradjustment, it is recommended that the relevant devices be locatedbetween 0.4m (15.75 inches) and 2.0m (78.75 inches) above theservicing level to facilitate maintenance. It is recommended thatterminals be at least 0.2m (7.88 inches) above the servicing leveland be so placed that conductors and cables can be easilyconnected to them.12.2.1.4. Threaded fasteners with machine threads shall be used toattach components to a sub plate and shall provide sufficientthread engagement to maintain secure mounting:12.2.1.4.1. Steel sub plate thickness shall provide engagement of atleast 2 full threads.12.2.1.4.2. Aluminum sub plate thickness shall provideengagement of at least 3 full threads.12.2.1.4.3. Thread cutting or thread forming screws shall bepermitted if the above thread engagement requirements are met.12.2.1.4.4. Sheet metal screws, rivets, welds, solders, or bondingmaterials shall not be used to mount components to a sub plate.Exception: Rivets shall be permitted to be used for attachingmounting rails and wiring channels.12.2.1.5. Swing frames or swing out panels shall be permitted,provided the swing is more than 110 degrees. Wiring shall notinhibit swing. Panel-mounted components behind swing framesshall be accessible when open.


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12.2.1.7 Where control devices are connected through plug-inarrangements, their association shall be made clear by type(shape), marking or reference designation, singly or incombination.Note: 14.4.5 contains addition information on attachment plug andreceptacle (plug/socket) combinations.12.2.1.8. Attachment plugs and receptacles (plug/socket)combinations that are handled during normal operation shall belocated and mounted as to provide unobstructed access.12.2.1.9 Test points, where provided, shall be mounted to provideunobstructed access, plainly marked to correspond with markingson the drawings, adequately insulated, and sufficiently spaced forconnection of test leads .12.2.2 Physical separation or grouping12.2.2.1. Machine compartments containing control equipment (built-incontrol) shall be completely isolated from coolant and oil reservoirs. Thecompartment shall be readily accessible and completely enclosed; it shallnot be considered enclosed where it is open to the floor, the foundationupon which the machine rests, or other compartments of the machine thatare not clean and dry.12.2.2.2. Pipelines, tubing, or devices (e.g.solenoid valves) forhandling air, gases, or liquids shall not be located in enclosures orcompartments containing electrical control equipment.Exception: Equipment for cooling electronic devices.12.2.2.3. Control devices mounted in the same location and connected tothe supply voltage, or to both supply and control voltages, shall begrouped separately from those connected only to the control voltages.12.2.2.4. Terminals shall be separated into groups for:power circuits;associated control circuits;other control circuits, fed from external sources (e.g. forinterlocking).12.2.2.5. The groups shall be permitted to be mounted adjacently,provided that each group can be readily identified (e.g. bymarkings, by use of different sizes, by use of barriers, by colors).12.2.3 Heating effectsHeat generating components (e.g. heat sinks, power resistors) shallbe so located that the temperature of each component in thevicinity remains within the component manufacturers specifiedlimits.12.3 Degrees of protection12.3.1 The protection of control equipment against ingress of solidforeign objects and of liquids shall be adequate taking into accountthe external influences under which the machine is intended tooperate (i.e. the location and the physical environmentalconditions)including dust, coolants, and swarf.)NOTE –The degrees of protection against ingress of water andother liquids are covered by NEMA 250. See also annex H.12.3.2. Enclosures of control equipment shall provide a degree ofprotection of at least NEMA Type 1.Exception No.1 Where removable collectors on collector wire orcollector bar systems are used and NEMA Type 1 enclosures arenot practicable, suitable protection shall be provided (e.g.elevation, guarding.)12.4 Enclosures, doors, and openings

12.4.1 Enclosures shall be constructed and finished using materialscapable of withstanding the mechanical, electrical and thermal stresses,as well as the effects of humidity and corrosion that are likely to beencountered in normal service.

12.4.2. Where corrosion protection beyond normal requirementsis needed, non-metallic enclosures identified for the purposes shallbe permitted if they meet the requirements of UL 508.

12.4.3. Subplates having a surface area of more than 15,484 sq.cm(2400 sq. in) shall have supports provided in addition to the panelmounting means to aid in subplate installation.

12.4.4. Enclosures and sub plates shall be free of burrs and sharpedges.

12.4.5. The exterior of the enclosure shall include a protectivefinish suitable for the intended environment.

12.4.6. Fasteners used to secure doors and covers shall be of thecaptive type. Windows provided for viewing internally mountedindicating devices should be of a material suitable to withstandmechanical stress and chemical attack [ e.g. toughened glass,polycarbonate sheet of 3mm (1/8-in.) thickness ] .

12.4.7. Door fasteners on enclosures and compartments with dooropenings less than 1016 mm (40 in.) tall shall be designed to seal

the door tightly around its perimeter with either captive fasteners orvault type hardware which latch at the top and bottom.

12.4.8. Door fasteners on enclosures and compartments with dooropenings 1016 mm (40 in.) tall or more shall be designed to sealthe door tightly around its perimeter with either captive fasteners orvault type hardware which latch at the top, center and bottom.

12.4.9. A print pocket sized to accommodate electrical diagramsshall be attached to the inside of the door of the control enclosureor compartment. Single-door and multidoor enclosures shall haveat least one print pocket.

12.4.10. The joints or gaskets of doors, lids, covers, externallymounted accessories , interconnect panels and enclosures shallwithstand the deleterious effects of liquids, vapors, or gases usedon the machine. The means used to maintain the degree ofprotection of an enclosure on doors, lids and covers that requireopening or removal for operation or maintenance shall: besecurely attached to either the door/cover or the enclosure ; andnot deteriorate due to removal or replacement of the door or thecover, and so impair the degree of protection.

12.4.11. All openings in the enclosure, including those towards thefloor or foundation or to other parts of the machine, shall beclosed by the supplier(s) in a manner ensuring the protectionspecified for the equipment. Openings for cable entries shall beeasily re-opened on site. A suitable opening shall be permitted inthe base of enclosures within the machine so that moisture due tocondensation is allowed to drain.

12.4.12. There shall be no opening between enclosures containingelectrical equipment and compartments containing coolant,lubricating or hydraulic fluids, or those into which oil, otherliquids, or dust can penetrate. This requirement does not apply toelectrical devices specifically designed to operate in oil (e.g.electromagnetic clutches) nor to electrical equipment in whichcoolants are used.

12.4.13. Where there are holes in an enclosure for mountingpurposes, care shall be taken so that after mounting, the holes donot impair the required protection.

12.4.14 Equipment that, in normal or abnormal operation, can attain asurface temperature sufficient to cause a risk of fire or harmful effect toan enclosure material:-- Shall be located within an enclosure that will withstand, withoutrisk of fire or harmful effect, such temperatures as may begenerated; and-- Shall be mounted and located at a sufficient distance fromadjacent equipment so as to allow safe dissipation of heat (see also12.2.3); or-- Shall be otherwise screened by material that can withstand,without risk of fire or harmful effect, the heat emitted by theequipment.

12.5 Access to control equipment

12.5.1. Working clearances: Sufficient space and access shall beprovided about all electrical equipment and enclosures to permitsafe operations and maintenance of such equipment. In all cases,the workspace shall permit at least 90-degree opening of the dooror hinged panel.

12.5.2. Access to control equipment shall be in accordance withNFPA 70, Section 110-26 for the requirements for working space inthe direction of access to live parts operating at 600 volts nominal,or less to ground and likely to require examination, adjustment,servicing, or maintenance while energized.Note: Additional clearance requirements are found in NFPA 70,670-5.

12.5.3. Door in gangways and for access to electrical operatingareas shall: be at least 0,7m wide and 2,0m (6 ft. 7 in.) high: openoutwards; have a means (e.g. panic bolts or panic bars) to allowopening from the inside without the use of a key or tool.[ add English units and remove , adding decimal]

12.6 Machine-mounted control equipment


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12.6.1 Control equipment (e.g. limit switches, brakes, solenoids,position sensors) shall be mounted rigidly in a reasonably dry andclean location, shall be protected from physical damage, and shallbe free from the possibility of accidental operation by normalmachine movements or by the operator. Such equipment shall bemounted with sufficient clearance from surrounding surfaces tomake its removal and replacement easy and shall have a suitableenclosure for the termination of conduit as well as provisions formaking electrical connections.

Exception No. 1: A solenoid sealed in an individual oil-filled containershall be permitted.Exception No. 2: Prewired devices, e.g. limit switches, proximityswitches) provided with an identified (see 3.49) cable need not beequipped with provisions for termination of conduit.

12.6.2 All limit switches or position sensors shall be installed sothat accidental over travel by the machine will not damage the limitswitch or sensor.

12.6.3 Solenoids for operating devices shall be mounted so thatliquids shall drain away from the electrical component enclosure.SUBSTANTIATION:Clause 12 Substantiation and Comments

12.0 Title covers existing NFPA 79 clauses 11 & 12. The clausetitle is changed from (11) Control Enclosures & Compartments &(12) Location & Mounting of Control Equipment to ControlEquipment; location, mounting and enclosures. Combine theappropriate text of NFPA 79-1997 into a new combined clause.

12.1 The sub-clause title was changed from “Type” to “GeneralRequirements.” More clearly reflect the content.

12.1.1 Recommendation: Accept new text.Substantiation: The present text including the exception was toospecific for general requirements. The intent is to provideguidance for minimum construction of enclosures but notmandate a listing requirement.

12.1.2 The proposed NFPA 79 text was accepted in order toprovide guidance for minimum construction of enclosures but notmandate a listing requirement. This will replace 11.2 & 11.4 with12.1.2

Reference to UL 50 is added to encompass enclosure constructiondetails. UL 50 covers more than just industrial machineapplications (e.g. junction boxes, cabinets and cutout boxes) andthe applicable requirements of UL 50 are presently included in UL508.

UL 508 covers industrial control enclosures that may be forindividual components as well as a group of components within acommon enclosure and provides information for enclosure sizesbased upon their wall thickness.

12.1.3 The present text was retained and relocated to NFPA 7912.1.3.

12.1.4 The present text was retained and relocated to NFPA 7912.1.4.

12.2 Accept proposed new title, adds additional content andinformation.

12.2.1 Accept proposed new title (Accessibility & Maintenance).Provides additional information.

12.2.1.1 Accept proposed new text because it provides morecomprehensive requirements for accessibility and serviceability.

12.2.2 Move NFPA 79 12.1.2 to proposed 12.2.2 “Physicalseparation and grouping.”

12.2.1.2 & 12.2.1 Move NFPA 79 12.1.2 to proposed 12.2.2“Physical separation and grouping.”

UL 50 covers more than just industrial machine applications (e.g.junction boxes, cabinets and cutout boxes) and the applicablerequirements of UL 50 are presently included in UL 508.

UL 508 covers industrial control enclosures that may be forindividual components as well as a group of components within a

common enclosure and provides information for enclosure sizesbased upon their wall thickness.

12.2.1.3 Accept proposed new text and add a note to provideguidance to location of components and to facilitate maintenance.The special tool is provided to assist in the maintenance of themachine where such parts must be removed.

12.2.1.4 Recommendation. Add new text.Substantiation: Provide a base line standard for mountingcomponents. Add an exception for mounting rails and wiringchannels.

12.2.1.5 Accept proposed new text for mounting plate informationfor steel.

12.2.1.6 Accept proposed new text for mounting plate informationfor aluminum.

12.2.1.7 Accept proposed new text for thread cutting.

12.2.1.8 Accept proposed new text to state what is not acceptablefor component mounting.

12.2.1.9 Accept proposed to provide information on swing framesand panels.

12.2.1.10 Accept new text providing information dealing with doormounted devices.

12.2.1.11 Accept new text providing information through plug indevices.

12.2.1.12 Accept proposed new text for attachments of plugs andreceptacles.

12.2.1.13 Retained present text and renumbered.

12.2.2 Accept proposed new title (Physical Separation orGrouping) as more descriptive.

12.2.2.1 The present text was retained and editorially revised toclarify the term “:built-in control” and renumbered.

12.2.2.2 The present text and exception was retained andrenumbered.

12.2.2.3 Recommendation: add new text.Substantiation: This requirement has been added to provide easeof maintenance and improve safety for personnel by separating andgrouping components.

12.2.2.4 Accept proposed new text providing information onterminal separation.

12.2.2.5 Accept proposed new text providing additionalinformation on devices and terminals.

12.2.3 Recommendation: Add new text.Substantiation: Accept proposed new text providing informationon locating of heat generating components. This is necessarybecause excessive heat can impact the reliability of sensitivecomponents. Compliance with UL 508 is considered to complywith this requirement.

12.3 Recommendation: add new title.Substantiation: Accept proposed new 12.3 title (Degrees ofProtection), 12.3.1 & 12.3.2 text. Providing information forenvironmental protection of swarf, etc.

12.3.1 Recommendation: Added new text that gives generalrequirements for control enclosures.Substantiation: These concepts are similar to the requirementsofNFPA 70-1997, 11.1.2 and 12.4.

12.3.2 Recommendation: Added new text that sets a minimumlevel of acceptable environmental protection with exceptions.Substantiation: This sets the minimum level of protection for theenclosure. NFPA 79-1997 did not contain such a minimumrequirement.


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12.4 Added new title 12.4 (Enclosures, doors and opening), andnew paragraphs 12.4.1, 12.4.2, 12.4.3, 12.4.4 & 12.4.5.

Substantiation: These requirements provide information onenclosure finishing, corrosion protection, supporting, sharp edgesand exterior details. NFPA 79-1997 did not contain such aminimum requirement.

NFPA 79-1997, 11.9Recommendation: Delete this section.Substantiation: This requirement is too restrictive.

12.4.6 Accept proposed new text accepted to provide door, coverand window requirements.

12.4.7 & 12.4.8 Recommendation: Revise NFPA 79-1997, 11.6 byremoving the requirements for hinged doors and adding specificrequirements for fasteners and deleting the exception.Substantiation: Accept proposed 12.4.7 and 12.4.8 text as moredescriptive and complete. The referenced UL Standards in 12.1.2covers the performance requirements, such as door thickness anfasteners.

12.4.9 Deleted title and absorbed text (12.4.9)

12.4.10 Deleted title and accepted proposed new text providingadditional detail.

12.4.11, 12.4.12, 12.4.13 & 12.4.14 Accepted proposed new text tocover openings in and between enclosures. Additionally providinginformation for openings in enclosures and normal and abnormalsurface temperatures.

12.5 Accept proposed new title (Access to Control Equipment),12.5.1 & 12.5.2 text for working clearances.

12.6 Retained NFPA 79 text and numbering sequence.

Clause 12 Cross Ref.

NFPA 79 1997 NFPA 79 2002

Clauses 11 & 12 Clause 12

11 12

11.1 12.1

11.1.1 &11.1.2 12.1.1

12.1.2

11.2 & 11.4 12.1.2

11.5 12.1.3

11.8 12.1.4

12 12.2

12.1 12.2.1

12.1.1 12.2.1.1

12.1.2 12.2.1

12.5.2 12.2.1.2

12.2.5, 12.2.6 & 12.3 12.2.1.3

12.2.1.4

12.2.1.4.1

12.2.1.4.2

12.2.1.4.3

12.2.1.4.4

12.2.1.5

12.2.1.6.

12.2.1.7

12.2.4 12.2.1.8

12.2.7 12.2.1.9

11.3 12.2.2

12.1.2 12.2.2.2

12.2.1 12.2.2.3

12.2.2 & 12.2.3 12.2.2.4

12.2.2.5

12.3

12.2.2

12.4 & 12.5.1 12.3.1

12.3.2

12.4

12.4.1

12.4.2

12.4.3

12.4.4

11.9 deleted 12.4.5

12.4.6

11.6 12.4.7

11.6 12.4.8

11.11 12.4.9

11.7 12.4.10

12.4.11

12.4.12

12.4.13

12.4.14

12.5

12.5.1

12.5.2

12.5.3

12.6

12.6.1

12.6.2

12.6.3

COMMITTEE ACTION: Accept in Principle. Revise text to read as follows:12 Control equipment: location, mounting, and enclosures12. 1 General requirements12.1.1. All control equipment shall be located and mounted so asto facilitate:Its accessibility and maintenance;Its protection against the external influences or conditions underwhich it is intended to operate;Operation and maintenance of the machine and its associatedequipment.12.1.2. For minimum Minimum construction requirements, seeshall comply with UL 508 & and U.L. 50 for metallic andnonmetallic enclosures.12.1.3. The depth of the enclosure or compartment including doors orcovers shall not be less than the maximum depth of the enclosedequipment plus the required electrical clearances.12.1.4. Any door(s) that permits access to live parts shall comply with6.3.2.5.12.2 Location and mounting12.2.1 Accessibility and maintenance12.2.1.1. All items of control equipment shall be placed andoriented so that they can be identified without moving them or thewiring. Where practicable, items that require checking oradjustment for correct operation or that are liable to need


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replacement, those actions shall be possible without dismantlingother equipment or parts of the machine (except opening doors orremoving covers). Terminals not associated with controlequipment shall also conform to these requirements.12.2.1.2 Terminal blocks shall be mounted to pro videunobstructed access to the terminals and their conductors.12.2.1.2 3 . Exposed, nonarcing, bare, live parts within an enclosureor compartment shall have an air space of not less than 13 mm(1/2 inch) between them and the uninsulated walls of theenclosure or compartment, including conduit fittings. The airspace for uninsulated covers or doors of the enclosure shall be notless than 25 mm (1 inch). Where barriers between metalenclosures or compartments and arcing parts are required, theyshall be of flame-retardant, noncarbonizing insulating materials.12.2.1.3 4 . All control equipmen t shall be mounted so as tofacilitate its operation and maintenance. Where a special tool isnecessary to remove a device, such a tool shall be supplied.Note: Where access is required for regular maintenance oradjustment, it is recommended that the relevant devices be locatedbetween 0.4 m (15.75 inches) and 2.0 m (78.75 inches) above theservicing level to facilitate maintenance. It is recommended thatterminals be at least 0.2 m (7.88 inches) above the servicing leveland be so placed that conductors and cables can be easilyconnected to them.12.2.1.4 5 . Threaded fasteners with machine threads shall be usedto attach components to a sub plate and shall provide sufficientthread engagement to maintain secure mounting:12.2.1.4 5 .1. Steel sub plate thickness shall provide engagement ofat least 2 full threads.12.2.1.4 5 .2. Aluminum sub plate thickness shall provideengagement of at least 3 full threads.12.2.1.4 5 .3. Thread cutting or thread forming screws shall bepermitted if the above thread engagement requirements are met.12.2.1.4 5 .4. Sheet metal screws, rivets, welds, solders, or bondingmaterials shall not be used to mount components to a sub plate.Exception: Rivets shall be permitted to be used for attachingmounting rails and wiring channels.12.2.1.5 6 . Swing frames or swing out panels shall be permitted,provided the swing is more than 110 degrees. Wiring shall notinhibit swing. Panel-mounted components behind swing framesshall be accessible when open.12.2.1.7 8 Where control devices are connected through plug-inarrangements, their association shall be made clear by type(shape), marking or reference designation, singly or incombination.Note: 14.4.5 contains addition information on attachment plug andreceptacle (plug/socket) combinations.12.2.1.8 9 . Attachment plugs and receptacles (plug/socket)combinations that are handled during normal operation shall belocated and mounted as to provide unobstructed access.12.2.1.9 10 Test points, where provided, shall be mounted toprovide unobstructed access, plainly marked to correspond withmarkings on the drawings, adequately insulated, and sufficientlyspaced for connection of test leads .

12.2.2 Physical separation or grouping12.2.2.1 Machine compartments containing control equipment (built-incontrol) shall be completely isolated from coolant and oil reservoirs. Thecompartment shall be readily accessible and completely enclosed; it shallnot be considered enclosed where it is open to the floor, the foundationupon which the machine rests, or other compartments of the machine thatare not clean and dry.12.2.2.2 Pipelines, tubing, or devices (e.g.solenoid valves) forhandling air, gases, or liquids shall not be located in enclosures orcompartments containing electrical control equipment.Exception: Equipment for cooling electronic devices.12.2.2.3 Control devices mounted in the same location within the controlenclosure and connected to the supply voltage, or to both supply andcontrol voltages, shall be grouped separately from those connected only tothe control voltages.12.2.2.4 Terminals shall be separated into groups for:power circuits; associated control circuits; other control circuits,fed from external sources (e.g. for interlocking).12.2.2.5 The groups shall be permitted to be mounted adjacently,provided that each group can be readily identified (e.g. bymarkings, by use of different sizes, by use of barriers, by colors).12.2.3 Heating effects. Heat generating components (e.g. heatsinks, power resistors) shall be so located that the temperature ofeach component in the vicinity remains within the componentmanufacturers specified limits.12.3 Degrees of protection.

12.3.1 The protection of control equipment against ingress of solidforeign objects and of liquids shall be adequate taking into accountthe external influences under which the machine is intended tooperate (i.e. the location and the physical environmentalconditions)including dust, coolants, and swarf.)NOTE –The degrees of protection against ingress of water andother liquids are covered by NEMA 250. See also annex H.12.3.2 Enclosures of control equipment shall provide a degree ofprotection of at least NEMA Type 1.Exception No.1 Where removable collectors on collector wire orcollector bar systems are used and NEMA Type 1 enclosures arenot practicable, suitable protection shall be provided (e.g.elevation, guarding.)12.4 Enclosures, doors, and openings12.4.1 Enclosures shall be constructed and finished using materialscapable of withstanding the mechanical, electrical and thermal stresses,as well as the effects of humidity and corrosion that are likely to beencountered in normal service.12.4.2 Where corrosion protection beyond normal requirements isneeded, non-metallic enclosures identified for the purposes shallbe permitted if they meet the requirements of UL 508.12.4.3 Subplates having a surface area of more than 15,484 sq cm(2400 sq in.) shall have supports provided in addition to the panelmounting means to aid in subplate installation.12.4.4 Enclosures and sub plates shall be free of burrs and sharpedges.12.4.5 The exterior of the enclosure shall :(1) be of a material suitable for the intended e nvironment, or(2) shall include a protective finish suitable for the intendedenvironment.12.4.6 Fasteners used to secure doors and covers shall be of thecaptive type. Windows provided for viewing internally mountedindicating devices should be of a material suitable to withstandmechanical stress and chemical attack [ e.g. toughened glass,polycarbonate sheet of 3-mm (1/8-in.) thickness ] .12.4.7 Door fasteners on enclosures and compartments with dooropenings less than 1016 mm (40 in.) tall shall be designed to sealthe door tightly around its perimeter with either captive fasteners orvault type hardware which latch at the top and bottom.12.4.8 Door fasteners on enclosures and compartments with dooropenings 1016 mm (40 in.) tall or more shall be designed to sealthe door tightly around its perimeter with either captive fasteners orvault type hardware which latch at the top, center and bottom.12.4.9 A print pocket sized to accommodate electrical diagramsshall be attached to the inside of the door of the control enclosureor compartment. Single-door and multidoor enclosures shall haveat least one print pocket.

12.4.10 The joints or gaskets of doors, lids, covers, externallymounted accessories , interconnect panels and enclosures shallwithstand the deleterious effects of liquids, vapors, or gases usedon the machine. The means used to maintain the degree ofprotection of an enclosure on doors, lids and covers that requireopening or removal for operation or maintenance shall: besecurely attached to either the door/cover or the enclosure ; andnot deteriorate due to removal or replacement of the door or thecover, and so impair the degree of protection.12.4.11 All openings in the enclosure, including those towards thefloor or foundation or to other parts of the machine, shall beclosed by the supplier(s) in a manner ensuring the protectionspecified for the equipment. Openings for cable entries shall beeasily re-opened on site. A suitable opening shall be permitted inthe base of enclosures within the machine so that moisture due tocondensation is allowed to drain.12.4.12 There shall be no opening between enclosures containingelectrical equipment and compartments containing coolant,lubricating or hydraulic fluids, or those into which oil, otherliquids, or dust can penetrate. This requirement does not apply toelectrical devices specifically designed to operate in oil (e.g.electromagnetic clutches) nor to electrical equipment in whichcoolants are used.12.4.13 Where there are holes in an enclosure for mountingpurposes, care shall be taken so that after mounting, the holes donot impair the required protection.12.4.14 Equipment that, in normal or abnormal operation, can attain asurface temperature sufficient to cause a risk of fire or harmful effect toan enclosure material:-- Shall be located within an enclosure that will withstand, withoutrisk of fire or harmful effect, such temperatures as may begenerated; and


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-- Shall be mounted and located at a sufficient distance fromadjacent equipment so as to allow safe dissipation of heat (see also12.2.3); or-- Shall be otherwise screened by material that can withstand,without risk of fire or harmful effect, the heat emitted by theequipment.12.5 Access to control equipment12.5.1 Working clearances: Sufficient space and access shall beprovided about all electrical equipment and enclosures to permitsafe operations and maintenance of such equipment. In all cases,the workspace shall permit at least 90-degree opening of the dooror hinged panel.12.5.2 Access to control equipment shall be in accordance withNFPA 70, Section 110-26 for the requirements for working space inthe direction of access to live parts operating at 600 volts nominal,or less to ground and likely to require examination, adjustment,servicing, or maintenance while energized.Note: Additional clearance requirements are found in NFPA 70,670-5.12.5.3 Door in gangways and for access to electrical operatingareas shall: be at least 0.7 m wide and 2.0 m (6 ft 7 in.) high: openoutwards; have a means (e.g. panic bolts or panic bars) to allowopening from the inside without the use of a key or tool. [addEnglish units and remove, adding decimal]12.6 Machine-mounted control equipment12.6.1 Control equipment (e.g. limit switches, brakes, solenoids,position sensors) shall be mounted rigidly in a reasonably dry andclean location, shall be protected from physical damage, and shallbe free from the possibility of accidental operation by normalmachine movements or by the operator. Such equipment shall bemounted with sufficient clearance from surrounding surfaces tomake its removal and replacement easy and shall have a suitableenclosure for the termination of conduit as well as provisions formaking electrical connections.Exception No. 1: A solenoid sealed in an individual oil-filled containershall be permitted.Exception No. 2: Prewired devices, (e.g. limit switches, proximityswitches) provided with an identified cable need not be equipped withprovisions for termination of conduit.12.6.2 All limit switches or position sensors shall be installed sothat accidental over travel by the machine will not damage the limitswitch or sensor.12.6.3 Solenoids for operating devices shall be mounted so thatliquids shall drain away from the electrical component enclosure.COMMITTEE STATEMENT: 1) Revise 12.1.2 to comply with theNFPA Manual of Style. 2) Editorially add "or adjustment" to 12.2.1.1. 3) 12.4.6 Delete "and covers". Covers is new material and isunsubstantiated. It does not agree with the definition of cover inUL 50. 4) The revision to Section 12.5 incorporates the CommitteeAction on Proposal 79-32 (Log #96).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Specifying the type or location of fasteners andother hardware, direction of swing of doors, etc. may inadvertentlybe limiting the ability of machine suppliers to freely design andbuild their own enclosures suitable for the intended environment.Delete 12.4.6, 12.4.7 and 12.4.8COMMENT ON AFFIRMATIVE: SAUNDERS: The revision of the definition of live parts from"Electric conductors, buses, terminals, or components that areuninsulated or exposed and a shock hazard exists" to "Energizedconductive components" alters the requirement found in 12.5.2significantly. No substantiation has been submitted to indicate thatthis previous requirement should be changed.During the committee meeting, it was recognized that there may besections where the change in definition may alter the requirementsand that these issues should be addressed during the commentstage. Recommendation: Revise 12.5.2 to read "access to live parts thatare uninsulated or exposed and a shock hazard exists operating at600 volts nominal…"

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(Log #114)79- 85 - (Clause 11 [12.2.2]): Accept in PrincipleSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add new text to read as follows: " Any device(s) mounted on the control panel, carrying linevoltage or a combination of line voltage and control voltage, shallbe grouped above or to the side and segreated from devices whichcarry only control voltage. Devices carrying control voltage other than 115 VAC or acombination of 115 VAC and lower control voltage, shall also besegregated from devices mentioned above. This does not apply where the line voltage is 115 VAC. In no caseshall any device be mounted directly above the disconnectingmeans. "SUBSTANTIATION: Reduction of shock hazard whenperforming troubleshooting procedures under "powered"conditions. When used with "color coding" of wire conductorsallow visual identification to the electrician of the voltage hazardpotential.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-84 (Log #54) (12.2.2.3 and 12.2.2.4 and12.2.2.5). See also Committee Action on Proposal 79-33 (Log #59)(5.3.1.3).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #103)79- 86 - (11.1.1 [12.1.1]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Revise text to read as follows: Control enclosures and compartments shall be nonventilated withconstruction and sealing suitable for the intended environmentconstructed in conformance with the applicable sections of thisstandard and both of the following: 1. NEMA Type 12 (See NEMA Standard IC-1, Industrial Controls) 2. Underwriter’s Laboratories Standard UL 508, Industrial ControlEquipment. Exception: Equipment normally requiring ventilation may behoused in ventilated enclosures or compartments, provided theyare located so that the equipment is capable of operatingsatisfactorily and without hazard.SUBSTANTIATION: This allows enclosures to be properly"labeled or identified" by a NRTL for use in the intended industrialenvironment normally encountered by equipment identified by theANSI B11 standards.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This standard covers machinesbeyond the scope of the ANSI B11 series. Equipment must beselected to be suitable for the environment.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: There is no data as to what percentage ofmachines are installed in each of the wide range of environmentsfrom cleanroom, to office-like, to light industrial, to heavyindustrial, to extremely harsh environments including outdoorinstallations. The general statement "suitable for the intendedenvironment" is appropriate because one generic standard has tofit all industries and all environments for both machines covered byANSI B11 series and machines not covered by the ANSI B11 series.

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(Log #131)79- 87 - (11.4 [12.1.2]): Accept in PrincipleSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Revise text as follows: 11.4 Minimum wall thickness and construction requirements The walls of compartments shall be not less than the following:.0625 in. (1.5 mm) for sheet metal; 1/8 in. (3.2 mm) for castmetal; or 3/32 in. (2.38 mm) for malleable iron. The minimum enclosure wall thickness and constructionrequirements shall meet UL 508.


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SUBSTANTIATION: The minimum thickness requirement asstated does not take into account the enclosure size. UL 508 hasminimum thickness tables based on the height and width of theenclosure. This provides guidance when enclosure sizes requirewall thickness greater than the minimum required thickness ascurrently stated. These tables are constructed based on deflectiontesting. UL 508 covers construction and testing of steel aluminum,cast and composite enclosures. (See the attached minimum sheetmetal thickness table). Note: Supporting material is available for review at NFPAHeadquarters.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-84 (Log #54) (12.1.2).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DEFELICE: Many machine manufacturers construct the electricalenclosures as an integral part of their machine. 12.1.2 mandatesthat these enclosures to be constructed to UL 508 standard. The requirement to construct the enclosure to the UL 508standard necessitates the purchase of this document ($355.00;almost 13 times the price of NFPA 79-1997). We have seen noevidence which supports the need for this requirement and believethat it is unduly restrictive.

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(Log #127)79- 88 - (11.6 [12.4.7 and 12.4.8]): Accept in PrincipleSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Add new text as follows: 11.6 Doors Enclosure or compartments shall have one or more hinged doorsthat shall swing about a vertical axis and shall be held closed withcaptive fasteners or vault-type hardware. The thickness of the doorshall not be less than that indicated in 11.4. The width of thedoors shall not exceed 40 inches. Exception: Where the motors on the machine totals twoHorsepower or less, eCovers held with captive screw-type fastenersshall be permitted where: - the motors on the machine totals two horsepower or less, or - access to enclosures is not required for normal maintenancesuch as junction and pull boxes. SUBSTANTIATION: The requirement for hinged doors providesease of access and a means for interlocking for enclosure doorswhich are opened frequently for maintenance and troubleshooting.Enclosures not normally accessed except during the assembly ofthe machine need not require a hinge the added exceptionaddresses this condition.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-65 (Log #84) (12.4.7) which meets the intent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: The references in the Committee Statement donot appear to match the proposal. I believe the correct referenceis the Committee Statement on Proposal 79-84 (Log #54) (12.4.6).

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(Log #129)79- 89 - (11.6 [12.4.7 and 12.4.8]): Accept in PrincipleSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Delete text to read as follows: 11.6 Doors. Enclosure or compartments shall have one or morehinged doors that shall swing about a vertical axis and shall be heldclosed with captive fasteners or vault-type hardware. The thicknessof the door shall not be less than that indicated in 11.4. The widthof the doors shall not exceed 40 inches.SUBSTANTIATION: The problem is some control enclosures arerequired and designed to be mounted in a landscape foot print;where they are wide and not very high. Many of these utilizehorizontal hinges ususally mounted to swing the door down.Consoles and desk top style enclosures also utilize horizontalhinges. Deleting the portion shown above allows for horizontalhinges.

COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-84 (Log #54) (12.4.8).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #19)79- 90 - (11.8 Exception No. 5 [6.2.3.5]): Accept in Principle TCC NOTE: The Technical Correlating Committee directs thecommittee to consider the comments expressed in the voting.This action will be considered by the committee as a publiccomment.SUBMITTER: Mark A. Rauch, Boeing CompanyRECOMMENDATION: Add Exception to read as follows: Exception No. 5: Where an electrical enclosure is not the maincontrol enclosure, and this control enclosure door or cover ismarked with a warning indicating that power shall be removed bythe disconnecting means before the enclosure is opened, andfurther provided that a tool is required to open the enclosure.SUBSTANTIATION: Machines often need modifications whereno room is available in the main control enclosure. An auxiliaryenclosure must be added to the machine, and requiring doorinterlocks is very burdensome, and does not add the electricalsafety of the machine, many machines have electrical doorinterlock overrides that are tool operated.COMMITTEE ACTION: Accept in Principle. Retain the language of proposed Exception No. 5 but move text tobe located as new Exception No. 5 to subclause 6.2.3.5.COMMITTEE STATEMENT: The text more appropriately belongas a new Exception No. 5 to subclause 6.2.3.5. The committee understands that this proposal modifies theCommittee Action on Proposal 79-25 (Log #68) [Clause 6].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: SAUNDERS: The panel action on Proposal 79-25 (Log #68) hasdeleted the referenced paragraph 6.2.3.5. The requirement for interlocking the enclosure door with thedisconnect device furnished within the enclosure should be basedon the same requirements whether the enclosure is the "main"control panel for a complex system or an enclosure fed fromanother "machine power panel" as part of a distributed system. If the interlock requirements are not necessary on the "distributedenclosures", where the hazard of unintended or uncontrolledaccess "could" be the same as for the "main" control enclosure,then the requirements for the "main" control enclosure should bereevaluated. The term "main" control enclosure, while often used and generallyunderstood, is not defined in this standard and will causeproblems in interpretation and enforcement.

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(Log #128)79- 91 - (11.9 [12.4.5]): RejectSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Revise text to read as follows: 11.9 Interior, exterior and panel(s) of control enclosures andexposed surfaces of panels mounted therein shall be have aprotective finished suitable for the intended environment in a lightcolor. Note: It is recommended the panel be finished white or in aprotective metallic finish. SUBSTANTIATION: The requirement to be light in color isvague and not clearly defined. Different users will specify specificcolors for the enclosure interior. There is a need to require adurable finish that will not deteriorate within its environment. Thenote was added to recommend a white or reflective panel toimprove visibility. The changed and added text addresses finish forboth interior and exterior of the enclosure and ensures a finishtype adequate for the environment.


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COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposal is too restrictive.Environmental concerns are addressed in the Action on Proposal79-24 (Log #60) (4.4.1). See Committee Action and Statement onProposal 79-84 (Log #54).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #6)79- 92 - (11.10 [17.2.1]): Accept in Principle in PartSUBMITTER: Loren Mills , Van Dorn Demag Corp./Rep. SPIRECOMMENDATION: Revise text to read as follows: 11.10 Warning mark Safety Sign for Electrical Enclosures Enclosures that do not clearly show that they contain electricaldevices shall be marked with a safety sign a black lightning flash ona yellow background within a black triangle, shaped in accordancewith the graphical symbol 5036 of IEC 417M, the whole inaccordance with symbol 13 of ISO 3864, as shown in Figure 3. ****Insert Figure 3 Here*** It is permitted to omit this warning safety sign on —an enclosure equipped with a supply disconnecting device; —an operator-machine interface or control station; —a single device with its own enclosure (e.g. position sensor). The warning safety sign shall be plainly visible on the enclosuredoor or cover.SUBSTANTIATION: The safety sign and description in Section11.10 of NFPA 79 does not meet the current requirements of theANSI Z535 safety sign standards.COMMITTEE ACTION: Accept in Principle in Part.1) Revise the title of 17.2 to read as follows: 17.2 Warning marking and signs Safety Signs for ElectricalEnclosures 2) Revise 17.2.2 to read as follows: 17.2.2 Safety signs shall be plainly visable on the enclosure dooror cover. 3) Revise 17.2.3 to read as follows:It shall be permitted to omit this warning safety signs on —an enclosure equipped with a supply disconnecting device; —an operator-machine interface or control station; —a single device with its own enclosure (e.g. position sensor). 4) The insertion of the artwork is rejected.COMMITTEE STATEMENT: 1) The revised title better reflects theintent of the committee and the material covered in 17.2. 2) This corrrelates with the change in title. 3) Changed "warning" to "safety" to correlate with the titlerevision. 4) The artwork has not been included because of the CommitteeAction on Proposal 79-93 (Log #20). 5) The part of the text that was not accepted is already covered bythe Committee Action on Proposal 79-93 (Log #20). 6) The committee understands that this proposal modifies theCommittee Action on Proposal 79-18 (Log #23).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: There is no justification to remove the safetysign printed in NFPA79-1997. Since this specific safety sign haspreviously printed in NFPA79-1997, new developments in ANSIZ535 should be added as an exception. The safety sign required byNFPA79-1997 has been included on all machines. This proposalwill not only reverse a practice used for years but will make theestablished safety sign unacceptable. Using English text per ANSIZ535 will require local language translation in all other countriesworldwide.

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(Log #20)79- 93 - (11.10 [17.2.1]): Accept in PartSUBMITTER: Marvin A. Salzenstein , Polytechnic, Inc.RECOMMENDATION: Add the following new text: 17.2.1 Enclosures that do not clearly show that they containelectrical devices shall be marked with a safety sign, in accordancewith ANSI Z535 series, dealing with product safety signs. If apictorial is employed as part of the sign to warn of live electricalparts, the following shall be used:

SUBSTANTIATION: NFPA 79, 1997, paragraph 11.10 contains apictorial which has not been generally recognized by the public.The proposed pictorial has been tested and found to comply withANSI Z535 criteria for pictorial acceptability. Further, the ANSI535 Series of standards prescribes procedures for preparingproduct warnings and should be adopted in the current proposal.COMMITTEE ACTION: Accept in Part. Add the following new text: 17.2.1 Enclosures that do not clearly show that the containelectrical devices shall be marked with a safety sign, in accordancewith ANSI Z535 series, dealing with product safety signs.COMMITTEE STATEMENT: The committee does not accept thesecond sentence and the associated artwork because it is overlyrestrictive. The committee understands that this proposal modifiesthe Committee Action on Proposal 79-18 (Log #23).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARSIDE: The proposed wording is too restrictive. The IECsymbol that has been permitted by the current version of NFPA 79,and is used in IEC/EN 60204-1, and (I believe) in other USstandards, is widely used and well understood. Use of the symbolalone should continue to be allowed. FREUDENBERG: There is no justification to remove the safetysign printed in NFPA79-1997. Since this specific safety sign haspreviously printed in NFPA79-1997, new developments in ANSIZ535 should be added as an exception. The safety sign required byNFPA79-1997 has been included on all machines. This proposalwill not only reverse a practice used for years but will make theestablished safety sign unacceptable. Using English text per ANSIZ535 will require local language translation by notified bodies andauthorities having jurisdiction in all other countries worldwide. SALZENSTEIN: A uniform and well-understood (by the generaland working public) pictorial is essential to warn off hazards. TheNFPA 79 Committee can do a great service to the public to specifythe submitted pictorial as a descriptor of the electrical hazard asopposed to having numerous graphics for the same issue.COMMENT ON AFFIRMATIVE: DOBROWSKY: In the Committee Action text the word "the"should be "they". WITHROW: Within the committee action, add the following newtext: 17.2.1 Enclosures that do not clearly show that they containelectrical devices shall be marked with a safety sign, in accordancewith ANSI Z535 Series, dealing with product safety signs. COMMENT: Strike ANSI Z535 Series and add the specific ANSIZ535 Standard such as ANSI Z535.4-1998. Add this ANSI Standardto Clause 2.

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(Log #115)79- 94 - (12.1 [12.2.1]): Accept in PrincipleSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add new text to read as follows: "Control stations (including that of auxiliary or third partysupplied equipment) shall be located within easy reach of theequipment operator and placed so that the operator does not haveto reach past moving parts, or through any safe guarding perimeterdevice."SUBSTANTIATION: With additional automation and presencesensing safe guarding devices being installed on existingequipment, many control enclosures are being located outside ofthe reach or observation of the machine operator, or due tomounting, requires the operator to penetrate the PSD perimeter(for the ease of the installer to mount).COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: The proposal is already covered in12.5.2 and 10.1.6.1. See Committee Action on Proposal 79-84 (Log#54) and 79-99 (Log #24).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #10)79- 95 - (12.1.2 Exception [12.2.2]): AcceptSUBMITTER: Frank C. DeFelice, Jr., Cytec Industries Inc.RECOMMENDATION: Add Exception No. 2 as follows: "Where pipelines, tubings, or devices are an integral part of listedequipment and are separated by suitable barriers."SUBSTANTIATION: Equipment containing hydraulic and/orpneumatic solenoids and similar devices, located within acompartment or enclosure common to electrical devices, has beenmanufactured for many years, with no history of fire or safetyproblems, provided sufficient barriers are provided.COMMITTEE ACTION: Accept. 1) Renumber existing 12.2.2.2, Exception as Exception No. 1. 2) Add new Exception No. 2 from this proposal.COMMITTEE STATEMENT: The committee understands that thisaction modifies the Committee Action on Proposal 79-59 (Log #62)in 12.2.2.2.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DEFELICE: Although the committee action on this proposal wasto "Accept", this change is not yet reflected in Document Number79-84 (Committee Action - Log 54). DOBROWSKY: The words "or labeled" should be inserted afterthe word "listed". Reason: Some equipment may be labeled by a qualified testinglaboratory but the equipment may technically not be listed. FISHER: In the original proposal, references to origin ofdefinitions were included in definitions and many have since beendeleted. Therefore the reference items that only appear indefinitions and do not create a normative reference are to bedeleted from the list. The items to be deleted include: 2.1, 2.2,2.3, 2.4, 2.5. 2.6, 2.7, 2.9, 2.13, 2.18, 2.21, 2.28.

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(Log #112)79- 96 - (12.2 [12.2.1.3]): Accept in PrincipleSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add new text to read as follows: "Where required for maintenance, space shall be providedadjacent to all devices mounted on the control panel."SUBSTANTIATION: Have found a number of designs that havecontained devices that needed adjustment ("trimming") to operateproperly, with the control points of devices blocked by otherdevices or located too close to the enclosure walls for ready access(the device had to be removed from the panel, an "adjustmentmade", re-installed, then tested to confirm performance).Maintenance and initial machine setup issue.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-84 (Log #54) (12.2.1.1 and 12.2.1.3) which meets the intent ofthe submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26

VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: The second reference should be 12.2.1.4.

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(Log #113)79- 97 - (12.2.2 [12.2.4]): Accept in PrincipleSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add text to read as follows: "Terminal blocks for all different voltages shall be groupedseparately from other voltages (line, AC control, DC control,instrumentation). Terminal blocks of different voltages mountedon a common mounting guide, shall be separated from each otherby a minimum of one unused terminal block for isolation."SUBSTANTIATION: Have had higher voltages induced by errorby maintenance and startup personnel (shorts between conductorsat the terminal block during troubleshooting) causing devicedamage or shock risk. Also have experienced induced "signals"into instrumentation circuits causing control errors (and un-commanded motion)COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action andStatement on Proposal 79-84 (Log #54) (12.2.2.4 and 12.2.2.5).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #133)79- 98 - (12.5.2 [12.2.1.2]): AcceptSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the following paragraph (12.2.1.2) 12.2.1.2 Exposed, nonarcing, bare, live parts within an enclosureor compartment shall have an air space of not less than 13 mm(1/2 inch) between them and the uninsulated walls of theenclosure or compartment, including conduit fittings. The airspace for uninsulated covers or doors of the enclosure shall be notless than 25 mm (1 inch). Where barriers between metalenclosures or compartments and arcing parts are required, theyshall be of flame-retardant, noncarbonizing insulating materials.SUBSTANTIATION: Many enclosures are assemblies boltedtogether whether the enclosing material is a wall or cover would bedifficult to enforce. The purpose of the requirement was torecognize the use of flexible material in panel door constructionthat might compromise safety; this proposal should not change theresults.COMMITTEE ACTION: Accept. The text of this proposal replaces Section 12.2.1.2.3. Exposed,nonarcing, bare, ..." of Proposal 79-84 (Log #54).COMMITTEE STATEMENT: The committee understands that theaction on this proposal modifies the Action on Proposal 79-84(Log #54) [Clause 12].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: Exposed?, nonarcing?, bare? The following textis more appropriate for the first sentence 12.2.1.2.3 Uninsulatedlive parts in the primary circuit shall have an air space of not lessthan 13 mm (1/2 inch) between exposed metal and theuninsulated walls of the enclosure or compartment, includingconduit fittings. "in the primary circuit" is an important limitationbecause you won't find and don't need 1/2 spacing between partsin secondary circuits & between secondary parts and the enclosure.COMMENT ON AFFIRMATIVE: ANDERSON: In many instances the accepted proposal is shownin the committee action log for the particular chapter, sometimesnot, thus the comment. In the committee statement the changes from log # 133 wereinadvertently not brought forward to the committee action for log54, also please see log 133 [which is accepted] in which subsubsection 12.2.1.2 is modified to read: 12.2.1.2. Exposed, non-arcing, bare, live parts within anenclosure or compartment shall have an air space of not less than13mm (1/2 inch) between them and the un-insulated walls of the


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enclosure or compartment, including conduit fittings. The airspace for un-insulated covers or doors of the enclosure shall be notless than 25 mm (1inch). Where barriers between metal enclosuresor compartments and arcing parts are required, they shall be offlame-retardant, non-carbonizing insulating materials.

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(Log #24)79- 99 - (Clause 13, 12.6.2 and 12.7 [Clause 10]): Accept inPrincipleSUBMITTER: Wayman L. Withrow, Cincinnati IncorporatedRECOMMENDATION: Revise NFPA 79-1997 Clause 13"Operator’s control stations and equipment", subclause 12.6.2, andsubclause 12.7 "Rotary control devices." Issue as proposed NFPA79-2002 Clause 10 "Operator interface and control devices asfollows:10 Operator interface and control devices.

10.1 General.

10.1.1 General device requirements. This clause containsrequirements for devices mounted outside or partially outsidecontrol enc losures.

Note: For further information on device selection, mounting,identification, and coding, see IEC 60073 and IEC 60447.

10.1.2 Location and Mounting.

10.1.2.1 Control devices. As far as is practicable, control devicesshall be:

— readily accessible for service and maintenance.— mounted in such a manner as to minimize the possibility ofdamage from activities such as material handling. 10.1.2.2 Hand operated control devices. The actuators of hand-operated control devices shall be selected and installed so that: — they are not less than 2 feet (0.6 m) above the servicing leveland are within easy reach of the normal working position of theoperator.— the operator is not placed in a hazardous situation whenoperating them.— the possibility of inadvertent operation is minimized. 10.1.3 Protection. Operator interface, control devices, andenclosures shall be suitable for the environment and shallwithstand the stresses of expected use. Note: For further information on degrees of protection, see UL50, UL 508, Annex XX and IEC 60529. 10.1.4 Position sensors. 10.1.4.1 Position sensors (e.g. limit switches, position switches,proximity switches) shall be so arranged that they will not bedamaged in the event of overtravel. 10.1.4.2 Position sensors used in circuits with safety-relatedfunctions either shall have positive (direct) opening operation orshall provide similar reliability. Note: For further information on positive (or direct) openingoperation, see IEC 60947-5-1. 10.1.5 Portable and pendant control stations. 10.1.5.1 Portable and pendant operator control stations and theircontrol devices shall be so selected and arranged to minimize thepossibility of inadvertent machine operations. 10.1.5.2 Pendant control stations that are vertically suspended fromoverhead shall be supported by suitable means or flexible electricalconduit or multiconductor cable or cord identified for thepurpose. 10.1.6 Operator interface devices. 10.1.6.1 Location of operator interface devices.

10.1.6.1.1 Operator interface devices shall be mounted in locationsthat will minimize exposure to oil, coolant, and othercontaminants. 10.1.6.1.2 Operator interface devices shall be within normal reachof the machine operator and shall be so placed that the operator isnot exposed to hazards. 10.1.6.1.3 Operator interface devices shall be located so thatunintentional operation by normal movement of the machine,operator, or work will be unlikely. 10.1.6.2 Arrangement of operator interface devices. All Startpushbuttons shall be mounted above or to the left of theirassociated Stop pushbuttons. Exception No. 1: Start pushbuttons in series, such as operatingpushbuttons on punch presses. Exception No. 2: Wobble-stick or rod-operated Emergency Stoppushbuttons mounted in the bottom of pendant stations. 10.1.7 Foot-operated switches. Foot-operated switches used forapplications where accidental actuation could create a hazardoussituation shall be protected to prevent accidental actuation byfalling or moving objects and from unintended operation byaccidental stepping onto the switch. Exception: Foot-operated switches used for emergency stop in accordancewith 10.7.2.1 shall not be of the covered or hooded type. 10.2 Push-button actuators and action initiating icons. Pushbuttonactuators used to initiate a stop function shall be of the extendedoperator or mushroom-head types. 10.2.1 Colors. Pushbutton actuators and action initiating icons ofcolor touch screen interfaces shall be color coded as follows: – Start or On - The preferred color of Start or On actuators isGREEN, except that BLACK, WHITE, or GRAY shall be permitted.Red shall not be used for Start or On actuators. – Stop or Off - The preferred color of Stop or Off actuators is RED,except that BLACK, WHITE, or GRAY shall be permitted. Greenshall not be used for Stop or Off actuators Exception: Stop function operators of the wobble-stick or rod-operatedtypes in the bottom of a pendant station need not be colored red. The color RED shall be used for, Emergency Stop actuators inaccordance with 10.7.4. – Alternate action - Pushbuttons that, when pressed, act alternatelyas Start and Stop or On and Off shall be BLACK, WHITE, orGRAY. RED or GREEN shall not be used. – Abnormal conditions - The color YELLOW shall be used foractuators used to respond to abnormal conditions. – Hold to operate - Pushbuttons that cause movement whenpressed and stop movement when they are released (e.g., jogging)shall be BLACK, WHITE, GRAY, or BLUE with a preference forBLACK. – Reset - Reset pushbuttons shall be BLUE, BLACK, WHITE, orGRAY except when they also act as a Stop or Off button, in whichcase they shall be RED. 10.2.2 Legends. 10.2.2.1 A legend shall be provided for each operator interfacedevice to identify its function and shall be located so that it can beeasily read by the machine operator from the normal operatorposition. The legends shall be durable and suitable for theoperating environment. 10.2.2.2 For illuminated pushbuttons the function(s) of the light isseparated from the function(s) of the button by a virgule (/). 10.3 Indicator lights and icons of visual display units.


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10.3.1 Modes of use. Indicator lights and icons used with visualdisplay units shall provide the following information: — indication: to attract the operator's attention or to indicatethat a certain task should be performed. The colors RED, YELLOW(AMBER), GREEN, and BLUE are normally used in this mode; — confirmation: to confirm a command, or a condition, or toconfirm the termination of a change or transition period. Thecolors BLUE and WHITE are normally used in this mode andGREEN shall be permitted to be used in some cases. 10.3.2 Colors. Indicator lights and icons of visual display unitsshall be color-coded with respect to the condition (status) of themachine in accordance with table XX. Alternate purposes shall bepermitted to indicate machine or process status. (See Tablebelow) 10.3.3 Flashing lights. Flashing lights shall be permi tted to be usedfor any of the following purposes: – to attract attention.– to request immediate action.– to indicate a discrepancy between the command and actualstates– to indicate a change in process (flashing during transition). 10.4 Illuminated push-buttons. Illuminated push-button actuatorsshall be color-coded in accordance with table XX. The color REDfor the emergency stop actuator shall not depend on theillumination source. 10.5 Rotary control devices. Devices having a rotational member,such as potentiometers and selector switches, shall be mounted insuch a way as to prevent rotation of the stationary member.Friction alone shall not be relied upon to prevent rotation. 10.6 Start devices. Actuators used to initiate a start function or themovement of machine elements (e.g. slides, spindles, carriers)shall be constructed and mounted to minimize inadvertentoperation. Mushroom-type actuators for two-hand controlinitiation shall conform to the requirements of 9.2.5.6 (two handcontrol). 10.7 Devices for stop and emergency stop. 10.7.1 Location and operation. 10.7.1.1 Stop and emergency stop pushbuttons shall becontinuously operable and readily accessible. 10.7.1.2 Stop and emergency stop pushbuttons shall be located ateach operator control station and at other locations whereemergency stop is required. 10.7.2 Types.

10.7.2.1 The types of device for emergency stop include, but arenot limited to: — push-button operated switches in accordance with 10.7.4.— pull-cord operated switches.— foot-operated switches without a mechanical guard— push bar operated switches.— rod operated switches. 10.7.2.2 Pushbutton type devices for emergency stop shall be of theself-latching type and shall have positive (direct) openingoperation. Note: For further information on positive (direct) openingoperation, see IEC 60947-5-1. Exception: For machines which employ only a single emergency stopdevice, emergency stop actuators of the momentary type shall be permitted. 10.7.3 Restoration of normal function after emergency stop. Itshall not be possible to restore an emergency stop circuit until theemergency stop device has been manually reset. Where severalemergency stop devices are provided in a circuit, it shall not bepossible to restore that circuit until all emergency stop devices thathave been operated have been reset. Exception: Where emergency stop device of the momentary type are usedin accordance with 10.7.2.2, exception, the emergency stop circuitshall be manually reset. 10.7.4 Emergency stop actuators. Actuators of emergency stopdevices shall be colored RED. The background immediatelyaround pushbuttons and disconnect switch actuators used asemergency stop devices shall be colored YELLOW. The actuator ofa pushbutton-operated device shall be of the palm or mushroom-head type. The RED/YELLOW color combination shall bereserved exclusively for emergency stop applications. Exception: The RED/YELLOW color combination shall be permitted foremergency off actuators in accordance w ith 10.8.4 10.7.5 Local operation of the supply disconnecting means to effect

emergency stop. 10.7.5.1 The supply disconnecting means shall be permitted to belocally operated to serve the function of emergency stop where : – it is readily accessible to the operator;– it is of the type described in 5.3.2 a), b) or c). 10.7.5.2 Where intended for such use, the supply disconnectingmeans shall meet the color requirements of 10.7.4. 10.8 Devices for emergency switching off. 10.8.1 Location. Emergency switching off devices as described in9.2.5.4.3 shall be located as necessary for the given application.

Table XX Colors for indicator lights and their purposes with respect to the condition of the machine

Color Purposes

Safety of persons or environment Condition of process State of Equipment RED Danger Emergency Faulty

YELLOW (AMBER)

Warning/Caution Abnormal Abnormal

GREEN Safe Normal Normal BLUE Mandatory action CLEAR WHITE GRAY BLACK

No specific meaning assigned


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10.8.2 Types. 10.8.2.1 The types of devices that initiate an emergency switchingoff operation shall be permitted to include, but are not limited to: — push-button operated switches.— pull-cord operated switches. 10.8.2.2 The push-button operated switch shall be permitted in abreak-glass enclosure. 10.8.3 Restoration of normal function after emergency switchingoff. It shall not be possible to restore an emergency switching offcircuit until the emergency switching off circuit has been manuallyreset. 10.8.4 Actuators. 10.8.4.1 Actuators of emergency switching off devices shall becolored RED. The background immediately around the deviceactuator shall be permitted to be colored YELLOW. 10.8.4.2 Where the emergency switching off initiating device isseparate from the emergency stop device, the emergency switchingoff initiating device shall be functionally identified. 10.8.5 Local operation of the supply disconnecting means toeffect emergency switching off. Where the supply disconnectingmeans is to be locally operated for emergency switching off, it shallbe readily accessible and shall meet the color requirements of10.8.4.1. 10.9 Displays. Displays (e.g. visual display units, alarmannunciators, indicator lights and the action initiating icons ofhuman-machine interface (HMI) devices) shall be selected andinstalled in such a manner as to be visible from the normalposition of the operator. Note: It is recommended that displays intended to be warningdevices be of the flashing or rotary type and be provided with anaudible warning device.

SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738.Historical Background










Result



The Task Group proposes to renumber NFPA 79-1997 Clause 13 tocorrespond with IEC 60204-1 Clause 10. The task group proposesthe following changes to further improve usability. Substantiation for changes to NFPA 79-1997 Clause 13, subclause12.6.2 and subclause 12.7 10 Operator interface and control devices Revise the NFPA 79-1997 Clause 13 heading “Operator’s controlstations and equipment” to harmonize with the IEC Clause 10heading “Operator interface and control devices.”

Substantiation: The new Clause 10 headingrecognizes that operator interfaces includes pushbuttons, foot-operated switches, and other types of devices.

10.1 General Add IEC 60204-1 subclause 10.1 heading.

Substantiation: The IEC subclause heading is addedfor general information on operator interface andcontrol devices.

10.1.1 General device requirements

(a) Add the IEC 60204-1 subclause 10.1.1 heading.

Substantiation: The new subclause clarifies theintent of subclause 10.1.

(b) Add the first paragraph of IEC 60204-1 subclause 10.1.

This clause contains requirements for devices mountedoutside or partially outside control enclosures.

Substantiation: This new paragraph specifies whichdevices are included in subclause 10.1.

(c) Add a note in place of the second paragraph of IEC

60204-1 subclause 10.1.1. This new note reads:

Note: For further information on device selection,mounting, identification, and coding, see IEC 60073 andIEC 60447.

Substantiation: This note provides additional

information where required for the application. 10.1.2 Location and mounting Add the IEC 60204-1 subclause 10.1.2 heading.

Substantiation: The IEC subclause heading is addedfor grouping of all proposed subclauses.

10.1.2.1 Control devices


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(a) Add a new subclause number 10.1.2.1 to be in compliancewith the NFPA Manual of Style and add the new heading“Control devices.”

Substantiation: The new subclause heading clarifiesthe intent of the subclause.

(b) Add the revised first paragraph of IEC 60204-1 and bullets ofsubclause 10.1.2: As far as is practicable, control devices shall be:

— readily accessible for service and maintenance.— mounted in such a manner as to minimize the

possibility of damage from activities such as materialhandling.”

Substantiation: This new paragraph simplifiesergonomic and machine protection criteria alreadycovered in NFPA 79-1997 subclause 12.6.

10.1.2.2 Hand operated control devices (a) Add a new subclause number 10.1.2.2 to be in compliance

with the NFPA Manual of Style and add the new heading“Hand operated control devices.”

Substantiation: The new subclause heading clarifiesthe intent of the subclause.

(b) Add the revised IEC 60204-1 second paragraph and bullets

of subclause IEC 10.1.2: The actuators of hand-operated control devices shall be selectedand installed so that:

— they are not less than 2 feet (0.6 m) above theservicing level and are within easy reach of thenormal working position of the operator.

— the operator is not placed in a hazardous situationwhen operating them.

— the possibility of inadvertent operation isminimized”.

Substantiation: This new paragraph amplifiesergonomic, safety and machine protection alreadycovered in NFPA 79-1997 subclause 12.6.

10.1.3 Protection (a) Add the IEC 60204-1 subclause 10.1.3 heading. (b) Delete the NFPA 79-1997 subclause 13.1.1 paragraph and

exception. (c) Add the revised first sentence of IEC 60204-1 subclause 10.1.3

and add a new note: Operator interface, control devices, and enclosures shall be

suitable for the environment and shall withstand thestresses of expected use.

Note: For further information on degrees of protection, see UL

50, UL 508, Annex XX and IEC 60529.

Substantiation: The proposed language permits abroader classification of devices to meetenvironmental conditions. NFPA 79-1997 subclause13.1.1 is too restrictive. Annex XXis a comparisonbetween IEC IP and NEMA/UL Type enclosures.

10.1.4 Position sensors Add the IEC 60204-1 subclause 10.1.4 heading. 10.1.4.1 (a) Add a new subclause number 10.4.1.1 to be in compliance

with the NFPA Manual of Style.

(b) Add the revised first paragraph of IEC 60204-1 subclause10.1.4:

Position sensors (e.g. limit switches, position switches, proximityswitches) shall be so arranged that they will not bedamaged in the event of overtravel.

(c) Delete the NFPA 79-1997 subclause 12.6.2 paragraph that

reads “All limit switches or position sensors shall beinstalled so that accidental overtravel by the machine willnot damage the limit switch or sensor.”

10.1.4.2 (a) Add a new subclause number 10.1.4.2 to be in compliance


(b) Add the revised second paragraph of IEC 60204-1subclause 10.1.4:

Position sensors used in circuits with safety-relatedfunctions either shall have positive (direct) openingoperation or shall provide similar reliability.

(c) Add a note in place of deleted IEC text in the second

paragraph: Note: For further information on positive (or direct) openingoperation, see IEC 60947-5-1.

Substantiation: The proposed language reflects theintent of this subclause and is harmonized with IEC60204-1. It states, in part, what already appears inNFPA 79-1997 subclause 12.6.2. “Positive openingor similar” provides additional safety to personneland equipment.

10.1.5 Portable and pendant control stations Revise the NFPA 79-1997 subclause 13.8 heading “Pendantstations” to harmonize with IEC 60204-1.

Substantiation: The proposed language reflects theintent of this subclause and is harmonized with IEC60204-1.

10.1.5.1 (a) Add a new subclause number 10.1.5.1 to be in compliancewith the NFPA Manual of Style.

(b) Add the revised paragraph of IEC 60204-1 subclause10.1.5:

Portable and pendant operator control stations and their control

devices shall be so selected and arranged to minimize thepossibility of inadvertent machine operations.

Substantiation: Safety requirement not covered inNFPA 79-1997. Provides additional safety topersonnel and protection to machinery.

(c) Delete the NFPA 79-1997 subclause 13.8.1 “Pendant

operator control station enclosures shall be oiltight.”

Substantiation: NFPA 79-1997 subclause 13.8.1 is toorestrictive and this requirement is covered under 10.1.3.

(d) Delete the NFPA 79-1997 subclause 13.8.2 “A wobble stickor rod operator at the bottom of the station shall bepermitted for Emergency Stop controls.”

Substantiation: This information is included in

subclause 10.2.1 Colors exception. 10.1.5.2 (a) Add a new subclause number 10.1.5.2 to be in compliancewith the NFPA Manual of Style.

(b) Revise the NFPA 79-1997 subclause 13.8.3 to read: Pendant control stations that are vertically suspended from

overhead shall be supported by suitable means or flexible


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electrical conduit or multiconductor cable or cordidentified for the purpose.

Substantiation: Clarification of NFPA 79-1997

subclause 13.8.3.

(c) Delete the NFPA 79-1997 subclause 13.8.4 “Groundingand bonding shall comply with 19.2, 19.3, 19.4, and 19.6.”

Substantiation: This is covered elsewhere in NFPA79-2002 10.1.6 Operator interface devices Add the new subclause 10.1.6 heading “Operator interface

devices.”

Substantiation: The new heading was added for theNFPA 79-1997 subclauses 13.4 and 13.7. Theoriginal heading was “Control station components”was changed it to “Operator interface devices.”Because the term more closely reflects thecomponents covered in clause 10 such as touchscreens and visual displays. The term is currentlyused in IEC 60204-1 extensively.

10.1.6.1 Location of operator interface devices

(a) Add a new subclause number 10.1.6.1 to be incompliance with the style manual.

(b) Add the new heading for 10.1.6.1 “Location of operatorinterface devices”

Substantiation: Locate text for NFPA 79-1997

subclause 13.4. 10.1.6.1.1 (a) Add a new subclause number 10.1.6.1.1 to be in compliancewith the NFPA Manual of Style.

(b) Revise the NFPA 79-1997 subclause 13.7.1 to read:

Operator interface devices shall be mounted in locationsthat will minimize exposure to oil, coolant, and othercontaminants.

Substantiation: “Operator interface devices” is usedinstead of “all stations” because 10.1.6 was revised.

(c) Delete the NFPA 79-1997 subclause 13.4 paragraph which

reads “All operator control station enclosures shall bedusttight, moisturetight, and oiltight.”

Substantiation: NFPA 79-1997 subclause 13.4 isdeleted to be consistent with 10.1.3. Similarenvironmental protection is provided in 10.1.6.1.1.

(d) Delete the exception in NFPA 79-1997 subclause 13.4

”Exception; Non-oiltight control station enclosures shallbe permitted on machines where suitable for theenvironment.”

Substantiation: Same as item (c).

(d) Delete the NFPA 79-1997 subclause 13.7 heading

“Location of control stations.”

Substantiation: This heading is Included in10.1.6.1. 10.1.6.1.2 (a) Add a new subclause number 10.1.6.1.2 to be in compliance


(b) Revise the NFPA 79-1997 subclause 13.7.2 to read: Operator interface devices shall be within normal reach of themachine operator and shall be so placed that the operator is notexposed to hazards.

10.1.6.1.3 (a) Add a new subclause number 10.1.6.1.3 to be in compliance

with the NFPA Manual of Style. (b) Revise the NFPA 79-1997 subclause 13.7.3 to read: Operator interface devices shall be located so that unintentional

operation by normal movement of the machine,operator, or work will be unlikely.

Substantiation: Restates what already appears inNFPA 79-1997 subclauses 13.7.1, 13.7.2, and 13.7.3.

10.1.6.2 Arrangement of operator interface devices

(a) Revise the NFPA 79-1997 subclause 13.5 heading“Arrangement of control station components” and theIEC 60204-1 subclause heading “Arrangement of controlstation components.”

Substantiation: Editorial change of subclause 13.5

heading to be consistent with 10.1.6.

(b) Insert NFPA 79-1997 subclause 13.5 without changes,including exceptions No.1 and No. 2.

All Start pushbuttons shall be mounted above or to the left of

their associated Stop pushbuttons. Exception No. 1: Start pushbuttons in series, such as operating

pushbuttons on punch presses. Exception No. 2: Wobble-stick or rod-operated Emergency Stop

pushbuttons mounted in the bottom of pendant stations. 10.1.7 Foot-operated switches

(a) Add the NFPA 79-1997 subclause 13.3 heading

(b) Revise the NFPA 79-1997 subclause 13.3.1 paragraph toread:

Foot-operated switches used for applications where accidentalactuation could create a hazardous situation shall be protected toprevent accidental actuation by falling or moving objects and fromunintended operation by accidental stepping onto the switch.

Substantiation: Re-statement on NFPA79-1997subclause 13.3.1, clarifying the conditions whereprotection is required.

(c) Add the new exception:

Exception: Foot-operated switches used for emergency stop in

accordance with 10.7.2 shall not be of the covered orhooded type.

Substantiation: Emergency stop actuators includingfoot-operated switches shall not be covered. It isimperative that emergency stop actuators be readilyaccessible.

10.2 Push-button actuators and action initiating icons

(a) Revise the NFPA 79-1997 subclause 13.1 heading“Pushbuttons, selector switches, indicating lights” and theIEC 60204-1 subclause 10.2 heading “Push-button.”

Substantiation: Change the heading to take intoaccount the usage of a variety of actuators, such aspush buttons, selectors and computer icons. Pushbuttons, selector switches and indicating lights areseparated into different headings in order toharmonize with IEC 60204-1

(b) Revise the NFPA 79-1997 subclause 13.1.3 to read:

Pushbutton actuators used to initiate a stop function shall be of

the extended operator or mushroom-head types.

Substantiation: NFPA 79-1997 subclause 13.1.3 ismodified to change “operators” to “actuators” so asto be more general and consistent with 10.2.


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10.2.1 Colors

(a) Add the IEC 60204-1 subclause 10.2.1 heading colors.


Pushbutton actuators and action initiating icons of color touchscreen interfaces shall be color coded as follows:

Substantiation: NFPA 79-1997 subclause 13.1.2 isexpanded to include computer icons and to beconsistent with 10.2.

(c) First bullet - Revise the NFPA 79-1997 subclause 13.1.2

second bullet to read: Start or On - The preferred color of Start or On actuators is

GREEN, except that BLACK, WHITE, or GRAY shall bepermitted. Red shall not be used for Start or Onactuators.

Substantiation: The prohibition of “red” for a “start”or “on” function is added to comport with industrialpractice and to prevent confusion with stopfunction.

(d) Second bullet – Create a new bullet to read:

Stop or Off - The preferred color of Stop or Off actuators is

RED, except that BLACK, WHITE, or GRAY shall bepermitted. Green shall not be used for Stop or Offactuators.

Substantiation: Colors other than red may be usedfor stop in order to harmonize with IEC 60204-1. Inaddition, there are certain integrated factoryapplications where differentiation is necessary. Thisrevision will permit the utilization of otherdesignated color schemes for STOP or OFFfunctions.

(e) Insert the NFPA 79-1997 subclause 13.1.2 exception after

“Stop or Off”: Exception: Stop function operators of the wobble-stick or rod-

operated types in the bottom of a pendant station neednot be colored red.

(f) Revise and insert after the exception NFPA 79-1997

subclause 13.1.2 first bullet to read: The color RED shall be used for Emergency Stop actuators in

accordance with 10.7.4..

Substantiation: Stop and emergency stop shall onlybe red in order to increase recognition of thefunction and improve safety.

(g) Third bullet – Revise the NFPA 79-1997 subclause 13.1.2

third bullet to read: Alternate action - Pushbuttons that, when pressed, act alternately

as Start and Stop or On and Off shall be BLACK,WHITE, or GRAY. RED or GREEN shall not be used.

(h) Fourth bullet - Add a new bullet to read:

Abnormal conditions - The color YELLOW shall be used for

actuators used to respond to abnormal conditions. Substantiation: Although not included in NFPA 79-1997, the use of “yellow” to signify response toabnormal conditions reflects current industrialpractice, and improves operator recognition andsafety.

(i) Fifth bullet - Revise the NFPA 79-1997 subclause 13.1.2

fourth bullet: Hold to operate - Pushbuttons that cause movement when

pressed and stop movement when they are released (e.g.,

jogging) shall be BLACK, WHITE, GRAY, or BLUE witha preference for BLACK.

(j) Sixth bullet - Retain NFPA 79-1997, 13.1.2, fifth bullet and

read: Reset - Reset pushbuttons shall be BLUE, BLACK, WHITE, or

GRAY. Where reset pushbuttons also act as a Stop or Offbutton, the preferred color is RED.

Substantiation: Clarification of reset button colorsso as not to conflict with other function/colorcombinations listed above.

(k) Delete NFPA 79-1997 Table 8 “Color coding for

pushbuttons, indicator (pilot) lights, and illuminatedpushbuttons”

Substantiation: The inclusion of the table adds

confusion to proper applications to the mandatory text. 10.2.2 Legends Insert NFPA 79-1997 subclause 13.6 Legends in place of IEC60204-1 subclause 10.2.2 Markings. 10.2.2.1

(a) Add a new subclause number 10.2.2.1 to be incompliance with the NFPA Manual of Style.

(b) Revise the NFPA 79-1997 subclause 13.6 first paragraph to

read: A legend shall be provided for each operator interface device toidentify its function and shall be located so that it can be easilyread by the machine operator from the normal operator position.The legends shall be durable and suitable for the operatingenvironment.

Substantiation: NFPA 79-1997 subclause 13.6 isadopted except “operator interface device” replaces“control station component”. Term is consistentwith 10.1.8.

10.2.2.2

(a) 10.2.2.2 Add a new subclause number 10.2.2.2 to be incompliance with the NFPA Manual of Style.

(b) Add the note at the bottom NFPA 79-1997 table 8:

For illuminated pushbuttons the function(s) of the light isseparated from the function(s) of the button by a virgule (/). Substantiation: Separate the titles for the light and pushbuttonfunctions on the legend plate. 10.3 Indicator lights and icons of visual display units Revise the NFPA 79-1997 subclause 13.1 heading “Pushbuttons,selector switches, indicating lights” and the IEC 60204-1 subclause10.3 heading “Indicator lights and displays.”

Substantiation; The heading was revised to reflectusage of computer icons as visual indicators and toconsistent with 10.2.1. Pushbuttons, selectorswitches and indicating lights are separated intodifferent headings in order to harmonize with IEC60204-1.

10.3.1 Modes of use


(b) Add the revised paragraph and bullets of IEC 60204-1subclause 10.3.1: Indicator lights and icons used with visual display units providethe following of information:

— indication: to attract the operator's attention or toindicate that a certain task should be performed.


1593

The colors RED, YELLOW (AMBER), GREEN, andBLUE are normally used in this mode;

— confirmation: to confirm a command, or a

condition, or to confirm the termination of achange or transition period. The colors BLUE andWHITE are normally used in this mode and GREENshall be permitted to be used in some cases.

Substantiation: Addressed, in part, by NFPA 79-1997,sub-clause 13.1.2 and table 8 and re-stated in 10.3.1.Visual computer display icons are added to reflectcurrent industrial practice. Modes of use aresimplified and reflect typical industrial practice.

10.3.2 Colors


(b) Add the revised IEC 60204-1 subclause 10.3.2 paragraph.

Indicator lights and icons of visual display units shall becolor-coded with respect to the condition (status) of themachine in accordance with table XX. Alternatepurposes shall be permitted to indicate machine orprocess status.

(c) Add the revised indicating light table from IEC 73. This

table replaces NFPA 79-1997 table 8 and IEC 60204-1table 3 (See Table below)

Substantiation: Addressed, in part, by NFPA 79-1997, sub-clause 13.1.2 and table 8 and re-statedin 10.3.1. Visual computer display icons areadded to reflect current industrial practice.Table XX reduces the number of meanings ofeach color to minimize operator confusion.Table XX reflects typical industrial practice.The color BLUE was changed from anyfunction not covered to a mandatory function.

10.3.3 Flashing lights

(a) Add the IEC 60204-1 subclause 10.3.3 heading

(b) Add the following new paragraph, bullets, and note: Flashing lights shall be permitted to be used for any of thefollowing purposes :

– to attract attention.– to request immediate action.– to indicate a discrepancy between the command and

actual states– to indicate a change in process (flashing during

transition).

Substantiation: A new subclause not addressed inNFPA 79-1997. Flashing lights increaseoperator/machine safety by calling attention toprocess faults or changes.

10.4 Illuminated push-buttons

(a) Add the IEC 60204-1 subclause 10.4 heading.

(b) Delete the NFPA 79-1997 subclause 13.1.2 paragraph“Pushbutton operator, indication (pilot) light lenses, andilluminated pushbutton lenses shall be color coded inaccordance with Table 8.”

Substantiation: This subclause was also deleted in

subclause 10.2.1 Colors.

(c) Add the modified IEC 60204-1 subclause 10.4 paragraph: Illuminated push-button actuators shall be color-coded inaccordance with table XX. The color RED for the emergency stopactuator shall not depend on the illumination source.

Substantiation: The color of illuminatedpushbuttons, pilot lights, and lenses is addressed inNFPA 79-1997 subclause 13.1.2; however, the colorsand their meanings have been modified, asdescribed to harmonize with IEC 60204-1 table 3.Operator and machine safety are enhanced if theemergency stop actuator appears red, whetherilluminated or not

10.5 Rotary control devices

(a) Retain the NFPA 79-1997 subclause 12.7 heading.

(b) Revise the NFPA 79 subclause 12.7 paragraph to read: Devices having a rotational member, such as potentiometers and

selector switches, shall be mounted in such a way as toprevent rotation of the stationary member. Frictionalone shall not be relied upon to prevent rotation.

Substantiation: Editorial change of NFPA 79-1997

subclause 12.7 10.6 Start devices

(a) Add the IEC 60204-1 subclause 10.6 heading.

(b) Add the revised IEC 60204-1 subclause 10.6 paragraph: Actuators used to initiate a start function or the movement of

machine elements (e.g. slides, spindles, carriers) shall beconstructed and mounted to minimize inadvertentoperation. Mushroom-type actuators for two-handcontrol initiation shall conform to the requirements of9.2.5.6 (two hand control).

Table XX Colors for indicator lights and their purposes with respect to the condition of the machine

Color Purposes

Safety of persons orenvironment

Condition of process State of Equipment

RED Danger Emergency Faulty YELLOW (AMBER)





1594

(c) Delete NFPA 79-1997 subclause 13.1.4 paragraph andexception

Pushbutton operators used to initiate a start function ormovement of machine elements (e.g. slides, spindles,and carriers) shall be constructed or mounted tominimize inadvertent operation.

Exception: Mushroom-head type operators shall be permitted to initiate

start functions where installed in accordance with 9.15”

Substantiation: Editorial change of NFPA 79-1997subclause 13.1.4 10.7 Devices for stop and emergency stop Revise the NFPA 79-1997 subclause 13.2 heading “Emergency stopdevices.”

Substantiation: This subclause also includesspecifications for stop devices. 10.7.1 Location and operation

Add the revised IEC 60204-1 subclause 10.7.1 heading.

Substantiation: This subclause includesspecifications for stop and emergency stop location and operation. 10.7.1.1 (a) Add a new subclause number 10.1.7.1 to be in compliance


(b) Revise the NFPA 79-1997 subclause 13.2.2 to read: Stop and emergency stop pushbuttons shall be continuously

operable and readily accessible.

Substantiation: Harmonization with IEC 60204-1.The term “readily accessible” was added to clarifythat “continuously operable” includes an element ofquick and ready access.

10.7.1.2 (a) Add a new subclause number 10.1.7.2 to be in compliance


(b) Revise the NFPA 79-1997 subclause 13.2.1 paragraph toread: Stop and emergency stop pushbuttons shall be located at each

operator control station and at other locations whereemergency stop is required.

Substantiation: Editorial change of NFPA 79-1997

subclause 13.2.1 to clarify location criteria. 10.7.2 Types

Add the IEC 60204-1 subclause 10.7.2 heading. 10.7.2.1 The types of device for emergency stop include, but arenot limited to:


(b) Add the revised IEC 60204-1 subclause 10.7.2 first

paragraph, and bullets: The types of device for emergency stop include, but are notlimited to:

— push-button operated switches in accordance with10.7.4.

— pull-cord operated switches.— foot-operated switches without a mechanical guard— push bar operated switches.— rod operated switches.

Substantiation: New material not addressed in NFPA79-1997. Includes examples of the types ofemergency stop devices.

10.7.2.2

(a) Add a new subclause number 10.7.2.2 to be in compliancewith the NFPA Manual of Style. .

(b) Add the revised IEC 60204-1 subclause 10.7.2 second

paragraph, exception, and note: Devices for emergency stop shall be of the self-latching

type and shall have positive (direct) opening operation. Note: For further information on positive (direct) openingoperation, see IEC 60947-5-1.

Exception: For machines which employ only a singleemergency stop device, emergency stop actuators of themomentary type shall be permitted.

(c) Delete the NFPA 79 subclause 13.2.4 “The emergency

stop actuator shall be either a momentary or self latchingtype.”

Substantiation: New material not addressed in NFPA79-1997. The use of self-latching devices improvessafety to personnel. For example, a self-latchingdevice would be beneficial in ensuring proper coildrop-out. The requirement for positive directoperation was added to ensure that in the event of afailure that results in direct welded contacts, it couldbe overcome. An exception is made for a singleemergency stop on the machine since it is typicallyin the same area as the other operating controls.Replaces NFPA 79-1997 subclause 13.2.4

10.7.3 Restoration of normal function after emergency stop


(b) Add the modified IEC 60204-1 subclause 10.7.3 paragraphand new exception: It shall not be possible to restore an emergency stop circuit until

the emergency stop device has been manually reset.Where several emergency stop devices are provided in acircuit, it shall not be possible to restore that circuit untilall emergency stop devices that have been operated havebeen reset.

Exception: Where emergency stop device of the momentary type are used

in accordance 10.7.2.2, exception, the emergency stopcircuit shall be manually reset.

Substantiation: New material not addressed in NFPA79-1997. The use of reset devices improves safety topersonnel. This is in harmonization with theproposed SAE HS 1738-2000 standard.

10.7.4 Emergency stop actuators



Actuators of emergency stop devices shall be colored RED. The

background immediately around pushbuttons anddisconnect switch actuators used as emergency stopdevices shall be colored YELLOW. The actuator of apushbutton-operated device shall be of the palm ormushroom-head type. The RED/YELLOW colorcombination shall be reserved exclusively for emergencystop applications.

Exception: The RED/YELLOW color combination shall be

permitted for emergency off actuators in accordance with10.8.4

Substantiation: Replaces NFPA 79-1997 subclause13.2.3, but remains the same in principle. Adds


1595

language to preserve prescribed colors to reduceconfusion to an operator and improve safety.Clarifies which actuators are to utilize the colorcombination.

10.7.5 Local operation of the supply disconnecting means to effect

emergency stop.

Add the revised IEC 60204-1 subclause 10.7.5 heading.

10.7.5.1

(a) Add a new subclause number 10.7.5.1 to be in compliancewith the NFPA Manual of Style.

(b) Add the IEC 60204-1 subclause 10.7.5 first paragraph and

bullets: The supply disconnecting means shall be permitted to be locallyoperated to serve the function of emergency stop where:

– it is readily accessible to the operator;– it of the type described in 5.3.2 a), b) or c).

10.7.5.2


(b) Add the IEC 60204-1 subclause 10.7.5 second paragraph:

Where intended for such use, the supply disconnecting meansshall meet the color requirements of 10.7.4.

Substantiation: 10.7.5.1 and 10.7.5.2 is new materialnot addressed in NFPA 79-1997. Allows anappropriate disconnect device to serve as anemergency stop under certain conditions. Moreeconomical for smaller machines but preservessafety to the operator.

10.8 Devices for emergency switching off.

Add the IEC 60204-1 subclause 10.8 heading 10.8.1 Location.

(a) Add the IEC 60204-1 subclause 10.8.1 heading

(b) Add the revised IEC 60204-1 subclause 10.8.1 paragraph: Emergency switching off devices as described in 9.2.5.4.3 shall belocated as necessary for the given application.

Substantiation: New material not addressed in NFPA79-1997. Allows for emergency switch off devices, tobe located as necessary. Improves safety topersonnel and provides additional protection tomachine and property.

10.8.2 Types.

Add the IEC 60204-1 subclause 10.8.2 heading 10.8.2.1 (a) Add a new subclause number 10.8.2.1 to be in compliancewith the NFPA Manual of Style. (b) Add the modified IEC 60204-1 paragraphs and bullets to10.8.2: The types of devices that initiate an emergency switching offoperation shall be permitted to include, but are not limited to:

— push-button operated switches.— pull-cord operated switches.

Substantiation: New material not addressed in NFPA79-1997. Describes appropriate devices foremergency switching off function. Reducesconfusion to an operator and improves safety.

10.8.2.2


(b) Add the IEC 60204-4 text:

The push-button operated switch shall be permitted in a break-glass enclosure.

10.8.3 Restoration of normal function after emergency switchingoff.

(a) Addition: Add the IEC 60204-1 subclause 10.8.3 heading.

(b) Addition: Add the revised IEC 60204-1 10.8.3paragraph:

It shall not be possible to restore an emergency switching offcircuit until the emergency switching off circuit has been manuallyreset.

Substantiation: New material not addressed in NFPA79-1997. Improves safety to personnel andprotection to machine and property.

10.8.4 Actuators.

Add the IEC 60204-1 subclause 10.8.4 heading.

10.8.4.1


(b) Add the IEC 60204-1 subclause 10.8.4 first paragraph:

Actuators of emergency switching off devices shall be coloredRED. The background immediately around the device actuatorshall be permitted to be colored YELLOW.

Substantiation: Where emergency stop devices arepresent, identification of function is required. Thecolor yellow reduces the confusion to the operatorand improves safety.

10.8.4.2


(b) Add the revised IEC 60204-1 subclause 10.8.4 secondparagraph:

Where the emergency switching off initiating device is separatefrom the emergency stop device, the emergency switching offinitiating device shall be functionally identified.

Substantiation: Where the emergency switching offinitiating device is separate from the emergency stopdevice, the emergency switching off initiating deviceshall be functionally identified.

10.8.5 Local operation of the supply disconnecting means toeffect emergency switching off.


(b) Add the modified IEC 60204-1 subclause 10.8.5paragraph:

Where the supply disconnecting means is to be locally operatedfor emergency switching off, it shall be readily accessible and shallmeet the color requirements of 10.8.4.1.

Substantiation: New material not addressed in NFPA79-1997. The switching off device is to be accessibleand appropriately colored, if the same as thedisconnect. Improves device recognition and safety.


1596

10.8.9 Displays

(a) Add the IEC 60204-1 subclause 10.9 heading

(b) Add the modified IEC 60204-1 subclause 10.9 paragraphand new note.

Displays (e.g. visual display units, alarm annunciators, indicatorlights and the action initiating icons of human-machineinterface (HMI) devices) shall be selected and installedin such a manner as to be visible from the normalposition of the operator.

Note: It is recommended that displays intended to be warningdevices be of the flashing or rotary type and be providedwith an audible warning device.

Substantiation: New material not addressed in NFPA79-1997. Improves safety of display and alarmdevices.

CLAUSE NUMBER CROSS REFERENCE --- NFPA 79-1997 AND PROPOSED NFPA 79-2002


Clause Heading Clause Heading 13 Operator's control stations and

equipment 10 Operator interface and control devices

10.2 Push-button actuators and action initiatingicons

13.1

Pushbutons, selector switches,indicating lights

10.3 Indicator lights and icons of visual displayunits

13.1.1 paragraph 10.1.3 Protection 10.2.1 Pushbutton colors 13.1.2 paragraph and bullets 10.4 Illuminated pushbuttons Deleted Colors, Push-buttons 13.1.2

Table 8 Color coding for pushbuttons,indicator (pilot) lights, andilluminated pushbuttons 10.3.2 Table XX Colors for indicating lights and their

meanings with respect to the condition of themachine

13.1.3 paragraph 10.2 Push-button actuators and action initiationicons - paragraph

13.1.4 paragraph 10.6 Start devices - paragraph 13.2 Emergency stop devices 10.7 Devices for stop and emergency stop 13.2.1 paragraph 10.7.1.2 paragraph 13.2.2 paragraph 10.7.1.1 paragraph 13.2.3 paragraph 10.7.4 Actuators 13.2.4 paragraph 10.7.2.2 paragraph 13.3 Foot-operated switches 10.1.7 Foot-operated switches 13.3.1 Paragraph 10.1.7 paragraph

Control station enclosures 10.1.6.1 Location of operator interface devices 13.4 paragraph 10.1.6.1.1 paragraph Arrangement of control stationcomponents

Arrangement of operator interface devices 13.5

paragraph

10.1.6.2

paragraph Legends 10.2.2 Legends 13.6 paragraph 10.2.2.1 paragraph

13.7 Location of control stations 10.1.6.1 Location of operator interface devices 13.7.1 paragraph 10.1.6.1.1 paragraph 13.7.2 paragraph 10.1.6.1.2 paragraph 13.7.3 paragraph 10.1.6.1.3 paragraph 13.8 Pendant stations 10.1.5 Portable and pendent control stations 13.8.1 paragraph Deleted 13.8.2 paragraph Deleted Included in 10.2.1 Colors exception 13.8.3 paragraph 10.1.5.2 paragraph 13.8.4 paragraph deleted 12.6.2 paragraph 10.1.4.1 paragraph 12.7 Rotary control devices 10.5 Rotary control devices


1597

CLAUSE NUMBER CROSS REFERENCE --- PROPOSED NFPA 79-2002 AND NFPA 79-1997

Proposed NFPA 79-2002 NFPA 79-1997

Clause Heading Clause Heading 10 Operator interface and control devices 13 Operator's control stations and

equipment 10.1 General 10.1.1 General device requirements 10.1.2 Location and mounting 10.1.2.1 Control devices 10.1.2.2 Hand operated control devices 10.1.3 Protection 13.1.1 paragraph 10.1.4 Position sensors 10.1.4.1 paragraph 12.6.2 paragraph 10.1.4.2 paragraph 10.1.5 Portable and pendant control stations 13.8 Pendant stations 10.1.5.1 paragraph 13.8.1 & 13.8.2 Deleted paragraphs 10.1.5.2 paragraph 13.8.3 paragraph 10.1.6 Operator interface devices 10.1.6.1 Location of operator interface devices 13.7 Location of control stations 10.1.6.1.1 paragraph 13.7.1 paragraph 10.1.6.1.2 paragraph 13.7.2 paragraph 10.1.6.1.3 Paragraph 13.7.3 paragraph 10.1.6.2 Arrangement of operator interface devices 13.5 Arrangement of control station

components 10.1.7 Foot-operated switches 13.3 & 13.3.1 Foot-operated switches 10.2 Push-button actuators and action initiating icons 13.1 & 13.1.3 Pushbutons, selector switches,

indicating lights Colors 13.1.2 Paragraph and bullets 10.2.1 Colors, Push-buttons – Table 8 Pushbutton colortable moved to Annex Z

13.1.2 Table 8 Color coding for pushbuttons,indicator (pilot) lights, andilluminated pushbuttons

10.2.2 Legends 13.6 Legends 10-2-2-1 paragraph 13.6 paragraph 10-2-2-2 paragraph Table 8 note Note at the bottom of Table 8 10.3 Indicator lights and icons of visual display units 13.1 Pushbuttons, selector switches,

indicator lights 10.3.1 Modes of use 10.3.2 Colors 10.3.2 TableXX

Colors for indicator lights and their meanings withrespect to the condition of the machine

13.1.2 Table 8 Color coding for pushbuttons,indicator (pilot) lights, andilluminated pushbuttons

10.3.3 Flashing lights 10.4 Illuminated push-buttons 13.1.2 paragraph 10.5 Rotary control devices 12.7 Rotary control devices 10.6 Start devices 13.1.4 paragraph 10.7 Devices for stop and emergency stop 13.2 Emergency stop devices 10.7.1 Location 10.7.1.1 paragraph 13.2.2 paragraph 10.7.1.2 paragraph 13.2.1 paragraph 10.7.2 Types 10.7.2.1 paragraph 10.7.2.2 paragraph 13.2.4 paragraph 10.7.3 Restoration of normal function after emergency stop 10.7.4 Emergency stop actuators 13.2.3 paragraph 10.7.5 Location of the supply disconnecting device to effect

emergency stop

10.7.5.1 paragraph 10.7.5.2 paragraph 10.8 Devices for emergency switching off 10.8.1 Location and paragraph 10.8.2 Types 10.8.2.1 Paragraph and bullets 10.8.2.2 paragraph 10.8.3 Restoration of normal function after emergency

switching off

10.8.4 Actuators 10.8.4.1 paragraph 10.8.4.2 paragraph 10.8.5 Local operation of the supply disconnecting device

to effect emergency switching off

10.9 Displays


1598

NFPA 79 SUBCLAUSE 12.6.2, SUBCLAUSE 12.7, AND CLAUSE 13 CROSS REFERENCE TO PROPOSED NFPA 79-2000

NFPA 79-1997 Proposed NFPA 79-2002 Comments

(see attachment B for details)

13 Operator's control stations andequipment

10 Operator interface and controldevices

Revise NFPA 79-1997 Clause 13heading and move to proposedNFPA 79-2002 Clause 10.

10.1 General

Add IEC 60204-1 subclause 10.1heading and move to proposedNFPA 79-2002 Clause 10.

10.1.1 General device requirements

This clause contains requirementsfor devices mounted outside orpartially outside control enclosures.

Note: For further information ondevice selection, mounting,identification, and coding, see IEC60073 and IEC 60447.

Add IEC 60204-1 subclause 10.1.1heading, add the first paragraph,revise the second paragraph into anote, and move to proposed NFPA79-2002 Clause 10.

10.1.2 Location and Mounting

Add IEC 60204-1 subclause 10.2heading and move to proposedNFPA 79-2002 Clause 10.

10.1.2.1 Control devices

As far as is practicable, controldevices shall be:

— readily accessible for serviceand maintenance.— mounted in such a manner asto minimize the possibility ofdamage from activities such asmaterial handling.

Add the proposed NFPA 79-2002subclause 10.1.2.1 heading. Add IEC 60204-1 subclause 10.1.2first paragraph with bullets, andmove to proposed NFPA 79-2002Clause 10.

10.1.2.2 Hand operated controldevices The actuators of hand-operatedcontrol devices shall be selected andinstalled so that: — they are not less than 2 feet (0.6m) above the servicing level and arewithin easy reach of the normalworking position of the operator.— the operator is not placed in ahazardous situation when operatingthem.— the possibility of inadvertentoperation is minimized.

Add the proposed NFPA 79-2002subclause 10.1.2.2 heading. Add the IEC 60204-1 subclause10.1.2 second paragraph withbullets, and move to proposedNFPA 79-2002 Clause 10.

13.1.1 All pushbutton and selectorswitch operators, indicating (pilot)lights, and illuminated pushbuttonsshall be of the oiltight type.

Exception: Machines identified (see 3.49)for the environment.

10.1.3 Protection Operator interface, control devices,and enclosures shall be suitable forthe environment and shall withstandthe stresses of expected use. Note: For further information ondegrees of protection, see UL 50, UL508, Annex XX and IEC 60529.

Delete NAPA 79-1997 subclause13.1.1 and exception. Add the IEC 60204-1 subclause10.1.3 heading, revise the firstparagraph, delete the bullets, revisethe note, and move to proposedNFPA 79-2002 Clause 10.

10.1.4 Position sensors

Add the IEC 60204-1 subclause10.1.4 heading and move to theproposed NFPA 79-2002 Clause 10.


1599

NFPA 79 SUBCLAUSE 12.6.2, SUBCLAUSE 12.7, AND CLAUSE 13 CROSS REFERENCE TO PROPOSED NFPA 79-2000 (Continued)

12.6.2 All limit switches or positionsensors shall be installed so thataccidental overtravel by the machinewill not damage the limit switch orsensor.

10.1.4.1 Position sensors (e.g. limitswitches, position switches,proximity switches) shall be soarranged that they will not bedamaged in the event of overtravel.

Delete NFPA 79-1997 subclause12.6.2. Add the proposed NFPA 79-2002subclause 10.1.4.1 number, add theIEC 60204-1 subclause 10.1.4 firstparagraph, and move to NFPA 79-2002 Clause 10.

10.1.4.2 Position sensors used incircuits with safety-related functionseither shall have positive (direct)opening operation or shall providesimilar reliability Note: For further information onpositive (or direct) openingoperation, see IEC 60947-5-1.

Add the proposed NFPA 79-2002subclause 10.1.4.2 number, add theIEC 60204-1 subclause 10.1.4 revisedsecond paragraph, and move toNFPA 79-2002 Clause 10.

13.8 Pendant stations 10.1.5 Portable and pendant controlstations

Delete the NFPA 79-1997 subclause13.8 heading. Add the IEC 60204-1subclause heading 10.1.5 and moveto NFPA 79-2002 Clause 10.

13.8.1 Pendant operator control stationenclosures shall be oiltight 13.8.2 A wobble stick or rod operatorat the bottom of the station shall bepermitted for Emergency Stop control.

10.1.5.1 Portable and pendantoperator control stations and theircontrol devices shall be so selectedand arranged to minimize thepossibility of inadvertent machineoperations.

Delete NFPA 79-1997 subclause13.8.1 and 13.8.2. Add the proposed NFPA 79-2002subclause 10.1.5.1 number, add theIEC 60204-1 subclause 10.1.5 revisedparagraph, and move to NFPA 79-2002 Clause 10.

13.8.3 Pendant pushbutton stationsshall be supported by suitable meansother than the flexible electricalconduit or multiconductor cable.

13.8.4 Grounding and bonding shallcomply with 19.2, 19.3, 19.4, and 19.6.

10.1.5.2 Pendant control stationsthat are vertically suspended fromoverhead shall be supported bysuitable means or flexible electricalconduit or multiconductor cable orcord identified for the purpose.

Add the proposed NFPA 79-2002subclause 10.1.5.2 number, revisethe NFPA 79-1997 subclause 13.8.3paragraph and move to NFPA 79-2002 Clause 10. Delete the NFPA 79-1997 subclause13.8.4 and move to another NFPA79-2002 Clause.

10.1.6 Operator interface devices

Add the proposed NFPA 79-2002subclause 10.1.6 heading to Clause10.

13.4 Control station enclosures

13.7 Location of control stations

10.1.6.1 Location of operatorinterface devices

Add the proposed NFPA 79-2002subclause 10.1.6.1.1 heading toClause 10. Delete NFPA 79-1997 subclause 13.4heading. Delete NFPA 79-1997 subclause 13.7.heading

13.4All operator control station enclosuresshall be dusttight, moisturetight, andoiltight.

Exception: Non-oiltight control stationenclosures shall be permitted on machineswhere suitable for the environment.

13.7.1 All stations shall be mounted inlocations that will minimize exposureto oil, coolant, and othercontaminants.

10.1.6.1.1 Operator interfacedevices shall be mounted inlocations that will minimizeexposure to oil, coolant, and othercontaminants.

Add the proposed NFPA 79-2002subclause 10.1.6.1.1 number, deleteNFPA 79-1997 subclause 13.4paragraph with exception, add theNFPA 79-1997 subclause 13.7.1revised paragraph, and move toNFPA 79-2002 Clause 10.


1600

NFPA 79 SUBCLAUSE 12.6.2, SUBCLAUSE 12.7, AND CLAUSE 13 CROSS REFERENCE TO PROPOSED NFPA 79-2000 (Continued)13.7.2 Controls shall be within normalreach of the machine operator andshall be so placed that the operatordoes not have to reach past spindles orother moving parts.

10.1.6.1.2 Operator interfacedevices shall be within normal reachof the machine operator and shallbe so placed that the operator is notexposed to hazards.

Add the proposed NFPA 79-2002subclause 10.1.6.1.2 number, addthe NFPA 79-1997 subclause 13.7.2revised paragraph, and move toNFPA 79-2002 Clause 10.

13.7.3 Controls shall be located sothat unintentional operation by normalmovement of the machine, operator,or work will be unlikely.

10.1.6.1.3 Operator interfacedevices shall be located so thatunintentional operation by normalmovement of the machine, operator,or work will be unlikely.

Add the proposed NFPA 79-2002subclause 10.1.6.1.3 number, addthe NFPA 79-1997 subclause 13.7.3revised paragraph, and move toNFPA 79-2002 Clause 10.

13.5 Arrangement of control stationcomponents

All Start pushbuttons shall be mountedabove or to the left of their associatedStop pushbuttons.

Exception No. 1: Start pushbuttons inseries, such as operating pushbuttons onpunch presses.

Exception No. 2: Wobble-stick or rod-operated Emergency Stop pushbuttonsmounted in the bottom of pendant stations.

10.1.6.2 Arrangement of operatorinterface devices All Start pushbuttons shall bemounted above or to the left of theirassociated Stop pushbuttons. Exception No. 1: Start pushbuttons inseries, such as operating pushbuttonson punch presses. Exception No. 2: Wobble-stick or rod-operated Emergency Stop pushbuttonsmounted in the bottom of pendantstations.

Add the NFPA 79-1997 subclause13.5 revised heading, add paragraphwith exceptions, and move to NFPA79-2002 Clause 10.

13.3 Foot-operated switches

13.3.1 Foot-operated switches shall beprotected to prevent accidentalactuation by falling or moving objectsand from unintended operation byaccidental stepping onto the switch.

10.1.7 Foot-operated switches Foot-operated switches used forapplications where accidentalactuation could create a hazardoussituation shall be protected toprevent accidental actuation byfalling or moving objects and fromunintended operation by accidentalstepping onto the switch. Exception: Foot-operated switches usedfor emergency stop in accordance with10.7.2.1 shall not be of the covered orhooded type.

Add the proposed NFPA 79-2002subclause number, add the NFPA79-1997 subclause 13.3 heading, addthe NFPA 79-1997 subclause 13.3.1revised paragraph, add theexception, and move to NFPA 79-2002 Clause 10.

13.1 Pushbuttons, selector switches,indicating lights

13.1.3 Pushbutton operators used toinitiate a stop function shall be of theextended operator or mushroom-headtypes.

10.2 Push-button actuators andaction initiating icons Pushbutton actuators used to initiatea stop function shall be of theextended operator or mushroom-head types.

Delete the NFPA 79-1997 subclause13.1.heading and add the IEC 60204-1 subclause 10.2 revised heading, Add the NFPA 79-1997 subclause13.1.3 paragraph and move to NFPA79-2002 Clause 10.


1601

NFPA 79 SUBCLAUSE 12.6.2, SUBCLAUSE 12.7, AND CLAUSE 13 CROSS REFERENCE TO PROPOSED NFPA 79-2000 (continued)

13.1.2 Pushbutton operators,indicating (pilot) light lenses, andilluminated pushbutton lenses shall becolor coded in accordance with Table8.

– The preferred color of Start or Onoperators is GREEN, except thatBLACK, WHITE, or GRAY shall bepermitted.

Exception: Stop function operators of thewobble-stick or rod-operated types in thebottom of a pendant station need not becolored red.

– The color RED shall be used forStop, Emergency Stop, or Offoperators only.

– Pushbuttons that, when pressed, actalternately as Start and Stopor On and Off shall beBLACK, WHITE, or GRAY.RED or GREEN shall not beused.

– Pushbuttons that cause movementwhen pressed and stopmovement when they arereleased (e.g., jogging) shallbe BLACK, WHITE, GRAY,or BLUE with a preferencefor BLACK.

– Reset pushbuttons shall be BLUE,BLACK, WHITE, or GRAY exceptwhen they also act as a Stop or Offbutton, in which case they shall beRED.

10.2.1 Colors Pushbutton actuators and actioninitiating icons of color touchscreen interfaces shall be colorcoded as follows: – Start or On - The preferred colorof Start or On actuators is GREEN,except that BLACK, WHITE, orGRAY shall be permitted. Red shallnot be used for Start or Onactuators. – Stop or Off - The preferred colorof Stop or Off actuators is RED,except that BLACK, WHITE, orGRAY shall be permitted. Greenshall not be used for Stop or Offactuators Exception: Stop function operators ofthe wobble-stick or rod-operated types inthe bottom of a pendant station need notbe colored red. The color RED shall be used for,Emergency Stop actuators inaccordance with 10.7.4. – Alternate action - Pushbuttonsthat, when pressed, act alternately asStart and Stop or On and Off shallbe BLACK, WHITE, or GRAY.RED or GREEN shall not be used. – Abnormal conditions - The colorYELLOW shall be used for actuatorsused to respond to abnormalconditions. – Hold to operate - Pushbuttons thatcause movement when pressed andstop movement when they arereleased (e.g., jogging) shall beBLACK, WHITE, GRAY, or BLUEwith a preference for BLACK. – Reset - Reset pushbuttons shall beBLUE, BLACK, WHITE, or GRAY.Where reset pushbuttons also act asa Stop or Off button, the preferredcolor is RED.

Add the IEC 60204-1 subclause10.2.1 heading and move to NFPA79-2002 Clause 10. Delete NFPA 79-1997 Table 8 forpushbuttons. Table adds confusionto proper applications to themandatory text. Add the NFPA 79-1997 subclause13.1.2 revised paragraph, revisedbullets, and move to NFPA 79-2002Clause 10. Colors other than red may be usedfor stop in order to harmonize withIEC 60204-1.

13.6 Legends 10.2.2 Legends

Move NFPA 79-1997 subclause 13.6Legends to proposed NFPA 79-2002subclause 10.2.2 in Clause 10.

13.6 Legends A legend shall beprovided for each control stationcomponent to identify its function andshall be located so that it can be readeasily by the equipment operator fromthe normal operator position. Thelegends shall be durable and suitablefor the operating environment.

10.2.2.1 A legend shall be providedfor each operator interface deviceto identify its function and shall belocated so that it can be easily readby the machine operator from thenormal operator position. Thelegends shall be durable andsuitable for the operatingenvironment.

Add the proposed NFPA 79-2002subclause 10.2.2.1 number, add theNFPA 79-1997 subclause 13.6 revisedparagraph, and move to NFPA 79-2002 Clause 10.


1602


Table 8 note For illuminated pushbuttons thefunction(s) of the light is separatedfrom the function(s) of the button by avirgule (/).

10.2.2.2 For illuminatedpushbuttons the function(s) of thelight is separated from thefunction(s) of the button by avirgule (/).

Add the proposed NFPA 79-2002subclause 10.2.2.2 number, add theNFPA 79-1997 table 8 note, andmove to NFPA 79-2002 Clause 10.

13.1 Pushbuttons, selector switches,indicating lights

10.3 Indicator lights and icons ofvisual display units

Delete NFPA 79-1997 subclause 13.1heading, add IEC subclause 10.3revised heading, and move to NFPA79-2002 Clause 10.

10.3.1 Modes of use Indicator lights and icons used withvisual display units provide thefollowing information: — indication: to attract theoperator's attention or to indicatethat a certain task should beperformed. The colors RED,YELLOW (AMBER), GREEN, andBLUE are normally used in thismode; — confirmation: to confirm acommand, or a condition, or toconfirm the termination of a changeor transition period. The colorsBLUE and WHITE are normallyused in this mode and GREEN shallbe permitted to be used in somecases.

Add the IEC 60204-2 subclause10.3.1 heading, revise paragraph andbullets, and move to NFPA 79-2002Clause 10.

(Table 8 is not shown here. See NFPA79-1997 page 27.)

10.3.2 Colors Indicator lights and icons of visualdisplay units shall be color-codedwith respect to the condition(status) of the machine inaccordance with table XX.Alternate purposes shall bepermitted to indicate machine orprocess status. (Table XX is not shown here. SeeTable XX in Attachment A.)

Add the IEC 60204-1 subclause10.3.2 heading, revise the paragraph,and move to NFPA 79-2002 Clause10. Add the revised IEC 73 table forindication lights, rename Table XX,and move to NFPA 79-2002 Clause10.

10.3.3 Flashing lights Flashing lights shall be permitted tobe used for any of the followingpurposes: – to attract attention.– to request immediate action.– to indicate a discrepancybetween the command and actualstates– to indicate a change in process(flashing during transition).

Add IEC 60204-1 subclause 10.3.3heading, revise the paragraph, andmove to NFPA 79-2002 Clause 10.

1 3.1.2 Pushbutton operator, indicating(pilot) light lenses, and illuminatedpushbutton lenses shall be colorcoded in accordance with Table 8

10.4 Illuminated push-buttons Illuminated push-button actuatorsshall be color-coded in accordancewith table XX. The color RED forthe emergency stop actuator shallnot depend on the illuminationsource.

Delete NFPA 79-1997 subclause 3.1.2paragraph. Add IEC 60204-1 subclause 10.4heading, revised paragraph, andmove to NFPA 79-2002 Clause 10.


1603


12.7 Rotary control devices Devices such as potentiometers andselector switches having a rotatingmember shall be mounted to preventrotation of the stationary member.Friction alone is not sufficient.

10.5 Rotary control devices Devices having a rotationalmember, such as potentiometersand selector switches, shall bemounted in such a way as to preventrotation of the stationary member.Friction alone shall not be reliedupon to prevent rotation.

Add NFPA 79-1997 subclause 12.7heading, revise paragraph and moveto NFPA 79-2002 subclause 10.5.

13.1.4 Pushbutton operators used toinitiate a start function or movement ofmachine elements ( e.g . slides,spindles, and carriers) shall beconstructed or mounted to minimizeinadvertent operation. Exception: Mushroom-head type operatorsshall be permitted to initiate startfunctions where installed in accordancewith 9.15.

10.6 Start devices Actuators used to initiate a startfunction or the movement ofmachine elements (e.g. slides,spindles, carriers) shall beconstructed and mounted tominimize inadvertent operation.Mushroom-type actuators for two-hand control initiation shallconform to the requirements of9.2.5.6 (two hand control).

Delete NFPA 79-1997 subclause13.1.4 paragraph and exception. Add IEC 60204-1 subclause 10.6heading, revise paragraph, and moveto NFPA 79-2002 Clause 10.

13.2 Emergency stop devices 10.7 Devices for stop andemergency stop

Delete NFPA 79-1997 subclause 13.2. Add IEC 60204-1 subclause 10.7revised heading.

10.7.1 Location and operation

Add IEC 60204-1 subclause 10.7.1revised heading.

13.2.2 Stop and emergency stoppushbuttons shall be continuouslyoperable from all control andoperating stations where located.

10.7.1.1 Stop and emergency stoppushbuttons shall be continuouslyoperable and readily accessible.

Add the NFPA 79-1997 subclause13.2.2 revise the paragraph, andmove to NFPA 79-2002 Clause 10.

13.2.1 Emergency stop pushbuttonsshall be located at each operatorcontrol station and at other operatingstations where emergency shutdownshall be required.

10.7.1.2 Stop and emergency stoppushbuttons shall be located at eachoperator control station and at otherlocations where emergency stop isrequired.

Add the NFPA 79-1997 subclause13.2.1 revise the paragraph, andmove to NFPA 79-2002 Clause 10.

10.7.2 Types

Add the IEC 60204-1 subclause10.7.2 heading and move to NFPA79-2002 Clause 10.

10.7.2.1 The types of device foremergency stop include, but are notlimited to: — push-button operated switchesin accordance with 10.7.4.— pull-cord operated switches.— foot-operated switches withouta mechanical guard— push bar operated switches.— rod operated switches.

Add the NFPA 790-2002 subclause10.7.2.1 heading number, add theIEC 60204-1 subclause 10.7.2 revisedfirst paragraph, add the revisedbullets, and move to NFPA 79-2002Clause 10.

13.2.4 The emergency stop actuatorshall be either a momentary or self-latching type.

10.7.2.2 Devices for emergency stopshall be of the self-latching type andshall have positive (direct) openingoperation. Note: For further information onpositive (direct) opening operation,see IEC 60947-5-1. Exception: For machines which employonly a single emergency stop device,emergency stop actuators of themomentary type shall be permitted.

Delete the NFPA 79-1997 subclause13.2.4 paragraph. Add the NFPA 790-2002 subclause10.7.2.2 heading number, add theIEC 60204-1 subclause 10.7.2 revisedfirst paragraph, add the revisedbullets, and move to NFPA 79-2002Clause 10.


1604


10.7.3 Restoration of normal

function after emergency stop It shall not be possible to restore anemergency stop circuit until theemergency stop device has beenmanually reset. Where severalemergency stop devices are providedin a circuit, it shall not be possibleto restore that circuit until allemergency stop devices that havebeen operated have been reset. Exception: Where emergency stopdevice of the momentary type are used inaccordance 10.7.2.2, exception, theemergency stop circuit shall bemanually reset.

Add the IEC 60204-4 subclause10.7.3 heading, add the revisedparagraph, and move to NFPA 79-2002 Clause 10.

13.2.3 Actuators of emergency stopdevices shall be colored RED. Thebackground immediately around thedevice actuator shall be coloredYELLOW. The actuator of apushbutton-operated device shall be ofthe palm or mushroom-head type.

10.7.4 Emergency stop actuators Actuators of emergency stop devicesshall be colored RED. Thebackground immediately aroundpushbuttons and disconnect switchactuators used as emergency stopdevices shall be colored YELLOW.The actuator of a pushbutton-operated device shall be of the palmor mushroom-head type. TheRED/YELLOW color combinationshall be reserved exclusively foremergency stop applications. Exception: The RED/YELLOW colorcombination shall be permitted foremergency off actuators in accordancewith 10.8.4

Delete NFPA 79-1997 subclause 13.2paragraph. Add the IEC 60204-1 subclause10.7.4 revised heading, add therevised paragraph, and move toNFPA 79-2002 Clause 10.

10.7.5 Local operation of the supply

disconnecting means to effect

emergency stop

Add IEC 60207-1 subclause 10.7.5heading and move to NFPA 79-2002Clause 10.

10.7.5.1 The supply disconnectingmeans shall be permitted to belocally operated to serve thefunction of emergency stop where: – it is readily accessible to theoperator;– it of the type described in 5.3.2a), b) or c).

Add the proposed NFPA 79-2002subclause number 10.7.5.1, add theIEC 60204-1 subclause 10.7.5 firstparagraph with bullets, and move toNFPA 79-2002 Clause 10.

10.7.5.2 Where intended for suchuse, the supply disconnecting meansshall meet the color requirements of10.7.4.

Add the proposed NFPA 79-2002subclause number 10.7.5.2, add theIEC 60204-1 subclause 10.7.5 secondparagraph, and move to NFPA 79-2002 Clause 10.

10.8 Devices for emergencyswitching off

Add the IEC 60204-1 subclause 10.8heading and move to NFPA 79-2002Clause 10.


1605

NFPA 79 SUBCLAUSE 12.6.2, SUBCLAUSE 12.7, AND CLAUSE 13 CROSS REFERENCE TO PROPOSED NFPA 79-2000 (continued) 10.8.1 Location

Emergency switching off devices asdescribed in 9.2.5.4.3 shall belocated as necessary for the givenapplication.


10.8.2 Types

Add the IEC 60204-1 subclause10.8.2 heading and move to NFPA79-2002 Subclause 10.

10.8.2.1 The types of devices thatinitiate an emergency switching offoperation include, but are notlimited to: — push-button operated switches.— pull-cord operated switches.

Add the proposed NFPA 79-2002subclause 10.8.2.1 number, IEC60204-1 subclause 10.8.2 firstparagraph with bullets, and move toNFPA 79-2002 Clause 10.

10.8.2.2 The push-button operatedswitch shall be permitted in a break-glass enclosure.

Add the proposed NFPA 79-2002subclause 10.8.2.2 number, add theIEC 60204-1 subclause 10.8.2 secondparagraph, and move to NFPA 79-2002 Clause 10.

10.8.3 Restoration of normalfunction after emergency switchingoff It shall not be possible to restore anemergency switching off circuit untilthe emergency switching off circuithas been manually reset.


10.8.4 Actuators

Add the IEC 60204-1 subclause10.8.4 heading and move to NFPA79-2002 Clause 10.

10.8.4.1 Actuators of emergencyswitching off devices shall becolored RED. The backgroundimmediately around the deviceactuator shall be permitted to becolored YELLOW.

Add the proposed NFPA 79-2002subclause 10.8.4.1 number, add theIEC 60204-1 subclause 10.8.4 revisedparagraph, and move to NFPA 79-2002 Clause 10.

10.8.4.2 Where the emergencyswitching off initiating device isseparate from the emergency stopdevice, the emergency switching offinitiating device shall be functionallyidentified.

Add the proposed NFPA 79-2002subclause 10.8.4.2 number, add thenew paragraph text, and move toNFPA 79-2002 Clause 10.

10.8.5 Local operation of thesupply disconnecting device toeffect emergency switching off Where the supply disconnectingdevice is to be locally operated foremergency switching off, it shall bereadily accessible and shall meet thecolor requirements of 10.8.4.1.

Add the IEC 60204-1 subclause10.8.5, add the IEC 60204-1 heading,add the revised paragraph, andmove to NFPA 79-2002 Clause 10.

10.9 Displays Displays (e.g. visual display units,alarm annunciators, indicator lightsand the action initiating icons ofhuman-machine interface (HMI)devices) shall be selected andinstalled in such a manner as to bevisible from the normal position ofthe operator. Note: It is recommended thatdisplays intended to be warningdevices be of the flashing or rotarytype and be provided with anaudible warning device.

Add the IEC 60204-1 subclause 10.9,IEC 60204-1 heading, add the revisedparagraph, and move to NFPA 79-2002 Clause 10.


1606

COMMITTEE ACTION: Accept in Principle.Revise as follows:10 Operator interface and control devices.

10.1 General.

10.1.1 General device requirements. This clause containsrequirements for devices mounted outside or partially outsidecontrol enclosures.

Note: For further information on device selection, mounting,identification, and coding, see IEC 60073 and IEC 60447.

10.1.2 Location and Mounting.

10.1.2.1 Control devices. As far as is practicable, control devicesshall be:

— readily accessible for service and maintenance.— mounted in such a manner as to minimize the possibility ofdamage from activities such as material handling. 10.1.2.2 Hand operated control devices. The actuators of hand-operated control devices shall be selected and installed so that: — they are not less than 2 feet (0.6 m) above the servicing leveland are within easy reach of the normal working position of theoperator.— the operator is not placed in a hazardous situation whenoperating them.— the possibility of inadvertent operation is minimized. 10.1.3 Protection. Operator interface, control devices, andenclosures shall be suitable for the environment and shallwithstand the stresses of expected use. Note: For further information on degrees of protection, see UL50, UL 508, Annex XX and IEC 60529. 10.1.4 Position sensors. 10.1.4.1 Position sensors (e.g. limit switches, position switches,proximity switches) shall be so arranged that they will not bedamaged in the event of overtravel. 10.1.4.2 Position sensors used in circuits with safety-relatedfunctions either shall have positive (direct) opening operation orshall provide similar reliability. Note: For further information on positive (or direct) openingoperation, see IEC 60947-5-1. 10.1.5 Portable and pendant control stations. 10.1.5.1 Portable and pendant operator control stations and theircontrol devices shall be so selected and arranged to minimize thepossibility of inadvertent machine operations. 10.1.5.2 Pendant control stations that are vertically suspended fromoverhead shall comply with 14.4.2.4 or 14.5.10. be supported bysuitable means or flexible electrical conduit or multiconductorcable or cord identified for the purpose. 10.1.6 Operator interface devices. 10.1.6.1 Location of operator interface devices. 10.1.6.1.1 Operator interface devices shall be mounted in locationsthat will minimize exposure to oil, coolant, and othercontaminants. 10.1.6.1.2 Operator interface devices shall be within normal reachof the machine operator and shall be so placed that the operator isnot exposed to hazards. 10.1.6.1.3 Operator interface devices shall be located so thatunintentional operation by normal movement of the machine,operator, or work will be unlikely. 10.1.6.2 Arrangement of operator interface devices. All Startpushbuttons shall be mounted above or to the left of theirassociated Stop pushbuttons.

Exception No. 1: Start pushbuttons in series, such as operatingpushbuttons on punch presses. Exception No. 2: Wobble-stick or rod-operated Emergency Stoppushbuttons mounted in the bottom of pendant stations. 10.1.7 Foot-operated switches. Foot-operated switches used forapplications where accidental actuation could create a hazardoussituation shall be protected to prevent accidental actuation byfalling or moving objects and from unintended operation byaccidental stepping onto the switch. Exception: Foot-operated switches used for emergency stop in accordancewith 10.7.2.1 shall not be of the covered or hooded type. 10.2 Push-button actuators and color graphic interface devices action initiating icons. 10.2.1 Pushbutton Actuators. Pushbutton actuators used to initiatea stop function shall be of the extended operator or mushroom-head types. 10.2.2 Colors. Pushbutton actuators and action initiating icons ofcolor touch screen graphic interface devices shall be color codedas follows: – Start or On - The preferred color of Start or On actuators isGREEN, except that BLACK, WHITE, or GRAY shall be permitted.Red shall not be used for Start or On. actuators. – Stop or Off - The preferred color of Stop or Off actuators is RED,except that BLACK, WHITE, or GRAY shall be permitted. Greenshall not be used for Stop or Off. actuators Exception: Stop function operators of the wobble-stick or rod-operatedtypes in the bottom of a pendant station need not be colored red. The color RED shall be used for, Emergency Stop actuators inaccordance with 10.7.4. – Alternate action - Pushbuttons that, when pressed, act alternatelyas Start and Stop or On and Off shall be BLACK, WHITE, orGRAY. RED or GREEN shall not be used. – Abnormal conditions - The color YELLOW shall be used foractuators used to respond to abnormal conditions. – Hold to operate - Pushbuttons that cause movement whenpressed and stop movement when they are released (e.g., jogging)shall be BLACK, WHITE, GRAY, or BLUE with a preference forBLACK. – Reset - Reset pushbuttons shall be BLUE, BLACK, WHITE, orGRAY except when they also act as a Stop or Off button, in whichcase they shall be RED. 10.2.3 Legends. 10.2.3.1 A legend shall be provided for each operator interfacedevice to identify its function and shall be located so that it can beeasily read by the machine operator from the normal operatorposition. The legends shall be durable and suitable for theoperating environment. 10.2.3.2 For illuminated pushbuttons the function(s) of the light isseparated from the function(s) of the button by a virgule (/). 10.3 Indicator lights and icons of visual display units color graphicinterface devices . 10.3.1 Modes of use. Indicator lights and icons used with visualdisplay units of color graphic interface devices shall provide thefollowing information: — indication: to attract the operator's attention or to indicatethat a certain task should be performed. The colors RED, YELLOW(AMBER), GREEN, and BLUE are normally used in this mode; — confirmation: to confirm a command, or a condition, or toconfirm the termination of a change or transition period. Thecolors BLUE and WHITE are normally used in this mode andGREEN shall be permitted to be used in some cases.


1607

10.3.2 Colors. Indicator lights and icons of color graphic interfacedevices of visual display units shall be color-coded with respect tothe condition (status) of the machine in accordance with tableXX. Alternate purposes shall be permitted to indicate machine orprocess status. (See table below) 10.3.3 Flashing lights. Flashing lights shall be permitted to be usedfor any of the following purposes: – to attract attention.– to request immediate action.– to indicate a discrepancy between the command and actualstates– to indicate a change in process (flashing during transition). 10.4 Illuminated push-buttons. Illuminated push-button actuatorsshall be color-coded in accordance with table XX. The color REDfor the emergency stop actuator shall not depend on theillumination source. 10.5 Rotary control devices. Devices having a rotational member,such as potentiometers and selector switches, shall be mounted insuch a way as to prevent rotation of the stationary member.Friction alone shall not be relied upon to prevent rotation. 10.6 Start devices. Actuators used to initiate a start function or themovement of machine elements (e.g. slides, spindles, carriers)shall be constructed and mounted to minimize inadvertentoperation. Mushroom-type actuators for two-hand controlinitiation shall conform to the requirements of 9.2.5.6 (two handcontrol). 10.7 Devices for stop and emergency stop. 10.7.1 Location and operation. 10.7.1.1 Stop and emergency stop pushbuttons shall becontinuously operable and readily accessible. 10.7.1.2 Stop and emergency stop pushbuttons shall be located ateach operator control station and at other locations whereemergency stop is required. 10.7.2 Types. 10.7.2.1 The types of device for emergency stop include, but arenot limited to: — push-button operated switches in accordance with 10.7.4.— pull-cord operated switches.— foot-operated switches without a mechanical guard— push bar operated switches.— rod operated switches. 10.7.2.2 Pushbutton type devices for emergency stop shall be of theself-latching type and shall have positive (direct) openingoperation.

Note: For further information on positive (direct) openingoperation, see IEC 60947-5-1. Exception: For machines which employ only a single emergency stopdevice, emergency stop actuators of the momentary type shall be permitted. 10.7.3 Restoration of normal function after emergency stop. Itshall not be possible to restore an emergency stop circuit until theemergency stop device has been manually reset. Where severalemergency stop devices are provided in a circuit, it shall not bepossible to restore that circuit until all emergency stop devices thathave been operated have been reset. Exception: Where emergency stop device of the momentary type are usedin accordance with 10.7.2.2, exception, the emergency stop circuitshall be manually reset. 10.7.4 Emergency stop actuators. Actuators of emergency stopdevices shall be colored RED. The background immediatelyaround pushbuttons and disconnect switch actuators used asemergency stop devices shall be colored YELLOW. The actuator ofa pushbutton-operated device shall be of the palm or mushroom-head type. The RED/YELLOW color combination shall bereserved exclusively for emergency stop applications. Exception: The RED/YELLOW color combination shall be permitted foremergency off actuators in accordance with 10.8.4 10.7.5 Local operation of the supply disconnecting means to effect

emergency stop. 10.7.5.1 The supply disconnecting means shall be permitted to belocally operated to serve the function of emergency stop where : – it is readily accessible to the operator;– it is of the type described in 5.3.2 a), b) or c). 10.7.5.2 Where intended for such use, the supply disconnectingmeans shall meet the color requirements of 10.7.4. 10.8 Devices for emergency switching off. 10.8.1 Location. Emergency switching off devices as described in9.2.5.4.3 shall be located as necessary for the given application. 10.8.2 Types. 10.8.2.1 The types of devices that initiate an emergency switchingoff operation shall be permitted to include, but are not limited to: — push-button operated switches.— pull-cord operated switches. 10.8.2.2 The push-button operated switch shall be permitted in abreak-glass enclosure. 10.8.3 Restoration of normal function after emergency switchingoff. It shall not be possible to restore an emergency switching offcircuit until the emergency switching off circuit has been manuallyreset. 10.8.4 Actuators.

Table XX Colors for indicator lights and icons of color graphic interface devices and their purposes withrespect to the condition of the machine Color

Purposes

Safety of persons orenvironment

Condition of process State of Equipment






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10.8.4.1 Actuators of emergency switching off devices shall becolored RED. The background immediately around the deviceactuator shall be permitted to be colored YELLOW. 10.8.4.2 Where the emergency switching off initiating device isseparate from the emergency stop device, the emergency switchingoff initiating device shall be functionally identified. 10.8.5 Local operation of the supply disconnecting means toeffect emergency switching off. Where the supply disconnectingmeans is to be locally operated for emergency switching off, it shallbe readily accessible and shall meet the color requirements of10.8.4.1. 10.9 Displays. Displays (e.g. visual display units, alarmannunciators, indicator lights and the action initiating icons ofhuman-machine interface (HMI) devices) shall be selected andinstalled in such a manner as to be visible from the normalposition of the operator. Note: It is recommended that displays intended to be warningdevices be of the flashing or rotary type and be provided with anaudible warning device.COMMITTEE STATEMENT: 1) The revision in 10.1.5.2 wastaken to correlate the provision of this section with therequirements in Clause 14. 2) Also an editorial revisions to avoid the use of the words "suchas" in 10.5. 3) 10.2.1 This text was renumbered and missing title. 4) 10.2.2 New Number 10.2.2 to correspond with new 10.2.1. 5) 10.2.2 "Color Graphic Interface Device" substituted for "touchscreen", to agree with the title of the section. 6) 10.2.2 The word "actuators" removed to add clarity. 7) 10.3 "Color Graphic Interface Device" substituted for "visualdisplay unit" to agree with term used in 10.3.2 and Table XX. 8) 10.3.1 "Color Graphic Interface Device" substituted for "visualdisplay unit" to agree with term used in 10.3.2 and Table XX.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KNECHT: We recommend putting back the color graphicinterface devices to what they were in NFPA 79. As proposed, it istoo confusing as to what it is we are talking about.COMMENT ON AFFIRMATIVE: BLOODGOOD: I recognize that considerable time and effortwent into the development of the proposed clause 10. Even so, iffind it unfortunate that a closer agreement between this proposaland the recommended color coding found in IEC 60204–1: 2000(ed. 4.1) could not have been reached. (See 10.2.1 in bothdocuments and table 3 in IEC 60204–1 and table XX in theproposal for the differences.) DEFELICE: To acquaint the reader with this term which nowappears in Clause 10, the committee may wish to insert thefollowing definition in Clause 3: Color Graphic Interface Device: an interface between theoperator and the machine, where a color video display and either atouch-screen or touch pad or keyboard or mouse are used toinitiate machine action by the selection of on-screen icons. (Thisdoes not include monochrome or black and white displays)

WITHROW: COMMITTEE STATEMENT: 2) Also an editorialrevision to avoid the use of the words "such as" in 10.5. 6) 10.2.2 The word "actuators" removed to add clarity. REFERENCE: NFPA 79-2002 10.5 Rotary control devices Devices having a rotational member, such as potentiometers andselector switches, shall be mounted in such a way as to preventrotation of the stationary member. Friction alone shall not berelied upon to prevent rotation. NFPA 79-1997 12.7 Rotary control devices Devices such as potentiometers and selector switches having arotating member shall be mounted to prevent rotation of thestationary member. Friction alone shall not be consideredsufficient. COMMENT: Item 2 - The Committee did not recommend aneditorial replacement for use of the words "such as" in 10.5. If theeditorial staff of NFPA can make this revision, this comment can beignored. Item 6 - Actuator was removed in the bullets for Start or On andStop or Off. If YELLOW is used for action indication icons, it isrecommended that the word "actuators" also be removed in thefourth bullet as follows: Abnormal Conditions – The color YELLOW shall be used foractuators used to respond to abnormal conditions.

___________________

(Log #11)79- 100 - (13.1.2 [10.2 and 10.3]): Accept in PrincipleSUBMITTER: Frank C. DeFelice, Jr., Cytec Industries Inc.RECOMMENDATION: Delete word "and" and insert comma;revise as follows: "and icons of devices which provide a graphic interface betweenthe equipment and its operator" shall be color coded inaccordance with Table 8.SUBSTANTIATION: Graphic interface devices such as MMI(man-machine interfaces) have replaced pushbuttons and pilotlights in an increasing number of applications. This will providecontinuity of the original intent of this section.COMMITTEE ACTION: Accept in Principle. Revise the first sentence of 10.3.2 to read as follows. 10.3.2 Colors. Indicator lights and icons of color graphic interfacedevices of visual display units shall be color-coded with respect tothe condition (status) of the machine in accordance with TableXX. The last sentence is to be retained.COMMITTEE STATEMENT: The added term " color graphicinterface devices " adds clarity of the section. The committeeunderstands that this proposal modifies the Committee Action onProposal 79-99 (Log #24) Clause 10].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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1609

(Log #121)79- 101 - (13.2.4 (10.7.2.2)): AcceptSUBMITTER: Richard Graham, Bridgeport MachinesLimited/Rep. CECIMO (European Committee for Co-operation ofthe Machine Tool IndustriesRECOMMENDATION: Reword text as follows: "Push button type devices for emergency stop shall be of the selflatching type and shall have positive (direct) opening contacts."There should be no exception as proposed by the committee.SUBSTANTIATION: The substantiation as proposed by thecommittee to get rid of momentary type devices is a soundtechnical argument. This argument carries no weight at all if thistype is permitted on machines with only one E-stop. The numberof switches should not allow the use of a less reliable switch. Manyvery large machines have only one E-stop. To say that themomentary switch can be used on machines employing only one E-stop believing that it only applies to small machines is incorrect.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the text of Proposal 79-99 (Log #24) [Clause10].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: This proposal should be rejected. Momentarytype stop devices have been safely used for many years. Manyexisting machines have this type of device.

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(Log #9)79- 102 - (13.2.4 [10.7.2.2]): Accept in PrincipleSUBMITTER: Stanley E. Parker, Sr., Advanced Drainage Systems,Inc.RECOMMENDATION: Section 13.2, Emergency Stop Devices. Item 13.2.4, add the following to existing wording: "If the area immediately at and around an emergency stoppushbutton is not able to be viewed (cannot be seen) from thecontrol station which contains the start pushbutton for that stopcircuit, the emergency stop actuator shall be of the maintained-pull/maintained-push type."SUBSTANTIATION: In the plastics industry, many of the plasticforming (corrugators, formers, etc.) machines have an emergencystop pushbutton at each corner of the machine. At one of ourplants, a maintenance man was working around a gearboxmechanism on a large corrugator. The guards were off and he hadto have the machine running to make an adjustment. All of asudden, his sleeve was caught in the gearing and as he was beingpulled into the machine, he hit one of the rear mountedemergency stop pushbuttons and stopped the machine. Thispushbutton momentarily de-energized the machine run circuit. The line operator, anxious to keep the plastic flowing and notknowing what was happening at the rear of the machine, pressedthe start pushbutton and restarted the machine, pulling themaintenance man further into it. Luckily, the man was able to hitthe E-stop button again and restop the machine. If the E-stoppushbutton had been of the maintained-pull/maintained-pushtype, the operator would have been unable to restart the machineand would have then looked for a reason why it had stopped in thefirst place.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-101 (Log #121).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #146)79- 103 - (13.2.4 Exception [10.7.2.2]): Accept in PrincipleSUBMITTER: Thomas Pilz , Pilz Industrial Electronics L.P.RECOMMENDATION: Revise as follows: Exception: For machines which employ only a single emergencystop device, emergency stop actuators of the momentary type shallbe permitted. Replace strike through text with: For machines which employ no control circuitry for theemergency stop, emergency stop actuators of the momentary typeshall be permitted.

SUBSTANTIATION: The problem with momentary emergencystop actuators is that the power source gets reconnected to theactuator when the button is released. Also the design of suchbuttons does not guarantee a breaking of the line, like pushbuttons of positive breaking design do. When such momentarybuttons are used in control circuitry it is possible that the actuationof the emergency stop button does not stop the hazardous motionor does allow restart immediately after release of the emergencystop button. Therefore, in control circuits the use of self-latchingdevices improves safety to personnel. For example, a self-latchingdevice would be beneficial in ensuring proper coil drop-out. Therequirement for positive direct operation ensures that in the eventof a failure that results in direct welded contact, it could beovercome. At small machinery however, the emergency stop actuator isemployed directly into the main circuit. Typically such machineshave only one start and one stop button. The stop button alsoserves as emergency stop button. At such machinery stop buttonsare usually of the momentary type. The requirement of a selflatching positive breaking emergency button would force thedesigner of such equipment to incorporate a separate safety controlcircuit as well as one additional self latching, positive breakingemergency stop button. This would not increase the operationalsafety, but impose unnecessary cost to the design of such simplemachinery. Therefore, an exception for such machinery has to bemade. The wording in the original proposal of the NFPA 79 allowsfor misinterpretation. By tying the exception to the number of e-stop actuators, the designer of a large machine could argue that itwas acceptable to use a momentary push button for the emergencystop, even so he has to tie the emergency stop button into thecontrol circuit due to the complexity of the large machine. Bylinking the exception to the method on how the emergency stopactuator is incorporated into the machine the describedmisinterpretation is avoided.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-101 (Log #121).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: GARVEY: I agree with the substantiation. The use of momentary-type push buttons should be limited to simple machines with noseparate control circuitry.

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(Log #3)79- 104 - (13.6 Exception (New) [10.2.2.1]): AcceptSUBMITTER: Robert Ziller, Doboy Div., Sig Packageing Tech.RECOMMENDATION: Add an Exception to Section 13.6 to readas follows: Exception: Emergency stop devices require no legend if they meetthe requirements of paragraph 13.2.3.SUBSTANTIATION: Emergency stop actuators with redmushroom pushbuttons and yellow background is sufficient to callattention to the function (also reference EN 60204-1992 paragraph18.3 and 10.7.4).COMMITTEE ACTION: Accept. Editorially correct the references as follows: Add a new exception to Section 10.2.2.1 to read as follows: Exception: Emergency stop devices require no legend if they meetthe requirements of paragraph 10.7.4.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Committe Action on Proposal 79-99 (Log#24) [Clause 10].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DROBNICK: I vote negative and urge my colleagues toreconsider. I believe that the red mushroom pushbutton with theyellow background combination is not currently nationally appliedor recognized. Additionally, a legend plate clarifies the purpose ofthis safety device and reduces the chance of pushing the wrongbutton during an emergency situation. Substantiation: Emergency stop pushbuttons are required to belabeled by ANSI B11.19-1990 E5.2.2.

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(Log #26)79- 105 - (Clause 14 [Clause 16]): Accept in PrincipleSUBMITTER: Jim F. Pierce, Intertek Testing ServicesRECOMMENDATION: Revise NFPA 70-1997 Clause 14"Assessories and lighting" and issue as new Clause 16 "Accessoriesand lighting" as follows: 16 Accessories and Lighting 16.1 Accessories 16.1.1 Where the machine or its associated equipment isprovided with receptacle-outlets to be used for accessoryequipment (e.g. hand-held power tools, test equipment), thefollowing conditions shall apply: a) Receptacles shall be of the grounding type, 125 volt, single-phase, 15 ampere configuration and listed for the applied voltage. b) Receptacles with their associated attachment plugs(plug/sockets) shall be provided with a grounding pole and soconstructed that the grounding pole is made before any current-carrying poles are made, and is not broken until all current-carrying poles of the attachment plug have been disconnected. Agrounding pole shall not be used as a current-carrying part. c) The continuity of the equipment grounding (protectivebonding) circuit to the receptacle-outlet shall be verified by clause19.2. Exception: Verification is not required for PELV circuits inaccordance with 19.2. d) All ungrounded (unearthed) conductors connected to thereceptacle-outlet shall be protected against overcurrent inaccordance with the provisions of 7.2 and 7.3 separately from theprotection of other circuits. e) Where the power supply to the receptacle-outlet is notdisconnected by the supply disconnecting device for the machineor section of the machine, the warning and marking requirementsof 5.3.5 shall apply. f) Shall be suitable for the environment. Receptacles mountedexternal to the enclosure shall be provided with a means to coverthe receptacle when the plug is removed. 16.1.2 Receptacles, part of the industrial machine, either internalor external to the control cabinet and intended for use bymaintenance personnel shall be GFCI protected. 16.2 Local lighting of the machine and equipment 16.2.1 General 16.2.1.1 Lighting circuits shall comply with the provisions of 8.5. 16.2.1.2 Where work lights are required, they shall be providedwith an ON-OFF switch conveniently located on the equipment.Lamp holders shall not incorporate a switch or receptacle. Worklights used in wet locations shall be provided with ground faultprotection. 16.2.1.3 The conductors to stationary lights used as an integralpart of the machine shall be Type MTW, and the conductors withinthe fixtures shall be not smaller than No. 18 AWG. 16.2.1.4 Flexible cords shall be Type SO, STO, STOW, or SJO,SJOW, SJTO and shall not incorporate in-line switches. 16.2.1.5 Stroboscopic effects from lights shall be avoided. 16.2.2 Supply 16.2.2.1 The lighting circuit voltage shall not exceed 150 voltsbetween conductors. 16.2.2.2 Lighting circuits shall have overcurrent protection per7.2.6 and shall be supplied from one of the following sources. a) A separate isolating transformer connected to the load side ofthe supply disconnecting means. Overcurrent protection shall beprovided in the secondary circuit. b) A separate isolating transformer connected to the line side ofthe supply disconnecting means shall be permitted for the supplyof a maintenance lighting circuit in control enclosures only.Overcurrent protection shall be provided in the secondary circuit. c) A grounded machine circuit with separate overcurrentprotection. d) An isolating transformer connected to the line side of thesupply disconnecting device when a separate primary disconnectingmeans and secondary overcurrent protection are provided andmounted within the control enclosure adjacent to the supplydisconnecting device. e) An externally supplied lighting circuit (e.g. factory lightingsupply). This shall be permitted in control enclosures and for themachine work light (s) where the total power rating does notexceed 3 kW. 16.2.3 Protection 16.2.3.1 Local lighting circuits shall be separately protected withovercurrent protection and shall not exceed 15 amperes. 16.2.4 Lighting Fixtures 16.2.4.1 Adjustable lighting fixtures shall be suitable for thephysical environment. 16.2.4.2 The lampholders shall be: a) Rated for the voltage and wattage of the lamp.

b) Constructed with an insulating material protecting the lampso as to prevent unintentional contact, except where fixed lightingis out of reach of operators during normal operations, theprovisions of this subclause do not apply. 16.2.4.3 Reflectors and protectors shall be supported by a bracketand not the lampholder.SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738.

Historical Background










Result



The Task Group proposes to renumber NFPA 79-1997 Clause 14 tocorrespond with IEC 60204-1 Clause 16. The task group proposesthe following changes to further improve usability.

Substantiation for changes to NFPA 79-1997 Clause 14

16 Accessories and Lighting

Revision: No change except numbering; Clause 14 nowClause 16.

16.1 Accessories

Add the IEC 60204-1 subclause 16.1 heading.

Substantiation: New subclause heading clarifiesthe intent of the subclause.


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16.1.1 Add IEC 60204-1 subclause 16.1.1.

Substantiation: This subclause clarifies asubject presently covered in subclause 14.1 ofNFPA 79-1997. This subclause is for receptaclesprovided for portable accessory equipment.New subclause 14.4.5 contains requirements forconnection and interconnection of equipmentintended to be part of the equipment andrequired for the typical operation of theequipment.

16.1.1 a) Revise NFPA 79 paragraph 14.1.1.

Substantiation: The requirements forattachment plugs is removed as this subclauseis only to address receptacles. For otherreceptacles with voltages greater than 300 voltsthe requirements are in new subclause 14.4.5.2.For other receptacles with current ratingsexceeding 20 amperes the requirements are innew subclause 14.4.5.5.

16.1.1 b) Revise NFPA 79 paragraph 14.1.2.

Substantiation: Editorial revision only.

16.1.1 c) Add IEC 60204-1 subclause 16.1, second bullet.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997 and is fromIEC60204-1. It better addresses the issue ofverifying the grounding continuity.

16.1.1 d) Add IEC 60204-1 subclause 16.1, third bullet.

Substantiation: This new subclause is from IEC60204-1 and is similar to NFPA 79 subclauses14.2.3 and 14.2.4 requiring overcurrentprotection.

16.1.1 e) Add IEC 60204-1 subclause 16.1, fourth bullet.

Substantiation: This subclause covers a subjectnot presently in NFPA 79 and is from IEC60204-1. It better addresses a warning markingstating that equipment that is live with thedisconnect in the OFF position and enhancessafety.

16.1.1 f) Add IEC 60204-1 subclause 16.1, fifth bullet.

Substantiation: This new subclause is from IEC60204-1 and is similar to NFPA 79 subclause 14.1.3 16.1.2 Add new requirement.

Substantiation: The subclause covers a subjectnot currently in NFPA 79-1997 and it isintended to increase safety to the service andmaintenance personnel using the accessoryreceptacles.

16.2 Local lighting of the machine and equipment Revised title. Substantiation: Revised title clarifies intent of

the subclause. 16.2.1 General

Add the IEC 60204-1 subclause 16.2.1 heading.

Substantiation: The new subclause clarifies theintent of the subclause.

16.2.1.1 Addition: Add IEC 60204-1 subclause 16.2.1first

paragraph.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause14.3.5 relating to grounding.

16.2.1.2 Recommendation: Revise NFPA 79-1997, 14.3.6. Add newmaterial.

Substantiation: The panel felt the addition ofGFCI requirements on work lights used in wetlocations enhanced safety to the personnelusing the equipment. The remainder of thesubclause contains only editorial revisions andis from NFPA 79 14.3.6.

16.2.1.3 Revision: No change except numbering; subclause 14.3.3now subclause 16.2.1.3. 16.2.1.4 Revision: No change except numbering; subclause 14.3.4

now subclause 16.2.1.4. 16.2.1.5 Revision: No change except numbering; subclause 14.3.7now subclause 16.2.1.5. 16.2.2 Supply Add the IEC 60204-1 subclause 16.2.2 heading.

Substantiation: The new subclause clarifies thecontent of the subclause.

16.2.2.1 Revision: No change except numbering; subclause 14.3.1now subclause 16.2.2.1.

16.2.2.2 Add the IEC 60204-1 subclause 16.2.2 second paragraph.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause14.3.2 relating to overcurrent protection.

16.2.2.2 a) Revisions: No change except numbering; subclause14.3.2a) now subclause 16.2.2.2a). 16.2.2.2 b) Revisions: No change except numbering; subclause14.3.2e) now subclause 16.2.2.2b). 16.2.2.2 c) Add the IEC 60204-1 subclause 16.2.2, secondparagraph, third bullet.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause14.3.2b) relating to the use of groundedmachine circuits lighting power.

16.2.2.2 d) Add the IEC 60204-1 subclause 16.2.2, second

paragraph, fourth bullet.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause14.3.2f) relating to the source of power fromthe line side of the disconnect.

16.2.2.2 e) Add the IEC 60204-1 subclause 16.2.2, third paragraph.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause14.3.2c) relating to the use of plant lightingcircuits.

16.2.3 Protection

Add the IEC 60204-1 heading for subclause 16.2.3

Substantiation: The new subclause headingclarifies the content of the subclause.

16.2.3.1 Add the IEC 60204-1 subclause 16.2.3.

Substantiation: The new subclause is from IEC60204-1 and is similar to NFPA 79 subclause8.10 relating to protection of lighting branchcircuits.

16.2.4 Lighting Fixtures


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Add new subclause heading.

Substantiation: The heading better describesthe content of the subclause.

16.2.4.1 Add the IEC 60204-1 subclause 16.2.4.

Substantiation: The new subclause is from hIEC 60204-1 and is similar to NFPA 79subclause 14.3.6 relating to suitability oflighting fixture to the physical environment.

16.2.4.2 Addition: Add the IEC 60204-1 subclause 16.2.4 secondparagraph.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997 and is from IEC60204-1. It better addresses requirements forlampholders of lighting fixtures on themachine.

16.2.4.2 a) Add new text.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997 and is from IEC60204-1. It addresses that the lampholdershould be rated for the intended lamp.

16.2.4.2 b) Add the IEC 60204-1 subclause 16.2.4 third paragraph.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997 and is from IEC60204-1. It address the issue of unintentionalcontact of the lampholder by the opera tor andincreases the safety of contacting the lamp.

16.2.4.3 Revision: No change except numbering; subclause 14.3.8now 16.2.4.3. (See table on following page.)

COMMITTEE ACTION: Accept in Principle.Revise Clause 16 to read as follows: 16 Accessories and Lighting 16.1 Accessories16.1.1 Where the machine or its associated equipment is providedwith receptacle-outlets to be used for accessory equipment (e.g.hand-held power tools, test equipment), the following conditionsshall apply: a) Receptacles shall be of the grounding type, 125 volt, single-phase, 15 ampere configuration and listed for the applied voltage. b) Receptacles with their associated attachment plugs(plug/sockets) shall be provided with a grounding pole and soconstructed that the grounding pole is made before any current-carrying poles are made, and is not broken until all current-carrying poles of the attachment plug have been disconnected. Agrounding pole shall not be used as a current-carrying part. c) The continuity of the equipment grounding (protectivebonding) circuit to the receptacle-outlet shall be verified by clause19.2. Exception: Verification is not required for PELV circuits inaccordance with 19.2. d) All ungrounded (unearthed) conductors connected to thereceptacle-outlet shall be protected against overcurrent inaccordance with the provisions of 7.2.5 and 7.3 separately from theprotection of other circuits.e) Where the power supply to the receptacle-outlet is notdisconnected by the supply disconnecting device for the machineor section of the machine, the warning and marking requirementsof 5.3.5 5.3.5.4 shall apply. f) Shall be suitable for the environment. Receptacles mountedexternal to the enclosure shall be provided with a means to coverthe receptacle when the plug is removed.

16.1.2 Receptacles, part of the industrial machine, either internalor external to the control cabinet and intended for use bymaintenance personnel shall be GFCI protected. 16.2 Locallighting of the machine and equipment 16.2.1 General 16.2.1.1 Lighting circuits shall comply with the provisions of 8.5. 16.2.1.2 Where work lights are required, they shall be providedwith an ON-OFF switch conveniently located on the equipment.Lamp holders shall not incorporate a switch or receptacle. Worklights used in wet locations shall be provided with ground faultprotection. 16.2.1.3 The conductors to stationary lights used as an integralpart of the machine shall be Type MTW, and the conductors withinthe fixtures shall be not smaller than No. 18 AWG. 16.2.1.4 Flexible cords shall be Type SO, STO, STOW, or SJO,SJOW, SJTO and shall not incorporate in-line switches. 16.2.1.5 Stroboscopic effects from lights shall be avoided. 16.2.2 Supply 16.2.2.1 The lighting circuit voltage shall not exceed 150 voltsbetween conductors. 16.2.2.2 Lighting circuits shall have overcurrent protectionper7.2.6 and shall be supplied from one of the following sources. a) A separate isolating transformer connected to the load side ofthe supply disconnecting means. Overcurrent protection shall beprovided in the secondary circuit. b) A separate isolating transformer connected to the line side ofthe supply disconnecting means shall be permitted for the supplyof a maintenance lighting circuit in control enclosures only.Overcurrent protection shall be provided in the secondary circuit. c) A grounded machine circuit with separate overcurrentprotection and not exceeding 150 volts to ground shall bepermitted. d) An isolating transformer connected to the line side of thesupply disconnecting device when a separate primary disconnectingmeans and secondary overcurrent protection are provided andmounted within the control enclosure adjacent to the supplydisconnecting device. e) An externally supplied lighting circuit (e.g. factory lightingsupply). This shall be permitted in control enclosures and for themachine work light (s) where the total power rating does notexceed 3 kW. 16.2.3 Protection 16.2.3.1 Local lighting circuits shall be separately protected withovercurrent protection and shall not exceed 15 amperes. 16.2.4 Lighting Fixtures 16.2.4.1 Adjustable lighting fixtures shall be suitable for thephysical environment. 16.2.4.2 The lampholders shall be:a) Rated for the voltage and wattage of the lamp. b) Constructed with an insulating material protecting the lampso as to prevent unintentional contact, except where fixed lightingis out of reach of operators during normal operations, theprovisions of this subclause do not apply. 16.2.4.3 Reflectors and protectors shall be supported by a bracketand not the lampholder.COMMITTEE STATEMENT: 1) Editorially correct cross referencein 16.1.1.

2) 16.2.2.2(c) was revised to more closely correlate with theprovisions on NFPA 79-1997, 14.3.2(b).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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CLAUSE NUMBERS: NFPA 79-1997 CROSS REF. TO PROPOSED NFPA 79-2002


Clause Heading (or topic) Clause Heading (or topic)14 Accessories and lighting 16 Accessories and lighting14.1 Attachment plugs and receptacles external

to the control enclosure16.1 Accessories

(new subclause not in NFPA 79) 16.1.1 (receptacles for use with hand tools, etc., shall )14.1.1 (listed and locking if >20amps, skirted if >

300)16.1.1 a)14.4.5.214.4.5.5

(listed, grounding type, 125 volt, single-phase, 15 or 20 amp)(skirted if > 300 volts)(locking type if > 20 amps)

14.1.2 (provided with grounding pole, makefirst/break last)

16.1.1 b) (provided with grounding pole, make first/break last)

14.1.3 (suitable for environment) 16.1.1 f) (suitable for environment)(new subclause not in NFPA 79) 16.1.1 c) (grounding continuity verified by Section 19.2)(new subclause not in NFPA 79) 16.1.1 e) (warning marking if power not disconnected from receptacle)

14.2 Receptacles internal to the controlenclosure

(not in new NFPA 79)

14.2.1 (permitted uses of maintenance and ACdistribution)


14.2.2 (parallel blade, 125 v, 15 A) 16.1.1 a) (15 or 20 ampere configurations)(new subclause not in NFPA 79) 16.1.2 (external receptacles for maintenance to be GFCI protected)

14.2.3 (120 volt source not exceeding 15 A) 16.1.1 d) (ungrounded conductors protected against overcurrent)14.2.4 (maintenance receptacles separated from

others)16.1.1 d) (individual/separate overcurrent protection from other ckts)

14.2.5 (source from isolating transformer orother)


14.2.6 (receptacles not accessible with doorsclosed)


14.3 Control panel, instrument, and machinework lights

16.2 Local lighting of the machine and equipment

(new heading not in NFPA 79) 16.2.1 General(new heading not in NFPA 79) 16.2.2 Supply

14.3.1 (not to exceed 150 volts and suppliedfrom:)

16.2.2.1 (not to exceed 150 volts)

14.3.2 (lights supplied from one of the following) 16.2.2.2 (overcurrent protected and supplied from one of the following)14.3.2 a) (iso trans on load side of machine

disconnect)16.2.2.2 a) (iso trans on load side of machine disconnect

14.3.2 b) (grounded 120 v machine control ckt witho/c protect)

16.2.2.2 c) (grounded machine circuit with overcurrent protection)

14.3.2 c) (plant lighting circuit for maintenancelighting in enclosure only)

16.2.2.2 e) (external factory lighting circuit in enclosure max 3kW capac)

14.3.2 d) (if motors 2 hp or less, can connect to plantlighting)

16.2.2.2 e) (if 3kW or less, can connect to plant lighting)

14.3.2 e) (separate iso transformer on line side ofmachine disconnect inside controlenclosure only)

16.2.2.2 b) (separate iso transformer on line side of machine disconnect incontrol enclosures only)

14.3.2 f) (separate iso transformer on line side ofmain disconnect when separate disconnectand secondary overcurrent protectionfurnished within control enclosure)

16.2.2.2 d) (separate iso transformer on line side of supply disconnect whenseparate primary disconnect and secondary overcurrent protectionfurnished within control enclosure)

(new heading not in NFPA 79) 16.2.3 Protection8.10 (lighting branch circuits not to exceed 15

amperes)16.2.3.1 (separately protected lighting branch circuits not to exceed 15

amperes)14.3.3 (stationary light conductors MTW and

min18 AWG conductors used inside fixture)16.2.1.3 (stationary light conductors MTW and min 18 AWG conductors

used inside fixture)14.3.4 (flex cord SO, STO, STOW, SJO, etc., no

switches)16.2.1.4 (flex cord SO, STO, STOW, SJO, etc, no switches in line)

14.3.5 (grounding per subclause 19.8) 16.2.1.1 (grounding per subclause 8.5)14.3.6 (no switches or receptacles in lights and not

exposed to liquids/mists)16.2.1.2 (ON-OFF switch provided on equipment, lamp holder not to have

switch or receptacle lights in wet location provided with GFCI)14.3.7 (stroboscopic effects to be avoided) 16.2.1.5 (stroboscopic effects to be avoided)14.3.8 (reflectors supported by bracket) 16.2.4.3 (reflectors supported by bracket)

(new subclause not in NFPA 79) 16.2.4 Lighting Fixtures(new subclause not in NFPA 79) 16.2.4.1 (adjustable fixtures suitable for the environment)(new subclause not in NFPA 79) 16.2.4.2 a) (lampholders shall be rated for voltage and wattage)(new subclause not in NFPA 79) 16.2.4.2 b) (lampholders constructed to prevent unintentional contact)


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(Log #169)79- 106 - ([16.1.1(b)]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the following paragraph(16.1.1(b)): (b) Receptacles with their associated attachment plugs(plug/sockets) shall be provided with a grounding pole and soconstructed that the grounding pole is made before any currentcarrying poles are made, and is not broken until all currentcarrying poles of the attachment plug have been disconnected. sodesigned that; a protective bonding (equipment grounding) circuitconnection is made before any live connections are made; and theprotective bonding (equipment grounding) circuit connection isnot disconnected until all live connections in the plug aredisconnected. A grounding pole shall not be used as a current-carrying part.SUBSTANTIATION: The requirement is covered in NFPA 79proposed 2002 Edition 16.1.1(b) and 14.4.5.3. The revision wouldmake 16.1.1(b), consistent with NFPA 79, 2000 edition 14.4.5.3which the full committee had used set the style for the samerequirement.COMMITTEE ACTION: Accept in Principle. Revise 16.1.1(b)to read as follows: Receptacles with theirassociated attachments plugs (plug/sockets) shall be inaccordance with 14.4.5.3.COMMITTEE STATEMENT: The committee revised the proposedwording of the submitter to reference rather than duplicate therequirements in 14.4.5.3. See the Committee Action and Statementon Proposal 79-122 (Log #55). The committee understands thatthis proposal modifies the Action on Proposal 79-105 (Log #26).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #170)79- 107 - ([16.1.1(f)]): RejectSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the following paragraph(16.1.1(f)): (f) Shall be suitable for the environment. Receptacles mountedexternal to the enclosure shall be provided with a means to coverthe receptacle when the plug is removed.SUBSTANTIATION: The requirement is covered in NFPA 79proposed 2002 edition 16.1.1(a) The revision would make thisconsistent with NFPA 79, 2000 edition 14.4.5.7 in which the fullcommittee had set the style for the same requirement.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The substantiation is incorrectbecause 16.1.1(a) does not cover this requirement.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #143)79- 108 - ([16.1.2 (New)]): RejectSUBMITTER: Paul Dobrowsky, Holley, NYRECOMMENDATION: Delete this subclause.SUBSTANTIATION: This requirement is overly restrictive. Anyreceptacle located anywhere -in, on or outside of a building couldbe used by maintenance personnel. The NEC does NOT requirethese receptacles to be GFCI protected. Receptacles located onwalls or columns right next to receptacles mounted on machinesdo not require GFCI protection. Predicting if a receptacle will beused for maintenance or machine lights, radios or other appliancesis too subjective. Adding this requirement does not support theharmonization effort. The present NFPA 79 nor IEC 60204 containthis requirement.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee reaffirms its positionin support of the substantiation submitted with Proposal 79-105(Log #26) which stated "It is intended to increase safety to theservice and maintenance personel using the accessory receptacle."It is not the intent of this committee that all receptacles circuitsprovided with Industrial Machines be protected by GFCI. Rather,it is the intent of this committee that all receptacles that are

intended to be used by maintenance personel provided onindustrial machines be provided with GFCI protection.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: This proposal should be accepted. The providedsubstantiation is insufficient. Requiring all receptacles to be GFCIprotected could also be considered as "increasing safety". GFCIprotection can be provided for maintenance activities by usingportable means as permitted in the NEC. Many machines arelocated in factories that are clean and well maintained. IEC 60204-1 does not have this requirement nor does the existing NFPA 79.The addition of this requirement does not promote theharmonization effort MONTEITH: I agree with Mr. Dobrowsky's Explanation ofNegative Vote. PADGET: I agree with Mr. Dobrowsky’s Explanation of NegativeVote.

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(Log #160)79- 109 - ([16.2.1.2]): RejectSUBMITTER: Paul Dobrowsky, Holley, NYRECOMMENDATION: Delete the last sentence.SUBSTANTIATION: Work lights (luminaires) are available thatare listed for that use without GFCI protection.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee reaffirms itsstatement from the substantiation of Proposal 79-105 (Log #26),16.2.1.2 which says: " The panel felt the addition of GFCIrequirements on work lights used in wet locations enhanced safetyto the personnel using the equipment. "NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: This proposal should be accepted. There aremany listed work lights that are suitable for use with GFCIprotection. Some are actually capable of being submersed. Manywork lights are not readily accessible. Requiring all light fixtureslocated outdoors to have GFCI protection would also "enhancesafety". IEC 60204-1 does not have this requirement nor does theexisting NFPA 79. The addition of this requirement does notpromote the harmonization effort. If qualified testing laboratorieshave evaluated and accepted products for this use without GFCIprotection, why should this standard require it? MONTEITH: I agree with Mr. Dobrowsky's Explanation ofNegative Vote. PADGET: I agree with Mr. Dobrowsky’s Explanation ofNegative Vote.

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(Log #124)79- 110 - (14.3.6 [16.2.1.2]): Accept in PrincipleSUBMITTER: Richard Graham, Bridgeport MachinesLimited/Rep. CECIMO (European Committee for Co-operation ofthe Machine Tool IndustriesRECOMMENDATION: Retain the current text.SUBSTANTIATION: The committee’s proposal to change thecurrent text to what is included in the new 16.2.1.2 has no technicaljustification. The substantiation is poor. Harmonization is noreason on it’s own. To say that it is similar to the existing clause isnot true. It is the opposite. On many machines the traditionallamp has been replaced with fluorescent lights that do not exhibitstroboscopic problems and on this type of light it is unusual tohave an ON/OFF switch.COMMITTEE ACTION: Accept in Principle. Add a new first sentence to 16.2.1.2 to read as follows: "Machine work lights shall not contain switches or receptacleswhere exposed to liquids or condensing mists unless identified forthe purpose." The committee understands that this action deletesthe first sentence only of 16.2.1.2 in Proposal 79-105 (Log #26)with the words of 14.3.6 of NFPA 79-1997. The last two sentence of16.2.1.2 remains unchanged.


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COMMITTEE STATEMENT: The committee understands that therecommended action of the submitter was intended to only deletethe first sentence of 16.2.1.2. The committee understands that thisproposal modifies the Action on Proposal 79-105 (Log #26)[Clause 16].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: SAUNDERS: This action if accepted would revise the newparagraph 16.2.1.2 as follows:"Where work lights are required, they shall be provided with anON-OFF switch conveniently located on the equipment." Machinework lights shall not contain switches or receptacles where exposedto liquids or condensing mists unless identified for the purpose. Lamp holders shall not incorporate a switch or receptacle. Worklights in wet locations shall be provided with ground faultprotection."Recommendation: The paragraph should be revised to read asfollows:"Where work lights are required, they shall be provided with anOn-Off switch conveniently located on the equipment. Lampholders shall not incorporate a switch or receptacle. Machine worklights shall be identified for the use. Work lights in wet locationsshall be provided with ground fault protection."

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(Log #159)79- 111 - ([16.2.1.5]): RejectSUBMITTER: Paul Dobrowsky, Holley, NYRECOMMENDATION: Add the following text: (1) Fluorescent lamps shall only use electronic ballasts. (2) Other electric discharge lamps shall be supplied by morethan one circuit from different phases.SUBSTANTIATION: The existing text is interpreted many ways.Some say more than one fixture is necessary. Some say more thanone circuit, more than one lamp, or more than one ballast. Highfrequency ballasts do not cause the problem.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The solution presented are not thesole solutions to the problem. The committee is not convincedthat adaquate substantiation has been provided.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #28)79- 112 - (Clause 15 [Clause 13]): Accept in PrincipleSUBMITTER: Melvin K. Sanders , TECo., Inc.RECOMMENDATION: Revise NFPA 79-1997 Clause 18 "Motorand motor compartments" and issue as new Clause 15 "Electricmotors and associated equipment" as follows:

13.1 General requirements

13.1.1 General.

Conductors and cables shall be selected so as to be suitable for theoperating conditions (e.g. voltage, current, protection againstelectric shock, grouping of cables) and external influences (e.g.ambient temperature, presence of water or corrosive substances,mechanical stresses (including stresses during installation), firehazards) that can exist. Cables and conductors shall be identifiedfor their intended use.

13.1.2 Wire insulation.

Conductors shall be insulated.

Exception No. 1: Bus bars shall not be required to be insulated.

Exception No. 2: Bare conductors, such as capacitor or resistor leads andjumpers between terminals, shall be permitted where the method ofsecuring provides electrical clearance.

Exception No. 3: Equipment grounding conductors and bonding jumpersshall be permitted to be covered or bare.

13.1.3 Mineral-insulated, metal-sheathed cable, Type MI, shall bepermitted. Temperature range -- 85°C (185°F) Dry and WetLocations.

13.1.4 Conductors smaller than 18 AWG used to connect electronicprogrammable control I/O, and static control, shall be listed.

13.2 Conductors.

13.2.1 Conductor Material.

Conductors shall be copper.

Exception No. 1: Aluminum alloy busbars, located internal to theenclosure, shall be permitted where suitable for the application.

Exception No. 2: The metal frame of the machine shall be permitted to beused as an equipment grounding (protective bonding) conductor.

13.2.2. Stranded Conductors.

Conductors of sizes 22 through 4/0 AWG and sizes 250 through1000 kcmil shall be only of stranded soft-annealed copper. SeeTable 9 for conductor cross-sectional area, dc resistance, andstranding.

Exception No. 1: Conductors with stranding other than that specified inTable 9 shall be permitted on individual devices that are purchasedcompletely wired (e.g., motor starters).

Exception No. 2: Conductors subject to temperatures, voltages,environmental conditions, or flexing exceeding the ratings listed in thisclause shall have suitable characteristics.


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13.2.3 Constant Flexing.

Where constant flexing service is required, conductor strandingshall conform to Table 9.

13.2.4 Solid Conductors.

Solid conductors 24-30 AWG of soft-annealed copper shall bepermitted for use within control enclosures where not subject toflexing.

13.2.5 Printed wire assemblies.

Printed wire assemblies of flame-retardant material shall bepermitted in place of conductor assemblies provided they arewithin control enclosures and are mounted in such a way as tominimize flexing or stress.

13.2.6 Shielded conductors

Where shielding is used around conductors in single ormulticonductor cables, a foil shield shall be permitted for non-flexing applications. A continuous drain wire shall be provided forfoil shield types. A braided shield shall be used where subject tolongitudinal flexing. Torsional flexing applications (e.g. a robotarm) shall require shields designed specifically for their use. Theshields and drain wire shall be covered with an outer jacket that issuitable for the environment. In all cases the shield shall provide acontinuous conduction surface in the presence of bending andflexing.

13.2.7 Special cables and conductors .

13.2.7.1 Other listed conductors and listed cables shall bepermitted.

13.2.7.2 Special conductors such as RG-/U transmission cable shallbe permitted where necessary for the proper functioning of theequipment.

13.3 Insulation

13.3.1 The insulation and the finished wires and cables shall haveflame retardant properties, and temperature limits andcharacteristics as listed below:

-- MTW–Moisture-, Heat-, and Oil-Resistant Thermoplastic60°C (140°F) Wet Locations90°C (194°F) Dry Locations

-- THHN–Heat-Resistant Thermoplastic 90°C (194°F) DryLocations

-- THW–Moisture- and Heat-Resistant Thermoplastic 75°C (167°F)Dry and Wet Locations

-- THWN–Moisture- and Heat-Resistant Thermoplastic 75°C(167°F) Dry and Wet Locations

13.3.3 The average and the minimum thickness of the insulation inconstructions A and B shall be in accordance with Table 10.

13.3.4 Construction B shall have a nylon jacket applied directly overthe insulation. The jacket shall be snug on the insulation and shallbe at least as thick as indicated in Table 10.

NFPA 79: Table 9 – Single conductor characteristics

Minimum number of strands

Size(AWG/kcmil)

Cross-sectional area– nominal

(CM/mm2)

DC resistance at25oC

(ohms/1000 ft)Nonflexing

(ASTM class)Flexing

(ASTM class)

Constant flex(ASTM class/AWG

size)

22201816141210864321

1/02/03/04/0

250 kcmil3003504004505005506006507007508009001000

640/0.3241020/0.5191620/0.8232580/1.314110/2.086530/3.31

10380/5.26116510/8.36726240/13.3041740/21.1552620/26.6766360/33.6283690/42.41105600/53.49133100/67.43167800/85.01211600/107.2

- /127– /152- /177- /203- /228- /253- /279- /304- /329- /355- /380- /405- /456- /507

17.210.76.774.262.681.681.0600.66630.41920.26360.20910.16590.13150.10420.082670.066580.052000.044010.036670.031440.027510.024450.022000.020000.018340.016920.015720.014670.013750.012220.01101

7(')10(K)16(K)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(B)19(B)19(B)19(B)19(B)37(B)37(B)37(B)37(B)37(B)37(B)61(B)61(B)61(B)61(B)61(B)61(B)61(B)61(B)

7(')10(K)16(K)26(K)41(K)65(K)104(K)

(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)

19(M/34)26(M/34)41(M/34)65(M/34)41(K/30)65(K/30)104(K/30)

(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)

(B, C, K) ASTM Class designation B and C per ASTM B 8-81, Class designation K per ASTM B 174-1971 (R1980)(') A class designation has not been assigned to this conductor but is designated as size 22-7 in ASTM B286-1974 (R1979) and iscomposed of strands 10 mils in diameter (No. 30 AWG).(`) Nonflexing construction shall be permitted for flexing service* Per ASTM Class designation B 174-1971 (R1980) Table 3(^) Constant flexing cables are not constructed in these sizes


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Table 10 – Single conductor insulation

Thickness of Insulation (Mils*)[Average/Minimum(Jacket)]

Wire Size A B22 AWG 30/27 15/13(4)

20 30/27 15/13(4)18 30/27 15/13(4)16 30/27 15/13(4)14 30/27 15/13(4)12 30/27 15/13(4)10 30/27 20/18(4)8 45/40 0/27(5)6 60/54 30/27(5)

4-2 60/54 40/36(6)1-4/0 80/72 50/45(7)

250-500 MCM 95/86 60/54(8)550-1000 110/99 70/63(9)

(*) UL 1063 Table 1.1 NEC ConstructionA No outer coveringB Nylon Covering

13.4 Wire markings.

13.4.1 A durable legend printed on the outer surface of theinsulation of construction A, on the outer surface of the nylonjacket of construction B, on the outer surface of the insulationunder the jacket of construction B (only if clearly legible throughthe nylon), or on the outer surface of the jacket of amulticonductor cable shall be repeated at intervals of no morethan 24 in. (610 mm) throughout the length of the single-conductor or the multiconductor cable.

Exception: Sizes smaller than 16 AWG shall be permitted to be marked onthe reel or on the smallest unit of the shipping carton.

13.4.2 The legend shall include the manufacturer's name ortrademark, the wire type, voltage rating, and gauge or size.

13.4.3 Where the conductor size is 16 through 10 AWG and thestranding is intended for flexing service, the legend shall include"flexing" or "Class K."

13.4.4 Wire insulation shall be identified and adequate for thevoltage on that conductor.

13.5 Conductor Ampacity.

The continuous current carried by conductors shall not exceed thevalues given in Table 11. Sizing of conductors within controlenclosures in wiring harnesses or wiring channels shall be basedon the ampacity in cable or raceway.

NFPA 79 Table 11 – Conductor ampacity based oncopper conductors with 60°C and 75°C insulation in an

ambient temperature of 30°C

Conductorsize

(AWG)

Ampacity

60oC 75o C30 – 0.528 – 0.826 – 124 2 222 3 320 5 518 7 716 10 1014 15 1512 20 2010 30 308 40 506 55 654 70 853 85 1002 95 1151 110 1300 125 150

2/0 145 1753/0 165 2004/0 195 230250 215 255300 240 285350 260 310400 280 335500 320 380600 355 420700 385 460750 400 475800 410 490900 435 5201000 455 545

NOTE 1: Wire types listed in Section 13.1 shall bepermitted to be used at the ampacities listed in thistableNOTE 2: The sources for the ampacities in this tableare Tables 310-16 of the NEC.


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13.5.1 Motor circuit conductors supplying a single motor shall havean ampacity not less than 125 percent of the motor full-loadcurrent rating.

13.5.2 Combined load conductors shall have an ampacity not lessthan 125 percent of the full-load current rating of all resistanceheating loads plus 125 percent of the full-load current rating of thehighest rated motor plus the sum of the full-load current ratings ofall other connected motors and apparatus that may be in operationat the same time.

13.5.3 Where ampacity derating is required for ambienttemperature correction for other than 30o C or adjusted for morethan three current-carrying conductors in a raceway or cable, thefactor(s) shall be taken from Table 13-3b. (See Table 13-3bbelow)

13.5.4. The maximum size of a conductor selected from Table 11and connected to a motor controller shall not exceed the valuesgiven in Table 12.

Exception: Where other motor controllers are used, the maximumconductor size shall not exceed that specified by the manufacturer.

13.5.5 Conductor/terminal compatibility

The conductor(s) shall be compatible with the device terminal(s),and the conductor size(s) shall not exceed the rangerecommended by the device manufacturer.

13.6 Conductor sizing.

Conductors shall not be smaller than:

13.6.1 Power circuits No. 14

Exception 1: No. 16 shall be permitted where applied as follows:a) For non-motor power circuits of 8 amperes or less where

protected in accordance with Clause 7 and with Class CC fusesrated at not more than 10 amperes,or

b) For motor loads with a full load ampacity of 8 amperes or less,where protected with Class CC fuses at not more than 250% offull load ampacity, and Class 10 overload protection per UL508, or

c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected with Class CC fuses at not more than250% of full load ampacity, and Class 20 overload protectionper UL 508, and

d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in acabinet or enclosure.

Exception 2: No. 18 shall be permitted where applied as follows:0 For non-motor power circuits of 5.6 amperes or less where protected inaccordance with Clause 7 and with Class CC fuses rated at not more than7 amperes, or1 For motor loads with a full load ampacity of 5 amperes or less, whereprotected with class CC fuses at not more than 250% of full loadampacity, and Class 10 overload protection per UL 508, or2 For motor loads with a full load ampacity of 3.5 amperes or less, whereprotected with class CC fuses at not more than 250% of full loadampacity, and Class 20 overload protection per UL 508, and3 Where part of a jacketed multiconductor cable assembly or flexible cord,or as individual conductors in a cabinet or enclosure.

13.6.2 Lighting and control circuits on the machine and inraceways No. 16

Exception: In a jacketed, multiconductor cable assembly, No. 18 shall bepermitted.

13.6.3 Control circuits within control enclosures or operatorstations No. 18.

13.6.4 Electronic programmable control I/O, and static control.

a) Conductors in raceways 24 AWG.

Exception: In a jacketed, multiconductor cable assembly or cord , 30AWG or larger shall be permitted.

b) Conductors within control enclosures No. 26 AWG

Exception: For jumpers and special wiring applications (e.g.,solderless wrap or wire-clip type connections or shieldedconductors), conductors No. 30 AWG or larger shall bepermitted.

13.6.5 Shielded conductors Shielded conductors shall consist ofstranded, annealed copper of 25 AWG or larger for singleconductors used in subassemblies and 22 AWG or larger for allother uses.

13.7 Conductors and cables used for flexing applications.

13.7.1 General

13.7.1.1 Conductors and cables used for flexing applications shallbe selected from Table 9.

13.7.1.2 Cables which are subjected to severe duties shall be ofadequate construction to protect against:− abrasion due to mechanical handling and dragging across

rough surfaces;− kinking due to operation without guides;− stress resulting from guide rollers and forced guiding, being

wound and re-wound on cable drums.

NOTE 1 - Cables for such conditions are specified in relevantnational standards.

NFPA 79 Table 12 – Maximum conductor size for givenmotor controller size*Motor Controller Size Maximum Conductor Size

AWG or MCM00012345

1410840

000500

*See ANSI/NEMA ICS 2-[1983] table 2, 110-1

Table 13-3bCorrection Factors Adjustment Factors

Ambient Temp.(°C)

Factor60OC 75O C

Number of Current-Carrying Conductors

Exceeding Three

Percent of Values inTables as Adjusted for

Ambient Temperature, ifNecessary

21-25 1.08 1.05 4 through 6 8026-30 1.00 1.00 7 through 9 7031-35 .91 .94 10 through 20 5036-40 .82 .88 21 through 30 4541-45 .71 .82 31 through 40 4046-50 .58 .75 41 and above 3551-55 .41 .6756-60 --- .5861-70 --- 33


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NOTE 2 - The operational life of the cable will be reducedwhere unfavourable operating conditions such as high tensilestress, small radii, bending into another plane and/or wherefrequent duty cycles coincide.

13.7.2 Mechanical rating The cable handling system of the machine shall be so designed tokeep the tensile stress of the conductors as low as practicableduring machine operations. Where copper conductors are used,the tensile stress shall not exceed 15 N/mm 2 of the copper cross-sectional area.

NOTE 1 - Where the demands of the application exceed thetensile stress limit of 15 N/mm2 , cables with specialconstruction features should be used. The allowed maximaltensile strength should be agreed upon with the cablemanufacturer. The allowed maximum stress of conductors of flexible cableswith material other than copper should be agreed upon withthe cable manufacturer. NOTE 2 - The following conditions affect the tensile stress ofthe conductors:− acceleration forces;− speed of motion;− dead (hanging) weight of the cables;− method of guiding;− design of cable drum system.

13.7.3 Current-carrying capacity of cables wound on drums Cables to be wound on drums shall be selected with conductors ofa cross-sectional area such that, when fully wound on and carryingthe normal service load, the maximum allowable operatingtemperature is not exceeded.

NOTE 1 - Where cables of circular cross-sectional area areinstalled on drums, the maximum current-carrying capacity infree air should be derated in accordance with table 13-6. Foradditional information, also refer to clause 44 of IEC 60621-3.

Table 13-6 – Derating fdactors for cables wound on drums

Drum type Number of layers of cable Any number 1 2 3 4 Cylindricalventilated

- 0,85 0,65 0,45 0,35

Radialventilated

0,85 - - - -

Radial non-ventilated

0,75 - - - -

NOTE 1 - A radial type drum is one where spiral layers of cable areaccommodated between closely spaced flanges; if fitted with solidflanges, the drum is described as non-ventilated and if the flanges havesuitable apertures, as ventilated. NOTE 2 - A ventilated cylinder drum is one where the layers of cableare accommodated between widely spaced flanges and the drum andend flanges have suitable ventilating apertures. NOTE 3 - It is recommended that the use of derating factors bediscussed with the cable and the cable drum manufacturers. This canresult in other factors being used.

13.9 Cords. Multiconductor flexible cords shall be suitable for theintended use.

SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738. Historical Background. In March of 1998, the NFPA 79 committee prepared a statement ofwork. The major elements of the statement of work are: Harmonization - Purpose

As the users and the manufacturers of industrial machines move towarda global manufacturing community, the need for a harmonized standardaffecting industrial machinery becomes an economic necessity. Generally,large users and manufacturers find regulations burdensome. However,multiple regulations as well as conflicting regulations are an economicdisincentive to global expansion. In order to ease the burden of differingregulation, and at the same time maintain the high standard of electricalmachine safety, the NFPA 79 committee has expressed their desire,through balloted vote, to harmonize NFPA 79 with IEC-60204-1. Importance of Issue - Harmonization Today's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly betransported to the domestic market. The reverse is also true. Differingelectrical standards add a large cost to multinational manufacturers asthey build and sometimes move manufacturing facilities. Harmonization - Objective This work is necessary to accomplish the goal of allowing industry toeconomically build one industrial machine capable of passing a detailedelectrical safety inspection using either IEC 60204-1 or NFPA 79standard. Both the NEC Technical Correlating Committee and the StandardsCouncil reviewed the statement of work in July of 1998. The TCCunanimously recommended the following action to the StandardsCouncil: "The Technical Correlating Committee agrees with the efforts of the NFPA79 committee to harmonize the technical requirements of NFPA 79 andIEC 60204, where feasible and where in concert with the NEC and itsrelated codes and standards." Result The NFPA Standards Council considered and concurred with therecommendation. In June of 1999, the NFPA 79 Committee formed20 Task Groups. Each Task Group was assigned one proposed newclause. The Task Group compared NFPA-79-1997, Clause 15 in its entiretyand Clause 16.3.5 with IEC 60204-1 Clause 13. The Task Grouppresented its work to the entire committee on several occasions forreview and comment. This proposal is a result of that work. The Task Group proposes to renumber Clause 15 of NFPA 79-1997to correspond with IEC 60204-1. The task group proposes thefollowing changes to further improve usability. 13 Conductors and cables Recommendation: Replace NFPA 79-1997 title “15 Conductors”with “13 Conductors and cables” Substantiation: The proposed title more clearly states the subjectmatter within this clause. 13.1 General requirements 13.1.1 General Recommendation: Move NFPA 79-1997 15.1.1 2nd sentence to13.3.1. Substantiation: A general reference is appropriate since it isdifficult to comply with all national standards simultaneously whichdeal with the design, testing and application of conductors andcable, or with those assemblies that include conductors and cable. 13.1.2 Wire insulation. Recommendation: Insert title of NFPA 79-1997 15.4 here andrenumber and add text that conductors are expected to beinsulated. Add three exceptions. Exception No. 1 added to address busbars within switchgear. Move NFPA 79-1997 15.4.5 Exception here and renumber asException No. 2. Substantiation: Added text is to disallow the use of bare or coveredconductors as a general condition. Exception No. 1 acknowledges that busbars within switchgear arebare. Exception No. 2 allows common practices within switchgear. Exception No. 3 was added in order to recognize that groundingconductors do not have to be insulated. 13.1.3 Recommendation: Insert NFPA 79-1997 15.1.3 and renumbered as13.1.3. Substantiation: Match new numbering sequence. 13.1.4 Recommendation: Retain NFPA 79-1997 15.1.4 here and renumberas 13.1.4. Substantiation: Match new numbering sequence. 13.2 Conductors. Recommendation: Retain NFPA 79-1997 title and renumber as13.2.


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Substantiation: Match new numbering sequence. 13.2.1 Conductor Material. Recommendation: Add title and retained the copper onlyrequirement. Moved the wire size text to 13.2.2. Add new Exception No. 1 for aluminum busbars. Add new Exception No. 2 for machine frame grounding. Substantiation: Wire sizes given are for stranded conductors andassigned new clause for clarity. Aluminum busbars are now permitted. Recognizes that machine frames are not insulated or covered. 13.2.2 Stranded Conductors. Recommendation: Move the wire size portion of NFPA –1997 15.2.1here and moved editorially revise retained and edited its 2ndsentence as follows: “ See Table 9 for conductor cross-sectionalarea, dc resistance, and stranding is listed in Table 9 shown on thefollowing page .” Add NFPA 15.2.1 Exception No. 1 to proposed clause 13.2.2 andedited as follows: “Exception No. 1. Conductors with insulationcharacteristics consistent with the provisions of this clause but withstranding other than that specified in Table 9 shall be permitted onindividual devices that are purchased completely wired (e.g., motorstarters).” Move NFPA 79-1997 15.2.1 Exception No. 2 here and renumber. Insert Table 9 following this Exception No. 2. Substantiation: Provides a clause for stranded type conductors andassociated exceptions. Revised 2nd sentence and Exceptions forclarity, directs users of this standard to Table 9, and tableplacement is unknown until press time. 13.2.3 Constant Flexing. Recommendation: Move NFPA 79-1997 15.2.2 here and renumber. Substantiation: Match new numbering sequence. 13.2.5 Printed wire assemblies. Recommendation: Move NFPA 79-1997 15.2.4 here add title andrenumber. Substantiation: Match new numbering sequence. 13.2.6 Shielded conductors Recommendation: Move the 1st sentence of NFPA 79-1997 15.2.5 tonew 13.6.5. Replace the remainder of the original text with theproposed text. Revise the 4th sentence as follows: The shields anddrain wire shall be covered with an outer jacket that is suitable forthe environment. oil and moisture resistant jacket. Substantiation: The first sentence covering the minimum size ofshielded conductors was relocated to new 13.6.5. The proposedtext is more informative and, in addition, provides information thatthere are differences in shielding, and foil shielding may not bedurable enough for any flexing applications. A drain wire isprovided because a foil shield itself does not lend itself totermination and a standard braided shield is not durable enoughfor torsion flexing applications. The requirement for the jacket tobe “oil and moisture resistant” was replaced with the words:“..outer jacket that is suitable for the environment.” because theoriginal words were considered too restrictive. The new phrasingwill require that an evaluation be made but not dictate anyparticular solution. 13.2.7 Special cables and conductors . Recommendation: Added new title; obtained from NFPA 79-199713.2.6 text. Substantiation: Meet Style Manual guidelines. 13.2.7.1 Recommendation: Add proposed text “Other listed conductorsand listed cables shall be permitted.” Substantiation: This will permit use of special assemblies for usewith adjustable speed drives and similar equipment. 13.2.7.2 Recommendation: Move NFPA 79-1997 15.2.6 here and renumber. Substantiation: Match new numbering sequence. 13.3 Insulation Recommendation: Replace NFPA 79-1997 title with “13.3Insulation.” Substantiation: Title change is more descriptive of the text. 13.3.1 Recommendation: Move 2nd sentence of NFPA 79-1997 15.1.1here, revise and renumber.

Insert the last sentence of NFPA 79-1997 Section 15.1.1 2ndsentence and its following four bullets as a new second paragraphto proposed 13.3.1 and replace the words “be suitably” with “have”,add “properties,” after “flame retardant” and delete the word “have”after “and”. Substantiation: Match new numbering sequence, topic sequencingand edited for clarity. 13.3.3 Recommendation: Retain NFPA 79-1997 15.4.3 and re-number. Substantiation: Match new numbering sequence. 13.3.4 Recommendation: Retain NFPA 79-1997 15.4.4 and re-number. Retain NFPA 79-1997 Table 10 and insert immediately followingClause 13.3.4 and renumber as necessary. Substantiation: Match new numbering sequence and provideguidance for table placement. 13.4 Wire markings. Recommendation: Retain NFPA 79 1997 15.6 title here andrenumber. Substantiation: Match new numbering sequence. 13.4.1 Recommendation: Retain NFPA 79-1997 15.6.1 and its Exception,re-number and editorially change text “Number” to “AWG”. Change “18” to “16.” Substantiation: Match new numbering sequence, and to allowconductors in additional small sizes to use this method for sizemarking. 13.4.2 Recommendation: Retain NFPA 79-1997 15.6.2 and renumber. Substantiation: Match new numbering sequence. 13.4.3 Recommendation: Add NFPA 79-1997 15.6.3 and renumber. Substantiation: Match new numbering sequence. 13.4.4 Recommendation: Retain NFPA 79-1997 15.4.5 1st sentence hereand renumber. Delete 15.4.5 2nd sentence. Re-number Clause 15.4.5 Exception and move to Clause 13.1.2 asException No. 2. Substantiation: Match new numbering sequence, NFPA 79-199715.4.5 2nd sentence has been deleted because it is a wiring practicethat is already covered in 14.1.3 text, and move 13.1.2 ExceptionNo. 2 for topic correlation. 13.5 Conductor Ampacity. Recommendation: Retain NFPA 79-1997 15.5 and renumber as13.5. Insert the “obelisk” note of NFPA 79 Table 11 as a new secondsentence to comply with the Style Manual and revise as follows:“Sizing of conductors within control enclosures in wiring harnessesor wiring channels shall be based on the ampacity for in cables orraceway .” Substantiation: Match the numbering sequence, the “obelisk” noteof NFPA 79 Table 11 was inserted into 13.5 as new second sentenceto comply with the style manual that mandatory language can notbe placed in Notes. Table 11 Control Enclosure column has been deleted becausenearly all devices are now rated for connection to NFPA 70, Table310-16, 75 degree C, selected wire. Reference to Table 310-17 is nolonger necessary with the column deletion. 13.5.1 Recommendation: Retain NFPA 79-1997 15.5.2 and renumber. Substantiation: Match new numbering sequence. 13.5.2 Recommendation: Retain NFPA 79-1997 15.5.3 and renumber. Substantiation: Match new numbering sequence. 13.5.3 Recommendation: Add new text, incorporating Table 11 NOTE 2,and renumber proposed table 13.3b as necessary. Substantiation: Provides ambient temperature information andminimize the number of references that is needed. The temperature correction factors of the proposed table havebeen correlated with NFPA 70 Table 310-16.


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13.5.4. Recommendation: Retain NFPA 79-1997 and renumber. Substantiation: Match new numbering sequence. 13.5.5 Conductor/terminal compatibility Recommendation: add new text. Substantiation: Provides information on termination requirements.This new text will help ensure that components will be compatible. 13.6 Conductor sizing. Recommendation: Retain NFPA 79-1997 title and renumber. Retain NFPA 79-1997 15.3 1st sentence and make a completesentence: “Conductors shall not be smaller than those required forthe following conditions.” Substantiation: Match new numbering sequence, and completesentence direction. 13.6.1 Recommendation: Retain NFPA 79-1997 15.3 (a) here andrenumber. Provide new exceptions to address small motor circuitry. NFPA 79-1997 15.3 (b) and Exception renumbered to 13.6.2 andException. NFPA 79-1997 15.3 (c) renumbered to 13.6.3. NFPA 79-1997 15.3 (d) renumbered to 13.3.4. NFPA 79-1997 15.3 (d)(1) and Exception renumbered to 13.6.4 (a)and Exception. NFPA 79-1997 15.3 (d)(2) and Exception renumbered to 13.6.4 (b)and Exception. Substantiation: The present parts of NFPA 79-1997 15.3 were re-identified to match the numbering sequence. These proposed new exceptions permit the use of 16/18 AWGconductors, and factory assembled 16/18 AWG multi-conductorcables, in small motor branch circuit applications. This exceptionwill also allow a common, desirable, practice unutilized on smallhorsepower, multi-motor machinery. Wire sizes of 0.75 mm2 and 1 mm2 are commonly applied where theload currents are very small in applications based upon the IEC60204-1. Wire sizes of 0.75 mm2 and 1 mm2 have an ampacitysimilar to 18 AWG and 16 AWG wire respectively. Conservative based calculations were evaluated relative to shortcircuit and overload concerns. After considering many variables, itwas determined that a similar use of 18 AWG and 16 AWG wirewould constitute a reasonable approach and give applicationguidance to a present practices under the detailed requirements asproposed in 13.6.1 Exceptions 1 and 2. In order to limit exposure to physical damage the use of theseconductors would be limited to multiconductor cables, and toindividual conductors when used in a cabinet or enclosure. The following information is provided to detail the evaluationprocess.

16 AWG Data Time Area (CM) Isc (Amps) 1

.004 2580 2160 .008 2580 1527 .0167 2580 1057 0.1 2580 432 1 2580 137 5 2580 61 10 2580 43 20 2580 31 30 2580 25

1 Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL508 Test Points Class Current @ 600% 2

10 40 20 33

2 Value shown in table is based upon 6 X the limited currentspecified in the proposed 13.6.1

UL 248 Test Point @ 50KA Time (sec) Max Current Allowed

(Amps) .004 707 3

3 Current Level Extrapolated from UL I 2t limit by dividing outtime (.004)

18 AWG Data Time Area (CM) Isc (Amps) 4

.004 1620 1356 .008 1620 959 .0167 1620 664 0.1 1620 271 1 1620 86 5 1620 38 10 1620 27 20 1620 19 30 1620 16

4 Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL508 Test Points

Class Current @ 600% 5

10 30 20 21

5 Value shown in table is based upon 6 X the limited currentspecified in the proposed 13.6.1

UL 248 Test Point @ 50KA Time (sec) Max Current Allowed

(Amps) .004 707 6

6 Current Level Extrapolated from UL I 2t limit by dividing outtime (.004)

The Insulated Cable Engineers Association (ICEA) tables forinsulation damage was used to create the worst case condition forthe wire. The formula as developed by ICEA is based upon anadiabatic process where all the heat will be contained within thewire(conductor). This does not take into account the heat bleedoff into the terminations and components. As a result, a damagecurve was generated for thermoplastic insulation at 150 deg. C.This was the worst case of the three main types evaluated by ICEAwhich include: - thermoplastic (150 deg. C) - rubber, paper, varnished cloth (200 deg. C) - crosslinked polyethylene & ethylene propylene rubber (250 deg.C)

This damage curve then supplied the worst possible condition towhich the wire (conductor) would be subjected.

After laying the groundwork for wire damage, variousovercurrent protective devices were reviewed.

Current limiting devices were decided upon in order to cover thevariety of fault current conditions that could apply to a machine.Upon examination of Underwriters Laboratories (UL) “GeneralInformation for Electrical Equipment” (White Book), peak let-through currents of various current limiting branch circuit fuseswere considered. Selecting Class CC fuses and protecting 16 and18 AWG wire according to UL limits allowed a maximum let-through current to be determined.

Next, motor controller characteristics were explored. Basedupon the information provided in UL508, test points were plottedon the time current curve to evaluate the performance of theoverload device under long term heating conditions. (Note:Under these conditions there is a high probability the heat will bedissipated from the conductor into the terminals and associatedcomponents).

Guidelines were selected for proper fuse sizing and maximumfull load current rating of motors based upon the above data. Thecriteria for determining the maximum full load current rating was(1) the maximum current value the conductor could handle forthe set amount of time (10 sec for class 10, etc.), (2) add 10% for aconservative heat bleed off factor, and (3) divide by 6 per therequirements of UL 508. This then derived the FLC value.


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16 AWG

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000

Current (amps)

Tim

e (

sec)

Insulation Damage 16AWGClass 10

Class CC Fuse

Class 20

(The upper square above the 10 second line is Class 20, thesquare on the 10 second line is Class 10, and the lower square is aClass CC fuse.)

18 AWG

0.001

0.01

0.1

1

10

100

1 10 100 1000 10000

C urrent ( mps)

Tim

e (

se

c) Insulation Damage 18 AWG

Class 10

Class 20

Cl ss CC

(The upper square above the 10 second line is Class 20, thesquare in the 10 second line is Class 10, and the lower square is aClass CC fuse.)

13.6.2Recommendation: NFPA 79-1997 15.3 (b) and Exception movedhere and renumbered.Substantiation: Match new numbering sequence

13.6.3Recommendation: NFPA 79-1997 15.3 (c) moved here andrenumbered.Substantiation: Match new numbering sequence

13.6.4Recommendation: NFPA 79-1997 15.3 (d) moved here andrenumbered.

Substantiation: Match new numbering sequence

13.6.5 Shielded conductors.Recommendation: Relocate existing first sentence of NFPA 79-1997, 15.2.5 here. This provides a minimum wire size for use insubassemblies that is less than for other uses.

13.7 Conductors and cables used for flexing applications.Recommendation: Add topic title.Substantiation: Proposed new title added to provide appropriatelocation for these wiring methods.

13.7.1 GeneralRecommendation: Add topic title.

Substantiation: Proposed new title provides for general conditions.

13.7.1.1Recommendation: Relocate NFPA 79-1997 16.3.5 here andrenumber. Replace “Connections for frequently moving parts” with“Conductors and cables used for flexing applications.”Deleted NFPA 79-1997 16.5.3 2nd sentence and Exception and referit to 14.1.4. “Conduit” is to be deleted at that time.Substantiation: Match new numbering sequence, and text ismodified because it is conductors and cables that are covered hereand not the connections.The deleted text is referred to 14.1.4 because it is a wiring practiceand not a wiring method. “Conduit” is not germane to the subject.

13.7.1.2Recommendation: This proposed new 13.7.1.2 providesinformation for cable mechanical considerations.Substantiation: No comparable text in NFPA 79-1997.

13.7.2 Mechanical ratingRecommendation: Proposed 13.7.2 text provides additionalinformation for cabling handling systems. The “Note” providesadditional items for consideration.Substantiation: No comparable text in NFPA 79-1997.

13.7.3 Current-carrying capacity of cables wound on drumsRecommendation: Proposed new 13.7.3 and proposed new Table13.6 provide additional information for cable conductor ampacitieswhen wound on a reel.Proposed table is to immediately follow Clause 13.7.3.Substantiation: No comparable text in NFPA 79-1997, and providesguidance for table placement.

13.9 Cords.Recommendation: Move NFPA 79-1997 15.1.2 here and renumber.Substantiation: Flexible cords must be suitable for the intendeduse. The “shopping” list has been deleted because the list is overlyrestrictive for some applications and may not be adequate for otherapplications.Attachment C – Cross reference for clause number changesbetween NFPA 79-1997 Clause 15 and new Clause 13.

From NFPA 79 1997 Edition To NFPA 79 2002 Edition15 1315.1 13.115.1.1 1st sentence 13.1.115.1.1 2nd sentence & bullets 13.3.115.1.2 13.915.1.3 13.1.315.1.4 13.1.415.2 13.215.2.1 13.2.215.2.1 Ex 1 13.2.2 Ex 115.2.1 Ex 2 13.2.2 Ex 215.2.2 13.2.315.2.3 13.2.415.2.4 13.2.515.2.5 1st sentence 13.6.515.2.7 13.2.7; 13.2.7.215.3 13.615.3(a) 13.6.1

13.6.1 Ex 113.6.1 Ex 2

15.3(b) 13.6.215.3 (c) 13.6.315.3(d) 13.6.415.3(d)(1) 13.6.4.115.3(d)(1) Ex 13.6.4.1 Ex15.3(d)(2) 13.6.4.215.3(d)(2) Ex 13.6.4.2 Ex15.4 13.315.4.1 13.1.215.4.2 Refer to Clause 1415.4.3 13.3.315.4.6 13.3.4 1st sentence was

not acted upon at 1streview but accepted atthe 2nd review; 2ndsentence was rejected at1st review but accepted at2nd review


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15.4.5 1st sentence 13.4.415.4.5 2nd sentence Moved to 13.4 and

deleted from 13.4 at 2ndreview

15.5 13.515.5.1 13.515.5.2 13.5.115.5.3 13.5.215.5.4 13.5.415.5.4 Ex 13.5.4 Ex15.6 13.415.6.1 13.4.115.6.1 Ex 13.4.1 Ex15.6.2 13.4.215.6.3 13.4.316.3.5 1st sentence 13.7.116.3.5 2nd sentence & Ex Move to Clause 14.1.4Table 09 Table 09 to follow 13.2.2

Ex 2Table 10 Table 10 to follow 13.3.4Table 11 Table 11 Obelisk Note

moved to 13.5 new 2ndsentence

Table 12 Table 12 to follow 13.5.4Ex

From NFPA 79 2002 Edition To NFPA 79 1997 Edition13 1513.1 15.113.1.1 15.1.1 1st sentence13.1.2 15.4.113.1.2 Ex 1 New13.1.2 Ex 2 15.4.5 Ex13.1.2 Ex 3 New13.1.3 15.1.313.1.4 15.1.413.2 15.213.2.1 15.213.2.1 Ex 1 New13.2.1 Ex 2 New13.2.2 15.2.113.2.2 Ex 1 15.2.1 Ex 113.2.2 Ex 2 15.2.1 Ex 2Table 09 Table 0913.2.3 15.2.213.2.4 15.2.313.2.5 15.2.413.2.6 New13.2.7 15.2.713.2.7.1 New13.2.7.2 15.2.713.3 15.413.3.1 15.1.1 2nd sentence13.3.2 New13.3.3 15.4.313.3.4 15.4.5Table 10 Table 1013.4 15.6 (15.4.5 2nd sentence

deleted from here;covered in 14.1.3)

13.4.1 15.6.113.4.1 Ex 15.6.1 Ex13.4.2 15.6.213.4.3 15.6.313.4.4 15.4.5 1st sentence13.5 Table 11 Note as new

2nd sentenceTable 11 Table 1113.5.1 15.5.213.5.2 15.5.313.5.3 NewTable 13-3b New13.5.4 15.5.413.5.4 Ex 15.5.4 ExTable 12 Table 1213.5.5 New13.6 15.313.6.1 15.3(a)13.6.1 Ex 1 New13.6.1 Ex 2 New13.6.2 & Exception 15.6(b) & Exception

13.6.3 15.6(c)

13.6.4 15.3(d)13.6.4 (a) 15.3(d)(1)13.6.4 (a) Ex 15.3(d)(1) Ex13.6.4 (b) 15.3(d)(2)13.6.4 (b) Ex 15.3(d)(2) Ex13.6.5 15.2.5 1st sentence13.7 New13.7.1 New13.7.1.1 16.3.5 1st sentence13.7.1.2 New13.7.2 New13.7.3 NewTable 13-6 New13.9 15.1.2

COMMITTEE ACTION: Accept in Principle. Revise to read as follows:3. Definitions

Note: Chapter 3, “Definitions” contains only those definitionsessential to the proper application of this Standard. It is notintended to include commonly defined general terms or commonlydefined technical terms from related codes and standards. Ingeneral, only those terms that are used in two or more places aredefined. Other definitions are included in the article in which theyare used. Spelling and definitions of general words and termsfollow Webster’s Collegiate Dictionar y, 10th edition.

The terms in parenthesis, used throughout this standard are fromthe English version of IEC 60204-1, and are based on the OxfordEnglish dictionary.<<end note>>







3.4 adjustable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included.

3.5 ambient temperature: The temperature of the air or othermedium where the equipment is to be used. [IEV 826-01-04]

NOTE—Ambient air temperature as applied to an enclosure orhousing is the average temperature of the surrounding air thatcomes in contact with the enclosure or housing. Ambient airtemperature as applied to a component or device within theenclosure is the average temperature of the surrounding air thatcomes in contact with the component.

3.6 ampacity: The current, in amperes, that a conductor can carrycontinuously under the conditions of use, without exceeding thedesign limits for the temperature rating of the insulation, theconductor and the wire termination.

3.6 ampacity: The current, in amperes, that a conductor can carrycontinuously under the conditions of use without exceeding itstemperature rating. (NFPA 70)


NOTE: The National Fire Protection Association does not approve,inspect, or certify any installations, procedures, equipment, or


1624

materials nor does it approve or evaluate testing laboratories. Indetermining the acceptability of installations or procedures,equipment, or materials, the “authority having jurisdiction” maybase acceptance on compliance with NFPA or other appropriatestandards. In the absence of such standards, said authority mayrequire evidence of proper installation, procedure, or use. The“authority having jurisdiction” may also refer to the listings orlabeling practices of an organization that is concerned with productevaluations and is thus in a position to determine compliance withappropriate standards for the current production of listed items.

3.8 attachment plug (plug cap) (plug): A device that, by insertionin a receptacle, establishes a connection between the conductors ofthe attached flexible cord and the conductors connectedpermanently to the receptacle. [NFPA 70]

3.9 Authority Having Jurisdiction : The organization, office, orindividual responsible for approving equipment, an installation, ora procedure.

NOTE: The phrase “authority having jurisdiction” is used in NFPAdocuments in a broad manner because jurisdictions and approvalagencies vary, as do their responsibilities. Where public safety isprimary, the authority having jurisdiction may be a federal, state,local, or other regional department or individual such as a firechief; fire marshal; chief of a fire prevention bureau, labordepartment, or health department; building official; electricalinspector; or others having statutory authority. For insurancepurposes, an insurance inspection department, rating bureau, orother insurance company representative may be the authorityhaving jurisdiction. In many circumstances, the property owner orhis or her designated agent assumes the role of the authority havingjurisdiction; at government installations, the commanding officeror departmental official may be the authority having jurisdiction.


3.10 Barrier. A physical obstruction that is intended to preventcontact with equipment or live parts or to prevent unauthorizedaccess to a work area. [NFPA 70E-2000]



3.12 branch circuit: The circuit conductors between the finalovercurrent device protecting the circuit and the outlet(s). (NFPA70)


3.14 cable trunking system: A system of enclosures comprised of abase and a removable cover intended for the complete surroundingof insulated conductors, cables , and cords [IEV 826-06-04,modified]


3.15 circuit breaker: A device designed to open and close a circuitby nonautomatic means and to open the circuit automatically on apredetermined overcurrent without damage to itself when properlyapplied within its rating. [NFPA 70]


3.17 conduit, intermediate metal: A listed steel raceway of circularcross-section with integral or associated couplings, connectors, andfittings approved for the installation of electrical conductors andused with listed fittings to provide electrical continuity. [NFPA 70]

3.18 conduit, rigid metal: Rigid metal conduit is a listed metalraceway of circular cross section with integral or associatedcouplings, approved for the installation of electrical conductorsand used with listed fittings to provide electrical continuity. [NFPA70]

3.19 conduit, rigid nonmetallic: A type of conduit and fittings ofsuitable nonmetallic material that is resistant to moisture andchemical atmospheres, flame retardant, resistant to impact andcrushing, and resistant to distortion from heat or low temperaturesunder conditions likely to be encountered in service. [NFPA 70]

3.20 control circuit (of a machine): The circuit of a controlapparatus or system that carries the electric signals directing theperformance of the controller but does not carry the main powercurrent.

Note: Power circuit protection can be provided by control shunt- tripping.

3.21 control circuit transformer: A voltage transformer utilized tosupply a voltage suitable for the operation of control devices. [IEEE100]

3.22 control circuit voltage: The voltage utilized for the operationof control devices.

3.23 control device: A device connected into the control circuitand used for controlling the operation of the machine (e.g.position sensor, manual control switch, relay, magneticallyoperated valve). [IEC 60204–1]


3.25 controlgear: A general term covering switching devices andtheir combination with associated control, measuring, protective,and regulating equipment, also assemblies of such devices andequipment with associated interconnections, accessories,enclosures, and supporting structures, intended in principle for thecontrol of electrical energy- consuming equipment. [IEV 441-11-03]<Possible alternate term: control equipment: Operating elementssuch as relays, contactors, circuit breakers, switches, solenoids,brakes and similar types of components, intended to govern orperform a given function in the operation, including measuring,sensing, monitoring, protection, and regulation of machinery

3.26 controller: A device or group of devices that serves to govern,in some predetermined manner, the electric power delivered to theapparatus to which it is connected. [NFPA 70]

3.27 cord(flexible): Flexible cords are constructed as described in,and listed for use in accordance with Article 400 of the NationalElectrical Code (NFPA 70). All conductors are stranded copper.


3.29 digital: Operated by the use of discrete signals to representdata in the form of numbers or other characters. [IEC-60204-1]



3.32 dry location: A location not normally subject to dampness orwetness.

Note: A location classified as dry may be temporarily subject todampness or wetness, as in the case of a building underconstruction. [NFPA 70]

3.33 duct: An enclosed channel designed expressly for holding andprotecting electrical conductors, cables, and busbars.

NOTE: Conduits, cable trunking systems (see 3.10) and underfloorchannels are types of duct. See “raceway.”



1625





3.39 Emergency switching off: An emergency operation intended toswitch off the supply of electrical energy to all or a part of aninstallation where a risk of electric shock or another risk ofelectrical origin is involved.


3.41 enclosure: A surrounding case constructed to provide a degreeof protection against incidental contact with the enclosedequipment and to provide a degree of protection to the enclosedequipment against specified environmental conditions.





4 NOTES—1 After failure the item has a fault.2 "Failure" is an event, as distinguished from "fault", which is a

state.3 This concept as defined does not apply to items consisting of

software only. [IEV 191-04-01]

3.46 fault: The state of an item characterized by inability to performa required function, excluding the inability, during preventivemaintenance or other planned actions, or due to lack of externalresources.

NOTE: A fault is often the result of a failure of the item itself, butmay exist without prior failure[IEV 191-05-01]

3.47 feeder: All circuit conductors between the service equipmentor the source of a separately derived system and the final branch-circuit overcurrent device. (NFPA 70)


3.49 ground: A conducting connection, whether intentional oraccidental, between an electrical circuit or equipment and theearth, or to some conducting body that serves in place of the earth.[NFPA 70]







3.56 harm: Physical injury or damage to health.

3.57 hazard: A source of possible injury or damage to health.[ISO/TR 12100-1, 3.5, modified]

3.58 hazardous condition situation: A circumstance in which aperson is exposed to a hazard(s). the exposure can immediately orover a long period of time have the potential to result in harm.

3.59 identified (as applied to equipment): Recognizable as suitablefor the specific purpose, function, use, environment, application,etc., where described in a particular code requirement. (See"equipment.")


3.60 indirect contact: Contact of persons with exposed conductiveparts which have become live under fault conditions. [IEV 826-03-06]

3.61 industrial machine: A power-driven machine (or a group ofmachines working together in a coordinated manner), not portableby hand while working, that is used to process material by cutting,forming, pressure, electrical, thermal, or optical techniques,lamination, or a combination of these processes. It can includeassociated equipment used to transfer material or tooling(including fixtures), assemble/disassemble, inspect or test, orpackage. (The associated electrical equipment including the logiccontroller(s) and associated software or logic together with themachine actuators and sensors are considered as part of theindustrial machine.)


3.63 Input1 The terminals where current, voltage, power, or driving forcemay be applied to a circuit or device;2 The state or sequence of states occurring on a specific inputchannel;3 The device or collective set of devices used for bringing data intoanother device. [IEC 60204–1]

3.64 In sight from, within sight from, within sight: Where thisstandard specifies that one equipment shall be "in sight from,""within sight from," or "within sight," etc., of another equipment,one of the equipments specified is to be visible and not more than50 ft (15.24 m) distant from the other. (NFPA 70)

3.65 inrush current (solenoid): The inrush current of a solenoid isthe steady-state current taken from the line at rated voltage andfrequency with the plunger blocked in the rated maximum openposition.

3.66 inrush locked rotor current (motor): See “locked rotor motorcurrent.”

3.67 (electrically) instructed person: A person adequately advisedor supervised by an electrically skilled person to enable him or her


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to perceive risks and to avoid hazards which electricity can create.[IEV 826-09-02, modified]



3.70 interrupting rating : The highest current at rated voltage that adevice is intended to interrupt under standard test conditions.

NOTE—Equipment intended to interrupt current at other thanfault levels may have its interrupting rating implied in other ratings,such as horsepower or locked motor current.


3.72 Labeled: Equipment or materials to which has been attacheda label, symbol, or other identifying mark of an organization that isacceptable to the authority having jurisdiction and concerned withproduct evaluation, that maintains periodic inspection ofproduction of labeled equipment or materials, and by whoselabeling the manufacturer indicates compliance with appropriatestandards or performance in a specified manner. [NFPA 70]



3.73 live part (as applied to being energized during normal use): Aconductor or conductive part intended to be energized in normaluse, including a neutral conductor, but, by convention, not a PENconductor.

NOTE—This term does not necessarily imply a risk of electricshock. [IEV 826-03-01]

3.74 live parts: Energized conductive components. [NFPA 70- 2002] (as applied to exposure to an existing shock hazard): Electricconductors, busses, terminals, or components that are uninsulatedor exposed and a shock hazard exists.




3.78 neutral conductor (symbol N) : A conductor connected to theneutral point of a system and capable of contributing to thetransmission of electrical energy. [IEV 826-01-03]




channel;

3. The device or collective set of devices used for taking data out ofanother device.


3.82 overload: Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that,when it persists for a sufficient length of time, would cause damageor dangerous overheating. A fault, such as a short circuit or aground fault, is not an overload. (See "overcurrent.") [NFPA 70]

NOTE – Overload should not be used as a synonym forovercurrent.

3.83 Panel: An element of an electric controller consisting of aslab or plate on with various component parts of the controller aremounted or wired. [IEEE 100]





3.87 programmable electronic system (PES) : A system based onone or more central processing units (CPUs), connected tosensors or actuators, or both, for the purpose of control ormonitoring.

NOTE: The term “ programmable electronic system” PES includesall elements in the system extending from sensors to other inputdevices via data highways or other communication paths to theactuators or other output devices.



3.90 qualified person: At a minimum, a qualified person shall betrained and knowledgeable of the construction and operation ofequipment or a specific work method, and be trained to recognizeand avoid the electrical hazards that might be present with respectto that equipment or work method. Such persons shall also befamiliar with the proper use of special precautionary techniques,personal protective equipment, insulating and shielding materials,and insulated tools and test equipment. [NFPA 70E]See “(electrically) instructed person” and “(electrically) skilledperson.”

3.91 raceway: An enclosed channel of metal or nonmetallic materialsdesigned expressly for holding wires, cables, or busbars, with additionalfunctions as permitted in this standard. Raceways include, but are notlimited to, rigid metal conduit, rigid nonmetallic conduit, intermediatemetal conduit, liquidtight flexible conduit, flexible metallic tubing,flexible metal conduit, electrical nonmetallic tubing, electrical metallictubing, wireways, and busways.


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3.95 relative humidity: The ratio between the amount of watervapor in the gas at the time of measurement and the amount ofwater vapor that could be in the gas when condensation begins, ata given temperature. [IEEE 100]




3.99 safeguarding: Those safety measures consisting of the use ofspecific means called safeguards to protect persons from hazardsthat cannot reasonably be removed or are not sufficiently limited bydesign.


3.101 safety function [safety measure ]: A means that eliminates orreduces a hazard. [IEC 60204–1]




3.105 should: Indicates a recommendation or that which isadvised but not required.


3.107 socket: See “receptacle.”





3.111 supplementary overcurrent protective device: A device usedwhere protection is required for lighting fixtures, appliances, andother equipment or for internal circuits and components ofequipment. It shall not be used as a substitute for power circuitovercurrent devices in place of the power circuit protection.


3.113 tap conductor: A conductor that has overcurrent protectionahead of its point of supply, that exceeds the value permitted forsimilar conductors that are protected as described elsewhere in thisstandard.


3.115 tight (suffix): So constructed that the specified material isexcluded under specified conditions. (ANSI/IEEE Standard No.100)

3.116 uncontrolled stop: The stopping of machine motion byremoving power to the machine actuators, all brakes and/or othermechanical stopping devices being activated. [IEC 60204–1]

3.117 undervoltage protection: The effect of a device that operateson the reduction or failure of voltage, to cause and maintain theinterruption of power.

NOTE—The principal objective of this device is to preventautomatic restarting of the equipment. Standard undervoltage orlow-voltage protection devices are not designed to become effectiveat any specific degree of voltage reduction.

3.118 user: An entity who utilizes the machine and its associatedelectrical equipment.

3.119 variable speed drives: An electrical device or group ofelectrical devices that alters the drive motor output speed over arange in a controlled manner. This includes ac and dc voltagemodes and frequency mode controls. Belt, chain, or roller shiftingcontrollers are not included.


3.121 Voltage, Nominal. A nominal value assigned to a circuit orsystem for the purpose of conveniently designating its voltage class(e.g., 120/240 volts, 480Y/277 volts, 600 volts).The actual voltage at which a circuit operates can vary from thenominal within a range that permits satisfactory operation ofequipment.


3.122 wireway: A sheet-metal or flame retardant nonmetallictrough with hinged or removable covers for housing and protectingelectric wires and cable and in which conductors are laid in placeafter the wireway has been installed as a complete system. [NFPA70]COMMITTEE STATEMENT: 1) Add title inadvertanly omitted. 2) Editorially correct phrase "Conductors and cables" to read"Conductors, cables and flexible cords." since cords are alreadypermitted. 3) Complete the cord requirements by an ampacity from Table400.5(A) from the 2002 NEC in 13.9.1NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DEFELICE: The text currently contained in 13.1.4 might be moreappropriately located in a new 13.2.7.3.


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SANDERS: The ROP Editorial Review Task group reported at theROP meeting concerning the original substantiation provided andmade the following observations.

The following is provided in response to the Editorial ReviewCommittee Report ROP meeting March 12-16, 2001.

This was originally submitted with the Proposal subsequentlyidentified as log 27 with Jack C. Sanders incorrectly identified asthe author, and is revised to respond to the ER committeecomments.

13 Conductors and cablesRecommendation: Replace NFPA 79-1997 title “15 Conductors”with “13 Conductors and cables”. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.Substantiation: The proposed title more clearly states the subjectmatter within this clause.13.1 General requirements

13.1.1 GeneralRecommendation: Move NFPA 79-1997 section 15.1.1 2ndsentence to clause 13.3.1.Substantiation: Retained by NFPA 79 Technical Committee action.A general reference is appropriate since it is difficult to complywith all national standards simultaneously which deal with thedesign, testing and application of conductors and cable, or withthose assemblies that include conductors and cable.

13.1.2 Wire insulation.

Recommendation: Insert title of NFPA 79-1997 section 15.4 here,renumber as clause 13.1.2 and add text that conductors areexpected to be insulated. Add three exceptions.Clause 13.1.2 Exception No. 1 added to address busbars withinswitchgear.Move NFPA 79-1997 section 15.4.5 Exception here and renumber asclause 13.1.2 Exception No. 2.Substantiation: Retained by NFPA 79 Technical Committee action.Added text is to disallow the use of bare or covered conductors asa general condition.Exception No. 1 acknowledges that busbars within switchgear arebare.Exception No. 2 allows common practices within switchgear.

Exception No. 3 was added in order to recognize that groundingconductors do not have to be insulated.

13.1.3Recommendation: Insert NFPA 79-1997 section 15.1.3 here andrenumber as clause 13.1.3.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.1.4Recommendation: Retain NFPA 79-1997 section 15.1.4 here andrenumber as clause 13.1.4.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.2 Conductors.Recommendation: Retain NFPA 79-1997 section 13.2 title andrenumber as clause 13.2 title.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.2.1 Conductor Material.Recommendation: Add title to clause13.2.1 and retained thecopper only requirement here.Moved the wire size text to clause 13.2.2.Add new clause 13.2.1 Exception No. 1 for aluminum busbars.Add new clause 13.2.1 Exception No. 2 for machine framegrounding.Substantiation: Retained by NFPA 79 Technical Committee action.Wire sizes given are for stranded conductors and assigned newclause number for clarity.Aluminum busbars are now permitted.Recognizes that machine frames are not insulated or covered.

13.2.2. Stranded Conductors.Recommendation: Move the wire size portion of NFPA –1997section 15.2.1 here, identify as clause 13.2.2 and editorially reviseand edit its 2nd sentence as follows: “ See Table 9 for conductorcross-sectional area, dc resistance, and stranding is listed in Table9 shown on the following page.”

[13.1] 13 15 Add Titleof Clause

“Conductors andcables”

AIP Missing from text.

<Response: Omitted by staff fromoriginally submitted material.>

[13.2] 13 15 <entireclause>

Text that has beenbrought over from IEC60204-1 must besubstantiated where itappears as a newrequirement in NFPA79.

AIP <Response: The proposed new text is partof the package of material submitted bythe NFPA WG subcommittee derived fromSAE HS-1738 review of IEC 60204-1. Notext was “brought over” directly from IEC60204-1.>

[13.3] 13.5 Delete the secondsentence

AIP Necessary to correlate with previous actionto delete 4 th column of the NFPA 79-1997,Table 11.

<Response: Do not delete this secondsentence. The adjustments andcorrections are necessary withinenclosures to control heating andtemperature rise where power and lightingconductors are in wiring channels orbundled. Control conductors are alsosubject to derating when the current flowthrough a conductor exceeds 10 percent ofthe conductor ampacity as determined inTable 11. (See NFPA 70-1999 Section 725-28(b))>

[13.4] 13.7.1.1

Delete the secondsentence of theRecommendation.

<Response: Second sentence should readas follows: “ NFPA 79-1997 16.3.5, secondsentence and exception have been movedto clause 14.4.3.1.” This provides a trail tofollow.>

[13.4] 13.7.1.1

Delete the secondsentence of thesubstantiation.

ACC This second sentence is inaccurateinformation and not required.


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Add NFPA section 15.2.1 Exception No. 1 to proposed clause13.2.2 and edited as follows: “Exception No. 1. Conductors withinsulation characteristics consistent with the provisions of thisclause but with stranding other than that specified in Table 9 shallbe permitted on individual devices that are purchased completelywired (e.g., motor starters).”Move NFPA 79-1997 section 15.2.1 Exception No. 2 here andrenumber as clause 13.2.2.Insert Table 9 immediately following clause 13.2.2 Exception No. 2.Substantiation: Retained by NFPA 79 Technical Committee action.Provides a clause for stranded type conductors and associatedexceptions. Revised 2nd sentence and Exceptions for clarity,directs users of this standard to Table 9. Exact table location isunknown until final editing.

13.2.3 Constant Flexing.Recommendation: Move NFPA 79-1997 section 15.2.2 here andrenumber as clause 13.2.3.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.2.5 Printed wire assemblies.Recommendation: Move NFPA 79-1997 section 15.2.4 here, addtitle and renumber as clause 13.2.5.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.2.6 Shielded conductorsRecommendation: Move the 1st sentence of NFPA 79-1997 section15.2.5 to new clause 13.6.5. Replace the remainder of the originaltext with the proposed text. Revise the 4th sentence as follows:The shields and drain wire shall be covered with an outer jacketthat is suitable for the environment. oil and moisture resistantjacket.Substantiation: Retained by NFPA 79 Technical Committee action.The first sentence covering the minimum size of shieldedconductors was relocated to new clause 13.6.5. The proposed textis more informative and, in addition, provides information thatthere are differences in shielding, and foil shielding may not bedurable enough for any flexing applications. A drain wire isprovided because a foil shield itself does not lend itself totermination and a standard braided shield is not durable enoughfor torsion flexing applications. The requirement for the jacket tobe “oil and moisture resistant” was replaced with the words:“..outer jacket that is suitable for the environment.” because theoriginal words were considered too restrictive. The new phrasingwill require that an evaluation be made but not dictate anyparticular solution.

13.2.7 Special cables and conductors.Recommendation: Added new title to identify clause 13.2.7;obtained from NFPA 79-1997 section 13.2.6 text.Substantiation: Retained by NFPA 79 Technical Committee action.Meet Style Manual guidelines.

13.2.7.1Recommendation: Add proposed text “Other listed conductorsand listed cables shall be permitted.” to clause `13.2.7.Substantiation: Retained by NFPA 79 Technical Committee action.This will permit use of special assemblies for use with adjustablespeed drives and similar equipment.

13.2.7.2Recommendation: Move NFPA 79-1997 section 15.2.6 here andrenumber as clause 13.2.7.2.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.3.1Recommendation: Move 2nd sentence of NFPA 79-1997 section15.1.1 here, revise and renumber as clause 13.2.1.Insert the last sentence of NFPA 79-1997 Section 15.1.1 2ndsentence and its following four bullets as a new second paragraphto proposed clause 13.3.1 and replace the words “be suitably” with“have”, add “properties,” after “flame retardant” and delete theword “have” after “and”.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence, topic sequencing and edited forclarity.

13.3.3Recommendation: Retain NFPA 79-1997 section 15.4.3 and re-number as clause 13.3.3.

Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.3.4Recommendation: Retain NFPA 79-1997 section 15.4.4 and re-number as clause 13.3.4.Retain NFPA 79-1997 Table 10 and insert immediately followingclause 13.3.4 and renumber as necessary.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence and provide guidance for tableplacement.

13.4 Wire markings.

Recommendation: Retain NFPA 79 1997 section 15.6 title here andrenumber as clause 13.4.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.4.1Recommendation: Retain NFPA 79-1997 section 15.6.1 and itsException here, re-number as clause 13.4.1 and editorially changetext “Number” to “AWG”.Change “18” to “16.”Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence, and to allow conductors inadditional small sizes to use this method for size marking.

13.4.2Recommendation: Retain NFPA 79-1997 section 15.6.2 andrenumber as clause 13.4.2.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.4.3Recommendation: Add NFPA 79-1997 section 15.6.3 andrenumber as clause 13.4.3.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.

13.4.4Recommendation: Retain NFPA 79-1997 section 15.4.5 1stsentence here and renumber as clause 13.4.4.Delete NFPA 79-1997 section 15.4.5 2nd sentence.Re-number section 15.4.5 Exception and move to clause 13.1.2 asException No. 2.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence, NFPA 79-1997 section 15.4.5 2ndsentence has been deleted because it is a wiring practice that isalready covered in proposed clause 14.1.3 text, and move to clause13.1.2 Exception No. 2 for topic correlation.

13.5 Conductor Ampacity.Recommendation: Retain NFPA 79-1997 section 15.5 andrenumber as clause 13.5.Insert the “obelisk” note of NFPA 79 Table 11 as a new secondsentence of clause 13.5 to comply with the Style Manual and reviseas follows: “Sizing of conductors within control enclosures inwiring harnesses or wiring channels shall be based on the ampacityfor in cables or raceway .”Existing Table 11 from the NFPA 79-1997 following this proposedclause 13.5 with modification and revise it by deleting the “ControlEnclosure” column and changing the middle column title asfollows: Ampacity in Cable or Raceway.”Delete NOTE 2 and renumber “NOTE 3” as “NOTE 2” and delete“...and 310-17...”Substantiation: Retained by NFPA 79 Technical Committee action.Match the numbering sequence, the “obelisk” note of NFPA 79Table 11 was inserted into clause 13.5 as new second sentence tocomply with the style manual that mandatory language can not beplaced in Notes.Revised the new 2nd sentence to add clarity and to emphasize it isthe ampacity of conductors being determined when within a cableor raceway, and it is not the cable or raceway that has theampacity.Table 11 Control Enclosure column has been deleted becausenearly all devices are now rated for connection to NFPA 70, Table310-16, 75 degree C, selected wire. Reference to Table 310-17 is nolonger necessary with the column deletion.Table 11 Note 2 information is covered by proposed new clause13.5.3.

13.5.1


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Recommendation: Retain NFPA 79-1997 section 15.5.2 andrenumber as clause 13.5.1.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence.


13.5.3Recommendation: Add new text, incorporating Table 11 NOTE 2,and renumber proposed table 13.3b as necessary.Substantiation: Retained by NFPA 79 Technical Committee action.Provides ambient temperature information and minimize thenumber of references that are needed.The temperature correction factors of the proposed table havebeen correlated with NFPA 70 Table 310-16.


13.5.5 Conductor/terminal compatibilityRecommendation: Add new text as clause 13.5.5.Substantiation: Provides information on terminationrequirements. This new text will help ensure that components willbe compatible.

13.6 Conductor sizing.Recommendation: Retain NFPA 79-1997 section 15.3 title andrenumber as clause 13.6.Retain NFPA 79-1997 section 15.3 1st sentence and make acomplete sentence: “Conductors shall not be smaller than thoserequired for the following conditions.”Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence, and complete sentence direction.

13.6.1Recommendation: Retain NFPA 79-1997 section 15.3 (a) here andrenumber as clause 13.6.1.Provide new exceptions to address small motor circuitry.NFPA 79-1997 section 15.3 (b) and Exception renumbered toclause 13.6.2 and Exception.NFPA 79-1997 section 15.3 (c) renumbered to clause 13.6.3.NFPA 79-1997 section 15.3 (d) renumbered to clause 13.3.4.NFPA 79-1997 section 15.3 (d)(1) and Exception renumbered toclause 13.6.4 (a) and Exception.NFPA 79-1997 section 15.3 (d)(2) and Exception renumbered toclause 13.6.4 (b) and Exception.Substantiation: Retained by NFPA 79 Technical Committee action.The present parts of NFPA 79-1997 section 15.3 were re-identifiedas clause 13.6.1, etc., to match the numbering sequence. Theseproposed new exceptions permit the use of 16/18 AWGconductors, and factory assembled 16/18 AWG multi-conductorcables, in small motor branch circuit applications. This exceptionwill also allow a common, desirable, practice unutilized on smallhorsepower, multi-motor machinery.Wire sizes of 0.75 mm2 and 1 mm2 are commonly applied where theload currents are very small in applications based upon the IEC60204-1.Wire sizes of 0.75 mm2 and 1 mm2 have an ampacity similar to 18AWG and 16 AWG wire respectively.Conservative based calculations were evaluated relative to shortcircuit and overload concerns. After considering many variables, itwas determined that a similar use of 18 AWG and 16 AWG wirewould constitute a reasonable approach and give applicationguidance to a present practices under the detailed requirements asproposed in 13.6.1 Exceptions 1 and 2.In order to limit exposure to physical damage the use of theseconductors would be limited to multiconductor cables, and toindividual conductors when used in a cabinet or enclosure.The following information is provided to detail the evaluationprocess.

16 AWG DataTime Area (CM) Isc (Amps) 1

.004 2580 2160

.008 2580 1527

.0167 2580 10570.1 2580 4321 2580 1375 2580 6110 2580 4320 2580 3130 2580 251 Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL508 Test PointsClass Current @ 600% 2

10 4020 332 Value shown in table is based upon 6 X the limitedcurrent specified in the proposed 13.6.1

UL 248 Test Point @ 50KATime (sec) Max Current Allowed (Amps).004 707 33 Current Level Extrapolated from UL I 2t limit bydividing out time (.004)

18 AWG Data

Time Area (CM) Isc (Amps) 4

.004 1620 1356

.008 1620 959

.0167 1620 6640.1 1620 2711 1620 865 1620 3810 1620 2720 1620 1930 1620 164 Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL508 Test PointsClass Current @ 600% 5

10 3020 215 Value shown in table is based upon 6 X the limitedcurrent specified in the proposed 13.6.1

UL 248 Test Point @ 50KATime (sec) Max Current Allowed (Amps).004 707 66 Current Level Extrapolated from UL I 2t limit bydividing out time (.004)

The Insulated Cable Engineers Association (ICEA) tables forinsulation damage was used to create the worst case condition forthe wire. The formula as developed by ICEA is based upon anadiabatic process where all the heat will be contained within thewire(conductor). This does not take into account the heat bleedoff into the terminations and components. As a result, a damagecurve was generated for thermoplastic insulation at 150 deg. C.This was the worst case of the three main types evaluated by ICEAwhich include:

- thermoplastic (150 deg. C) - rubber, paper, varnished cloth (200 deg. C) - crosslinked polyethylene & ethylene propylene rubber (250 deg.C)


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This damage curve then supplied the worst possible condition towhich the wire (conductor) would be subjected.

After laying the groundwork for wire damage, variousovercurrent protective devices were reviewed.

Current limiting devices were decided upon in order to cover thevariety of fault current conditions that could apply to a machine.Upon examination of Underwriters Laboratories (UL) “GeneralInformation for Electrical Equipment” (White Book), peak let-through currents of various current limiting branch circuit fuseswere considered. Selecting Class CC fuses and protecting 16 and18 AWG wire according to UL limits allowed a maximum let-through current to be determined.

Next, motor controller characteristics were explored. Basedupon the information provided in UL508, test points were plottedon the time current curve to evaluate the performance of theoverload device under long term heating conditions. (Note:Under these conditions there is a high probability the heat will bedissipated from the conductor into the terminals and associatedcomponents).

Guidelines were selected for proper fuse sizing and maximumfull load current rating of motors based upon the above data. Thecriteria for determining the maximum full load current rating was(1) the maximum current value the conductor could handle forthe set amount of time (10 sec for class 10, etc.), (2) add 10% for aconservative heat bleed off factor, and (3) divide by 6 per therequirements of UL 508. This then derived the FLC value.

Existing Figure16 AWG

Existing Figure18 AWG

13.6.2Recommendation: NFPA 79-1997 section 15.3 (b) and Exceptionmoved here and renumbered as clause 13.6.2.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence

13.6.3Recommendation: NFPA 79-1997 section 15.3 (c) moved here andrenumbered as clause 13.6.3.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence

13.6.4Recommendation: NFPA 79-1997 section 15.3 (d) moved here andrenumbered as clause 13.6.4.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence

13.6.5 Shielded conductors.Recommendation: Relocate existing first sentence of NFPA 79-1997section 15.2.5 here and renumber as clause 13.6.5.Substantiation: Retained by NFPA 79 Technical Committee action.This provides a minimum wire size for use in subassemblies that isless than for other uses.

13.7 Conductors and cables used for flexing applications.Recommendation: Add topic clause 13.7 title.Substantiation: Retained by NFPA 79 Technical Committee action.Proposed new title added to provide appropriate location for thesewiring methods.

13.7.1 GeneralRecommendation: Add topic clause 13.7.1 title.Substantiation: Retained by NFPA 79 Technical Committee action.Proposed new title provides for general conditions.

13.7.1.1Recommendation: Relocate NFPA 79-1997 section 16.3.5 here andrenumber as clause 13.7.1. Replace “Connections for frequentlymoving parts” with “Conductors and cables used for flexingapplications.”Deleted NFPA 79-1997 section 16.5.3 2nd sentence and Exceptionand refer it to clause 14.1.4. “Conduit” is to be deleted at that time.Substantiation: Retained by NFPA 79 Technical Committee action.Match new numbering sequence, and text is modified because it isconductors and cables that are covered here and not theconnections.

The deleted text is referred to clause 14.1.4 because it is a wiringpractice and not a wiring method. “Conduit” is not germane to thesubject.13.7.1.2Recommendation: This proposed new clause 13.7.1.2 providesinformation for cable mechanical considerations. This proposal ispart of the package of material submitted by the NFPA WGsubcommittee derived from SAE HS-1738 review of IEC 60204-1.Substantiation: Provides information for which there is nocomparable text in NFPA 79-1997.

13.7.2 Mechanical ratingRecommendation: Proposed clause 13.7.2 text provides additionalinformation for cabling handling systems. The “Note” providesadditional items for consideration. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.Substantiation: Provides information for which there is nocomparable text in NFPA 79-1997.

13.7.3 Current-carrying capacity of cables wound on drumsRecommendation: Proposed new clause 13.7.3 and proposed newTable 13.6 provide additional information for cable conductorampacities when wound on a reel. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.Proposed table is to immediately follow clause 13.7.3.Substantiation: Provides information for which there is nocomparable text in NFPA 79-1997, and provides guidance for tableplacement.

13.9 Cords.Recommendation: Move NFPA 79-1997 section 15.1.2 here andrenumber as clause 13.9.Substantiation: Retained by NFPA 79 Technical Committee action.Flexible cords must be suitable for the intended use. The“shopping” list has been deleted because the list is overly restrictivefor some applications and may not be adequate for otherapplications.

Proposal Number: 79-112Log Number: 28Type: Affirmative CommentThe original recommendation dated 3-26-01 should have read:“Revise NFPA 79-1997 “Clause 15 Conductors” and issue as new“Clause 13 Conductors and cables”. The committee shouldcontinue to accept the resultant Technical Committee action tofurther change the title to “13 Conductors, Cable, and FlexibleCords”, as shown on page 1 of 1 8 and identified as “NFPA 79 /Log #28 / Committee Action / A2002 ROP / Page 1 of 1 (sic)”.

Proposal Number: 79-112Log Number: 28Type: Affirmative CommentThe following text is provided to consolidate the ROP actionstaken and to provide a working draft for ease of review. Theunderlined items are explained immediately following the draft13.9.1.2.

13 Conductors, Cables, and Flexible Cords13.1 General requirements13.1.1 General.Conductors , and cables and flexible cords shall be selected so as tobe suitable for the operating conditions (e.g. voltage, current,protection against electric shock, grouping of cables) and externalinfluences (e.g. ambient temperature, presence of water orcorrosive substances, mechanical stresses (including stressesduring installation), fire hazards) that can exist. Conductors, Cc ables, and conductors flexible cords shall be identified for theirintended use.13.1.2 Wire insulation.Conductors shall be insulated.Exception No. 1: Bus bars shall not be required to be insulated.Exception No. 2: Bare conductors, such as capacitor or resistor leads andjumpers between terminals, shall be permitted where the method ofsecuring provides electrical clearance.Exception No. 3: Equipment grounding conductors and bonding jumpersshall be permitted to be covered or bare.13.1.3 Mineral-insulated, metal-sheathed cable, Type MI, shall bepermitted. Temperature range -- 85°C (185°F) Dry and WetLocations.13.1.4 Conductors smaller than 18 AWG used to connect electronicprogrammable control I/O, and static control, shall be listed.


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13.2 Conductors.13.2.1 Conductor Material.Conductors shall be copper.Exception No. 1: Aluminum alloy busbars, located internal to theenclosure, shall be permitted where suitable for the application.Exception No. 2: The metal frame of the machine shall be permitted to beused as an equipment grounding (protective bonding) conductor.13.2.2. Stranded Conductors.Conductors of sizes 22 through 4/0 AWG and sizes 250 through1000 kcmil shall be only of stranded soft-annealed copper. SeeTable 9 for conductor cross-sectional area, dc resistance, andstranding.Exception No. 1: Conductors with stranding other than that specified inTable 9 shall be permitted on individual devices that are purchasedcompletely wired (e.g., motor starters).Exception No. 2: Conductors subject to temperatures, voltages,environmental conditions, or flexing exceeding the ratings listed in thisclause shall have suitable characteristics.

NFPA 79: Table 9 – Single conductor characteristics

Minimum number of strands

Size(AWG/kcmil)

Cross-sectionalarea – nominal

(CM/mm2)

DC resistance at25oC

(ohms/1000 ft)Nonflexing

(ASTM class)Flexing

(ASTM class)

Constant flex(ASTM

class/AWGsize)

22201816141210864321

1/02/03/04/0

250 kcmil3003504004505005506006507007508009001000

640/0.3241020/0.5191620/0.8232580/1.314110/2.086530/3.31

10380/5.26116510/8.36726240/13.3041740/21.1552620/26.6766360/33.6283690/42.41105600/53.49133100/67.43167800/85.01211600/107.2

- /127– /152- /177- /203- /228- /253- /279- /304- /329- /355- /380- /405- /456- /507

17.210.76.774.262.681.681.0600.66630.41920.26360.20910.16590.13150.10420.082670.066580.052000.044010.036670.031440.027510.024450.022000.020000.018340.016920.015720.014670.013750.012220.01101

7(')10(K)16(K)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(C)19(B)19(B)19(B)19(B)19(B)37(B)37(B)37(B)37(B)37(B)37(B)61(B)61(B)61(B)61(B)61(B)61(B)61(B)61(B)

7(')10(K)16(K)26(K)41(K)65(K)104(K)

(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)(`)

19(M/34)26(M/34)41(M/34)65(M/34)41(K/30)65(K/30)104(K/30)

(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)(^)

(B, C, K) ASTM Class designation B and C per ASTM B 8-81, Class designation K per ASTM B 174-1971(R1980)(') A class designation has not been assigned to this conductor but is designated as size 22-7 in ASTM B286-1974 (R1979) and is composed of strands 10 mils in diameter (No. 30 AWG).(`) Nonflexing construction shall be permitted for flexing service* Per ASTM Class designation B 174-1971 (R1980) Table 3(^) Constant flexing cables are not constructed in these sizes


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13.2.3 Constant Flexing.Where constant flexing service is required, conductor strandingshall conform to Table 9.13.2.4 Solid Conductors.Solid conductors 24-30 AWG of soft-annealed copper shall bepermitted for use within control enclosures where not subject toflexing.13.2.5 Printed wire assemblies.Printed wire assemblies of flame-retardant material shall bepermitted in place of conductor assemblies provided they arewithin control enclosures and are mounted in such a way as tominimize flexing or stress.13.2.6 Shielded conductorsWhere shielding is used around conductors in single ormulticonductor cables, a foil shield shall be permitted for non-flexing applications. A continuous drain wire shall be provided forfoil shield types. A braided shield shall be used where subject tolongitudinal flexing. Torsional flexing applications (e.g. a robotarm) shall require shields designed specifically for their use. Theshields and drain wire shall be covered with an outer jacket that issuitable for the environment. In all cases the shield shall provide acontinuous conduction surface in the presence of bending andflexing.13.2.7 Special cables and conductors .13.2.7.1 Other listed conductors and listed cables shall bepermitted.13.2.7.2 Special conductors such as RG-/U transmission cable shallbe permitted where necessary for the proper functioning of theequipment.13.3 Insulation13.3.1 The insulation and the finished wires and cables shall haveflame retardant properties, and temperature limits andcharacteristics as listed below:-- MTW–Moisture-, Heat-, and Oil-Resistant Thermoplastic

60°C (140°F) Wet Locations90°C (194°F) Dry Locations

-- THHN–Heat-Resistant Thermoplastic 90°C (194°F) DryLocations

-- THW–Moisture- and Heat-Resistant Thermoplastic 75°C (167°F)Dry and Wet Locations

-- THWN–Moisture- and Heat-Resistant Thermoplastic 75°C(167°F) Dry and Wet Locations

13.3.3 The average and the minimum thickness of the insulation inconstructions A and B shall be in accordance with Table 10.13.3.4 Construction B shall have a nylon jacket applied directly overthe insulation. The jacket shall be snug on the insulation and shallbe at least as thick as indicated in Table 10.

Table 10 – Single conductor insulation

Thickness of Insulation (Mils*)[Average/Minimum(Jacket)]

Wire Size A B22 AWG 30/27 15/13(4)

20 30/27 15/13(4)18 30/27 15/13(4)16 30/27 15/13(4)14 30/27 15/13(4)12 30/27 15/13(4)10 30/27 20/18(4)8 45/40 0/27(5)6 60/54 30/27(5)

4-2 60/54 40/36(6)1-4/0 80/72 50/45(7)

250-500 MCM 95/86 60/54(8)550-1000 110/99 70/63(9)

(*) UL 1063 Table 1.1 NEC ConstructionA No outer coveringB Nylon Covering

13.4 Wire markings.13.4.1 A durable legend printed on the outer surface of theinsulation of construction A, on the outer surface of the nylonjacket of construction B, on the outer surface of the insulationunder the jacket of construction B (only if clearly legible throughthe nylon), or on the outer surface of the jacket of amulticonductor cable shall be repeated at intervals of no morethan 24 in. (610 mm) throughout the length of the single-conductor or the multiconductor cable.Exception: Sizes smaller than 16 AWG shall be permitted to be marked onthe reel or on the smallest unit of the shipping carton.

13.4.2 The legend shall include the manufacturer's name ortrademark, the wire type, voltage rating, and gauge or size.13.4.3 Where the conductor size is 16 through 10 AWG and thestranding is intended for flexing service, the legend shall include"flexing" or "Class K."13.4.4 Wire insulation shall be identified and adequate for thevoltage on that conductor.13.5 Conductor Ampacity.The continuous current carried by conductors shall not exceed thevalues given in Table 11. Sizing of conductors within controlenclosures in wiring harnesses or wiring channels shall be basedon the ampacity in cable or raceway.

NFPA 79 Table 11 – Conductor ampacity based oncopper conductors with 60°C and 75°C insulation in

an ambient temperature of 30°C

Conductorsize

(AWG)

Ampacity

60oC 75oC30 – 0.528 – 0.826 – 124 2 222 3 320 5 518 7 716 10 1014 15 1512 20 2010 30 308 40 506 55 654 70 853 85 1002 95 1151 110 1300 125 150

2/0 145 1753/0 165 2004/0 195 230250 215 255300 240 285350 260 310400 280 335500 320 380600 355 420700 385 460750 400 475800 410 490900 435 5201000 455 545

NOTE 1: Wire types listed in Section 13.1 shall bepermitted to be used at the ampacities listed in thistableNOTE 2: The sources for the ampacities in thistable are Tables 310-16 of the NEC.

13.5.1 Motor circuit conductors supplying a single motor shall havean ampacity not less than 125 percent of the motor full-loadcurrent rating.

13.5.2 Combined load conductors shall have an ampacity not lessthan 125 percent of the full-load current rating of all resistanceheating loads plus 125 percent of the full-load current rating of thehighest rated motor plus the sum of the full-load current ratings ofall other connected motors and apparatus that may be in operationat the same time.13.5.3 Where ampacity derating is required for ambienttemperature correction for other than 30o C or adjusted for morethan three current-carrying conductors in a raceway or cable, thefactor(s) shall be taken from Table 13-3b. Sizing of conductorswithin control enclosures in wiring harnesses or wiring channelsshall be based on the ampacity in cable or raceway.


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13.5.4. The maximum size of a conductor selected from Table 11and connected to a motor controller shall not exceed the valuesgiven in Table 12.Exception: Where other motor controllers are used, the maximumconductor size shall not exceed that specified by the manufacturer.

NFPA 79 Table 12 – Maximum conductor size forgiven motor controller size*Motor Controller Size Maximum Conductor

Size AWG or MCM00012345

1410840

000500

*See ANSI/NEMA ICS 2-[1983] table 2, 110-1

13.5.5 Conductor/terminal compatibilityThe conductor(s) shall be compatible with the device terminal(s),and the conductor size(s) shall not exceed the rangerecommended by the device manufacturer.13.6 Conductor sizing. Conductors shall not be smaller than:13.6.1 Power circuits No. 14Exception 1: No. 16 shall be permitted where applied as follows:

a) For non-motor power circuits of 8 amperes or less whereprotected in accordance with Clause 7 and with branch circuitrated circuit breakers listed for use with No. 16 wire or ClassCC , J, or T fuses rated at not more than 10 amperes,or

b) For motor loads with a full load ampacity of 8 amperes or less,where protected in accordance Clause 7 with branch circuitrated circuit breakers listed for use with No. 16 wire or ClassCC , J, or T fuses at not more than 250% of full load ampacity,and Class 10 overload protection per UL 508, or

c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected in accordance with Clause 7 with branchcircuit rated circuit breakers listed for use with No. 16 wire or Class CC , or J, or T fuses at not more than 250% of full loadampacity, and Class 20 overload protection per UL 508, and

d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in acabinet or enclosure.

Exception 2: No. 18 shall be permitted where applied as follows:a) For non-motor power circuits of 5.6 amperes or less where

protected in accordance with Clause 7 and with branch circuitrated circuit breakers listed for use with No. 18 wire or ClassCC , J, or T fuses rated at not more than 7 amperes, or

b) For motor loads with a full load ampacity of 5 amperes or less,where protected in accordance with Clause 7 with branchcircuit rated circuit breakers listed for use with No. 18 wire orclass CC , J, or T fuses at not more than 250% of full loadampacity, and Class 10 overload protection per UL 508, or

c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected in accordance with Clause 7 with branchcircuit rated circuit breakers listed for use with No. 18 wire orclass CC , J, or T fuses at not more than 250% of full loadampacity, and Class 20 overload protection per UL 508, and

d) Where part of a multiconductor cable assembly or flexible cord,or as individual conductors in a cabinet or enclosure.

13.6.2 Lighting and control circuits on the machine and inraceways No. 16Exception: In a jacketed, multiconductor cable assembly, No. 18 shall bepermitted.13.6.3 Control circuits within control enclosures or operatorstations No. 18.13.6.4 Electronic programmable control I/O, and static control.a) Conductors in raceways 24 AWG.Exception: In a jacketed, multiconductor cable assembly or cord , 30AWG or larger shall be permitted.b) Conductors within control enclosures No. 26 AWG

Exception: For jumpers and special wiringapplications (e.g., solderless wrap or wire-clip type connections orshielded conductors), conductors No. 30 AWG or larger shall bepermitted.13.6.5 Shielded conductors Shielded conductors shall consist ofstranded, annealed copper of 25 AWG or larger for singleconductors used in subassemblies and 22 AWG or larger for allother uses.13.7 Conductors and cables used for flexing applications.13.7.1 General13.7.1.1 Conductors and cables used for flexing applications shallbe selected from Table 9.13.7.1.2 Cables which are subjected to severe duties shall be ofadequate construction to protect against: - abrasion due to mechanical handling and dragging acrossrough surfaces; - kinking due to operation without guides; - stress resulting from guide rollers and forced guiding, beingwound and re-wound on cable drums.

NOTE 1 - Cables for such conditions are specified in relevantnational standards. NOTE 2 - The operational life of the cable will be reducedwhere unfavourable operating conditions such as high tensilestress, small radii, bending into another plane and/or wherefrequent duty cycles coincide.

13.7.2 Mechanical rating The cable handling system of the machine shall be so designed tokeep the tensile stress of the conductors as low as practicableduring machine operations. Where copper conductors are used,the tensile stress shall not exceed 15 N/mm 2 of the copper cross-sectional area.

NOTE 1 - Where the demands of the application exceed thetensile stress limit of 15 N/mm2 , cables with specialconstruction features should be used. The allowed maximaltensile strength should be agreed upon with the cablemanufacturer. The allowed maximum stress of conductors of flexible cableswith material other than copper should be agreed upon withthe cable manufacturer. NOTE 2 - The following conditions affect the tensile stress ofthe conductors:− acceleration forces;− speed of motion;− dead (hanging) weight of the cables;− method of guiding;− design of cable drum system.

Table 13-3b

Table 13-3(b)(1) Correction Factors Table 13-3(b)(2) Adjustment FactorsAmbient Temp.

(°C)Factor

60OC 75 OCNumber of Current-Carrying Conductors

Exceeding Three

Percent of Values in Tables asAdjusted for Ambient

Temperature, if Necessary21-25 1.08 1.05 4 through 6 8026-30 1.00 1.00 7 through 9 7031-35 .91 .94 10 through 20 5036-40 .82 .88 21 through 30 4541-45 .71 .82 31 through 40 4046-50 .58 .75 41 and above 3551-55 .41 .6756-60 --- .5861-70 --- 33


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13.7.3 Current-carrying capacity of cables wound on drumsCables to be wound on drums shall be selected with conductors ofa cross-sectional area such that, when fully wound on and carryingthe normal service load, the maximum allowable operatingtemperature is not exceeded.NOTE 1 - Where cables of circular cross-sectional area areinstalled on drums, the maximum current-carrying capacity in freeair should be derated in accordance with table 13-6. For additionalinformation, also refer to clause 44 of IEC 60621-3.

Table 13-6Derating factors for cables wound on drums

Drumtype

Number of layers of cable

Anynumber

1 2 3 4

Cylindricalventilated

- 0,85

0,65

0,45

0,35

Radialventilated

0,85 - - - -

Radialnon-ventilated

0,75 - - - -

NOTE 1 - A radial type drum is one where spiral layers ofcable are accommodated between closely spaced flanges;if fitted with solid flanges, the drum is described as non-ventilated and if the flanges have suitable apertures, asventilated.

NOTE 2 - A ventilated cylinder drum is one where thelayers of cable are accommodated between widely spacedflanges and the drum and end flanges have suitableventilating apertures.

NOTE 3 - It is recommended that the use of deratingfactors be discussed with the cable and the cable drummanufacturers. This can result in other factors beingused.

13.9 Flexible Cords. Multiconductor flexible cords shall besuitable for the intended use.13.9.1 Ampacity of Flexible Cords. The continuous current byflexible cords shall not exceed the values given in Table XX.Existing NFPA 70-2002, Table 400-5(A) along with notesNote: The following items are not part of clause 13 and are only toclarify the actions taken at the ROP meeting in order to correct themutilation of the original submitted document for ROP review.This will provide the committee with a working draft and isintended to incorporate all ROP actions except for the Staffinsertion of ROP mandated NFPA 70-2002 Table 400-5(A), whichis to immediately follow proposed 13.9.1.1. Add the clause title “Conductors and cables”omitted from the originally submitted text. NFPA 79 TechnicalCommittee accepted the proposed title and further modified it asfollows: “13 Conductors , and C c ables , and Flexible Cords” ,because clause 13 covers flexible cords as well as conductors andcables.2. Change 13.1.1 last sentence from originally textsubmitted: “Cables and conductors shall be identified for theirintended use” to ROP accepted “ Conductors, C c ables, andconductors flexible cords shall be identified for their intendeduse.”

This will parallel the word sequence of the title.3. The relocation of the second sentence of 13.5 “Sizing ofconductors within control enclosures in wiring harnesses or wiringchannels shall be based on the ampacity in cable or raceway.” to13.5.3 follows the action of ROP 79-120 Log 90.4. Table 13-3(b) was split in two and re-identified as “Table13-3(b)(1) Adjustment” and “Table 13-3(b)(2) Correction” undera single heading to reflect the committee’s action on ROP 79-121Log 91 and meet the intent of the submitter.5. The change to 13.6.1 Exception Nos. 1 and 2incorporates committee actions on ROP 79-116 Log 162, ROP 79-118 Log 120, and ROP 79-50 Log 32.

6. Add the following text: “13.9.1 Ampacity of FlexibleCords. The continuous current by flexible cords shall not exceedthe values given in Table XX.”

Existing NFPA 70-2002, Table 400-5(A) along with notesThis reflects the committee’s action at the ROP meeting

in the clause title change and the text change in 13.1.1. Thecommittee elected to include flexible cord ampacities here toenhance usability, and Staff has agreed to assign an appropriatetable number.

Proposal Number: 79-112Log Number: 28Type: Affirmative CommentIn Note 2 of 13.7.1.2 change “unfavourable” to “unfavorable” forediting purposes only as found on the page identified as page 7 of 78 “NFPA 79 / Log #28 / Committee Action / A2002 ROP / Page 7of 7 (sic)”.

Proposal Number: 79-112Log Number: 28Type: Affirmative CommentRenumber 13.9 and change “by” to “for” so it will read as follows: “13.9 Flexible Cords.13.9.1 Multiconductor flexible cords shall be suitable for theintended use.13.9.1 2 Ampacity of Flexible Cords. The continuous current byfor flexible cords shall not exceed the values given in Table XX.Renumber per MOS, and text change is to clarify it is the currentrating for flexible cords being added.

___________________

(Log #8b)79- 113 - (Clause 15 [13.2]): RejectSUBMITTER: Endel Mell, Husky Injection Molding Systems Ltd.RECOMMENDATION: Add some wording to outline what are thepermitted types of conductors.SUBSTANTIATION: Permissible cords are given, andrequirements for certain types of conductors are given. There is noindication of what types of conductors are permitted/required.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposal does not comply withthe Regulations Governing Committee projects, Section 4.3.3(c)since the submitter has not provided the specific recommendedtext.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARSIDE: The current standard is indeed vague. For example,it states,"15.1.2 Multiconductor flexible cords, Type SO, STO,STOW or SJO, SJOW, SJTO shall be permitted." It does not giveany guidance as to whether they can be used for any connectionwithin a machine, or only for certain connections. Many machinesare therefore incorrectly (IMHO) built using SO-type flexiblecords for functions where MTW cable should be used, forexample, in place of the fixed wiring of the machine.

___________________

(Log #145)79- 114 - ([13.2.1 Exception No. 2]): RejectSUBMITTER: Melvin K. Sanders , TECo., Inc.RECOMMENDATION: Delete the proposed Exception No. 2 to13.2.1 in its entirety. The original propose text is as follows: 13.2.1 Conductor Material. Conductors shall be copper. Exception No. 1: Aluminum alloy busbars, located internal to theenclosure, shall be permitted where suitable for the application. Exception No 2: The metal frame of the machine shall bepermitted to be used as an equipment grounding (protectivebonding) conductor.SUBSTANTIATION: The proposed Exception No. 2 violates theparent document NFPA 70 1999 Edition of Section 250-118 for thetypes of permitted equipment grounding conductors. They arelimited to the following: copper or other corrosion resistantconductor, rigid or IMC or EMT raceway, flexible metal conduitwhere both the conduit and fittings are listed, and certain types ofnon-listed flexible metal conduit, listed liquidtight flexible metalconduit meeting certain criteria, flexible metal tubing with fittingsthat meet certain criteria, Type AC armored cable, copper sheath


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of MI cable, some MC types, certain cable trays, cablebusframework or other electrically continuous metal raceway listed forgrounding. In addition, it violates the parent document NFPA 70 1999 Editionof Section 300-3(b) that requires that all conductors of the samecircuit and, where used, the grounded conductor and allequipment grounding conductors to be contained within the sameraceway, auxiliary gutter, cable tray, trench, cable, or cord, unlesspermitted in accordance with 4 conditions (paralleled, shortflexible wiring methods, nonferrous wiring methods and column-type panelboards).COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The committee disagrees with thesubmitters substantiation. Machine frames have been successfullyused for this purpose with no reported problems.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARVEY: The submitter’s substantiation is correct. The metalconduits permitted as equipment grounding conductors aregenerally galvanized. In addition, the NEC requires raceways usedas equipment grounding conductors to be installed as a completesystem prior to pulling a single wire. All connections must bemade up tight. Additional rules assure continuity when the systemoperates at over 250-volts to ground. And the NEC rules nevercontemplate that the equipment-grounding conductor may betaken apart, shipped out on a rail car and reassembled in anotherplant. SANDERS: Delete the second sentence of 13.2.1: 13.2.1 Conductor Material. Conductors shall be copper. Exception No. 1: Aluminum alloy busbars, located internal to theenclosure, shall be permitted where suitable for the application. Exception No. 2: The metal frame of the machine shall bepermitted to be used as an equipment grounding (protectivebonding) conductor. I submit the following: The committee response that there are no reported problemsignores the fact that these tend to contribute to other problems andmay not be seen as a separate item. They may be masked by havingno physical symptom until failure and then take years to match theproblem with the solution; the solution arrived at only by applyingelectrical theory which may task the capabilities of the harriedelectrical personnel charged with maintaining production. There are many reasons why this practice should be discontinued.Among them are: 1. If this is retained, it would be possible to connect a permittedsupplemental equipment grounding electrode to any part/portionof the machine structural member as long as the termination metthe objective of 8.2.7. If the main purpose of the supplementalelectrode is to provide a reference for electronic control activity, itsusefulness would be compromised if not negated. 2. The stated objective of this revision is to move closer to otherinternational documents (i.e. IEC 60204-1) and this Exceptionwould not advance that concept. The uncontrolled use of machinestructural members where personnel safety and electronic controlsmay be compromised is simply unconscionable. A copy of IEC60204-1 (1997 Edition) clause 8 Figure 3 is provided at the end ofthis discussion for the committee’s review once more. Note thatthe possible termination points are to electrical terminals and notthe machine structural members. 3. The use of machine members as an equipment groundingconductor is no longer suitable for the modern machine age.Machines are using ASD control and replacing mechanical speedchanging mechanisms where none were contemplated just a fewmonths ago, such as single motor drill presses, conveyors, blowers,heaters and the like. These must have a reliable groundingreference and a defined path controlled by the designer foroptimum result. 4. The proposal would permit the use of metals of dubiouselectrical conductivity not contemplated by the NEC. Machineparts are too prone to corrosions, non-conductive painted surfacesand paint bonding agents, and loose fittings for them to provide areliable grounding path and be used as an equipment groundingconductor from any point on the machine to any other point onthe machine. This Standard should not be considered complete ifit addresses grounding and bonding concerns that are effective at 3kHz or less but is compromised at higher frequencies. 5. Machines operating solely with 60 Hz equipment may very wellfunction with grounding and bonding following the parent NFPA70 but with machine rebuilds to extend machine life employing the

latest techniques, they as well as new equipment "out of the box"become susceptible to radiated frequencies and energies. 6. Using a machine frame as part of the equipment groundingpath eliminates the first line of defense in maintaining powerquality. The use of machine members to provide protectionagainst touch hazard potentials at 60 Hz for personnel safety is onlypart of the answer. Employing recommended equipment bondingand equipment grounding procedures will also provide protectionagainst machine malfunctioning and as well as providing forpersonnel safety. 7. Many organizations are devoting much time and effort to alertindustrial users to some of the problems and solutions. Amongthem the Institute of Electrical and Electronic Engineers (IEEE)Standard 1100-1999 (aka Emerald Book) is greatly concerned aboutgrounding as it relates to power, safety and performance ofelectronic equipment in the commercial and industrialenvironment. Chapter 4 Fundamentals, Section 4.2 Impedance considerationsstates four fundamental parts: power source; distribution; loadimpedances; grounding/bonding system’s impedances (e.g.,power/safety and performance parts). Section 4.2.1 indicates thepower safety range is from DC to 10’s of fundamental frequencyharmonics, typically to the 50th harmonic (3 kHZ for 60 Hz) andthe NEC mandated safety features work well in this range. However, Section 4.2.1.2 Performance range (defined as betweenten’s of kHz and tens of MHz) other features become important aswell such as conducted, coupled, and radiated electromagneticenergy that can have significant impact on the performance of mostelectronic equipment. The area of concern is where theconductive path is approximately 1/20th of the frequencywavelength under consideration. Normal circuit theory, that workswell at NEC contemplated frequencies, no longer applies unlessaugmented by special design techniques, Wave and transmission line theory (once the domain of radio-frequency applications) must be applied when addressing theperformance needs of electronic equipment as they respond tothese extremely short wavelengths and their harmonics. Previously benign paths may be the source or at least part of theproblem instead of being part of the solution. Those who believethey are immune because their equipment operate with pulsecounters, etc., appearing to operate at lower frequencies are notimmune, because embedded in each pulse is the higher frequencyof the electronic controller that generates the pulsed signal in thefirst place. Local distribution systems in buildings and the like are mostlyresistive and inductive at 60 Hz to 3 kHz (h = 50) and mostlyinductive and capacitive at higher frequencies, especially above 1MHz. At the higher frequencies, circuit wave theory predominatesover power circuit theory and impedance mismatches can occur ateach end, at midpoint or some other point between. This willproduce reflections and re-reflections of transient currents (orvoltages) on the circuit path. For purposes of safety, effective grounding and bonding consist ofconductors interconnected and terminated that, taken together,form a usefully low impedance path for all frequencies of interestand provide for current flow through them. Depending uponmachine mating surfaces to meet all the conditions for power,safety and performance demanded by the modern industrialenvironment is simply unsound. It must be stressed that the low and high frequency characteristicsof most grounding related bonding techniques are quite different.Six major concerns are: (1) contact resistance (at terminationand mating parts surfaces, aging effects); (2) dissimilar materials(galvanic half-cells, corrosion failure, EMI generation); (3) skineffect (shallow penetrations into conductive materials, highfrequency effect on bonding paths); (4) bond reactance (size,shape, introduce reactance, avoid self-inductance); (5) conductorresistance (DC and frequency effect on voltage drops across parts);and (6) overheating and fusing parts (with respect to NECampacity limits on I2R fusing of conductors or terminations). The shallow penetration of conductive paths due to frequencydriven skin effects (approximately 8.5 mm (5/16-in.)at 60 Hz andreducing to 0.066 mm (0.0026 in.) at 1 MHz) and the resultantreduced cross-sectional-area (CSA) of the effectivegrounding/bonding path more closely couples the return currentpath to the source path, and sets up reflection and re-reflectionwaves between assumed conductive points. In addition, normalmachine operations, causing vibration, oscillation and incidentalmachine movement, makes connections that are tight when firstinstalled to become loose and will compromise the bestgrounding/bonding path. (NFPA 70 1981 and earlier editionsused to take note of the frequency effect and provided 60 Hzmultipliers in Chapter 9, Table 9.)


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Using machine parts for any possible kind of circuit path that hasunknown and unsuspecting impact on machine operations,ranging from machine in-operation to machine malfunction, eitherposing a threat to personnel safety should not be tolerated.

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(Log #132)79- 115 - (15.3 [13.6.1]): RejectSUBMITTER: Craig J. Fabbo , Speedline Technologies, Inc.RECOMMENDATION: Revise text to read as follows: 3. Proposal - Add the underscored text to the text proposed by theCommittee under N13 PRF03.DOC (proposal date 11/20/00,posted to NFPA 79 Web Board 11/14/00 Clause 13.6.1. Thereference Clause is a renumbering with revisions and additionaltext of Clause 15.3 of NFPA 79. 1997 edition. 13.6.1 Power circuits No. 14 Exception 1: No. 16 shall be permitted where applied as follows: a) For non-motor power circuits of 8 amperes or less whereprotected in accordance with Clause 7 and with Class CC fusesrated at not more than 10 amperes, or b) For motor loads with a full load ampacity of 8 amperes orless, where protected with Class CC fuses at not more than 250% offull load ampacity, and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 5.5. amperes orless, where protected with Class CC fuses at not more than 250% offull load ampacity, and Class 20 overload protection per UL 508,and d) Where part of a jacketed multiconductor cable assembly offlexible cord, or as individual conductors when used in a cabinetor enclosure. e) For stepper-motor loads, servo-motor loads, impedance- protected motor loads and thermally-protected motor loads of 8amperes or less, where part of a jacketed multiconductor cableassembly or flexible cord, or as individual conductors when usedin a cabinet or enclosure, and f) Where protected in accordance with Clause 7 with Class CCfuses rated at not more than 10 amperes. Exception 2: No. 18 shall be permitted where applied as follows: a) For non-motor power circuits of 5.6 amperes or less whereprotected in accordance with Clause 7 and with Class CC fusesrated at not more than 7 amperes, or b) For motor loads with a full load ampacity of 5 amperes orless, where protected with Class CC fuses at not more than 250% offull load ampacity, and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected with Class CC fuses at not more than 250%of full load ampacity, and Class 20 overload protection pr UL 508,and d) Where part of a jacketed multiconductor cable assembly offlexible cord, or as individual conductors when used in a cabinetor enclosure. e) For stepper-motor loads, servo-motor loads, impedance- protected motor loads and thermally-protected motor loads of 5amperes or less, where part of a jacketed multiconductor cableassembly or flexible cord, or as individual conductors when usedin a cabinet or enclosure, and f) Where protected in accordance with Clause 7 with Class CCfuses rated at not more than 7 amperes. SUBSTANTIATION: 4.1 - Automation equipment commonlyutilizes small-frame motors that provide current and thermallimitation under overload or locked rotor conditions without theneed for external overload protection. Such motor circuits include: a) Stepper-motor circuits, which draw constant current regardlessof speed, load or overload conditions. b) Servo-motor circuits, which shut down in response to overloadconditions. c) Impedance-protected motor circuits, which limit fault currentunder overload conditions. d) Thermally protected motor circuits, which shut down inresponse to overload conditions. 4.2 - The text proposed under N13 PRF03.DOC (proposal date11/20/00, posted to NFPA 79 Web Board 11/14/00) Clause 13.6.1,Exceptions 1 and 2, does not take into account the inherentoverload protection provided by the above types of motors andmotor/drive systems. The addition of external overload protectionwould not provide additional protection from electrical shock andfire.

4.3 - The application of overload devices between a servo orstepper motor driver and its motor is not recommended by motordrive manufacturers. Transients created by interruption of currentbetween a stepper or servo motor drive and its motor when underload will commonly result in the destruction of the drive. 4.4 - Machinery used in the Surface Mount Technology (SMT) /Printed Circuit Assembly (PCA). Industry machinery commonlyutilizes ten to twenty-five small stepper or servo motors, each withfour power conductors. It would often be impossible toaccommodate the number of overload protection devices called forby the proposed text of N13 PRF03.DOC within the envelope of anSMT / PCA machine. 4.5 - The proposed additional exceptions allow for use of 16 or 18gauge wire for the specified motor circuits when such wires areprotected by Class CC fuses in accordance with Table11.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Subclause 13.6.1 deals spoecificallywith wire size. The submitters recommended text argues thenecessity of overcurrent protection is addressed by clause 7. Thesubmitters intended use is addressed by Proposal 79-112 (Log #28),specifically 13.6.1, Exceptions No. 1 and No. 2.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #162)79- 116 - (15.3(a) [13.6.1]): Accept in PrincipleSUBMITTER: Todd Lottmann, Washington, MORECOMMENDATION: Reword the exceptions to read as follows: 1997 Edition Subclause 15.3(a) and proposed 2002 Editionsubclause 13.6.1 Exception 1: No. 16 shall be permitted where applied as follows: a) For non-motor power circuits of 8 amperes or less whereprotected in accordance with Clause 7 and with Class CC , J, or T fuses rated at not more than 10 amperes or b) For motor loads with a full load ampacity of 8 amperes orless, where protected in accordance with Clause 7 with Class CC , J,or T fuses at not more than 250 percent of full load ampacity andClass 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected in accordance with Clause 7 with Class CC , J,or T fuses at not more than 250 percent of full load ampacity andClass 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure. Exception 2: No. 18 shall be permitted where applied as follows: a) For non-motor power circuits of 5.6 amperes or less whereprotected in accordance with Clause 7 and with Class CC , J, or T fuses rated at not more than 7 amperes or b) For motor loads with a full load ampacity of 5 amperes orless, where protected in accordance with Clause 7 with Class CC , J,or T fuses at not more than 250 percent of full load ampacity andClass 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected in accordance with Clause 7 with Class CC , J,or T fuses at not more than 250 percent of full load ampacity andClass 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure.SUBSTANTIATION: Further research was put into this areabased upon the ground work already put forth to add Exception 1and 2 using engineering analysis, and UL witnessed testing tosupport the analysis. The purpose of this research was to broadenthe list of allowable types of overcurrent protection to be used toprotect 16 and 18 gauge wire.

UL Class of Fuse CurrentRating

Between Threshold and50 KA

At 100 KA At 200 KA

Ip (A) I2t (A2 s) Ip (A) I2t (A2 s) Ip (A) I2t (A2 s)

Class CC 30 6,000 7,000 7,500 7,000 12,000 7,000Class J 30 6,000 7,000 7,500 7,000 12,000 7,000Class T (600V) 30 6,000 7,000 7,500 7,000 12,000 7,000


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Further research of the UL standard for low voltage fuses, UL248,uncovered that fuses other than just Class CC have establishedU.L.I2t let through values that prove they could be used to protect16 and 18 gauge wire. Since UL has umbrella limits for let throughcurrents on fuses a comparison could be made to the other classesof fuses. The following table shows the limits set forth in UL248:

The values shown in this table are the maximum acceptable levelsin order to achieve UL listing. The testing is conducted on onefuse, at a full 600V. Also the test uses a controlled closing angle forthe voltage in order to achieve the highest instantaneous voltagepossible during opening of the fault current. The values shown inthe table are true worst case and can be used as a ceiling for letthrough energy that would be imposed on the conductor duringfault conditions. These Ul I2t limits are measurable performancecriteria for the overcurrent protective devices and are periodicallychecked by U.L. follow up tests. The Insulated Cable Engineers Association (ICEA) tables forinsulation damage was used to create the worst case condition forthe wire. The formula as developed by ICEA is based upon anadiabatic process where all the heat will be contained within thewire (conductor). This does not take into account the heat bleedoff into the terminations and components. As a result, a damagecurve was generated for thermoplastic insulation at 150°C. Thiswas the worst case of the three main types evaluated by ICEA whichinclude: - thermoplastic (150°C) - rubber, paper, varnished cloth (200°C) - crosslinked polyethylene and ehtylene propylene rubber (250°C) The following data can be used to perform an engineeringanalysis on the protection of the cable. The I2 levels can be used to verifying the heating effects thatwould be imposed on the wire. The insulated cable withstand I2levels are as follows: Wiring Size I 2 t No. 16 wire 18,662 A2s No. 18 wire 7,355 A2s Noting the maximum permissible levels allowed by UL, it isshown that under all conditions of heating imposed by short circuitcurrents, both the 16 and 18 AWG wire will be protected, evenunder worst case conditions. Lower level overcurrents will be taken care of by the class 10 or 20overload relay on motor circuits and the fuses on non motorcircuits. This proposal will be supported by actual testing in order to showthat the engineering analysis conducted here is accurate.COMMITTEE ACTION: Accept in Principle.Revise text to read as follows: 13.6.1 Exception 1: No. 16 shall be permitted where applied as follows: a) For non-motor power circuits of 8 amperes or less whereprotected in accordance with Clause 7 and with branch circuitrated circuit breakers listed for use with No.16 wire or Class CC, J,or T fuses rated at not more than 10 amperes or b) For motor loads with a full load ampacity of 8 amperes or less,where protected in accordance with Clause 7 with branch circuitrated circuit breakers listed for use with No.16 wire or Class CC, J,or T fuses and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected in accordance with Clause 7 with branchcircuit rated circuit breakers listed for use with No.16 wire or ClassCC, J, or T fuses and Class 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure. Exception 2: No. 18 shall be permitted where applied as follows: a) For non-motor power circuits of 5.6 amperes or less whereprotected in accordance with Clause 7 and with branch circuitrated circuit breakers listed for use with No. 18 wire or Class CC, J,or T fuses rated at not more than 7 amperes or b) For motor loads with a full load ampacity of 5 amperes or less,where protected in accordance with Clause 7 with branch circuitrated circuit breakers listed for use with No. 18 wire or Class CC, J,or T fuses and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected in accordance with Clause 7 branch circuitrated circuit breakers listed for use with No. 18 wire or with ClassCC, J, or T fuses and Class 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure.

COMMITTEE STATEMENT: The language is modified to includeall appropriate means of overcurrent protection as substantiated inProposal 79-118 (Log #120). The words "branch circuit rated"were added for consistancy with Proposal 79-50 (Log #32). Thecommittee understands that this proposal modifies the action onProposal 79-112 (Log# 28).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KNECHT: The reference was made to Listed circuit breakers thatdon’t exist yet and the UL rep at the meeting didn’t know about it.There was no indication that UL is pursuing this. We don’t evenknow if this is what they might call these breakers or if the markingwill be "circuit breakers for use with 16 AWG or 18 AWG wire...".Why didn’t we give this same latitude to Mr. Pilz regarding histesting done on safety control circuits? In addition, a good powerpoint presentation with some test results noted...these details weresubmitted but not substantiated by a third party. I do notrecommend going forward with this wording on circuit breakersuntil we have some assurance from UL that this even exists.COMMENT ON AFFIRMATIVE: ANDERSON: The attempt in using the "branch circuit ratedcircuit breakers" requirement is to clarify that supplementaryprotection devices are not to be considered for use in powercircuit, protection applications. The proposal modification is touse "branch circuit rated circuit breakers", however this "rated"requirement is not directly defined. Defined terminology needs tobe found and applied, e.g. "circuit breakers suitable for branchcircuit over current protection".

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(Log #98)79- 117 - (15.3(a) Exception (New) [13.6.1 Exception]): Accept inPrincipleSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to add new text to NFPA79-1997 as additional content for the newly proposed Clause 13which was reconciled with EN 60204-1 by Technical Committee onElectrical Equipment of Industrial Machinery action. Add text to read as follows: 13.6.1 Power Circuits No. 14 Exception 1: No. 16 shall be permitted where applied as follows: a) For non-motor power circuits of 8 amperes or less whereprotected in accordance Clause 7 and with Class CC fuses rated atnot more than 10 amperes, or b) For motor loads with a full load ampacity of 8 amperes orless, where protected with Class CC fuses at not more than 250percent of full load ampacity, and Class 10 overload protection perUL 508, or c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected with Class CC fuses at not more than 250percent of full load ampacity, and Class 20 overload protection perUL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure. Exception 2: No. 18 shall be permitted where applied as follows: a) For non-motor power circuits of 5.6 amperes or less whereprotected in accordance with Clause 7 and Class CC fuses rated atnot more than 7 amperes, or b) For motor loads with a full load ampacity of 5 amperes orless, where protected with class CC fuses at not more than 250percent of full load ampacity and Class 10 overload protection perUL 508, or c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected with class CC fuses at not more than 250percent of full load ampacity and Class 20 overload protection perUL 508, and d) Where part of a jacketed multiconductor cable or flexiblecord, or as individual conductors in a cabinet or enclosure.SUBSTANTIATION: The present parts of NFPA 79-1997 15.3(a) was reidentified tomatch the numbering sequence. These proposed new exceptions permit the use of 16/18 AWGconductors, and factory assembled 16/18 AWG multi-conductorcables, in small motor branch circuit applications. This exceptionwill also allow a common, desirable, practice unutilized on smallhorsepower, multi-power machinery.


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Wire sizes of 0.75 mm2 and 1 mm2 are commonly applied wherethe load currents are very small in applications based upon the IEC60204-1. Wire sizes of 0.75 mm2 and 1 mm2 have an ampacitysimilar to 18 AWG and 16 AWG wire respectively. Conservative based calculations were evaluated relative to shortcircuit and overload concerns. After considering many variables, itwas determined that a similar 18 AWG and 16 AWG wire wouldconstitute a reasonable approach and give application guidance toa present practices under the detailed requirements as proposed in13.6.1 Exceptions 1 and 2. In order to limit exposure to physical damage the use of theseconductors would be limited to multiconductor cables, and toindividual conductors when used in a cabinet or enclosure. The following information is provided to detail the evaluationprocess.


.004 2580 2160

.008 2580 1527

.0167 2580 10570.1 2580 4321 2580 1375 2580 6110 2580 4320 2580 3130 2580 251Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL508 Test PointsClass Current @ 600%2

10 4020 332Value shown in table is based upon 6 X the limitedcurrent specified in the proposed 13.6.1

UL 248 Test Point @ 50KATime (sec) Max Current Allowed (Amps.004 7073

3Current Level Extrapolated from UL I2 t limit bydividing out time (.004)


.004 1620 1356

.008 1620 959

.0167 1620 6640.1 1620 2711 1620 865 1620 3810 1620 2720 1620 1930 1620 164Data based upon ICEA (Insulated Cable EngineersAssociation) insulation Damage Formulas

UL 508 Test PointsClass Current @ 600%5

10 3020 215Value shown in table is based upon 6 X the limitedcurrent specified in the proposed 13.6.1

UL 248 Test Point @ 50KATime (sec) Max Current Allowed (Amps).004 7076

6Current Level Extrapolated from UL I2 t limit by dividing outtime (.004)

The Insulated Cable Engineers Association (ICEA) tables forinsulation damage was used to create the worst case condition forthe wire. The formula as developed by ICEA is based upon anadiabatic process where all the heat will be contained within thewire (conductor). This does not take into account the heat bleed

off into the terminations and components. As a result, a damagecurve was generated for thermoplastic insulation at 150°C. Thiswas the worst case of the three main types evaluated by ICEA whichinclude: - thermoplastic (150°C) - rubber, paper, varnished cloth (200°C) - crosslinked polyethylene and ethylene propylene rubber (250°C) This damage curve then supplied the worst possible condition towhich the wire (conductor) would be subjected. After laying the groundwork for wire damage, various overcurrentprotective devices were reviewed. Current limiting devices were decided upon in order to cover thevariety of a fault conditions that could apply to a machine. Uponexamination of Underwriters Laboratories (UL) “GeneralInformation for Electrical Equipment” (White Book), peak let-through currents of various current limiting branch circuit fuseswere considered. Selecting Class CC fuses and protecting 16 and18 AWG wire according to UL limits allowed a maximum let-through current to be determined. Next, motor controller characteristics were explored. Basedupon the information provided in UL508, test points were plottedon the time current curve to evaluate the performance of theoverload device under long term heating conditions. (Note:Under these conditions there is a high probability the heat will bedissipated from the conductor into the terminals and associatedcomponents). Guidelines were selected for proper fuse sizing and maximum fullload current rating of motors based upon the above data. Thecriteria for determining the maximum full load current rating was(1) the maximum current value the conductor could handle forthe set amount of time (10 sec for class 10, etc.), (2) add 10percent for a conservative heat bleed off factor, and (3) divide by 6per the requirements of UL 508. This then derived the FLC factor.

Existing 16 AWG

Existing 18 AWG

COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action onProposal 79-116 (Log #162).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KNECHT: See my Explanation of Negative Vote on Proposal 79-116 (Log #162).

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(Log #120)79- 118 - (15.3 [13.6.1 (Exc.)]): Accept in PrincipleSUBMITTER: George Gregory , Square D CompanyRECOMMENDATION: This is a proposed revision to a revisionalready under consideration by the NFPA 79 Committee.Underlined words are added. 13.6 Conductor sizing. Conductors shall not be smaller than: 13.6.1 Power circuits . . . . . . . . . . . . No. 14 Exception 1: No. 16 shall be permitted where applied as follows: a) For non-motor power circuits of 8 amperes or less whereprotected in accordance with Clause 7 and with circuit breakerslisted for use with No. 16 wire or Class CC fuses rated at not morethan 10 amperes, or b) For motor loads with a full load ampacity of 8 amperes orless, where protected with circuit breakers listed for use with No.16 wire or Class CC fuses at not more than 250 percent of full loadampacity, and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 5.5 amperes orless, where protected with circuit breakers listed for use with No.16 wire or Class CC fuses at not more than 250 percent of full loadampacity, and Class 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors when used in a cabinetor enclosure. Exception 2: No. 18 shall be permitted where applied as follows: a) For non-motor power circuits of 5.6 amperes or less whereprotected in accordance with Clause 7 and with circuit breakerslisted for use with No. 18 wire or Class CC fuses rated at not morethan 7 amperes, or


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b) For motor loads with a full load ampacity of 5 amperes or less,where protected with circuit breakers listed for use with No. 16wire or Class CC fuses at not more than 250 percent of full loadampacity, and Class 10 overload protection per UL 508, or c) For motor loads with a full load ampacity of 3.5 amperes orless, where protected with circuit breakers listed for use with No.16 wire or Class CC fuses at not more than 250 percent of full loadampacity, and Class 20 overload protection per UL 508, and d) Where part of a jacketed multiconductor cable assembly orflexible cord, or as individual conductors in a cabinet orenclosure.SUBSTANTIATION: The purpose of this proposal is to includethe application of circuit breakers that have been shown by test toprotect No. 16 and/or 18 AWG wires in addition to Class CC fusesif the panel determines that application of No. 16 and 18 wires isacceptable. Listed circuit breakers exist in ratings of 10 amperesand less, however, they are tested with the expectation that they willbe applied with No. 14 AWG wire under the NEC for powercircuits. Some of these circuit breakers will protect the smaller No.16 and 18 AWG wires. The proposal to use No. 16 and 18 wires in power circuits is new.Up to this time, none of the industry standards or listing programsfor branch-circuit overcurrent protective devices (circuit breakersor fuses) covers protection of wires small than No. 14. The UL 489Standard for Safety for Molded-case Circuit Breakers can be revisedto add requirements for protection of the smaller wire if there is alegitimate application for them. Submitted with this substantiation was a test report thatdemonstrates protection of No. 18 AWG wire with thermoplasticinsulation by a 10-ampere circuit breaker at its interrupting ratingof 10,000 amperes at 250 Vac. It is not the intent of this proposalto determine the test program for applying overcurrent protectivedevices with the smaller wires. The test program should bedetermined by the standard development organization and shouldbe administered by third party listing organizations. The TestReport is included only to verify that circuit breakers are capable ofprotecting the smaller wire under short circuit conditions at theirinterrupting rating. The proposer suggests that additional testing isnecessary at lower levels, however, the specific test levels and detailsshould be determined by the standards development organization. If the committee determines that No. 16 and 18 wires areacceptable for application as indicated in the proposal, circuitbreakers should not be excluded as the overcurrent protectivedevice. However, the requirement must indicate that they are to belisted for protection of the smaller wire. A unique marking on thecircuit breaker would indicate this feature.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action onProposal 79-114 (Log #162).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KNECHT: See my Explanation of Negative Vote on Proposal 79-116 (Log #162).COMMENT ON AFFIRMATIVE: DOBROWSKY: In the Committee Statement the correct proposalnumber is 79-116.

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(Log #8)79- 119 - (15.3(c) and (d) [13.2]): RejectSUBMITTER: Endel Mell, Husky Injection Molding Systems Ltd.RECOMMENDATION: Revise the wording of (c) and (d) tomake them more distinct.SUBSTANTIATION: "Electronic programmable control IO" issubject to considerable judgement, since electronic programmablecontrol IO is not defined. Is it: --- PLC IO --- electronic amplifiers with electronic overcurrent protection,connected to PLC IO --- PLC IO of low current (say less than 1A)? It's clear that it's reasonable and safe to wire an analog input, or acommunication circuit with 24 or 26 gauge wire. It's less clear thatit would be reasonable to wire a solenoid circuit that is poweredfrom an electronic amplifier with electronic overcurrent protectionthat is connected to PLC with 20 gauge wire — the overcurrentprotection is set for 1.8A, and the solenoid draws less than that.With this ambiguity, different inspectors have the option to hold usto different requirements (18 gauge wire presents other problems).

COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposal does not comply withthe Regulations Governing Committee projects, Section 4.3.3(c)since the submitter has not provided the specific recommendedtext.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #90)79- 120 - (15.5.1 Table 11 [13.5]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify 1997 NFPA 79, Clause 15 orproposed rewrite Clause 13 in 13.5. Delete the second sentence.SUBSTANTIATION: Since Table 11, referred to in the proposednew rewrite clause 13.5 does not contain the last column of Table11 in NFPA 79-1997, this sentence is not needed nor is itappropriate to include.COMMITTEE ACTION: Accept in Principle. Instead of deleting this sentence, relocate the sentence to 13.5.3.COMMITTEE STATEMENT: The committee agrees that thelocation is inappropriate and desires to relocate the provision to13.5.3 to ensure that the provision remains in the standard. Thecommittee understands that this proposal modifies the Action onProposal 79-112 (Log #28).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: SANDERS: The committee action resulted in the following text: "13.5.3 Where ampacity derating is required for ambienttemperature correction for other than 30oC or adjusted for morethan three current-carrying conductors in a raceway or cable, thefactor(s) shall be taken from Table 13-3b. Sizing of conductorswithin control enclosures in wiring harnesses or wiring channelsshall be based on the ampacity in cable or raceway. " By bringing this sentence to 13.5.3, I believe that additionalclarification is possible and propose the following: "13.5.3 Where ampacity derating is required for ambienttemperature correction for other than 30oC or adjusted for morethan three current-carrying power and lighting conductors in araceway, or in a cable , or within control enclosures in wiringharnesses or wiring channels, the factor(s) shall be taken fromTable 13-3b. Sizing of conductors within control enclosures inwiring harnesses or wiring channels shall be based on the ampacityin cable or raceway. These factors shall also apply to controlconductors where their continuous load exceeds 10 percent of theconductor ampacity. " This will clarify that derating is also required for all power andlighting conductors bundled within wiring harnesses or channelswithin an enclosure. The proposed new last sentence correlateswith NFPA 70-1999 Section 725-28 (a) and (b).

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(Log #91)79- 121 - (15.5.1 [13.5.3 Table 13-3(b)]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify 1997 NFPA 79, Clause 15 orproposed rewrite Clause 13 in 13.5.3. Separate the proposed Table 13-3b of rewrite Clause 13 in 13.5.3.into the two tables currently contained in Clause 310 of the NEC.These tables are those at the bottom of Table 310-16 (left side) oncorrection factors, and the table 310-15(b)(2)(a) on more thanthree current carrying conductors that relate to Ampacity Tables of0 to 2000 Volts. Provide a separate new table number for each table.SUBSTANTIATION: Separating the distinctly different parts ofthe proposed table will more clearly show that there are twoindependent variables to be considered in the determination ofampacity: ambient temperature in the first case, and number ofconductors in the second case.


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COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on 79-112 (Log #28).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #55)79- 122 - (Clause 16 and 17 [Clause 14]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: 14 Wiring practices14.1 Connections and routing14.1.1 General requirements14.1.1.1 All connections shall be secured against accidentalloosening and shall ensure a thoroughly good connection.14.1.1.2 The means of connection shall be identified for the cross-sectional areas and type of the conductors being terminated.14.1.1.3 The connection of two or more conductors to oneterminal is permitted only in those cases where the terminal isdesigned for that purpose. However, only one equipmentgrounding or one bonding conductor (protective conductor) shallbe connected to one terminal connecting point.14.1.1.4 A power distribution block designed for multiple tapconductors (e.g., single or multiple conductors “in” and multipleconductors “out”) shall be permitted for additional tapconnections and circuit branching.14.1.1.5 Soldered connections shall only be permitted whereterminals are provided which are identified for soldering.14.1.1.6 Terminals on terminal blocks shall be plainly identified tocorrespond with markings on the diagrams.14.1.1.7 The installation of flexible conduits and cables shall besuch that liquids shall drain away from the fittings. Wherepracticable, raceway connections shall enter the sides or bottom ofan enclosure or box.14.1.1.8 Means of retaining conductor strands shall be providedwhen terminating conductors at devices or terminals that are notequipped with this facility. Solder shall not be used for thatpurpose.14.1.1.9 Shielded conductors shall be terminated so as to preventfraying of strands and to permit easy disconnection.14.1.1.10 Identification tags shall be readable, permanent, andidentified for use in the physical environment.NOTE: A single tag bearing the complete identification ispreferred.14.1.1.11 Terminal blocks shall be mounted and wired so that theinternal and external wiring does not cross over the terminalsNote: For additional information on terminal blocks, refer toIEC 60947-7-1 “Low-voltage switchgear and control gear Part 7:Ancillary equipment Section one Terminal blocks for copperconductors”).14.1.2 Conductor and cable runs14.1.2.1 Conductors and cables shall be run from terminal toterminal without splices or joints.

Exception No. 1: Splices shall be permitted to leads attached to electricalequipment, such as motors and solenoids; such splices shall be insulatedwith oil-resistant electrical tape or insulation equivalent to that of theconductors and installed in a suitable enclosure.Exception No. 2: Where it is impracticable to provide terminals in ajunction box (e.g. on mobile machines, on machines having long flexiblecables) the use of splices or joints shall be permitted.14.1.2.2 Factory applied connectors molded onto cables shall bepermitted. Such connectors shall not be considered as splices orjoints.14.1.2.3 Where it is necessary to connect and disconnect cables andcable assemblies, an additional length shall be provided for thatpurpose.14.1.2.4 The terminations of cables shall be supported to preventmechanical stresses at the termination of the conductors.14.1.3 Conductors of different circuitsConductors of different circuits shall be permitted to be laid sideby side, and occupy the same raceway (duct) e.g. wireway (cabletrunking), or be in the same multiconductor cable assemblyprovided that the arrangement does not impair the functioning ofthe respective circuit. Functionally associated circuit conductorsincluding power, control, remote I/O, signaling, andcommunication cables shall be permitted in the same raceway orcable assembly regardless of voltage, provided all are insulated forthe maximum voltage of any circuit within the raceway or cableassembly. Where those circuits operate at different voltages, the

conductors shall be separated by barriers or shall be insulated forthe highest voltage to which any conductor within the same raceway(duct) or cable assembly is subjected.Exception: Different voltage insulation levels or conductor propertiesshall be permitted in the same cable assembly, provided the cable assemblyhas been designed and tested to the identified application.14.1.4. Cables14.1.4.1 Cables run exposed along the structure of the equipmentor system, or in the chases of the machinery shall be permitted.Exposed cables shall be installed to closely follow the surface andstructural members of the machinery.14.1.4.2 Cables shall be supported by the equipment or systemstructure as follows:

(1) In such a manner that the cable will not be damaged bynormal equipment use

(2) Every 12 inches in a non-vertical runException: The supporting distance may be increased up to 36 incheswhere the structure of the machine or system makes support impracticalevery 12 inches.

(3) Every 36 inches in a vertical runException: Supporting distance may be increased to 96 inches, where thestructure of the machine or system makes support impractical every 36inches.

(4) When suspended in air spanning a distance up to 18 inchesException: Span distance may be increased up to 36 inches, where thestructure of the machine or system makes support impractical every 18inches.14.1.4.3 Cables shall not be supported by machinery guard worklikely to be removed for maintenance access.14.1.4.4 Multiple cables can be supported and fastened together ina bundle provided the method of support and fastening is sufficientto support the mechanical weight and strain of the bundle.14.1.4.5 Cables shall be fastened where supported.Exception No. 1: Where horizontal runs are inherently supported by themachine or system structure, or by a floor or deck, fastening is notrequired.Exception No. 2: Where run at not more than a 45 degree angle fromhorizontal, fastening is not required.14.1.4.6 Cables shall be fastened with cable ties supported by any ofthe following methods:

(1) Screw-on cable tie mounts(2) Hammer-on cable tie mounting clips(3) Around the machine or system structural members(4) Through holes in the machine or system structural

members(5) Cable mounting clamps(6) Other methods identified as acceptable for the purpose

14.1.4.7 The free ends of cable ties shall be cut flush after finaladjustment and fastening. Cable ties of the reusable or releasabletype shall not be permitted for use as a permanent fasteningmethod14.1.4.8 Cables shall be protected from physical damage wherefollows:

(1) By alternative routing(2) With additional guarding or railings(3) When supported by flooring or decking, with walk over or

drive over cable protective devices(4) By installation in a wire way(5) By installation in a floor or deck covering trapezoidal walk

over raceway specifically designed for cable protection14.1.4.9 Bends in cables shall be made so as not to cause unduestress. The radius of the curve of the inner edge of any bend shallnot be less than five times the diameter of the cable.14.1.4.10 Where a cable is used in a length longer than optimallyrequired, the excess cable shall be coiled in loops at or near theload end. The coil shall be fastened to itself and to the machinerystructure.Exception: When an excess cable is associated with a horizontal cable runthat is inherently and fully supported, the coil is not required to befastened to the equipment or system structure.14.2 Identification of conductors14.2.1 General requirements14.2.1.1 Conductors shall be identified at each termination bynumber, letter, color (either solid or with one or more stripes), ora combination thereof and shall correspond with the technicaldocumentation.


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Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).Exception 3: Where multiconductor cable is used and other means ofpermanent identification is provided.14.2.1.2 When numbers are used, they shall be Arabic; letters shallbe Roman (either upper or lower case).14.2.2 Identification of the equipment grounding (protective)conductor14.2.2.1 The color GREEN (with or without one or more YELLOWstripes) shall be used to identify the equipment-groundingconductor where insulated or covered. This color identificationshall be strictly reserved for the equipment grounding (protective)conductor.Exception No. 1: In multiconductor cable-connected assemblies whereequipment grounding is not required, the solid color GREEN shall bepermitted for other than equipment grounding.Exception No. 2: It shall be permitted to use conductors of other colorsprovided the insulation or cover is appropriately identified at all points ofaccess.Exception No. 3: For grounded control circuits use of a GREEN insulatedconductor (with or without one or more YELLOW stripes) or a bareconductor from the transformer terminal to a grounding terminal on thecontrol panel shall be permitted.Note: The international standards reserve the use of bicolorcombination GREEN-AND-YELLOW for this purpose. The bicolorcombination is such that on any 15-mm (0.6-inch) length, one ofthe colors covers at least 30 % and not more than 70 % of thesurface of the conductor, the other color covering the remainder ofthe surface14.2.2.2 Where the equipment grounding (protective) conductor isidentified by its shape, position, or construction (e.g. a braidedconductor), or where the insulated conductor is not readilyaccessible, color coding throughout its length is not necessary.But the ends or accessible positions shall be clearly identified bythe 1999 NEC figure 250-126 grounding symbol, (IEC60417-symbolnumber-5019), or by the color GREEN (with or without one ormore YELLOW stripes) or the bicolor combination GREEN-AND-YELLOW.14.2.3 Identification of the grounded circuit conductor14.2.3.1 Where an AC circuit includes a grounded conductor, thisconductor shall be WHITE, GRAY or three continuous WHITEstripes on other than GREEN, BLUE, YELLOW insulation along itsentire length.NOTE: IEC 60204-1 requires the use of the color LIGHT BLUE forthe neutral conductor where color is the sole means ofidentification.14.2.3.2 The use of other colors for the following applications shallbe as follows:

(1) WHITE WITH BLUE STRIPE – grounded (currentcarrying) DC circuit conductor

(2) WHITE WITH YELLOW STRIPE – grounded (currentcarrying) AC circuit conductor which remains energizedwhen the main disconnecting means is in the off position

14.2.3.3 Where identification by color is used, bus bars used asgrounded conductors shall be either colored by a stripe, 15 mm(0.6 inch) to 100 mm (3.9 inch) wide in each compartment or unitor at each accessible position, or colored throughout their length.14.2.4 Identification by color for other conductors14.2.4.1 Ungrounded circuit conductors that remain energizedwhen the main disconnecting means is in the OFF position shallbe either YELLOW or ORANGE (see 5.3.5 “Excepted circuits”).These color identifications shall be strictly reserved for thisapplication only.Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).14.2.4.2 Where color is used for identification, the color shall beused throughout the length of the conductor either by the color ofthe insulation or by color markers.Exception: Multiconductor cables shall be permitted to be permanently re-identified at the time of installations.

14.2.4.3 The use of other colors for the purpose of identificationshall be as follows:

(1) BLACK: Ungrounded line, load, and control conductors atline voltage.

(2) RED: Ungrounded ac control conductors, at less than linevoltage.

(3) BLUE: Ungrounded dc control conductors.Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).Exception 3: Where multiconductor cable is used and other means ofpermanent identification is provided.14.3 Wiring inside enclosures14.3.1 Panel conductors shall be supported where necessary tokeep them in place. Non-metallic ducts shall be permitted onlywhen they are made with a flame-retardant insulating material.Note: For additional information on Flame retardant materials,refer to IEC 60332-1 “ Tests on electric cables under fire conditions– Part 1: Test on a single vertical insulated wire or cable”.14.3.2 Electrical equipment mounted inside enclosures shall beinstalled in such a way as to permit access to the wiring.14.3.3 Connections to devices mounted on doors or to othermovable parts shall be made using flexible conductors inaccordance with 13.7. “Conductors and cables used for flexingapplications” to allow for the movement of the part. Theconductors shall be anchored to the fixed part and to the movablepart independently of the electrical connection.14.3.4 Conductors that do not run in ducts shall be supported.14.3.5 Multiple-device control panels shall be equipped withterminal blocks or with attachment plugs and receptacles for alloutgoing control conductors.14.3.6 The direct connection of Power cables and cables ofmeasuring circuits, to the terminals of the devices for which theconnections were intended shall be permitted.14.3.7 AC receptacles, AC plugs, flexible cords, appliance couplers,power cord sets, etc. shall be permitted inside enclosures forinternal wiring and connections between assemblies with AC powerwhere used in accordance with their listing.14.4 Wiring outside enclosures14.4.1 General requirements

The means of introduction of cables or ducts with their individualglands, bushings, etc., into an enclosure shall ensure that thedegree of protection is not reduced.14. 4. 2 External raceways (ducts)14.4.2.1 All conductors of the same AC circuit routed to the samelocation shall be contained in the same raceway (duct).14.4.2.2 Conductors external to the electrical equipmentenclosure(s) shall be enclosed in raceway (duct) described in 14.5.Exception: Cables and cable connectors need not be enclosed in a racewaywhere they are otherwise protected and supported.14.4.2.3 Fittings used with raceways (ducts) or multiconductorcable shall be identified for use in the physical environment.14.4.2.4 Flexible conduit or multiconductor cable with flexibleproperties shall be used where it is necessary to employ flexibleconnections to pendant push-button stations. The weight of thependant stations shall be supported by means other than theflexible conduit or the multiconductor cable with flexibleproperties, except where the conduit or cable is specificallydesigned for that purpose.14.4.2.5 Flexible conduit or multiconductor cable with flexibleproperties shall be used for connections involving small orinfrequent movements. They shall also be permitted to completethe connection to stationary motors, to position switches, and toother externally mounted devices. Where pre-wired devices (e.g.position switches, proximity switches) are supplied, the integralcable need not be enclosed in a raceway (duct).14.4.3 Connection to moving elements of the machine14.4.3.1 Connections to moving parts shall be made usingconductors in accordance with 13.7. Flexible cable and conduitshall have vertical connections and shall be installed to avoidexcessive flexing and straining. Horizontal connections shall bepermitted where the flexible cable or conduit is adequatelysupported. Cable with flexible properties and flexible conduit shallbe so installed as to prevent excessive flexing and straining,particularly at the fittings.14.4.3.2 Cables with flexible properties subject to movement shallbe supported in such a way that there is neither mechanical strainon the connection points nor any sharp flexing. When this isachieved by the use of a loop, it shall provide for a bending radiusof the cable of at least 10 times the diameter of cables.14.4.3.3 Cable with flexible properties of machines shall be soinstalled or protected as to minimize the possibility of externaldamage due to factors that include the following cable use orpotential abuse:


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(1) Being run over by the machine itself(2) Being run over by vehicles or other machines(3) Coming into contact with the machine structure during

movements(4) Running in and out on cable baskets, or on or off cable

drums(5) Acceleration forces and wind forces on festoon systems or

suspended cables(6) Excessive rubbing by cable collector(7) Exposure to an excessive radiated heat source

14.4.3.4 The cable sheath shall be resistant to the wear frommovement and the effects of atmospheric contaminants (e.g. oil,water, coolants, and dust).14.4.3.5 Where cables subject to movement are close to movingparts, precautions shall be taken to maintain a sp ace o f at least 25.4- mm (1-in ch ) b et ween t h e mo vi n g p arts an d th e cabl es. Wh ereth at d ist an ces i s n o t pr actica bl e, fixed bar riers sh all b e p ro vi d edb etw een th e cabl es an d t h e mo vi n g p arts .14.4.3.6 The cable handling system shall be so designed that lateralcable angles do not exceed 5°, avoiding torsion in the cable when:

(1) Being wound on and off cable-drums and(2) Approaching and leaving cable guidance devices

14.4.3.7 Measures shall be taken to ensure that at least two turns offlexible cables always remain on a drum.14.4.3.8 Devices serving to guide and carry a cable with flexibleproperties, shall be so designed that the inner bending radius isnot less than the values given in table XW, unless the smallerbending radius is agreed to by the cable manufacturer, taking intoaccount the permissible tension and the expected fatigue life.

Table XW – Minimum permitted bending radii for theforced guiding of flexible cables

Application Cable diameter or thickness of flatcable (d)mmd ≤ 8 8 < d ≤ 20 d >20

Cable drumsGuide rollersFestoon systemsAll others

6 d6 d6 d6 d

6 d8 d6 d6 d

8 d8 d8 d8 d

Table XW note: 8mm = 0.315-inch, 20mm = 0.787-inch

14.4.3.9 The straight section between two bends, in an S-shapedlength, and a bend into another plane shall be at least 20 times thediameter of the cable.14.4.3.10 Where flexible conduit is adjacent to moving parts, theconstruction and supporting means shall prevent damage to theflexible conduit under all conditions of operation. Flexiblemetallic conduit shall not be used for rapid movements exceptwhen specifically designed for that purpose.14.4.4 Interconnection of devices on the machineWhere practicable, machine-mounted switching devices (e.g.position sensors, push buttons) are connected in series or inparallel, the connections between those devices shall be madethrough terminals forming intermediate test points. Such terminalsshall be conveniently placed, protected from the environment, andshown on the relevant diagrams.14.4.5 Attachment plug and receptacle (plug/socket) combinations14.4.5.1 Where equipment is removable, connections to it througha polarized attachment plug and receptacle (plug/socket)combination shall be permitted. The male plug shall beconnected to the load circuit.14.4.5.2 Attachment plug and receptacle (plug/socket)combinations shall be listed for the intended use and shall be ofthe locking type where rated greater than 20 amperes. Where usedon circuits of more than 300 volts to ground or 300 volts phase-to-phase, they shall be skirted and constructed to contain any arcgenerated when a connection is made or broken.

14.4.5.3 Attachment plug and receptacle (plug/socket)combinations, shall be so designed that; a protective bonding(equipment grounding) circuit connection is made before any liveconnections are made; and the protective bonding (equipmentgrounding) circuit connection is not disconnected until all liveconnections in the plug are disconnected; except for connectionsused in PELV circuits, or the connectors used only to facilitateassembling / disassembling (multi-pole connectors).14.4.5.4 Attachment plugs and receptacles (plug and socket)combinations used for carrying motor loads shall meet theconditions of 5.3.3.3 if the circuit is likely to be opened under load.14.4.5.5 Where more than one attachment plug and receptacle(plug/socket) combination is used at the same location, they shallbe mechanically coded to prevent incorrect insertion or be clearlyidentified.14.4.5.6 Attachment Plug/socket combinations that are used forindustrial power purposes or of a type used for domesticapplications shall not be used for control circuits.14.4.5.7 Means shall be provided to cover the receptacle when theplug is removed.14.4.6 Dismantling for shipmentWhere it is necessary that wiring be disconnected for shipment andwhere practicable, terminals or attachment plug and receptacle(plug/socket) combinations shall be provided at the sectionalpoints. Such terminals shall be suitably enclosed and attachmentplug and receptacle (plug/socket) combinations shall be protectedfrom the physical environment during transportation and storage.Raceway and enclosure openings shall be sealed prior to shipment.14.5 Raceways (ducts), support systems (cable supports),connection boxes and other boxes14.5.1 General requirements14.5.1.1 Raceways (ducts) shall be identified for the environment.14.5.1.2 All sharp-edges, flash, burrs, rough-surfaces, or threadsthat the insulation of the conductors can come in contact shall beremoved from raceways (ducts) and fittings. Where necessary,additional protection consisting of a flame-retardant, oil-resistantinsulating material shall be provided to protect conductorinsulation.14.5.1.3 Drain holes shall not be permitted in raceways (ducts),junction boxes, and pull boxes where the holes would compromisethe intended enclosure integrity. Drain holes of 6.4 mm (1/4inch) diameter shall be permitted in wireways (cable trunkingsystems), connection boxes, and other boxes used for wiringpurposes that are subject to accumulations of oil or moisture.14.5.2 Percentage fills of raceways (ducts)The combined cross-sectional area of all conductors and cablesshall not exceed 50 percent of the interior cross-sectional area ofthe raceway (duct). The fill provisions shall be based on the actualdimensions of the conductors or cables used.Note: It should be recognized that, for certain conditions, a largersize raceway or a lesser raceway fill should be considered.14.5.3 Rigid conduit and fittings14.5.3.1General requirements14.5.3.1.1 The minimum electrical trade size shall be 1/2 inch.14.5.3.1.2 The maximum electrical trade size shall be 6 inch.Note: Metric trade numerical designations for rigid metal conduitare the same as those found in Extra-heavy Duty Rigid SteelConduits for Electrical Installations, IEC 981-1989; namely: 1/2 =16, 3/4 = 21, 1 = 27, 1 1/4 = 35, 1_ = 41, 2 = 53, 2 1/2 = 63, 3 = 78, 31/2 = 91, 4 = 103, 5 = 129, and 6 = 155.14.5.3.1.3 Where conduit enters a box or enclosure, a bushing orfitting providing a smoothly rounded insulating surface shall beinstalled to protect the conductors from abrasion, unless thedesign of the box or enclosure is such that it provides the sameprotection. Where conduit bushings are constructed wholly ofinsulating material, a locknut shall be provided both inside andoutside the enclosure to which the conduit is attached.Exception: Where threaded hubs or bosses that are an integral part of anenclosure provide a smoothly rounded or flared entry for conductors.14.5.3.1.4 Conduit bends shall be made in such a manner that theconduit shall not be damaged and the internal diameter of theconduit shall not be effectively reduced. The radius of the curve ofany field bend shall be not less than shown in Table XX.


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Table XX – Minimum Radius of Conduit BendsSize ofConduit

Radius of BendDone by

Radius of Bend Doneby

(in.) Hand (in.) Machine (in.)1/2 4 43/4 5 41/21 6 51/411/4 8 71/411/2 10 81/42 12 91/221/2 15 101/23 18 1331/2 21 154 24 1641/2 27 205 30 246 36 30

Table XX: SI units: (Radius) 25mm = 1 in.NOTE 1: For field bends done by hand, the radius is measured tothe inner edge of the bend.NOTE 2: For a single-operation (one-shot) bending machinedesigned for the purpose, the radius is measured to the centerlineof the conduit14.5.3.1.5 A run of conduit shall contain not more than four-quarter bends or a combination of bends totaling 360 degrees,between pull points.14.5.3.2 Metal type nonflexible conduit14.5.3.2.1 General requirements14.5.3.2.1.1 Conduits shall be securely held in place and supportedat each end.14.5.3.2.1.2 Fittings shall be compatible with the conduit andidentified for the application. Fittings and conduits shall bethreaded using an electrical conduit die unless structuraldifficulties prevent assembly. Running threads shall not be used onconduit for connection at couplings. Metallic tubing shall not bethreaded. Where threadless fittings are used, the conduit shall besecurely fastened to the equipment.14.5.3.2.2 Rigid metal conduit and fittingsRigid metal conduit and fittings shall be of galvanized steel or of acorrosion-resistant material identified for the conditions of service.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.2.3 Intermediate metal conduitIntermediate metal conduit shall be a steel raceway of circularcross section with integral or associated couplings, approved forthe installation of electrical conductors and used with approvedfittings to provide electrical continuity.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.2.4 Electrical metallic tubingElectrical metallic (steel) tubing shall be a metallic tubing ofcircular cross section approved for the installation of electricalconductors when joined together with approved fittings. Themaximum size of tubing shall be the 4-in. electrical trade size.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.3 Rigid non-metallic conduit (PVC Schedule 80)14.5.3.3.1 Rigid non-metallic conduit (PVC schedule 80) shall beof suitable nonmetallic material approved for the installation ofelectrical conductors and identified for use where subject tophysical damage.Note: For additional information about rigid non-metallicconduit, refer to UL 651.14.5.3.3.2 Conduit shall be securely held in place and supported asfollows:

Maximum Spacing

Conduit Size (in)Maximum Spacing

Between Supports (ft) 1/2 - 11 1/4 - 22 1/2 - 33 1/2 - 5

6

35678

Note: For SI units, 1 ft = 0.3048 m (supports).

In addition, conduit shall be securely fastened within 3 ft (914mm) of each box, enclosure, or other conduit termination.

14.5.3.3.3 Expansion fittings shall be installed to compensate forthermal expansion and contraction. (NFPA 70-1999 “Table 347-9(A). Expansion Characteristics of PVC Rigid Nonmetallic ConduitCoefficient of Thermal Expansion = 3.38 x 10-5 in./in./º F “)14.5.3.3.4 All joints between lengths of conduit, and betweenconduit and couplings, fittings, and boxes, shall be made withfittings approved for the purpose14.5.4 Flexible metal conduit and fittings14.5.4.1 General requirements14.5.4.1.1 Flexible metal conduit and liquidtight flexible metalconduit, minimum electrical trade size shall be 3/8 inch.Exception: Thermocouples and other sensors.14.5.4.1.2 The maximum size of flexible metal conduit andliquidtight flexible metal conduit, shall be 4-in trade size.Note: Metric trade numerical designations for flexible metalconduit and liquidtight flexible metal conduit, are 3/8 = 12, 1/2 =16, 3/4 = 21, 1 = 27, 1 1/2 = 35, 1_ = 41, 2 = 53, 2 1/2 = 63, 3 = 78, 31/2 = 91, and 4 = 103.14.5.4.1.3 Flexible metal conduit and liquidtight flexible metalconduit shall be installed in such a manner that liquids will tend torun off the surface instead of draining toward the fittings.14.5.4.1.4 Fittings shall be compatible with the conduit andidentified for the application. Connectors shall be the “union”types.14.5.4.2 Flexible metal conduitFlexible metal conduit is a raceway of circular cross section madeof helical wound, formed, and interlocked metal strip. Flexiblemetal conduit shall be identified for use in the expected physicalenvironment.14.5.4.3 Liquidtight flexible metal conduitLiquidtight flexible metal conduit is a approved raceway of circularcross section having an outer liquidtight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core with associatedcouplings, connectors, and fittings and approved for theinstallation of electric conductors. Liquidtight flexible metalconduit shall be identified for use in the expected physicalenvironment.14.5.5 Flexible non-metallic conduit and fittings14.5.5.1 Liquidtight flexible nonmetallic conduit is a raceway ofcircular cross section of various types:

(1) A smooth, seamless inner core and cover bonded togetherand having one or more reinforcement layers between thecore and cover

(2) A smoother inner surface with integral reinforcement withinthe conduit wall

(3) A corrugated internal and external surface with or withoutintegral reinforcement within the conduit wall

(4) Liquidtight flexible nonmetallic conduit is oil-, water-, andflame-resistant and, with fittings, is approved for theinstallation of electrical conductors

14.5.5.2 A flexible non-metallic conduit shall be resistant to kinkingand shall have physical characteristics of the sheath ofmulticonductor cables.14.5.5.3 The conduit shall be identified for use in the expectedphysical environment.14.5.5.4 Liquidtight flexible nonmetallic conduit minimumelectrical trade size shall be 3/8 inch.14.5.5.5 The maximum size of liquidtight flexible nonmetallicconduit shall be 4-in trade size.Note: Metric trade numerical designations for liquidtight flexiblenonmetallic conduit are 3/8 = 12, 1/2= 16, 3/4 = 21, 1 = 27, 1 1/2 =35, 1_ = 41, 2 = 53, 2 1/2 = 63, 3 = 78, 3 1/2 = 91, and 4 = 103.14.5.5.6 Fittings shall be compatible with the conduit and identifiedfor the application.14.5.5.7 Flexible conduit shall be installed in such a manner thatliquids will tend to run off the surface instead of draining towardthe fittings.14.5.6 Wireways (cable trunking systems)14.5.6.1 Wireways (cable trunking systems) external to enclosuresshall be rigidly supported and clear of all moving or contaminatingportions of the machine.14.5.6.2 Covers shall be shaped to overlap the sides; gaskets shall bepermitted. Covers shall be attached to wireways (cable trunkingsystems) by hinges or chains and held closed by means of captivescrews or other suitable fasteners. On horizontal wireway (cabletrunking systems), the cover shall not be on the bottom. Hingedcovers shall be capable of opening at least 90 degrees.14.5.6.3 Where the wireway (cable trunking system) is furnished insections, the joints between sections shall fit tightly but shall not berequired to be gasketed.14.5.6.4 The only openings permitted shall be those required forwiring or for drainage.


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14.5.6.5 Wireways (cable trunking systems) shall not have openedbut unused knockouts.14.5.7 Machine compartments and wireway (cable trunkingsystems)The use of compartments or wireways (cable trunking systems)within the column or base of a machine to enclose conductorsshall be permitted provided the compartments or wireways (cabletrunking systems) are isolated from coolant or oil reservoirs andare entirely enclosed. Conductors run in enclosed compartmentswireways (cable trunking systems) shall be so secured and arrangedthat they can not be subject to damage. (See 17.2.”Warningmarking and signs”)14.5.8 Connection boxes and other boxes14.5.8.1 Connection boxes and other boxes used for wiringpurposes shall be readily accessible for maintenance. Those boxesshall provide protection against the ingress of solid bodies andliquids, taking into account the external influences under whichthe machine is intended to operate14.5.8.2 Those boxes shall not have opened but unused knockoutsor any other openings and shall be so constructed as to excludematerials such as dust, flyings, oil, and coolant.14.5.9 Motor connection boxes14.5.9.1 Motor connection boxes shall enclose only connections tothe motor and motor-mounted devices (e.g. brakes, temperaturesensors, plugging switches, tachometer generators).14.5.9.2 Electrical connections to motors, solenoids and otherdevices with integral leads, sizes No. 14 AWG through No. 4 AWG,shall be made with ring type pressure connectors (pressure-toolapplied) and bolted.14.5.9.3 Connectors shall be insulated with a material that will notsupport combustion.14.5.9.4 Soldered or insulation piercing type connectors (lugs)shall not be used.14.5.10 Cord.14.5.10.1 Manufactured assemblies with factory applied moldedconnectors applied to cord shall be permitted.Note: For additional information on flexible cords, refer to ANSI/ UL 62 “Flexible cord and fixture wire”14.5.10.2 The use of cord shall be limited to individual exposedlengths of 50 feet or less.14.5.10.3 Cord shall be installed in accordance with the provisionof clause 14.1.4.14.5.10.4 Cord shall be permitted for use for flexible connectionsto pendant push-button stations. Chains or wire rope external tothe cord shall support the weight of pendant stations.14.5.10.5 Cord shall be permitted for use for connections involvingsmall or infrequent movements. Cord shall also be permitted tocomplete the connection to normally stationary motors, limitswitches, and other externally mounted devices.14.5.10.6 Connections to frequently moving parts shall be madewith conductors for flexing service in accordance with 13.7. Cordwith conductors for flexing service shall have vertical connectionsand shall be installed to avoid excessive flexing and straining.Exception: Horizontal connections shall be permitted where the cord isadequately supported.14.5.11 Cable traysCable trays to be used for cable or raceway support on industrialmachines shall be permitted. Cable trays shall be permitted tosupport single conductors 1/0 or larger that are otherwisepermitted on industrial machines, cables that are otherwisepermitted on industrial machines, and raceways functionallyassociated with industrial manufacturing systems.SUBSTANTIATION:Historical Background.


Harmonization - PurposeAs the users and the manufacturers of industrial machines movetoward a global manufacturing community, the need for aharmonized standard affecting industrial machinery becomes aneconomic necessity. Generally, large users and manufacturers findregulations burdensome. However, multiple regulations as well asconflicting regulations are an economic disincentive to globalexpansion. In order to ease the burden of differing regulation, andat the same time maintain the high standard of electrical machinesafety, the NFPA 79 committee has expressed their desire, throughballoted vote, to harmonize NFPA 79 with IEC-60204-1.

Importance of Issue - HarmonizationToday's industrial machines are very complex and expensive. Asmanufacturing lines become modular and transportable, industrialmachines originally produced for a foreign market may quickly be

transported to the domestic market. The reverse is also true.Differing electrical standards add a large cost to multinationalmanufacturers as they build and sometimes move manufacturingfacilities.

Harmonization - ObjectiveThis work is necessary to accomplish the goal of allowing industryto economically build one industrial machine capable of passing adetailed electrical safety inspection using either IEC 60204-1 orNFPA 79 standard.


"The Technical Correlating Committee agrees with the efforts of the NFPA79 committee to harmonize the technical requirements of NFPA 79 andIEC 60204, where feasible and where in concert with the NEC and itsrelated codes and standards."

Result


The Task Group for Clause 14 consisted of Bill Anderson, FrankDeFleice Jr., Gary Locke, and John Knecht. The Task Groupcompared NFPA-79-1997, Clauses 16 and 17 and related materialwith IEC 60204-1 Clause 14. The Task Group presented its work tothe entire committee on several occasions for review and comment.This proposal is a result of that work.

The Task Group proposes to renumber Clauses 16 and 17 of NFPA79-1997 to correspond with IEC 60204-1. The task group proposesthe following changes to further improve usability.

Substantiation for NFPA 79-2002 Chapter 14 Wiring practices

14

Recommendation: Combine NFPA 79 1997 Editions Clause 16title, "Wiring methods and practices” and Clause 17 title,"Raceways, junction boxes, and pull boxes with Chapter 14 title,"Wiring practices”Substantiation: The proposed new title more accurately reflects thetext. Editorial addition to help organize the material and followIEC 60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.14.1Recommendation: Relocate NFPA 79 1997 Edition 16.4 title to 14.1and revise as follows: “Wire c C onnectors and connectionsrouting .”Substantiation: Delete “Wire” as unnecessary and change“connections” to “routing” encompasses the circuit fromtermination to termination and reflects the additional materialincluded in section 14.1. Chapter 14 is divided into 5 sections 1Connections and routing, 2 Identification of conductors, 3 Wiringinside enclosures, 4 Wiring outside enclosures and 5 Raceways(ducts), support systems (cable supports), connection boxes andother boxes. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.14.1.1Recommendation: Add new title, “General requirements”.Substantiation: This sub-subsection, “General requirements”, isused to consolidate information that applies to all the parts of thesection 14.1 into one area for clarity. Editorial change to NFPA 791997 Edition 16.1 location following IEC 60204-1 1997 Edition.Section 14.1 is divided into 4 subsections 1 General requirements, 2Conductor and cable runs, 3 Conductors of different circuits, and4 Cables. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition..14.1.1.1Recommendation: Revise NFPA 79 1997 Edition 16.1.9 with newtext, “All connections shall be secured against accidental looseningand shall ensure a thoroughly good connection”. Move to 14.1.1.1Substantiation: Proposed text is more inclusive and adds theinformation connections are to be secured against loosening to


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clarify the quality of work requirements. “Thoroughly goodconnection” from NFPA 70:1999 110-14 “Electrical Connections”(a) “Terminals”, to clarify the quality of work requirements.14.1.1.2Recommendation: Add new text ”The means of connection shallbe identified for the cross-sectional areas and type of theconductors being terminated”.Substantiation: Provides additional information for connections.14.1.1.3Recommendation: Replace NFPA 79 1997 Edition 16.1.8 2ndsentence and exception with the proposed new text. Move NFPA79 1997 Edition 16.1.8 the 1st sentence to 14.1.11.

Substantiation: The restriction for the equipment-groundingconductor is a part of the general requirements for the connectionsand routing.The 1st sentence is moved to 14.1.11 as the more logical location.14.1.1.4Recommendation: Add new text.Substantiation: Text has been added to recognize current practiceand the need for connection of multiple conductors. UL “GeneralInformation for Electrical Equipment”, states that a powerdistribution block consists of a connector(s) mounted on aninsulating base. Each individual connector has provisions forconnection of one or more conductors and multiple smaller tap-off conductors.14.1.1.5Recommendation: New text replacing NFPA 79 1997 Edition 16.4.2text and NFPA79 1997 Edition 16.4.1 Exception No.1Substantiation: New text states the restrictions on the use ofsoldered connections. NFPA 79 1997 16.4.2 concerning solderconnections is too prescriptive concerning solder connections, isunnecessary and prohibits other current and possible futuremethods and materials.

14.1.1.6Recommendation: Insert NFPA 79 1997 Edition 16.1.5 andrenumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.1.1.7

Recommendation: Relocate NFPA 79 1997 Edition 16.3.11 here,renumber and add: “Where practicable, raceway connections shallenter the sides or bottom of an enclosure or box.”Substantiation: The added restriction on enclosure entry reflectscurrent practice.

14.1.1.8

Recommendation: Replace NFPA 79 1997 Edition 16.4.1 with newtext.Substantiation: Provides less prescriptive language and meets theintent of the present standard. NFPA79 1997 Edition 16.4.1Exception No. 1 was moved to 14.1.1.5. Exception No. 2 was notretained as the practice is limited in use.

14.1.1.9Recommendation: Relocate NFPA 79 1997 Edition 16.1.6 here andrenumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.1.1.10Recommendation: Replace NFPA 79 1997 Edition 16.1.7 with newtext and note.Substantiation: The new text contains the desired results withoutthe existing text requirements that contain design details that arenot in common use today. The note states the preferred currentpractice without restricting other acceptable options.

14.1.1.11Recommendation: Locate NFPA 79 1997 Edition 16.1.8 1st sentencehere, renumber and replace the 2nd sentence by adding thefollowing as a note: “For additional information on Terminalblocks refer to IEC 60947-7-1 “Low-voltage switchgear and controlgear Part 7: Ancillary equipment Section one Terminal blocks forcopper conductors.”Substantiation: The added text provides an additional source ofinformation for terminal blocks.

NFPA 79 1997 Edition 16.1.8 2nd sentence and exception arecovered in proposed 14.1.1.3. 14.1.2Recommendation: Add clause title “ Conductor and cable runs”.Substantiation: Section 14.1 is divided into 4 subsections 1 Generalrequirements, 2 Conductor and cable runs, 3 Conductors ofdifferent circuits, and 4 Cables. Editorial addition to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.1.2.1 Recommendation: Replace NFPA 79 1997 Edition 16.1.4 withsimilar text. Retain exception from NFPA 79:1997 16.14 exceptionas Exception #1 to 14.1.2.1 and add “...and installed in a suitableenclosure.” at the end.Add a new exception number two for those situations where anenclosure is not practical.Substantiation: The term “joints” is added for clarity, as the termssplice and joint are used to describe the original intent of NFPA 791997 Edition 16.1.4, both terms are used in IEEE Dictionary ofTerms to describe joining of conductors and cables. Theexceptions add additional information and provides for situationswhere splices or joints are necessary.

14.1.2.2Recommendation: Add new text to reflect current technology.Substantiation: Factory applied connectors molded onto cables arecommonly utilized on the electrical equipment of industrialmachinery. Such connectors are attached in a controlledenvironment where comprehensive quality assurance, test, andvalidation measures are applied. The robust design and successfulutilization history of such connectors indicate that such productsare not a safety risk. These connectors are not considered as splicesor joints in cable runs for the purpose of this clause.

14.1.2.3Recommendation: Add new text to reflect current technology.Substantiation: Provides for the current good practice, of providingadditional length to cable and cable assemblies to facilitateconnection and disconnection, that is not presently covered inNFPA 79 1997 Edition.

14.1.2.4 Recommendation: Add new text to reflect current technology.Substantiation: Provides for the support for cable conductorsmechanical stresses at the termination point which, althoughconsidered good practice, is not presently covered in the NFPA 791997 Edition.

14.1.3Recommendation: Add clause title ”Conductors of differentcircuits”. Add new text representing current practice, insert NFPA79 1997 Edition 16.3.8, allowing the grouping of functionallyassociated circuits as the 2nd sentence and insulating requirementsfrom the 2nd sentence of NFPA 79 1997 Edition 15.4.5.Substantiation: The text additions provide installation guidelinesand incorporates functional grouping from NFPA 79 1997 Edition16.3.8 and voltage level insulation requirements from the 2ndsentence of NFPA 79 1997 Edition 15.4.5. This paragraph willaddress the need for composite cables for specific machineapplications. The added exception permits current practice andallows for the use of special cables with multiple voltage circuitssuch as those presently tested and used for servo motor circuits.Section 14.1 is divided into 4 subsections 1 General requirements, 2Conductor and cable runs, 3 Conductors of different circuits, and4 Cables. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.1.4.Recommendation: Add new title, “Cables”.Substantiation: As a common practice cables are extensivelyapplied as part of the electrical controls of industrial machinery.NFPA 79 and EN60201 are both silent on safe cable applicationmethodology, which forces industry to utilize a plethora of ad hoc,and sometimes questionable, measures. In order to facilitate thesafe and uniform utilization of cables, this text is proposed. It is theintent of these paragraphs [14.1.4.x] to provide cable applicationmethodology that is at least as comprehensive as the methodologyoutlined for many wiring methods found in Chapter 3 of NFPA 70.Section 14.1 is divided into 4 subsections 1 General requirements, 2Conductor and cable runs, 3 Conductors of different circuits, and4 Cables. Editorial addition to help organize the material and


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follow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.1.4.1Recommendation: Add new text to provide installationinformation.Substantiation: Specific application analysis will identify preciselyhow cables need to be run. In addition to conventional cablerouting methodology, the routing of cables along either the insideor outside of the machine will at some point typically becomenecessary. Clause 14.1.4.1 recognizes and permits cables routedalong the exterior of the surface of the structural members of themachinery, as well as cables routed through chases inherent to themachinery structure, or through chases added to the machinerystructure for the purpose. Cables associated with a machine ormachinery system is an integral part of that machine or machinerysystem. Supporting cables by the equipment or system structureclearly indicates and maintains that association.14.1.4.2Recommendation: Add new text to provide cable supportrequirements.Substantiation: Provides information not in the present standard.Some cable types may be more susceptible to physical damage thatothers. Care should be taken to ensure that all applied cables typewould not be subjected to physical damage under conditions ofnormal use. Although this requirement may appear obvious tomost readers, Clause 14.1.4.2(a) codifies a requirement that theproper care be taken to ensure the integrity of the cableinstallation.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessupported at greater that 12 inches in a non-vertical run can makefor an installation that would not satisfy a reasonable personsunderstanding of what constitutes “a neat and workman like”installation. Clause 14.1.4.2(b) helps ensure a conscientious“workman like” installation of cables.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may beimpractical or undesirable to support cables in a non-vertical runat 12 inches intervals at all times. This exception to Clause14.1.4.2(b) allows a reasonable extension of the support distanceto cover such circumstances.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessupported at less that 36 inches in a vertical run can make for aninstallation that would not satisfy a reasonable personsunderstanding of what constitutes “a neat and workman like”installation. Clause 14.1.4.2(c) helps ensure a conscientious“workman like” installation of cables.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may beimpractical or undesirable to support cables in a vertical run at 36inches intervals at all times. This exception to Clause 14.1.4.2(c)allows a reasonable extension of the support distance to cover suchcircumstances.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessuspended in air spanning a distance greater that 18 inches canmake for an installation that would not satisfy a reasonable personsunderstanding of what constitutes “a neat and workman like”installation. Clause 14.1.4.2(d) helps ensure a conscientious“workman like” installation of cables.Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may bepractical or desirable for cables to span distances greater than 18inches at some times. This exception to Clause 14.1.4.2(d) allows areasonable extension of the span distance to cover suchcircumstances.

14.1.4.3Recommendation: Add new text prohibiting supporting cables onremovable machinery guard work.Substantiation: The supporting of cables on machinery guard workthat is likely to be removed for maintenance access would make fora potentially unsafe installation. The integrity of the installationwould be compromised as soon as maintenance access to theequipment behind the guard work was required. Guard work likelyto be removed for maintenance access may be removed on aroutine basis. It is therefore reasonable to expect that the integrityof the cable installation will ultimately not be restored, and istherefore prohibited.

14.1.4.4Recommendation: Add new text on multiple cable support.Substantiation: Where multiple cables are routed together, it isoften common practice to fasten those cables together in a bundleso as to create a neat and workman like installation. Clause14.1.4.4, recognizes this practice, and requires that the fastenersand supports employed be of such construction so as to beingsubstantial enough for the application.

14.1.4.5Recommendation: Add new text requiring attachment of cables totheir support and exceptions where the nature of the support doesnot need the cable to be fastened.Substantiation: In order to maintain a well managed, safe,installation effected in a neat and workman like manner, cablesmust be fastened where supported. Unfastened cables may become a hazard if left hanging around unfastened. Unfastenedcables may cause a person or object (e.g. tools) to hang up on theequipment causing personal injury or equipment damage.Exception 1 allows horizontal runs of cables where inherentlysupported by the machine or machinery system structure, floor ordeck, to lay where supported without fastening. Fastening is notpractical when cables are laying on the floor or deck within thestructure of the machine or machinery system. Fasting is notwarranted where the inherent design and natural construction ofthe machine or machinery system naturally supports the cable runs.Exception 2 allows runs of cables at 45 degrees or less withoutfastening. Fastening is not practical when cables are lying withinthe structure of the machine or machinery system, and is notwarranted where the inherent design and natural construction ofthe machine or machinery system naturally supports the cable runs.At 45 degrees or less cables are not likely to move once in place.

14.1.4.6Recommendation: Add new text describing acceptable cablefastening methods.Substantiation: Cable clamps and cables ties are a readily available,low cost and effective method of fastening cables in place, and areused in common practice for the purpose. Cable ties alone,however, are not a complete fastening solution. In order to fasten acable with a cable ties additional hardware is required. Thatadditional hardware is defined in the text of 14.1.4.6.Cable tie mounts are a common usage item. A substantialmechanical fastening method for cable tie mounts is desirable inorder to maintain the integrity of the assembly. Screw fastening issuch a substantial method. The structural members of machinesare typically of substantial construction, and can serve as a safe andeffective fastening platform when cables are fastened with cable tiesaround the members or through holes in the members.Cable mounting clamps are common usage items that are expresslyintended for the purpose of fastening cables in place. As such,cable mounting clamps are acceptable means.Other methods of cable fastening may be deemed acceptable basedon the judgment of the applicable authority having jurisdiction.

14.1.4.7

Recommendation: Add new text describing current practices.Substantiation: In order to maintain a neat and workman likeassembly, cable ties should be cut flush once installed. Reusablecable ties have a propensity to loosen with time, and therefore donot maintain the integrity of the assembly over time.

14.1.4.8Recommendation: Add new text describing protection of cable.Substantiation: Cables must not be subjected to physical damage.Clause 14.1.4.8 identifies methods by which physical damage to acable can be avoided.Routing cables in such a way so as to ensure that cable runs cannotbe damaged, or using a commercially available walk or drive overcable protective devices are acceptable and effective methods ofprotection.Routing cables in a cable trunk (wire way) or using a trapezoidalwalk over raceway can be specifically designed and constructed bythe machinery supplier for the purpose cable protection are alsoacceptable and effective methods of protecting cables.

14.1.4.9Recommendation: Add new text restricting the cable-bendingradius.Substantiation: Bends in cables should not be made in a mannerthat places undue stress on the integrity of the cable. Arequirement for a inner edge bend radius of not less than five timesthe diameter of the cable will ensure the integrity of the cable at


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bends in the cable run. A typical cable manufacturerrecommended minimum bending radius, for fixed installation ofcables, is between 3 and 5 times the cable diameter.

14.1.4.10Recommendation: Add new text concerning the handling of excesscable installed on a machine.Substantiation: Cables, as typically applied for industrial machinerycan be either of a perfect length, or longer than required. Clause14.1.4.10 provides requirements for the neat and workman likehandling of excess cable lengths in a consistent, identifiablemanner. The exception to Clause 14.1.4.10 is consistent with thepractices outlined in Exception 1 to Clause 14.1.4.5.

14.2Recommendation: Add new title, “Identification of conductors”.New add new section and name “14.2 Identification ofconductors”, section contents, relocated from NFPA 79:1997 16.1.1through 16.1.3 materialSubstantiation: Chapter 14 is divided into 5 sections 1 Connectionsand routing, 2 Identification of conductors, 3 Wiring insideenclosures, 4 Wiring outside enclosures and 5 Raceways (ducts),support systems (cable supports), connection boxes and otherboxes. The proposed new title more accurately reflects the text.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

Under the old 16.1 General requirements, 16.1.1 through 16.1.3,though not in the title, deals with the general topic of theidentification of conductors. In the new proposal for section 14.2,the topic, identification or conductors, is more broadly covered infour subsections

14.2.1 Recommendation: Relocate NFPA 79 1997 Edition 16.1 title,“General requirements to 14.2.1 and renumber.Substantiation: This subsection, “General requirements”, is used toconsolidate information that applies to all the parts of the section14.2 into one area for clarity. Section 14.2 is divided into 4subsections 1 General requirements, 2 Identification of theequipment grounding (protective) conductor, 3 Identification ofthe grounded circuit conductor, and 4 Identification by color forother conductors. Editorial addition to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.2.1.1Recommendation: Replace existing NFPA 79 1997 Edition 16.1.11st sentence with new text expanding general identification ofconductors requirements. Move existing NFPA 79 1997 Edition16.1.3 Exception 1, Exception 2, Exception 3 to proposed 14.2.1.1“General requirements” of “Identification of conductors”.Substantiation: The requirements from the existing NFPA 79 1997Edition 16.1.1. first sentence are covered in 14.2.1.1. Therequirement for the identification to appear on the diagrams iscovered in new proposed chapter 18. Position of exceptions 1 & 3to clarify when it is to apply. Previous position NFPA79 1997 16.1.3did not reflect the original intention that it should apply toconductors identified either by number / letter or by color.Position of exception 2 to clarify when it is to apply. Previousposition NFPA79 1997 16.1.3 did not reflect the original intentionthat it should apply to conductors identified by color..<<NFPA 79 1997 Edition 16.1.1 2nd sentence references for colorcoding [NFPA 79 1997 Edition 16.1.2 and 16.1.3] are covered innew 14.2.2 and 14.2.3. >>

<<The requirements from the existing 16.1.1, first sentence arecovered in 14.2.1.1, and the second sentence is covered in 14.2.2.1and 14.2.3.1.>>

14.2.1.2Recommendation: Add new text clarifying conductor identificationmarking requirementsSubstantiation: Although not specifically stated in the currentNFPA79 the use of Arabic numbers and Roman letters is still theexpected normal practice. The most direct reference to theexclusive use of Roman letters and Arabic numbers in NFPA 791997 Annex E Device and component designations.

14.2.2Recommendation: Add new title, “Identification of the equipmentgrounding (protective) conductor”. Move 16.1.2 to subsection

14.2.2 “Identification of the equipment grounding (protective)conductor”. The subsection includes the material from 16.1.2 andsome additional materialSubstantiation: Section 14.2 is divided into 4 subsections 1 Generalrequirements, 2 Identification of the equipment grounding(protective) conductor, 3 Identification of the grounded circuitconductor, and 4 Identification by color for other conductors.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

<<NFPA 79 1997 Edition 16.1.1 2nd sentence references for colorcoding [NFPA 79 1997 Edition 16.1.2 and 16.1.3] are covered innew 14.2.2 and 14.2.3. >>

14.2.2.1

Recommendation: Retain NFPA 79 1997 Edition 16.1.2 andrenumber as 14.2.2.1, and add a new 2nd sentence: “This coloridentification shall be strictly reserved for the equipment grounding(protective) conductor”. Add exception 1, which is exception 3from NFPA 79 1997 Edition 16.1.3, it is added here to clarify that itis also directed to the equipment-grounding conductor. MoveNFPA 79 1997 Edition 16.1.2 Exception 1 to 14.2.2.1 Exception 2.Move NFPA 79 1997 Edition 16.1.2 Exception 2 to 14.2.2.1Exception 3. Move the note from NFPA 79 1997 16.1.2, as a notein 14.2.2.1.

“European standards require the use of the bicolor (GREEN-AND-YELLOW for this purpose”, has been corrected. The word “require“ is not a correct statement. The note was correct only when coloris the sole means of identification, additional information may befound in IEC 60204-1: 1997 14.2.2.

Added a description of bicolor marking to the note.Substantiation: Other than clarifications, and a correction andaddition to the note, there are no changes to the existing NFPA 791997 Edition 16.1.2. Editorial change to NFPA 79 1997 Edition16.1.2 location following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

<< The requirements from the existing NFPA 79 1997 Edition16.1.1,1st sentence is covered in 14.2.1.1, and the second sentence iscovered in 14.2.2.1 and 14.2.3.1. >>

14.2.2.2

Recommendation: Add new equipment grounding (protective)conductor is identified option text.Substantiation: The new text adds a solution to the situation wherethe identification of the equipment grounding conductor isdifficult, to at least require that it be clearly identify at the ends oraccessible position in a uniform way.

14.2.3 Recommendation: Add title, “Identification of the grounded circuitconductor”. Move the part of NFPA 79 1997 Edition 16.1.3 thatcovers the identification of the grounded circuit conductor tosubsection 14.2.3Substantiation: NFPA 79 1997 Edition 16.1.3 covers two items thatit is broken down and covered in 14.2.3 Identification of thegrounded circuit conductor and 14.2.4 Identification by color forother conductors. In 14.2.3 the identification of the groundedcircuit conductor, though the requirement is clearer it has notchanged. Section 14.2 is divided into 4 subsections 1 Generalrequirements, 2 Identification of the equipment grounding(protective) conductor, 3 Identification of the grounded circuitconductor, and 4 Identification by color for other conductors.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

<<NFPA 79 1997 Edition 16.1.1 2nd sentence references for colorcoding [NFPA 79 1997 Edition 16.1.2 and 16.1.3] are covered innew 14.2.2 and 14.2.3. >>14.2.3.1

Recommendation: Locate NFPA 79 1997 Edition 16.1.3requirements for a grounded circuit conductor, the 5th and 6thbulleted items, and the note following the 6th bullet here,editorially revise text and renumber.Substantiation: In 14.2.3.1 the identification of the grounded circuitconductor, though the requirement is clearer, it has not changed.Natural Gray will become just Gray in the next edition of the NEC.


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The existing note was corrected, the color light blue is onlyrequired when color is the sole means of identification ref. IEC60204-1. Editorial change to NFPA 79 1997 Edition 16.1.3, materiallocation is following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

<< The requirements from the existing NFPA 79 1997 Edition16.1.1,1st sentence is covered in 14.2.1.1, and the second sentence iscovered in 14.2.2.1 and 14.2.3.1. >>

14.2.3.2Recommendation: Retain NFPA 79 1997 Edition 16.1.3, 6th bulletand 7th bullet, the 1st sentence of bullet 7 is revised and renumber.Substantiation: In 14.2.3.2 the identification of other groundedcircuit conductors, though the requirement is clearer, it has notchanged. Information for use of other than grounded conductorsplaced here for clarity, and revised for grammar. Editorial changeto NFPA 79 1997 Edition 16.1.3, material location is following IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition

14.2.3.3Recommendation: Add new color identification of groundedcircuit bus bar text.Substantiation: Opens the possibility of using color to identify thegrounded circuit conductor when bus bars are used.

14.2.4 Recommendation: Add new title, “Identification by color for otherconductors”. Move the part of NFPA 79 1997 Edition 16.1.3 thatcovers the identification by color for other conductors tosubsection 14.2.4Substantiation: NFPA 79 1997 Edition 16.1.3 covers two items that itare proposed to be broken down and covered in 14.2.4Identification by color for other conductors, and 14.2.3Identification of the grounded circuit conductor. Section 14.2 isdivided into 4 subsections 1 General requirements, 2 Identificationof the equipment grounding (protective) conductor, 3Identification of the grounded circuit conductor, and 4Identification by color for other conductors. Editorial addition tohelp organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.2.4.1

Recommendation: Retain and revise NFPA 79 1997 Edition 16.1.34th bullet here that covers the identification by color forconductors that remain energized when the main disconnectingmeans is in the OFF position. Move existing NFPA 79 1997 Edition16.1.3 Exception 1 to proposed 14.2.1.1 and 14.2.4.1“Generalrequirements” and “ Identification of color for other conductors”of section 14.2.“Identification of conductors”. Move NFPA 79 1997Edition 16.1.3 Exception 2 to 14.2.4.1 Exception 2. NFPA 79 1997Edition 16.1.3 Exception 3 applied to ungrounded circuitconductors is covered in 14.2.4.2.Substantiation: Clarifies that the reserved colors yellow or orangeare for circuits that remain energized when the main disconnect isin the off position. The note following the NFPA 79 1997 Edition16.1.3 4th bullet, has been revised to allow for the use of eitheryellow or orange identification for this purpose. 14.2.4.1 Clarifiesthat the reserved colors yellow or orange are for circuits thatremain energized when the main disconnect is in the off position.This is not a new requirement only expands to either yellow ororange are to be used for this purpose. The original choice ofyellow over orange was the then availability of orange wire versesyellow. Orange is used in IEC built machines to warn of andoutside voltage for control circuits in a cabinet that remainenergized when the main disconnect is in the off position. Yellow isused in NEMA built machines to warn of a outside voltage forcontrol circuits in a cabinet that remain energized when the maindisconnect is in the off position. Either color would represent thesame hazard; thus both colors are reserved for this use. Editorialaddition to help organize the material and follow IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.2.4.2Recommendation: The new text adds the requirement, that whencolor is used for identification, that it be consistent and reflects thecurrent good practice. The exception adds the option to be able tore-identify color coding on multi conductor cables

Substantiation: Adds the requirement that when color is used foridentification, it is to be consistent throughout, and to be able tore-identify by color coding conductors in multi conductor cables.The exception also requires the re-identification formulticonductor cables to be made at time of installation. Therequirement is consistent with the identification / re-identificationmeans in NFPA 70: 1999: 2000 “Use and Identification ofGrounded conductors” –6 “Means of Identifying GroundedConductors” (e) “Grounded Conductors of MulticonductorCables” Exception 1. Also 250 “Grounding” –119 “Identification ofEquipment Grounding conductors.” (b) “Multiconductor Cable.”

14.2.4.3

Recommendation: Move NFPA 79 1997 Edition 16.1.3 1st, 2nd and3rd bulleted items and include copy of the exceptions to clarifywhere they do apply. Substantiation: Editorial addition to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.3

Recommendation: Locate NFPA 79 1997 Edition 16.2 title “Panelwiring”, to 14.3, change to “Wiring inside enclosures” andrenumber. Section contents include, material relocated fromNFPA 79:1997 Edition 16.2.1 through 16.2.3 and additional16.4.1matrialSubstantiation: The new name “Wiring inside enclosure”,recognizes that the topic covers more than just the wiring on themounting plate [panel]. Chapter 14 is divided into 5 sections 1Connections and routing, 2 Identification of conductors, 3 Wiringinside enclosures, 4 Wiring outside enclosures and 5 Raceways(ducts), support systems (cable supports), connection boxes andother boxes. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.3.1Recommendation: Locate NFPA 79 1997 Edition 16.2.1 andrenumber. Make editorial change to the 2nd sentence.Substantiation: Revised the 2nd sentence for clarity, and add notewith additional information. Editorial additions are to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

14.3.2Recommendation: Replace NFPA 79 1997 Edition 16.2.2 with newtext that require the same results but allows additional methods toachieve those results.Substantiation: The text revision will ensure adequate access to allequipment and to correlate with NFPA 79 1997 Edition 12.2.6.Editorial structure changes are to follow IEC 60204-1 1997 andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.3.3Recommendation: Add text representing current practice formounted devices on occasionally moved movable parts of amachine such as on panel doors. Requiring conductors to beanchored is consistent with 14.1.2.4Substantiation: Acknowledge the current practice of mountingsome equipment on occasionally moved machine parts such as thepanel door. By adding the practice to NFPA79 is also clarify thatthe other construction requirements of NFPA 79 need to befollowed for this type of mounted installation of equipment, suchas conductor support.

14.3.4Recommendation: Add new text to require support for allconductors in panel.Substantiation: 14.3.1 could be read that only panel conductorshave to be supported, this additional text is to clarify that allconductors in a panel need to have support, consistent withcurrent practice

14.3.5Recommendation: Move NFPA 79 1997 Edition 16.2.3 here andrenumber.Substantiation: Editorial structure changes are to follow IEC 60204-1 1997 and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.


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14.3.6

Recommendation: Add new text to clarify that the requirement of14.3.5 for control wiring is not a requirement for power andinstrument measuring circuits.Substantiation: Provides information for a practice not presentlycovered in this standard.

14.3.7Recommendation: Add new text to include current practice ofusing AC receptacles, AC plugs, flexible cords, appliance couplers,power cord sets in panel wiring schemes.Substantiation: Provides information for a current acceptablepractice not presently covered in this standard.

14.4

Recommendation: Move NFPA 79 1997 Edition 16.3 title,“Machine wiring”, to section 14.4 “Wiring outside enclosures” [andmodify title]. Section contents include, material relocated fromNFPA 79:1997 Edition 16.3.1 through 16.3.12 and 16.5 andadditional NFPA 79:1997 14.1 attachment plugs materialSubstantiation: Chapter 14 is divided into 5 sections 1 Connectionsand routing, 2 Identification of conductors, 3 Wiring insideenclosures, 4 Wiring outside enclosures and 5 Raceways (ducts),support systems (cable supports), connection boxes and otherboxes. The proposed new title more accurately reflects the text.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

14.4.1Recommendation: Add new title “General requirements”, and text.Substantiation: Provides information that, though not directlystated, is consistent with existing requirements presently in NFPA79:1997 Edition. This subsection, “General requirements”, is usedto consolidate information that applies to all the parts of thesection 14.4 into one area for clarity. Section 14.4 is divided into 6subsections 1 General requirements, 2 External raceways (ducts), 3Connection to moving elements of the machine, 4 Interconnectionof devices on the machine, 5 Attachment plug and receptacle(plug/socket) combinations, and 6 Dismantling for shipment.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

14. 4. 2Recommendation: Add new title ”External raceways (ducts)”.Substantiation: Section 14.4 is divided into 6 subsections 1 Generalrequirements, 2 External raceways (ducts), 3 Connection to movingelements of the machine, 4 Interconnection of devices on themachine, 5 Attachment plug and receptacle (plug/socket)combinations, and 6 Dismantling for shipment. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.4.2.1Recommendation: Replace NFPA 79 1997 Edition 16.3.7 witheditorial changes to text.Substantiation: Clarifies it is the conductors of the same circuit thatare to be routed together. Editorial addition to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.4.2.2Recommendation: NFPA 79 1997 Edition 16.3.1 relocated to14.4.2.2, with editorial changes to text, the change in reference to14.5 reflects moving material from clause 17 to 14.5.and exceptionreflecting current acceptable practice added.Substantiation: Editorial additions are to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition. Providesadditional guidance on cable installations.

14.4.2.3Recommendation: Replace NFPA 79 1997 Edition 16.3.2 and16.3.12 with broader requirement text that also effectively includesthe exception in NFPA 79 1997 Edition 16.3.2.Substantiation: Provides for broader selection of fittings, but thatselection must still be identified for the purpose applied. Editorialadditions are to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA Technical

Committee Documents 2000 Edition. Provides additional guidanceon cable installations.

14.4.2.4Recommendation: Replace NFPA 79 1997 Edition 16.3.3 with textthat allows a broader selection of material identified for theapplication.Substantiation: New text includes the use of conduit or cableidentified for use in the physical environment. This addition willhelp to consolidate similar requirements into one area. Editorialchange to NFPA 79 1997 Edition material location is following IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition

14.4.2.5Recommendation: Replace NFPA 79 1997 Edition 16.3.4 with textthat allows a broader selection of material identified for theapplication. Effectively includes the NFPA 79 1997 Edition 16.3.6exception.Substantiation: Provides additional information. New text includesthe use of conduit or cable identified for use in the physicalenvironment. This addition will help to consolidate similarrequirements into one area. NFPA 79 1997 Edition 16.3.4 wasrelocated to 14.4.2.5, the clarification and exception are covered by14.5.1.1 which requires the use of raceway (duct) be identified foruse in the physical environment. Note: Paragraph 14.5.10.6 addressinstallation concerns from NFPA 79 1997 Edition 16.3.4 for the usesof cords. Editorial change made to NFPA 79 1997 Edition materiallocations are following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.4.3Recommendation: Add new title, “Connection to moving elementsof the machine”.Substantiation: Section 14.4 is divided into 6 subsections 1 Generalrequirements, 2 External raceways (ducts), 3 Connection to movingelements of the machine, 4 Interconnection of devices on themachine, 5 Attachment plug and receptacle (plug/socket)combinations, and 6 Dismantling for shipment. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.4.3.1

Recommendation: Update NFPA 79 1997 Edition 16.3.5 witheditorial changes to the text to include the exception and referenceto the same conductor requirements in NFPA 79 1997 Edition thathave been relocated in this new edition. .Substantiation: NFPA 79 1997 Edition 16.3.5 requirements havebeen relocated to 14.4.3.1 and 14.4.3.2 and 14.5.10.6. Paragraph14.4.3.1 addresses more completely in the reference to 13.7, theconstruction of conductors that are used for flexible and flexingservice. The editorial addition is to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.4.3.2

Recommendation: Update NFPA 79 1997 Edition 16.3.5 withadditional new text.Substantiation: NFPA 79 1997 Edition 16.3.5 material has beenrelocated to the proposed 14.4.3.1 and 14.4.3.2 and 14.5.10.6.Paragraph 14.4.3.2 and 14.5.10.6 address installation concerns. Theeditorial addition is to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

14.4.3.3Recommendation: Add new text for installation practices and useof cables with flexible properties.Substantiation: Provides information not presently covered in thisstandard. Requirements were added to this subclause to specifyprotection for flexible cables against potential abuse. NFPA 791997 Edition 16.3.6 is relocated to the new proposed 14.4.3.10 withclarification as to how to accomplish the requirement in the newproposed 14.4.3.3 and 14.4.3.5. The NFPA 79 1997 Edition 16.3.6exception is covered in the new proposed 14.4.2.5. Editorialadditions are to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.


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14.4.3.4Recommendation: Add new text for cable sheath suitability.Substantiation: Requirements were added to this subclause for theuse of a type of cable sheath that is suitable for the environment.

14.4.3.5

Recommendation: Add new text for clarification.Substantiation: NFPA 79 1997 Edition 16.3.6 is relocated to thenew proposed 14.4.3.10 with clarification as to how to accomplishthe requirement in the new proposed 14.4.3.3 and 14.4.3.5. TheNFPA 79 1997 Edition 16.3.6 exception is covered in the newproposed 14.4.2.5. Editorial additions are to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.4.3.6Recommendation: Add new text reflecting current practice.Substantiation: Provides information not presently in this standard.



Table XWRecommendation: Add new Table XW referenced in 14.4.3.8.Substantiation: Provides information not presently in this standard.


14.4.3.10

Recommendation: Relocate NFPA 79 1997 Edition 16.3.6 to14.4.3.10Substantiation: NFPA 79 1997 Edition 16.3.6 is relocated to the newproposed 14.4.3.10 with clarification as to how to accomplish therequirement in the new proposed 14.4.3.3 and 14.4.3.5. The NFPA79 1997 Edition 16.3.6 exception is covered in the new proposed14.4.2.5. Editorial additions are to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.4.4Recommendation: Add new title, “Interconnection of devices onthe machine” and add new text to recommend that accessible testpoints be provide to assist in maintenance of these devices.Substantiation: In many cases the new text represents currentpractice consistent with the requirements in NFPA 79 1997 Edition12.2 and 12.6, it enhances the safety efficiency during maintenanceof the machine. The where practicable is to allow for thoseapplications where this requirement cannot be met. Section 14.4 isdivided into 6 subsections 1 General requirements, 2 Externalraceways (ducts), 3 Connection to moving elements of themachine, 4 Interconnection of devices on the machine, 5Attachment plug and receptacle (plug/socket) combinations, and6 Dismantling for shipment. Editorial addition to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.4.5Recommendation: Add new title, “Attachment plug and receptacle(plug/socket) combinations”.Substantiation: Section 14.4 is divided into 6 subsections 1 Generalrequirements, 2 External raceways (ducts), 3 Connection to movingelements of the machine, 4 Interconnection of devices on themachine, 5 Attachment plug and receptacle (plug/socket)combinations, and 6 Dismantling for shipment. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.14.4.5.1Recommendation: NFPA 79 1997 Edition 16.3.9 is relocated to14.4.5.1 with slight editorial revision [change “are permitted” to “shall be permitted”].Substantiation: Revised for clarity. This change will help toconsolidate information into one area. Editorial change to NFPA79 1997 Edition material location following IEC 60204-1 1997

Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition

14.4.5.2Recommendation: Move NFPA 79 1997 Edition 14.1.1 here, reviseand renumber.Substantiation: Added plug/socket information, 300-voltplug/socket skirting addresses the arcing hazard with interruptinginductive loads. This will help to consolidate information into onearea. Editorial change to NFPA 79 1997 Edition material locationfollowing IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition

14.4.5.3Recommendation: Locate NFPA 79 1997 Edition 14.1.2 here, reviseand add an exception for PELV circuits. Move the 2nd sentence tonew proposed 16.1.1(b).Substantiation: Editorial revisions were made to NFPA 79:199714.1.2. The exception was provided for PELV circuits and thoseusing multipole connectors because such applications do notrequire an equipment grounding conductor.

14.4.5.4Recommendation: Added a new requirement to use a load-breakrated receptacle or interlocked with a load break switch for motorloads only.Substantiation: Plugs and receptacles used for motor loadapplications which are likely to be opened under load must meetthe disconnection requirements of 5.3.3.3 to reduce the hazard topersonal.

14.4.5.5Recommendation: Add new text.Substantiation: Marking plugs and receptacles enhances safety.Mechanical coding ensures the circuit is connected to the intendedequipment.

14.4.5.6

Recommendation: Add new text.Substantiation: This requirement prevents the use of powerreceptacles on control circuits.

14.4.5.7Recommendation: Delete the first sentence of NFPA 79-1997Edition 14.1.3. Revise the second sentence. Delete the exception.Substantiation: The provisions of the first sentence and theexception are sufficiently covered in the newly proposed 14.4.5.2that require the attachment plugs and receptacles to be listed forthe intended use.

14.4.6Recommendation: Add new title, “Dismantling for shipment”.Move NFPA 79 1997 Edition 16.3.10 here, revise the 1st sentence,and add a new 2nd and 3rd sentence.Substantiation: Providing temporary protection will help ensurereliable reinstallation and prevent contaminants from entering theraceways and control enclosure. “Where practicable” was added toexempt special situations from having to comply with thisrequirement, because in some cases, additional terminations canreduce reliability. Section 14.4 is divided into 6 subsections 1General requirements, 2 External raceways (ducts), 3 Connectionto moving elements of the machine, 4 Interconnection of deviceson the machine, 5 Attachment plug and receptacle (plug/socket)combinations, and 6 Dismantling for shipment. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5

Recommendation: Relocate NFPA 79 1997 Edition 17 title,“Raceways, junction boxes, and pull boxes”, to 14.5, revise“Raceways (ducts), support systems (cable supports), connectionboxes and other boxes”. Section contents include, materialrelocated from NFPA 79:1997, 17 and additional material.Substantiation: Revised title because it provides additionalinformation about the section content. Chapter 14 is divided into 5sections 1 Connections and routing, 2 Identification of conductors,3 Wiring inside enclosures, 4 Wiring outside enclosures and 5Raceways (ducts), support systems (cable supports), connectionboxes and other boxes. Editorial addition to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.


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14.5.1Recommendation: Move NFPA 79 1997 Edition 17.1 title, “Generalrequirements”, to 14.5.1 and renumber. This gives a place for theparagraphs and other material that apply to the entire sectionSubstantiation: This subsection, “General requirements”, is used toconsolidate information that applies to all the parts of the section14.5 into one area for clarity. Section 14.5 is divided into 11subsections: 1 General requirements, 2 Percentage fills of raceways(ducts), 3 Rigid conduit and fittings, 4 Flexible conduit andfittings, 5 Flexible non-metallic conduit an fittings, 6 Wireways(cable trunking systems), 7 Machine compartments and wireway(cable trunking systems), 8 Connection boxes and other boxes, 9Motor connection boxes, 10 Cord, and 11 Cable trays. Editorialaddition to help organize the material and follow IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.5.1.1Recommendation: Add new text.Substantiation: Provides information not in the present standard.The new text is consistent with NFPA 70-1999, Section 110-3(a).

14.5.1.2Recommendation: Move NFPA 79 1997 Edition 17.1.1 here, withminor editorial changes [“May” changed to “can” and “ducts”added following “raceways”] and renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition

14.5.1.3

Recommendation: Replace NFPA 79 1997 Edition 17.1.2 with newtext. Delete Note.Substantiation: Limits use of drain holes so not to compromiseenclosure integrity, and the note is covered in Chapter 8 thatcontains the grounding information.

14.5.2

Recommendation: Add title “Percentage fills of raceways (ducts)”.Move NFPA 79 1997 Edition 17.2 to 14.5.2 and renumber. AddNote from NFPA 70 1999 edition Chapter 9 Table 1 FPN No. 1,2nd sentence.Substantiation: Section 14.5 is divided into 11 subsections: 1General requirements, 2 Percentage fills of raceways (ducts), 3Rigid conduit and fittings, 4 Flexible conduit and fittings, 5Flexible non-metallic conduit an fittings, 6 Wireways (cabletrunking systems), 7 Machine compartments and wireway (cabletrunking systems), 8 Connection boxes and other boxes, 9 Motorconnection boxes, 10 Cord, and 11 Cable trays. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.3

Recommendation: Add title, “ Rigid conduit and fittings”, to 14.5.3,revise and renumber.Substantiation: This revision is to have this clause cover all conduittypes not just metallic. This will help to consolidate informationinto one area. All non-flexible conduits added or moved under14.5.3 with common requirements under 14.5.3.1 “Generalrequirements”. Section 14.5 is divided into 11 subsections: 1General requirements, 2 Percentage fills of raceways (ducts), 3Rigid conduit and fittings, 4 Flexible conduit and fittings, 5Flexible non-metallic conduit an fittings, 6 Wireways (cabletrunking systems), 7 Machine compartments and wireway (cabletrunking systems), 8 Connection boxes and other boxes, 9 Motorconnection boxes, 10 Cord, and 11 Cable trays. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.3.1Recommendation: Add title, “General requirements” toconsolidate common requirements for rigid conduit from existingNFPA79.Substantiation: This addition will help to organize and consolidatecommon requirements. This (sub)sub-subsection, “Generalrequirements”, is used to consolidate information that applies toall the parts of the subsection 14.5.3 into one area for clarity.Subsection 14.5.3 is divided into 3 sub-subsections 1 Generalrequirements, 2 Metal type nonflexible conduit, and 3 Rigid non-

metallic conduit (PVC Schedule 80). Editorial relocation to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

14.5.3.1.1Recommendation: Move NFPA 79 1997 Edition 17.3.2, 17.4reference to 17.3.2,17.5 reference to 17.3.2 and 17.6.2 here,combine and renumber.Substantiation: This will consolidate existing common minimumsize clause for metallic and nonmetallic nonflexible conduit intoone area. Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.NFPA 79 is original text. Also NFPA79 1997 17.4 NEC 1999 345-6(a), Also NFPA79 1997 17.3.2 NEC 1999 346-6 (a), Also NFPA791997 17.6.2 NEC 1999 347-10 (a), Also NFPA79 1997 17.5 NEC 1999348-7 (a), are referenced.

14.5.3.1.2

Recommendation: Add new text and note.Substantiation: This will help consolidate non-flexing conduitinformation into one clause, and is consistent with: NFPA 70 1999Edition; Article 345-6(b) and FPN; Article 346-6(b) and FPN;Article 347-10(b) and FPN; and, Article 348-7(b) and FPN on therange of conduit sizes and metric conversion of conduit size.

14.5.3.1.3Recommendation: Move NFPA 79 1997 Edition 17.3.6, 17.4reference to 17.3.6 and 17.6.5 here, combine, and renumber. Move17.3.6 Exception to 14.5.3.1.3 Exception.Substantiation: This will help consolidate non-flexing conduitbushing requirements into one area. Editorial change to NFPA 791997 Edition material location following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition. NFPA 79 is original text. Also NFPA791997 17.4 NEC 1999 345-15, Also NFPA79 1997 17.3.6 NEC 1999 346-15, Also NFPA79 1997 17.6.5 NEC 1999 347-12, are referenced.Note 17.5 reference to 17.3.6 does not make sense for bushingrequirements.

14.5.3.1.4

Recommendation: Move NFPA 79 1997 Edition 17.3.7, 17.4reference to 17.3.7,17.5 reference to 17.3.7 and 17.6.6 here,combine and renumber.Substantiation: This will consolidate existing conduit minimumbend requirements for metallic and nonmetallic nonflexibleconduit into one area. Editorial change to NFPA 79 1997 Editionmaterial location following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition. NFPA 79 is original text. Also NFPA79 1997 17.4 NEC1999 345-10, Also NFPA79 1997 17.3.7 NEC 1999 346-10, AlsoNFPA79 1997 17.6.6 NEC 1999 347-13, Also NFPA79 1997 17.5 NEC1999 348-11, are referenced.

<<Insert NFPA 79 1997 Edition Table 13 and Notes 1 and 2 here. >>

Recommendation: <<Table 13 is to be editorially re- designatedduring publication to meet Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition and referenced in theproposed 14.5.3.1.4 as table XX [editorially TBD]. >>Revise table XX SI units note from 1 in = 25.4mm to 25mm = 1inchSubstantiation: This will consolidate existing conduit minimumbend requirements for metallic and nonmetallic non-flexibleconduit into one area. Editorial change to NFPA 79 1997 Editionmaterial location following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition. NFPA 79 is original table.

14.5.3.1.5

Recommendation: Move NFPA 79 1997 Edition 17.3.8, 17.4reference to 17.3.8,17.5 reference to 17.3.8 and 17.6.7 here,combine and renumber.Substantiation: This will consolidate existing conduit maximumnumber of bends requirement for metallic and nonmetallic non-flexible conduit into one area. Editorial change to NFPA 79 1997Edition material location following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition. NFPA 79 is original text. Also NFPA791997 17.4 NEC 1999 345-11, Also NFPA79 1997 17.3.8 NEC 1999 346-


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11, Also NFPA79 1997 17.6.7 NEC 1999 347-14, Also NFPA79 199717.5 NEC 1999 348-12, are referenced.

14.5.3.2

Recommendation: Add new title “Metal type non flexible conduit”.Substantiation: All metal type, non-flexible, conduit moved to14.5.3.2 with common NFPA 79 1997 original text requirements to14.5.3.2.1 “General requirements”. Subsection 14.5.3 is dividedinto 3 sub-subsections 1 General requirements, 2 Metal typenonflexible conduit, and 3 Rigid non-metallic conduit (PVCSchedule 80). Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.5.3.2.1

Recommendation: Add new title, ”General requirements”.Substantiation: Sub-subsection 14.5.3.2 is divided into 4 (sub)sub-subsections 1 General requirements, 2 Rigid metal conduit andfittings, 3 Intermediate metal conduit, and 4 Electrical metallictubing. Editorial relocation to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.This (sub)sub-subsection, “General requirements”, is used toconsolidate information that applies to all the parts of thesubsection 14.5.3.2 into one area for clarity

14.5.3.2.1.1

Recommendation: Move and consolidate NFPA 79 1997 Edition17.3.3, 17.4 reference to 17.3.3, 17.5 reference to 17.3.3, here andrenumber.Substantiation: All metal type, non-flexible, conduit support,requirements moved to 14.5.3.2.1.1 with common NFPA 79 1997original text. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.5.3.2.1.2

Recommendation: Move NFPA 79 1997 Edition: 17.3.4, 17.4reference to 17.3.4, 17.5 reference to 17.3.4; and 17.3.5, 17.4reference to 17.3.5, 17.5 reference to 17.3.5; here, revise andrenumber.Substantiation: All metal type, non-flexible, conduit fitting andthread, requirements moved to 14.5.3.2.1.2 with common, originaltext, from NFPA 79 1997 used. Editorial addition to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.5.3.2.2Recommendation: Move NFPA 79 1997 Edition 17.3 title, “Rigidmetal conduit and fittings”. Move NFPA 79 1997 Edition 17.3.1 tohere, move some text to a note, revise and renumber.Substantiation: This clause will help to consolidate Rigid metalconduit and fittings requirements into one area. The specificationsfor a particular type of rigid metal conduit are not needed and therequirement “identified for the conditions of service” is sufficient.The caution about dissimilar materials is moved to a note. TheNFPA 79 1997 Edition 17.3.1 exception is for a practice notcurrently in wide spread use is not needed. This will help toconsolidate information into one area. Sub-subsection 14.5.3.2 isdivided into 4 (sub)sub-subsections 1 General requirements, 2Rigid metal conduit and fittings, 3 Intermediate metal conduit, and4 Electrical metallic tubing. Editorial relocation to help organizethe material and follow IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.5.3.2.3Recommendation: Move NFPA 79 1997 Edition 17.4 title,“Intermediate metal conduit”, and definition text here, add a noteand renumber.Substantiation: This will help consolidate Intermediate metalconduit information to one area. A note has been addedconcerning dissimilar metals. Sub-subsection 14.5.3.2 is dividedinto 4 (sub)sub-subsections 1 General requirements, 2 Rigid metalconduit and fittings, 3 Intermediate metal conduit, and 4 Electricalmetallic tubing. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.5.3.2.4Recommendation: Move NFPA 79 1997 Edition 17.5 title,“Electrical metallic tubing”, and definition text here, add a noteand renumber.Substantiation: This will help consolidate Electrical metallic tubinginformation to one area. A note has been added concerningdissimilar metals. Sub-subsection 14.5.3.2 is divided into 4(sub)sub-subsections 1 General requirements, 2 Rigid metalconduit and fittings, 3 Intermediate metal conduit, and 4 Electricalmetallic tubing. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.5.3.3

Recommendation: Move NFPA 79 1997 Edition 17.6 title, “Rigidnon-metallic conduit (PVC Schedule 80)”, here, and renumber.Substantiation: Subsection 14.5.3.3 “Rigid non-metallic conduit(PVC Schedule 80) paragraph 14.5.3.3.1 through 14.5.3.3.4consolidates details specific to rigid non-metallic conduit (PVCSchedule 80). Subsection 14.5.3 is divided into 3 sub-subsections 1General requirements, 2 Metal type nonflexible conduit, and 3Rigid non-metallic conduit (PVC Schedule 80). Editorialrelocation to help organize the material and follow IEC 60204-11997 Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.5.3.3.1

Recommendation: Relocate NFPA 79 1997 Edition 17.6.1 to14.5.3.3.1 revise to reflect NFPA 70 1999 347 requirements.Substantiation: The change follows description and construction ofrigid non-metallic conduit, NFPA 70 1999 347-1 and 347-17. Addreference to UL 651 for listing information.

14.5.3.3.2

Recommendation: Locate NFPA 79 1997 Edition 17.6.3, originaltext and tabulated information here and renumber.<<Insert table heading: “Maximum Spacing”. Following paragraph14.5.3.3.2 colons then follow with “In addition, conduit shall besecurely fastened within 3 ft (914 mm) of each box, enclosure, orother conduit termination.”>>Substantiation: Editorial for the location, and table heading willmake the information easier to locate. Editorial change to NFPA79 1997 Edition location following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition

14.5.3.3.3

Recommendation: Move NFPA 79 1997 Edition 17.6.4 here, reviseand renumber. Add new text from NFPA 70 1999 Table 347-9 (A).Substantiation: The NFPA 79 1997 Edition 17.6.4 reference nolonger exists. NFPA 79 1997 Edition17.6.4 updated to the currentequivalent reference in NFPA 70 1999 Edition Table 347-9 (A)

14.5.3.3.4

Recommendation: Move NFPA 79 1997 Edition 17.6.8 here, reviseand renumber. This will change “designed” to “approved”.Substantiation: The change follows NFPA 70 1999 347-6. Editorialchange to NFPA 79 1997 Edition material location following IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition

14.5.4

Recommendation: Add title, “ Flexible metal conduit and fittings”.Move NFPA 79 1997 Edition 17.7, and 17.9 titles to 14.5.4, combine,revise and renumber.Substantiation: This will help to consolidate flexible metal conduitand fittings information into one area. Section 14.5 is divided into11 subsections: 1 General requirements, 2 Percentage fills ofraceways (ducts), 3 Rigid conduit and fittings, 4 Flexible conduitand fittings, 5 Flexible non-metallic conduit an fittings, 6 Wireways(cable trunking systems), 7 Machine compartments and wireway(cable trunking systems), 8 Connection boxes and other boxes, 9Motor connection boxes, 10 Cord, and 11 Cable trays. Editorialaddition to help organize the material and follow IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.


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14.5.4.1

Recommendation: Add new title, “General requirements”, andsubsection.Substantiation: This will help consolidate requirements in onearea. Collected general requirements for Flexible metal conduitsNFPA79 19976 Edition 17.9 & 17.7. This sub-subsection, “Generalrequirements”, is used to consolidate information that applies toall the parts of the subsection 14.5.4 into one area for clarity.Subsection 14.5.4 is divided into 3 sub-subsections 1 Generalrequirements, 2 Flexible metal conduit, and 3 Liquidtight flexiblemetal conduit. Editorial relocation to help organize the materialand follow IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.

14.5.4.1.1

Recommendation: Move NFPA 79 1997 Edition 17.7.3 and 17.9.3and exception here and renumber.Substantiation: This will help to consolidate information into onearea. Editorial change to NFPA 79 1997 Edition material locationfollowing IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition.Reference NFPA 70 1999 Edition 351-5 (a) and exception

14.5.4.1.2

Recommendation: Add new maximum size text including note.Substantiation: This helps to consolidate information into one areaand to be consistent with NEC on the range of conduit sizes fromNFPA 70-1999, 351-5 (b) and FPN

14.5.4.1.3

Recommendation: Move NFPA 79 1997 Edition 17.7.5 here, reviseand renumber. Add “metal” and “liquidtight flexible metalconduit”.Substantiation: This will help to consolidate information into onearea. Editorial change to NFPA 79 1997 Edition material locationfollowing IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition

14.5.4.1.4

Recommendation: Move NFPA 79 1997 Edition 17.7.2 and 17.9.2here, revise and renumber. Expanded concept to include anyflexible conduit. Add as a new 2nd sentence “Connectors shall beof the “union” type.”Substantiation: This will help to consolidate information into onearea. Editorial change to NFPA 79 1997 Edition material locationfollowing IEC 60204-1 1997 Edition structure and Manual of Stylefor NFPA Technical Committee Documents 2000 Edition

14.5.4.2

Recommendation: Add title, “Flexible metal conduit”, Move NFPA79 1997 Edition 17.9 and 17.9.1 to 14.5.4.2, revise definition andrenumber.Substantiation: Flexible metal conduit definition from NFPA 701999 Edition 350-2. Subsection 14.5.4 is divided into 3 sub-subsections 1 General requirements, 2 Flexible metal conduit, and3 Liquidtight flexible metal conduit. Editorial relocation to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

14.5.4.3

Recommendation: Add title, “Liquidtight flexible metal conduit”.Move NFPA 79 1997 Edition 17.7.1 and 17.7.4 to 14.5.4.3, revise andrenumber.Substantiation: Liquidtight flexible metal conduit from NFPA 701999 Edition NEC 351-2. Subsection 14.5.4 is divided into 3 sub-subsections 1 General requirements, 2 Flexible metal conduit, and3 Liquidtight flexible metal conduit. Editorial relocation to helporganize the material and follow IEC 60204-1 1997 Edition structureand Manual of Style for NFPA Technical Committee Documents2000 Edition.

14.5.5

Recommendation: Move NFPA 79 1997 Edition 17.8 title, “Flexiblenon-metallic conduit and fittings”, to 14.5.5, revise and renumber.Substantiation: Deleted “liquidtight” to be more inclusive. Section14.5 is divided into 11 subsections: 1 General requirements, 2

Percentage fills of raceways (ducts), 3 Rigid conduit and fittings, 4Flexible conduit and fittings, 5 Flexible non-metallic conduit anfittings, 6 Wireways (cable trunking systems), 7 Machinecompartments and wireway (cable trunking systems), 8 Connectionboxes and other boxes, 9 Motor connection boxes, 10 Cord, and 11Cable trays. Editorial addition to help organize the material andfollow IEC 60204-1 1997 Edition structure and Manual of Style forNFPA Technical Committee Documents 2000 Edition.

14.5.5.1

Recommendation: Move NFPA 79 1997 Edition 17.8.1 here, reviseand renumber.Substantiation: “This” in last paragraph changed to “Liquidtightflexible nonmetallic” for clarity. Editorial change to NFPA 79 1997Edition material location following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition

14.5.5.2

Recommendation: Move NFPA 79 1997 Edition 17.8.2 here, reviseand renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition

14.5.5.3

Recommendation: Move NFPA 79 1997 Edition 17.8.3 here, revisetext and renumber.Substantiation: Specific conditions changed to more generic asother factors than stated may be involved e.g. dew point.

14.5.5.4

Recommendation: Move NFPA 79 1997 Edition 17.8.5 here, reviseand renumber.Substantiation: Original NFPA 79 1997 edition 17.8.5 text.Reference NFPA 70 1999 Edition 351-5 (a) and exception

14.5.5.5

Recommendation: Maximum trade size and metric conversionnote.Substantiation: To be consistent with NEC on range of conduitsizes from NFPA 70 1999 Edition 351-5 (b) and FPN

14.5.5.6

Recommendation: Move NFPA 79 1997 Edition 17.8.4 here, revisewith editorial clarification and renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.5.5.7

Recommendation: Move NFPA 79 1997 Edition 17.8.6 here andrenumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation following IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.5.6

Recommendation: Move NFPA 79 1997 Edition 17.10, title ”Wireways”, to 14.5.6 and include IEC nomenclature “(cabletrunking systems)”.Substantiation: Section 14.5 is divided into 11 subsections: 1General requirements, 2 Percentage fills of raceways (ducts), 3Rigid conduit and fittings, 4 Flexible conduit and fittings, 5Flexible non-metallic conduit an fittings, 6 Wireways (cabletrunking systems), 7 Machine compartments and wireway (cabletrunking systems), 8 Connection boxes and other boxes, 9 Motorconnection boxes, 10 Cord, and 11 Cable trays. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.6.1

Recommendation: Move NFPA 79 1997 Edition 17.10.1 here,editorially revise for clarity and renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation and add IEC nomenclature, following IEC 60204-1 1997


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Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

<< Delete NFPA 79 1997 Edition 17.10.2. >>Substantiation: Too prescriptive.

14.5.6.2

Recommendation: Move NFPA 79 1997 Edition 17.10.3 here, reviseand renumber. Added requirement for hinged covers.Substantiation: The requirement was added to clarify that the 90-degree cover requirement in NFPA 70-1999, Article 670-5 shouldapply to wireways.

14.5.6.3Recommendation: Move NFPA 79 1997 Edition 17.10.4 here, reviseand renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation and add IEC nomenclature, following IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.5.6.4Recommendation: Move NFPA 79 1997 Edition 17.10.5, 1 st sentencehere, revise and renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation and add IEC nomenclature, following IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.5.6.5Recommendation: Move NFPA 79 1997 Edition 17.10.5, 2 nd

sentence here, revise and renumber.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation and add IEC nomenclature, following IEC 60204-1 1997Edition structure and Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.

14.5.7

Recommendation: Move NFPA 79 1997edition 17.11 title” Machinecompartments and raceways”, is relocated and raceway is changedto wireway and IEC nomenclature “(cable trunking systems)”, isadded to title 14.5.7. Existing NFPA79 1997 Edition 17.11 text isincluded with minor editorial revisions, re-number.Substantiation: Section 14.5 is divided into 11 subsections: 1General requirements, 2 Percentage fills of raceways (ducts), 3Rigid conduit and fittings, 4 Flexible conduit and fittings, 5Flexible non-metallic conduit an fittings, 6 Wireways (cabletrunking systems), 7 Machine compartments and wireway (cabletrunking systems), 8 Connection boxes and other boxes, 9 Motorconnection boxes, 10 Cord, and 11 Cable trays. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.8Recommendation: Change NFPA 79 1997 Edition 17.12 title,“Junction and pull boxes”, to “14.5.8 Connection boxes and otherboxes”.Substantiation: NFPA 79 1997 Edition 17.12 title is relocated to14.5.8. Section 14.5 is divided into 11 subsections: 1 Generalrequirements, 2 Percentage fills of raceways (ducts), 3 Rigidconduit and fittings, 4 Flexible conduit and fittings, 5 Flexible non-metallic conduit an fittings, 6 Wireways (cable trunking systems), 7Machine compartments and wireway (cable trunking systems), 8Connection boxes and other boxes, 9 Motor connection boxes, 10Cord, and 11 Cable trays. Editorial addition to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.5.8.1

Recommendation: Add new accessibility text.Substantiation: This new text clarifies that the accessibility,required in existing NFPA 79 1997 11.3, still includes connectionboxes

14.5.8.2

Recommendation: Change NFPA 79 1997 Edition 17.12 to theproposed text.Substantiation: Clarifies that the general rule of the existing NFPA79 1997 Edition 11.3 applies to these terminal boxes as well.Editorial change to NFPA 79 1997 Edition material location and

add IEC nomenclature, following IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.9Recommendation: Replace NFPA 79 1997 Edition 17.13 title.“Motor terminal boxes”. Change “terminal” to “connection”.Substantiation: Section 14.5 is divided into 11 subsections: 1General requirements, 2 Percentage fills of raceways (ducts), 3Rigid conduit and fittings, 4 Flexible conduit and fittings, 5Flexible non-metallic conduit an fittings, 6 Wireways (cabletrunking systems), 7 Machine compartments and wireway (cabletrunking systems), 8 Connection boxes and other boxes, 9 Motorconnection boxes, 10 Cord, and 11 Cable trays. Editorial additionto help organize the material and follow IEC 60204-1 1997 Editionstructure and Manual of Style for NFPA Technical CommitteeDocuments 2000 Edition.

14.5.9.1Recommendation: Relocate NFPA 79 1997 Edition 17.13 to14.5.9.1. Change “terminal” to “connection”; clarify that the NFPA79 1997 Edition 17.13 contains only a list of example motormounted devices and, that that is not an exhaustive list.Substantiation: Editorial change to NFPA 79 1997 Edition materiallocation and add clarification and IEC terminology, following IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

14.5.9.2Recommendation: Add new text.Substantiation: Provides direction for termination to specific typesof equipment. The requirements represent current good practice

14.5.9.3

Recommendation: Add new text.Substantiation: Change represents current good practice.

14.5.9.4

Recommendation: Add new text.Substantiation: The prohibition of soldered or insulation piercingtype termination’s for motors, and that the new text representcurrent "good practice".

14.5.10

Recommendation: Provide a title, “Cord”, for this new subsection.Substantiation: Because the construction of cord is different thanthat of cable its use is limited. 14.5.10 was added for applicationpurposes. Section 14.5 is divided into 11 subsections: 1 Generalrequirements, 2 Percentage fills of raceways (ducts), 3 Rigidconduit and fittings, 4 Flexible conduit and fittings, 5 Flexible non-metallic conduit an fittings, 6 Wireways (cable trunking systems), 7Machine compartments and wireway (cable trunking systems), 8Connection boxes and other boxes, 9 Motor connection boxes, 10Cord, and 11 Cable trays. Editorial addition to help organize thematerial and follow IEC 60204-1 1997 Edition structure and Manualof Style for NFPA Technical Committee Documents 2000 Edition.

14.5.10.1

Recommendation: Add new text and note.Substantiation: Adds cord to machine wiring practice. Factoryapplied connectors molded onto cord are commonly utilized onthe electrical equipment of industrial machinery. Such connectorsare attached in a controlled environment where comprehensivequality assurance, test, and validation measures are applied.

14.5.10.2

Recommendation: Add new text.Substantiation: Adds cords to machine wiring practice forutilization of cord for connection to the field I/O and similar.Length of a cord is restricted to 50 feet to limit exposure to physicaldamage.

14.5.10.3Recommendation: Add new text.Substantiation: Provides reference for application methodology.


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14.5.10.4

Recommendation: Locate NFPA 79 1997 Edition 16.3.3 here andrevise 1st sentence.Substantiation: The 1st sentence revision will allow cords to beused.

14.5.10.5

Recommendation: Locate NFPA 79 1997 Edition 16.3.4 text here,renumber and revise the 1st sentence to add cord to be used forthis purpose.Substantiation: Covers material not presently in this standard. Theexception is deleted as not pertinent to cord installations. Editorialchange to NFPA 79 1997 Edition material location and add IECnomenclature, following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition.

14.5.10.6

Recommendation: Copy NFPA 79 1997 Edition 16.3.5 here andrevise the 2nd sentence by changing “Flexible cable and conduit” to“Cords with conductors for flexing service”. And adding exceptionSubstantiation: More logical topic location and better covers theanticipated usage. NFPA 79 1997 Edition 16.3.5 has been relocatedto the proposed 14.4.3.1 and 14.4.3.2 and 14.5.10.6. Paragraph14.5.10.6 address installation concerns for the uses of cords.

14.5.11Recommendation: Add title and text for cable tray to be arecognized support system for machinesSubstantiation: Wire and cable that is currently allowed to besupported by the machine frame and other means would not placeany additional hazard if a standard cable tray support system wasused for those same wire and cables on a machine. Section 14.5 isdivided into 11 subsections: 1 General requirements, 2 Percentagefills of raceways (ducts), 3 Rigid conduit and fittings, 4 Flexibleconduit and fittings, 5 Flexible non-metallic conduit an fittings, 6Wireways (cable trunking systems), 7 Machine compartments andwireway (cable trunking systems), 8 Connection boxes and otherboxes, 9 Motor connection boxes, 10 Cord, and 11 Cable trays.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition.

NFPA 79 1997 Edition 14.1.3 Exception

Recommendation: Delete NFPA 79 1997 Edition 14.1.3 Exception.Substantiation: The exception is sufficiently covered in the newproposal for NFPA 79 29002 Edition 14.4.5.2, “listed for theintended use”.

NFPA 79 1997 Edition 16.1.3 First Note

Recommendation: Delete NFPA 79 1997 Edition 16.1.3, first note.Substantiation: When color is used to identify conductors eitheryellow or orange conductors will be encountered with the sameexpectation of a remote disconnection point should be expected.In view if more harmonization the note is not relevant.

NFPA 79 1997 Edition 16.4.1 Exception 2

Recommendation: Delete NFPA 79 1997 Edition 16.4.1 Exception2.Substantiation: NFPA 79 1997 Edition 16.4.1 Exception 2, “Wire-wrapped connections” was not retained as the practice is limited inuse, if at all, for industrial machine construction.

NFPA 79 1997 Edition 16.4.2

Recommendation: Delete NFPA 79 1997 16.4.2 concerning solderconnections.Substantiation: NFPA 79 1997 16.4.2 concerning solder connectionsis too prescriptive concerning solder connections, is unnecessaryand prohibits other current and possible future methods andmaterials .

NFPA 79 1997 Edition 16.5

Recommendation: Delete NFPA 79 1997 Edition 16.5.Substantiation: The necessary requirements for wiring betweenmachines are included in the scope 1.1.4. The requirements in 16.5were to describe the needed support system for the Scope 1.1.4exception, however the support system requirements in the new14.5meets the original need for 16.5 thus 16.5 is not retainedNFPA 79 1997 Edition 17.1.2 Note

Recommendation: Delete NFPA 79 1997 Edition 17.1.2 noteSubstantiation: Grounding issues are covered in the new proposedchapter 8

NFPA 79 1997 Edition 17.3.1 Exception

Recommendation: Delete NFPA 79 1997 Edition 17.1.2. ExceptionSubstantiation: The NFPA 79 1997 Edition 17.3.1 exception is for apractice not currently in wide spread use and is not needed.

NFPA 79 1997 Edition 17.10.2

Recommendation: Delete NFPA 79 1997 Edition 17.10.2.Substantiation: Too proscriptive, necessary requirements coveredin listing tests and 14.5.1.1.

CLAUSE NUMBERS: NFPA 79-1997 VERSUS PROPOSED NFPA79-2002Proposed NFPA 79: 20002 clauses not listed in this table areincluded as additions to NFPA 79: 2000


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Clauses in Substantiation are in numerical order, Last section 14.5.11 and plus proposed deletions

NFPA 79: 1997 Proposed NFPA 79: 2002

Clause Heading / description/ notes Chapter/Sections

Heading / description / notes

14.1.1 14.4.5.214.1.2 14.4.5.314.1.3 14.4.5.714.1.3 Exception 14.4.5.2 In revised text16 Wiring methods and practices 14 Wiring practices16.1 General requirements 14.2.1 General requirements16.1.1 14.2.1.116.1.2 Grounding conductor 14.2.2.116.1.2 Note 14.2.2.116.1.2 Exception 1 14.2.2.116.1.2 Exception 2 14.2.2.116.1.3 Ungrounded conductor ( Black, Red and Blue) 14.2.4.316.1.3 Ungrounded conductor 14.2.4.116.1.3 Ungrounded conductor note Not carried forward16.1.3 Grounded conductor 14.2.3 Identification of the grounded circuit conductor

subsection16.1.3 Grounded conductor note 14.2.3.116.1.3 Exception 1Ungrounded conductor ( Black, Red

and Blue14.2.4.3 Exception 1Ungrounded conductor ( Black, Red and

Blue16.1.3 Exception 1Ungrounded conductor 14.2.4.1 Exception 1Ungrounded conductor16.1.3 Exception 2Ungrounded conductor ( Black, Red


Blue16.1.3 Exception 2Ungrounded conductor 14.2.4.1 Exception 2Ungrounded conductor16.1.3 Exception 3Ungrounded conductor ( Black, Red


Blue16.1.3 Exception 3 Ungrounded conductor 14.2.4.2 In revised text16.1.4 14.1.2.116.1.4 Exception 14.1.2.1 Exception 116.1.5 14.1.1.616.1.6 14.1.1.916.1.7 14.1.1.1016.1.8 First sentence 14.1.1.1116.1.8 Second sentence 14.1.1.316.1.8 Exception 14.1.1.3 In revised text16.1.9 14.1.1.116.2 Panel wiring 14.3 Wiring inside enclosure16.2.1 14.3.116.2.2 14.3.216.2.3 14.3.516.3 Machine wiring 14.4 Wiring outside enclosures16.3.1 14.4.2.216.3.2 14.4.2.316.3.2 Exception 14.4.2.3 In revised text16.3.3 14.4.2.416.3.4 14.4.2.516.3.4 Exception 14.5.1.1 In revised text16.3.5 14.4.3.116.3.5 Exception 14.4.3.1 In revised text16.3.6 14.4.3.1016.3.6 Exception 14.4.2.5 In revised text16.3.7 14.4.2.116.3.8 14.1.3 Conductors of different circuits16.3.9 14.4.5.116.3.10 14.4.6 Dismantling for shipment16.3.11 14.1.1.716.3.12 14.4.2.316.4 Wire connectors and connections 14.1 Connections and routing16.4.1 14.1.1.816.4.1 Exception 1 14.1.1.5 In revised text16.4.1 Exception 2 Not carried forward16.4.2 Not carried forward16.5 Wiring between machines Not carried forward17 Raceways, Junction boxes, and pull boxes 14.5 Raceways (ducts), support systems (cable supports),

connection boxes and other boxes17.1 General requirements 14.5.1 General requirements


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Clauses in Substantiation are in numerical order, Last section 14.5.11 and plus proposed deletions (continued)

17.1.1 14.5.1.217.1.2 14.5.1.317.1.2 Note Not carried forward17.2 Percent fill of raceways 14.5.2 Percentage fills of raceways (ducts)17.3 Rigid metal conduit and fittings 14.5.3 Metal type non flexible conduit17.3.1 14.5.3.2.2 Rigid metal conduit and fittings17.3.1 Exception Not carried forward17.3.2 14.5.3.1.117.3.3 14.5.3.2.1.117.3.4 14.5.3.2.1.217.3.5 14.5.3.2.1.217.3.6 14.5.3.1.317.3.6 Exception 14.5.3.1.3 In revised text17.3.7 14.5.3.1.417.3.7 Table 13 14.5.3.1.4 Table XX17.3.8 14.5.3.1.517.4 Intermediate metal conduit 14.5.3.2.3 Intermediate metal conduit17.4 Ref. To 17.3.2 14.5.3.1.117.4 Ref. To 17.3.3 14.5.3.2.1.117.4 Ref. To 17.3.4 14.5.3.2.1.217.4 Ref. To 17.3.5 14.5.3.2.1.217.4 Ref. To 17.3.6 14.5.3.1.317.4 Ref. To 17.3.7 14.5.3.1.417.4 Ref. To 17.3.8 14.5.3.1.517.5 Electrical metallic tubing 14.5.3.2.4 Electrical metallic tubing17.5 Ref. To 17.3.2 14.5.3.1.117.5 Ref. To 17.3.3 14.5.3.2.1.117.5 Ref. To 17.3.4 14.5.3.2.1.217.5 Ref. To 17.3.5 14.5.3.2.1.217.5 Ref. To 17.3.6 14.5.3.1.317.5 Ref. To 17.3.7 14.5.3.1.417.5 Ref. To 17.3.8 14.5.3.1.517.6 Schedule 80 rigid nonmetallic conduit 14.5.3.3 Rigid non-metallic conduit (PVC Schedule

80)17.6.1 14.5.3.3.117.6.2 14.5.3.1.117.6.3 14.5.3.3.217.6.4 14.5.3.3.317.6.5 14.5.3.1.317.6.6 14.5.3.1.417.6.7 14.5.3.1.517.6.8 14.5.3.3.417.7 Liquidtight flexible metal conduit and fittings 14.5.4.3 Liquidtight flexible metal conduit17.7.1 14.5.4.317.7.2 14.5.4.1.417.7.3 14.5.4.1.117.7.4 14.5.4.317.7.5 14.5.4.1.317.8 Liquidtight flexible nonmetallic conduit and

fittings14.5.5 Flexible non-metallic conduit and fittings

17.8.1 14.5.5.117.8.2 14.5.5.217.8.3 14.5.5.317.8.4 14.5.5.617.8.5 14.5.5.417.8.6 14.5.5.717.9 Flexible metal (non-liquidtight) conduit and

fittings14.5.4.2 Flexible metal conduit

17.9.1 14.5.4.217.9.2 14.5.4.1.417.9.3 14.5.4.1.117.9.3 Exception 14.5.4.1.1 Exception17.10 Wireways 14.5.6 Wireways (cable trunking systems)17.10.1 14.5.6.117.10.2 Not carried forward17.10.3 14.5.6.217.10.4 14.5.6.317.10.5 14.5.6.4 And 14.5.6.517.11 Machine compartments and raceways 14.5.7 Machine compartments and wireway (cable

trunking system subsection17.12 Junction and pull boxes 14.5.8 Connection boxes and other boxes subsection17.13 Motor terminal boxes 14.5.9 Motor connection boxes subsection


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Proposed new Table of content

Chapter Section

SubsectionSub-subsection

Sub-sub-subsection

14 Wiring practices

14.1 Connections and routing

14.1.1 General requirements14.1.2 Conductor and cable runs14.1.3 Conductors of different circuits14.1.4 Cable runs

14.2 Identification of conductors

14.2.1 General requirements14.2.2 Identification of the equipment grounding

(protective) conductor14.2.3 Identification of the grounded circuit

conductor14.2.4 Identification by color for other conductors

14.3 Wiring inside enclosures

14.4 Wiring outside enclosures

14.4.1 General requirements14.4.2 External raceways (ducts)14.4.3 Connection to moving elements of the

machine14.4.4 Interconnection of devices on the machine14.4.5 Attachment plug and receptacle

(plug/socket) combinations14.4.6 Dismantling for shipment

14.5 Raceways (ducts) support systems ( cable supports),connection boxes and other boxes

14.5.1 General requirements14.5.2 Percentage fills of raceways14.5.3 Rigid conduit and fittings

14.5.3.1 General requirements14.5.3.2 Metal type nonflexible conduit

14.5.3.2.1 Generalrequirements

14.5.3.2.2 Rigid metalconduit and fittings

14.5.3.2.3 Intermediatemetal conduit

14.5.3.2.4 Electricalmetallic tubing

14.5.3.3 Rigid non metallic conduit(PVC Schedule 80)

14.5.4 Flexible metal conduit an fittings

14.5.4.1 General requirements14.5.4.2 Flexible metal conduit14.5.4.3 Liquidtight flexible metal

conduit

14.5.5 Flexible non-metallic conduit and fittings14.5.6 Wireways (cable trunking systems)14.5.7 Machine compartments and wireway (cable

trunking system)14.5.8 Connection boxes and other boxes14.5.9 Motor connection boxes14.5.10 Cord14.5.11 Cable trays

COMMITTEE ACTION: Accept in Principle.14 Wiring practices14.1 Connections and routing14.1.1 General requirements14.1.1.1 All connections shall be secured against accidentalloosening and shall ensure a thoroughly good connection.

14.1.1.2 The means of connection shall be identified for the cross-sectional areas and type of the conductors being terminated.14.1.1.3 The connection of two or more conductors to oneterminal is permitted only in those cases where the terminal isdesigned for that purpose. However, only one equipmentgrounding or one bonding conductor (protective conductor) shallbe connected to one terminal connecting point.Terminals for more than one conductor shall be so identified.14.1.1.4 A power distribution block designed for multiple tapconductors (e.g., single or multiple conductors “in” and multipleconductors “out”) shall be permitted for additional tapconnections and circuit branching.14.1.1.5 Soldered connections shall only be permitted whereterminals are provided which are identified for soldering.14.1.1.6 Terminals on terminal blocks shall be plainly identified tocorrespond with markings on the diagrams.14.1.1.7 The installation of flexible conduits and cables shall besuch that liquids shall drain away from the fittings. Wherepracticable, raceway connections shall enter the sides or bottom ofan enclosure or box.14.1.1.8 Means of retaining conductor strands shall be providedwhen terminating conductors at devices or terminals that are notequipped with this facility. Solder shall not be used for thatpurpose.14.1.1.9 Shielded conductors shall be terminated so as to preventfraying of strands and to permit easy disconnection.14.1.1.10 Identification tags shall be readable, permanent, andidentified for use in the physical environment.NOTE: A single tag bearing the complete identification ispreferred.14.1.1.11 Terminal blocks shall be mounted and wired so that theinternal and external wiring does not cross over the terminalsNote: For additional information on terminal blocks, refer toIEC 60947-7-1 “Low-voltage switchgear and control gear Part 7:Ancillary equipment Section one Terminal blocks for copperconductors”).14.1.2 Conductor and cable runs14.1.2.1 Conductors and cables shall be run from terminal toterminal without splices or joints.

Exception No. 1: Splices shall be permitted to leads attached to electricalequipment, such as motors and solenoids; such splices shall be insulatedwith oil-resistant electrical tape or insulation equivalent to that of theconductors and installed in a suitable enclosure.Exception No. 2: Where it is impracticable to provide terminals in ajunction box (e.g. on mobile machines, on machines having long flexiblecables) the use of splices or joints shall be permitted.14.1.2.2 Factory applied connectors molded onto cables shall bepermitted. Such connectors shall not be considered as splices orjoints.14.1.2.3 Where it is necessary to connect and disconnect cables andcable assemblies, an additional length shall be provided for thatpurpose.14.1.2.4 The terminations of cables shall be supported to preventmechanical stresses at the termination of the conductors.14.1.3 Conductors of different circuitsConductors of different circuits shall be permitted to be laid sideby side, and occupy the same raceway (duct) e.g. wireway (cabletrunking), or be in the same multiconductor cable assemblyprovided that the arrangement does not impair the functioning ofthe respective circuit. Functionally associated circuit conductorsincluding power, control, remote I/O, signaling, andcommunication cables shall be permitted in the same raceway orcable assembly regardless of voltage, provided all are insulated forthe maximum voltage of any circuit within the raceway or cableassembly. Where those circuits operate at different voltages, theconductors shall be separated by barriers or shall be insulated forthe highest voltage to which any conductor within the same raceway(duct) or cable assembly is subjected.Exception: Different voltage insulation levels or conductor propertiesshall be permitted in the same cable assembly, provided the cable assemblyhas been designed and tested to the identified application.14.1.4. Cables14.1.4.1 Cables run exposed along the structure of the equipmentor system, or in the chases of the machinery shall be permitted.Exposed cables shall be installed to closely follow the surface andstructural members of the machinery.14.1.4.2 Cables shall be supported by the equipment or systemstructure as follows: (1) In such a manner that the cable will not be damaged bynormal equipment use(2) Every 12 inches in a non-vertical run


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Exception: The supporting distance may be increased up to 36 incheswhere the structure of the machine or system makes support impracticalevery 12 inches. (3) Every 36 inches in a vertical runException: Supporting distance may be increased to 96 inches, where thestructure of the machine or system makes support impractical every 36inches. (4) When suspended in air spanning a distance up to 18 inchesException: Span distance may be increased up to 36 inches, where thestructure of the machine or system makes support impractical every 18inches.14.1.4.3 Cables shall not be supported by machinery guard worklikely to be removed for maintenance access.14.1.4.4 Multiple cables can be supported and fastened together ina bundle provided the method of support and fastening is sufficientto support the mechanical weight and strain of the bundle.14.1.4.5 Cables shall be fastened where supported.Exception No. 1: Where horizontal runs are inherently supported by themachine or system structure, or by a floor or deck, fastening is notrequired.Exception No. 2: Where run at not more than a 45 degree angle fromhorizontal, fastening is not required.14.1.4.6 Cables shall be fastened with cable ties supported by any ofthe following methods: (1) Screw-on cable tie mounts(2) Hammer-on cable tie mounting clips(3) Around the machine or system structural members(4) Through ho les in the machine or system structuralmembers(5) Cable mounting clamps(6) Other methods identified as acceptable for the purpose14.1.4.7 The free ends of cable ties shall be cut flush after finaladjustment and fastening. Cable ties of the reusable or releasabletype shall not be permitted for use as a permanent fasteningmethod14.1.4.8 Cables shall be protected from physical damage wherefollows: (1) By alternative routing(2) With additional guarding or railings(3) When supported by flooring or decking, with walk over ordrive over cable protective devices(4) By installation in a wire way(5) By installation in a floor or deck covering trapezoidalwalk over raceway specifically designed for cable protection14.1.4.9 Bends in cables shall be made so as not to cause unduestress. The radius of the curve of the inner edge of any bend shallnot be less than five times the diameter of the cable.14.1.4.10 Where a cable is used in a length longer than optimallyrequired, the excess cable shall be coiled in loops at or near theload end. The coil shall be fastened to itself and to the machinerystructure.Exception: When an excess cable is associated with a horizontal cable runthat is inherently and fully supported, the coil is not required to befastened to the equipment or system structure.14.2 Identification of conductors14.2.1 General requirements14.2.1.1 Conductors shall be identified at each termination bynumber, letter, color (either solid or with one or more stripes), ora combination thereof and shall correspond with the technicaldocumentation.Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).Exception 3: Where multiconductor cable is used and other means ofpermanent identification is provided.14.2.1.2 When numbers are used, they shall be Arabic; letters shallbe Roman (either upper or lower case).14.2.2 Identification of the equipment grounding (protective)conductor14.2.2.1 The color GREEN (with or without one or more YELLOWstripes) shall be used to identify the equipment-groundingconductor where insulated or covered. This color identificationshall be strictly reserved for the equipment grounding (protective)conductor.Exception No. 1: In multiconductor cable-connected assemblies whereequipment grounding is not required, the solid color GREEN shall bepermitted for other than equipment grounding.Exception No. 2: It shall be permitted to use conductors of other colorsprovided the insulation or cover is appropriately identified at all points ofaccess.

Exception No. 3: For grounded control circuits use of a GREEN insulatedconductor (with or without one or more YELLOW stripes) or a bareconductor from the transformer terminal to a grounding terminal on thecontrol panel shall be permitted.Note: The international standards reserve the use of bicolorcombination GREEN-AND-YELLOW for this purpose. The bicolorcombination is such that on any 15-mm (0.6-inch) length, one ofthe colors covers at least 30 % and not more than 70 % of thesurface of the conductor, the other color covering the remainder ofthe surface14.2.2.2 Where the equipment grounding (protective) conductor isidentified by its shape, position, or construction (e.g. a braidedconductor), or where the insulated conductor is not readilyaccessible, color coding throughout its length is not necessary.But the ends or accessible positions shall be clearly identified bythe 1999 NEC figure 250-126 grounding symbol, (IEC60417-symbolnumber-5019), or by the color GREEN (with or without one ormore YELLOW stripes) or the bicolor combination GREEN-AND-YELLOW.14.2.3 Identification of the grounded circuit conductor14.2.3.1 Where an AC circuit includes a grounded conductor, thisconductor shall be WHITE, GRAY, or three continuous WHITEstripes on other than GREEN, BLUE, ORANGE, YELLOWinsulation along its entire length.NOTE: IEC 60204-1 requires the use of the color LIGHT BLUE forthe neutral conductor where color is the sole means ofidentification.14.2.3.2 The use of other colors for the following applications shallbe as follows:(1) WHITE WITH BLUE STRIPE – grounded (currentcarrying) DC circuit conductor(2) WHITE WITH ORANGE STRIPE OR WHITE WITHYELLOW STRIPE – grounded (current carrying) AC circuitconductor which remains energized when the main disconnectingmeans is in the off position. The color choice of the stripe shall beconsistent with the ungrounded conductor of the excepted circuit.14.2.3.3 Where identification by color is used, bus bars used asgrounded conductors shall be either colored by a stripe, 15 mm(0.6 inch) to 100 mm (3.9 inch) wide in each compartment or unitor at each accessible position, or colored throughout their length.14.2.4 Identification by color for other conductors14.2.4.1 Ungrounded circuit conductors that remain energizedwhen the main disconnecting means is in the OFF position shallbe either YELLOW or ORANGE (see 5.3.5 “Excepted circuits”).These color identifications shall be strictly reserved for thisapplication only.Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).14.2.4.2 Where color is used for identification, the color shall beused throughout the length of the conductor either by the color ofthe insulation or by color markers.Exception: Multiconductor cables shall be permitted to be permanently re-identified at the time of installations.

14.2.4.3 The use of other colors for the purpose of identificationshall be as follows: (1) BLACK: Ungrounded line, load, and control conductorsat line voltage.(2) RED: Ungrounded ac control conductors, at less thanline voltage.(3) BLUE: Ungrounded dc control conductors.Exception 1: Internal wiring on individual devices purchased completelywired.Exception 2: Where the insulation used is not available in the colorsrequired (e.g., high temperature insulation, and chemically resistantinsulation).Exception 3: Where multiconductor cable is used and other means ofpermanent identification is provided.14.3 Wiring inside enclosures14.3.1 Panel conductors shall be supported where necessary tokeep them in place. Non-metallic ducts shall be permitted onlywhen they are made with a flame-retardant insulating material.Note: For additional information on Flame retardant materials,refer to IEC 60332-1 “ Tests on electric cables under fire conditions– Part 1: Test on a single vertical insulated wire or cable”.14.3.2 Electrical equipment mounted inside enclosures shall beinstalled in such a way as to permit access to the wiring.14.3.3 Connections to devices mounted on doors or to othermovable parts shall be made using flexible conductors inaccordance with 13.7. “Conductors and cables used for flexing


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applications” to allow for the movement of the part. Theconductors shall be anchored to the fixed part and to the movablepart independently of the electrical connection.14.3.4 Conductors that do not run in ducts shall be supported.14.3.5 Multiple-device control panels shall be equipped withterminal blocks or with attachment plugs and receptacles for alloutgoing control conductors.14.3.6 The direct connection of Power cables and cables ofmeasuring circuits, to the terminals of the devices for which theconnections were intended shall be permitted.14.3.7 AC receptacles, AC plugs, flexible cords, appliance couplers,power cord sets, etc. shall be permitted inside enclosures forinternal wiring and connections between assemblies with AC powerwhere used in accordance with their listing.14.4 Wiring outside enclosures14.4.1 General requirements

The means of introduction of cables or ducts with their individualglands, bushings, etc., into an enclosure shall ensure that thedegree of protection is not reduced.14. 4. 2 External raceways (ducts)14.4.2.1 All conductors of the same AC circuit routed to the samelocation shall be contained in the same raceway (duct).14.4.2.2 Conductors external to the electrical equipmentenclosure(s) shall be enclosed in raceway (duct) described in 14.5.Exception: Cables and cable connectors need not be enclosed in a racewaywhere they are otherwise protected and supported.14.4.2.3 Fittings used with raceways (ducts) or multiconductorcable shall be identified for use in the physical environment.14.4.2.4 Flexible conduit or multiconductor cable with flexibleproperties shall be used where it is necessary to employ flexibleconnections to pendant push-button stations. The weight of thependant stations shall be supported by means other than theflexible conduit or the multiconductor cable with flexibleproperties, except where the conduit or cable is specificallydesigned for that purpose.14.4.2.5 Flexible conduit or multiconductor cable with flexibleproperties shall be used for connections involving small orinfrequent movements. They shall also be permitted to completethe connection to stationary motors, to position switches, and toother externally mounted devices. Where pre-wired devices (e.g.position switches, proximity switches) are supplied, the integralcable need not be enclosed in a raceway (duct).14.4.3 Connection to moving elements of the machine14.4.3.1 Connections to moving parts shall be made usingconductors in accordance with 13.7. Flexible cable and conduitshall have vertical connections and shall be installed to avoidexcessive flexing and straining. Horizontal connections shall bepermitted where the flexible cable or conduit is adequatelysupported. Cable with flexible properties and flexible conduit shallbe so installed as to prevent excessive flexing and straining,particularly at the fittings.14.4.3.2 Cables with flexible properties subject to movement shallbe supported in such a way that there is neither mechanical strainon the connection points nor any sharp flexing. When this isachieved by the use of a loop, it shall provide for a bending radiusof the cable of at least 10 times the diameter of cables.14.4.3.3 Cable with flexible properties of machines shall be soinstalled or protected as to minimize the possibility of externaldamage due to factors that include the following cable use orpotential abuse:(1) Being run over by the machine itself(2) Being run over by vehicles or other machines(3) Coming into contact with the machine structure duringmovements(4) Running in and out on cable baskets, or on or off cab ledrums(5) Acceleration forces and wind forces on festoon systemsor suspended cables(6) Excessive rubbing by cable collector(7) Exposure to an excessive radiated heat source14.4.3.4 The cable sheath shall be resistant to the wear frommovement and the effects of atmospheric contaminants (e.g. oil,water, coolants, and dust).14.4.3.5 Where cables subject to movement are close to movingparts, precautions shall be taken to maintain a sp ace o f at least 25.4- mm (1-in ch ) b et ween t h e mo vi n g p arts an d th e cabl es. Wh ereth at d ist an ces i s n o t pr actica bl e, fixed bar riers sh all b e p ro vi d edb etw een th e cabl es an d t h e mo vi n g p arts .14.4.3.6 The cable handling system shall be so designed that lateralcable angles do not exceed 5°, avoiding torsion in the cable when:(1) Being wound on and off cable-drums and(2) Approaching and leaving cable guidance devices

14.4.3.7 Measures shall be taken to ensure that at least two turns offlexible cables always remain on a drum.14.4.3.8 Devices serving to guide and carry a cable with flexibleproperties, shall be so designed that the inner bending radius isnot less than the values given in table XW, unless the smallerbending radius is agreed to by the cable manufacturer, taking intoaccount the permissible tension and the expected fatigue life.

Table XW – Minimum permitted bending radii for the forcedguiding of flexible cables

Application Cable diameter or thickness of flat cable (d)mmd ≤ 8 8 < d ≤ 20 d >20

Cable drumsGuide rollersFestoon systemsAll others

6 d6 d6 d6 d

6 d8 d6 d6 d

8 d8 d8 d8 d

Table XW note: 8mm = 0.315-inch, 20mm = 0.787-inch

14.4.3.9 The straight section between two bends, in an S-shapedlength, and a bend into another plane shall be at least 20 times thediameter of the cable.14.4.3.10 Where flexible conduit is adjacent to moving parts, theconstruction and supporting means shall prevent damage to theflexible conduit under all conditions of operation. Flexiblemetallic conduit shall not be used for rapid movements exceptwhen specifically designed for that purpose.14.4.4 Interconnection of devices on the machineWhere practicable, machine-mounted switching devices (e.g.position sensors, push buttons) are connected in series or inparallel, the connections between those devices shall be madethrough terminals forming intermediate test points. Such terminalsshall be conveniently placed, protected from the environment, andshown on the relevant diagrams.14.4.5 Attachment plug and receptacle (plug/socket) combinations14.4.5.1 Where equipment is removable, connections to it througha polarized attachment plug and receptacle (plug/socket)combination shall be permitted. The male plug shall beconnected to the load circuit.14.4.5.2 Attachment plug and receptacle (plug/socket)combinations shall be listed for the intended use and shall be ofthe locking type where rated greater than 20 amperes. Where usedon circuits of more than 300 volts to ground or 300 volts phase-to-phase, they shall be skirted and constructed to contain any arcgenerated when a connection is made or broken.14.4.5.3 Attachment plug and receptacle (plug/socket)combinations, shall be so designed that; a protective bonding(equipment grounding) circuit connection is made before any liveconnections are made; and the protective bonding (equipmentgrounding) circuit connection is not disconnected until all liveconnections in the plug are disconnected; except for connectionsused in PELV circuits, or the connectors used only to facilitateassembling / disassembling (multi-pole connectors).14.4.5.4 Attachment plugs and receptacles (plug and socket)combinations used for carrying motor loads shall meet theconditions of 5.3.3.3 if the circuit is likely to be opened under load.14.4.5.5 Where more than one attachment plug and receptacle(plug/socket) combination is used at the same location, they shallbe mechanically coded to prevent incorrect insertion or be clearlyidentified.14.4.5.6 Attachment Plug/socket combinations that are used forindustrial power purposes or of a type used for domesticapplications shall not be used for control circuits.14.4.5.7 Means shall be provided to cover externally mounted receptacles (socket) when the plugs are removed.14.4.6 Dismantling for shipment. Where it is necessary that wiringbe disconnected for shipment and where practicable, terminals orattachment plug and receptacle (plug/socket) combinations shallbe provided at the sectional points. Such terminals shall be suitablyenclosed and attachment plug and receptacle (plug/socket)combinations shall be protected from the physical environmentduring transportation and storage. Raceway and enclosureopenings shall be sealed prior to shipment.14.5 Raceways (ducts), support systems (cable supports),connection boxes and other boxes14.5.1 General requirements14.5.1.1 Raceways (ducts) shall be identified for the environment.14.5.1.2 All sharp-edges, flash, burrs, rough-surfaces, or threadsthat the insulation of the conductors can come in contact shall beremoved from raceways (ducts) and fittings. Where necessary,additional protection consisting of a flame-retardant, oil-resistantinsulating material shall be provided to protect conductorinsulation.


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14.5.1.3 Drain holes shall not be permitted in raceways (ducts),junction boxes, and pull boxes where the holes would compromisethe intended enclosure integrity. Drain holes of 6.4 mm (1/4inch) diameter shall be permitted in wireways (cable trunkingsystems), connection boxes, and other boxes used for wiringpurposes that are subject to accumulations of oil or moisture.14.5.2 Percentage fills of raceways (ducts). The combined cross-sectional area of all conductors and cables shall not exceed 50percent of the interior cross-sectional area of the raceway (duct).The fill provisions shall be based on the actual dimensions of theconductors or cables used.Note: It should be recognized that, for certain conditions, a largersize raceway or a lesser raceway fill should be considered.14.5.3 Rigid conduit and fittings14.5.3.1General requirements14.5.3.1.1 The minimum electrical trade size shall be 1/2 inch.14.5.3.1.2 The maximum electrical trade size shall be 6 inch.Note: Metric trade numerical designations for rigid metal conduitare the same as those found in Extra-heavy Duty Rigid SteelConduits for Electrical Installations, IEC 981-1989; namely: _ = 16, _= 21, 1 = 27, 1_ = 35, 1_ = 41, 2 = 53, 2_ = 63, 3 = 78, 3_ = 91, 4 = 103,5 = 129, and 6 = 155.14.5.3.1.3 Where conduit enters a box or enclosure, a bushing orfitting providing a smoothly rounded insulating surface shall beinstalled to protect the conductors from abrasion, unless thedesign of the box or enclosure is such that it provides the sameprotection. Where conduit bushings are constructed wholly ofinsulating material, a locknut shall be provided both inside andoutside the enclosure to which the conduit is attached.Exception: Where threaded hubs or bosses that are an integral part of anenclosure provide a smoothly rounded or flared entry for conductors.14.5.3.1.4 Conduit bends shall be made in such a manner that theconduit shall not be damaged and the internal diameter of theconduit shall not be effectively reduced. The radius of the curve ofany field bend shall be not less than shown in Table XX.

Table XX – Minimum Radius of Conduit BendsSize ofConduit

Radius of BendDone by

Radius of Bend Doneby

(in.) Hand (in.) Machine (in.)1/2 4 43/4 5 41/21 6 51/411/4 8 71/411/2 10 81/42 12 91/221/2 15 101/23 18 1331/2 21 154 24 1641/2 27 205 30 246 36 30

Table XX: SI units: (Radius) 25mm = 1 in.NOTE 1: For field bends done by hand, the radius is measuredto the inner edge of the bend.NOTE 2: For a single-operation (one-shot) bending machinedesigned for the purpose, the radius is measured to thecenterline of the conduit

14.5.3.1.5 A run of conduit shall contain not more than four-quarter bends or a combination of bends totaling 360 degrees,between pull points.14.5.3.2 Metal type nonflexible conduit14.5.3.2.1 General requirements14.5.3.2.1.1 Conduits shall be securely held in place and supportedat each end.14.5.3.2.1.2 Fittings shall be compatible with the conduit andidentified for the application. Fittings and conduits shall bethreaded using an electrical conduit die unless structuraldifficulties prevent assembly. Running threads shall not be used onconduit for connection at couplings. Metallic tubing shall not bethreaded. Where threadless fittings are used, the conduit shall besecurely fastened to the equipment.14.5.3.2.2 Rigid metal conduit and fittings. Rigid metal conduitand fittings shall be of galvanized steel or of a corrosion-resistantmaterial identified for the conditions of service.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.2.3 Intermediate metal conduit. Intermediate metal conduitshall be a steel raceway of circular cross section with integral orassociated couplings, approved for the installation of electrical

conductors and used with approved fittings to provide electricalcontinuity.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.2.4 Electrical metallic tubing. Electrical metallic (steel)tubing shall be a metallic tubing of circular cross section approvedfor the installation of electrical conductors when joined togetherwith approved fittings. The maximum size of tubing shall be the 4-in. electrical trade size.Note: The use of dissimilar metals in contact that can causegalvanic action should be avoided.14.5.3.3 Rigid non-metallic conduit (PVC Schedule 80)14.5.3.3.1 Rigid non-metallic conduit (PVC schedule 80) shall beof suitable nonmetallic material approved for the installation ofelectrical conductors and identified for use where subject tophysical damage.Note: For additional information about rigid non-metallicconduit, refer to UL 651.14.5.3.3.2 Conduit shall be securely held in place and supported asfollows:

Maximum Spacing

Conduit Size (in)Maximum Spacing

Between Supports (ft) 1/2 - 11 1/4 - 22 1/2 - 33 1/2 - 5

6

35678

Note: For SI units, 1 ft = 0.3048 m (supports).

In addition, conduit shall be securely fastened within 3 ft (914mm) of each box, enclosure, or other conduit termination.14.5.3.3.3 Expansion fittings shall be installed to compensate forthermal expansion and contraction. (NFPA 70-1999 “Table 347-9(A). Expansion Characteristics of PVC Rigid Nonmetallic ConduitCoefficient of Thermal Expansion = 3.38 x 10-5 in./in./º F “)14.5.3.3.4 All joints between lengths of conduit, and betweenconduit and couplings, fittings, and boxes, shall be made withfittings approved for the purpose14.5.4 Flexible metal conduit and fittings14.5.4.1 General requirements14.5.4.1.1 Flexible metal conduit and liquidtight flexible metalconduit, minimum electrical trade size shall be 3/8 inch.Exception: Thermocouples and other sensors.14.5.4.1.2 The maximum size of flexible metal conduit andliquidtight flexible metal conduit, shall be 4-in trade size.Note: Metric trade numerical designations for flexible metalconduit and liquidtight flexible metal conduit, are 3/8 = 12, _ = 16,_ = 21, 1 = 27, 1_ = 35, 1_ = 41, 2 = 53, 2_ = 63, 3 = 78, 3_ = 91, and 4= 103.14.5.4.1.3 Flexible metal conduit and liquidtight flexible metalconduit shall be installed in such a manner that liquids will tend torun off the surface instead of draining toward the fittings.14.5.4.1.4 Fittings shall be compatible with the conduit andidentified for the application. Connectors shall be the “union”types.14.5.4.2 Flexible metal conduit. Flexible metal conduit is a racewayof circular cross section made of helical wound, formed, andinterlocked metal strip. Flexible metal conduit shall be identifiedfor use in the expected physical environment.14.5.4.3 Liquidtight flexible metal conduit. Liquidtight flexiblemetal conduit is a approved raceway of circular cross sectionhaving an outer liquidtight, nonmetallic, sunlight-resistant jacketover an inner flexible metal core with associated couplings,connectors, and fittings and approved for the installation of electricconductors. Liquidtight flexible metal conduit shall be identifiedfor use in the expected physical environment.14.5.5 Flexible non-metallic conduit and fittings14.5.5.1 Liquidtight flexible nonmetallic conduit is a raceway ofcircular cross section of various types:(1) A smooth, seamless inner core and cover bondedtogether and having one or more reinforcement layers between thecore and cover(2) A smoother inner surface with integral reinforcementwithin the conduit wall(3) A corrugated internal and external surface with orwithout integral reinforcement within the conduit wall(4) Liquidtight flexible nonmetallic conduit is oil-, water-,and flame-resistant and, with fittings, is approved for theinstallation of electrical conductors


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14.5.5.2 A flexible non-metallic conduit shall be resistant to kinkingand shall have physical characteristics of the sheath ofmulticonductor cables.14.5.5.3 The conduit shall be identified for use in the expectedphysical environment.14.5.5.4 Liquidtight flexible nonmetallic conduit minimumelectrical trade size shall be 3/8 inch.14.5.5.5 The maximum size of liquidtight flexible nonmetallicconduit shall be 4-in trade size.Note: Metric trade numerical designations for liquidtight flexiblenonmetallic conduit are 3/8 = 12, _ = 16, _ = 21, 1 = 27, 1_ = 35, 1_= 41, 2 = 53, 2_ = 63, 3 = 78, 3_ = 91, and 4 = 103.14.5.5.6 Fittings shall be compatible with the conduit and identifiedfor the application.14.5.5.7 Flexible conduit shall be installed in such a manner thatliquids will tend to run off the surface instead of draining towardthe fittings.14.5.6 Wireways (cable trunking systems)14.5.6.1 Wireways (cable trunking systems) external to enclosuresshall be rigidly supported and clear of all moving or contaminatingportions of the machine.14.5.6.2 Covers shall be shaped to overlap the sides; gaskets shall bepermitted. Covers shall be attached to wireways (cable trunkingsystems) by hinges or chains and held closed by means of captivescrews or other suitable fasteners. On horizontal wireway (cabletrunking systems), the cover shall not be on the bottom. Hingedcovers shall be capable of opening at least 90 degrees.14.5.6.3 Where the wireway (cable trunking system) is furnished insections, the joints between sections shall fit tightly but shall not berequired to be gasketed.14.5.6.4 The only openings permitted shall be those required forwiring or for drainage.14.5.6.5 Wireways (cable trunking systems) shall not have openedbut unused knockouts.14.5.7 Machine compartments and wireway (cable trunkingsystems). The use of compartments or wireways (cable trunkingsystems) within the column or base of a machine to encloseconductors shall be permitted provided the compartments orwireways (cable trunking systems) are isolated from coolant or oilreservoirs and are entirely enclosed. Conductors run in enclosedcompartments wireways (cable trunking systems) shall be sosecured and arranged that they can not be subject to damage. (See17.2.”Warning marking and signs”)14.5.8 Connection boxes and other boxes14.5.8.1 Connection boxes and other boxes used for wiringpurposes shall be readily accessible for maintenance. Those boxesshall provide protection against the ingress of solid bodies andliquids, taking into account the external influences under whichthe machine is intended to operate14.5.8.2 Those boxes shall not have opened but unused knockoutsor any other openings and shall be so constructed as to excludematerials such as dust, flyings, oil, and coolant.14.5.9 Motor connection boxes14.5.9.1 Motor connection boxes shall enclose only connections tothe motor and motor-mounted devices (e.g. brakes, temperaturesensors, plugging switches, tachometer generators).14.5.9.2 Electrical connections to motors, solenoids and otherdevices with integral leads, sizes No. 14 AWG through No. 4 AWG,shall be made with ring type pressure connectors (pressure-toolapplied) and bolted.14.5.9.3 Connectors shall be insulated with a material that will notsupport combustion.14.5.9.4 Soldered or insulation piercing type connectors (lugs)shall not be used.14.5.10 Cord.14.5.10.1 Manufactured assemblies with factory applied moldedconnectors applied to cord shall be permitted.Note: For additional information on flexible cords, refer toANSI/UL 62 “Flexible cord and fixture wire”14.5.10.2 The use of cord shall be limited to individual exposedlengths of 50 feet or less.14.5.10.3 Cord shall be installed in accordance with the provisionof clause 14.1.4.14.5.10.4 Cord shall be permitted for use for flexible connectionsto pendant push-button stations. Chains or wire rope external tothe cord shall support the weight of pendant stations.14.5.10.5 Cord shall be permitted for use for connections involvingsmall or infrequent movements. Cord shall also be permitted tocomplete the connection to normally stationary motors, limitswitches, and other externally mounted devices.14.5.10.6 Connections to frequently moving parts shall be madewith conductors for flexing service in accordance with 13.7. Cordwith conductors for flexing service shall have vertical connectionsand shall be installed to avoid excessive flexing and straining.

Exception: Horizontal connections shall be permitted where the cord isadequately supported.14.5.11 Cable trays. Cable trays to be used for cable or racewaysupport on industrial machines shall be permitted. Cable traysshall be permitted to support single conductors 1/0 or larger thatare otherwise permitted on industrial machines, cables that areotherwise permitted on industrial machines, and racewaysfunctionally associated with industrial manufacturing systems.COMMITTEE STATEMENT: Additional change to Clause 14 weremade for the following reasons: 1) A change was made in 14.1.1.3 to more closely align with andcomply with the NFPA 70-1999, Section 110-14(b). 2) The text in 14.1.4.10 about the requirements for loops at loadend was removed because it is too restrictive and loops should bepermitted at both ends. 3) In 14.2.3.1, the color ORANGE was added to the list ofprohibited colors for use with the three white stripes to correlatewith the uses of the color ORANGE. 4) n 14.2.3.2, the committee desired to be inclusive with thegrounded conductor in excepted circuits. Grounded conductors ofAC and DC excepted circuits are required to be color coded inaccordance item (2) to identify the grounded conductor ofexcepted circuits. 5) Section 14.4.5.7 was editorially revised to clarify that theprovision only applies to externally mounted receptacle.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: KNECHT: Clause 14.1.1.3: Observation: The second sentence which did not allow morethan one conductor per connection, if removed may create asituation when the bonding path is interrupted when a bondingconductor is inadvertently disconnected when another groundinglead in the same connection point is disconnected. The avoid this situation, the sentence should be added, "Only oneequipment grounding conductor or one bonding conductor shallbe connected to one terminal connecting point." Clause 14.2 Observation: I interpret the requirements to say that only thegrounding (green/yellow), neutral, and continuously on (orange)conductors must always be color coded.COMMENT ON AFFIRMATIVE: BLOODGOOD: Is it necessary for this proposal to be 57 pages?I only use this as an example in noting the problem in reviewingthe massive amount of paper that has to be studied to makeintelligent voting decisions. DOBROWSKY: Much of the proposed information is toodetailed and can be covered using a few generic requirements toincrease usability. Some requirements for wiring methods that arecommon to industrial machinery should be retained and areference to the NEC should be provided for more detailedrequirements. FISHER: It is noted that the term ‘cable trunking system’ isindicated to the synonymous with ‘wireways’. A ‘cable trunkingsystem’ is not equivalent to a ‘cable tray system’ as cover in Article318 of the NEC. FREUDENBERG: Color coding requirements used 50% of thetime is much more dangerous than no color code at all.The falseperception of relying on color is a dangerous work practice. Theentrenched them versus us stalemate on color coding around theworld is inane because today's multinational suppliers and usersare often both them and us where country of origin for systems,assemblies and components is not clearand country of use oftenshifts with production demands. Many machines are capitalequipment that can be transferred down the road or around theworld a few times during its useful life. Color coding is the mostrestrictive barrier to free trade that exists today where we can't moveour own manufacturing machines between our own plants withouta worldwide solution that removes ALL the color preferences.NFPA79 is moving in the right direction on this issue.

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(Log #63)79- 123 - (16.1.2 [14.2.2]): RejectSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Revise text as follows: "The color YELLOW-GREEN GREEN (with or without one ormore YELLOW stripes) shall be used to identify the equipmentgrounding conductor where insulated or covered."SUBSTANTIATION: The definition "YELLOW-GREEN" is moreprecise than the alternatives "GREEN (with or without one or moreYELLOW stripes". Only one color type should be defined in orderto avoid unnecessary conductor variations for the machine toolbuilders.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The extension of the existing greento include green yellow is to allow for the harmonization with otherinternational standards. Present proposed colors are consistentwith NFPA 70-1999 [NEC-250-119].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #15)79- 124 - (16.1.2 Note [14.2.2]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the Note to read as follows: NOTE: The international and European standards requirereserve the use of the bicolor GREEN-AND-YELLOW for thispurpose. (See IEC 204-1 for specific requirements.)SUBSTANTIATION: The note is in error. IEC 60204-1:199714.2.2. "The protective conductor shall be readily distinguishable byshape, location, marking, or color When identification is by coloralone, the bicolor combination GREEN-AND-YELLOW shall beused throughout the length of the conductor. This coloridentification is strictly reserved for the protective conductor. "COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: The concerns of the submitter arealready met in Committee Action on Proposal 79-122 (Log #55)(14.2, Note)NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #64)79- 125 - (16.1.3 [14.2.4.3]): RejectSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Revise text as follows: "The color BLUE shall be used for 24 V AC control circuits."SUBSTANTIATION: For the 115 V control conductors RED andWHITE are defined in IEC 60204. This is acceptable, but for 24 VAC control conductors the color BLUE has to be allowed for bothwires.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The color blue is a reserved colorfor identifying ungrounded DC control conductors and this is inaccordance with the recommendations of IEC 60204-1.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55).

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(Log #17)79- 126 - (16.1.3 Note 2 [14.2.3.1 Note]): AcceptSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Revise the Note to read as follows: NOTE: The international and European standards requirereserve the use of the color LIGHT BLUE for the neutralconductor and requires its’ use when identification is by color .(See IEC 204-1 for specific requirements.)

SUBSTANTIATION: The note is in error. IEC 60204-1:199714.2.3. "Where a circuit includes a neutral conductor identified by color, the color shall be LIGHT BLUE (see 3.1.2 of IEC 60446). LIGHTBLUE shall not be used for identifying any other conductor whereconfusion is possible. Where identification by color is used, bare conductors used asneutral conductors shall be either colored by a LIGHT BLUEstripe, 15 mm to 100 mm wide in each compartment or unit or ateach accessible position, or colored LIGHT BLUE throughouttheir length.COMMITTEE ACTION: Accept. Revise the Note to 14.2.3.1 to read as follows: NOTE: IEC 60204-1 reserves the use of the color LIGHT BLUEfor the neutral conductor and requires its’ use when identificationis by color .COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Committee Action on Proposal 79-122 (Log#55).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #7)79- 127 - (16.1.3 [14.2.4]): RejectSUBMITTER: Bruce Fairweather, Electrical Safety EngineeringInc.RECOMMENDATION: Revise text: BLACK: Ungrounded line, load and control conductors at linevoltage. Add "ac and dc" after ungrounded. Delete "line voltage",add "hazardous voltage levels". RED: Ungrounded ac control conductors at less than linevoltage. Delete "line voltage", add "hazardous voltage levels." BLUE: Ungrounded dc control conductors. Add "at less thanhazardous voltage levels."SUBSTANTIATION: The change in wording of the statementswill comply with OSHA terminology and hazardous voltage levelguidelines. More importantly it will provide maintenance personnela better visual identification of potential danger.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The term "hazardous" related tovoltage is not defined. Adding this term does not add clarity.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55).

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(Log #56)79- 128 - (16.1.3 [14.2.4.3]): Accept in PrincipleSUBMITTER: Wayman L. Withrow, Cincinnati IncorporatedRECOMMENDATION: The proposed NFPA 79-2002 subclause14.2.4.3 is as follows: 14.2.4.3 The use of other colors for the purpose of identificationshall be as follows: – BLACK: Ungrounded line, load, and control circuits at linevoltage. – RED: Ungrounded AC control circuits, at less than line voltage. – BLUE: Ungrounded DC control circuits. Exception No. 1: Internal wiring on individual devices purchasedcompletely wired. Exception No. 2: Where the insulation used is not available in thecolors required (e.g. high temperature insulation, chemicallyresistant insulation). Exception No. 3: Where multiconductor cable is used. Revise the proposed NFPA 79-2002 subclause 14.2.4.3 paragraphand exceptions to read as follows: 14.2.4.3 It shall be permitted to use additional identification atselected locations as an alternative. This means of identificationshall be permitted to be by separate color coding, marking tape,tagging, or other approved means and shall be permanently postedon the inside of the main electrical control panel enclosure in avisible location. The preferred colors for AC and DC powercircuits, AC control circuits, and DC control circuits shall be asfollows:


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– BLACK: Ungrounded line, load, and control circuits at linevoltage. – RED: Ungrounded AC control circuits, at less than line voltage. – BLUE: Ungrounded DC control circuits.SUBSTANTIATION: The mandatory ungrounded power andcontrol wire color coding is used in the majority of metal workingmachine tools manufactured for use in the United States.However, some machine tool manufacturers have specificicapplications for wire identification, such as different levels of acand dc voltages. In order to identify the wiring for these specialapplications, an exception is given to the mandatory color codes. This addition will harmonize the proposed NFPA 79-2002, IEC60204-1: 1997, and the proposed SAE HS1738. The adition of thesentence "It shall be permitted to use additional identification atselected locations as an alternative." permits the use of thecurrently recognized color codes for power and control circuitwiring and allows an exception for machines with specialrequirments.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-129 (Log #57).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 23 NEGATIVE: 2 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DROBNICK: I believe that straying from the current wire colorcodes which have been adhered to for years will compromise thesafety of electrical personnel. I believe that the first threeexceptions allow for current industry practice without the necessityfor Exception No. 4. GARVEY: The proposed new exception is unenforceable. Whodetermines when compliance is "too restrictive for specificapplications"? The exception effectively renders the generalrequirements of 14.2.4.3 useless. I do agree with the submitter’ssubstantiation that some limited exceptions are appropriate.COMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55).

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(Log #57)79- 129 - (16.1.3 [14.2.4.3]): AcceptSUBMITTER: Wayman L. Withrow, Cincinnati IncorporatedRECOMMENDATION: The proposed NFPA 79-2002 subclause14.2.4.3 is as follows: 14.2.4.3 The use of other colors for the purpose of identificationshall be as follows: – BLACK: Ungrounded line, load, and control circuits at linevoltage. – RED: Ungrounded AC control circuits, at less than line voltage. – BLUE: Ungrounded DC control circuits. Exception No. 1: Internal wiring on individual devices purchasedcompletely wired. Exception No. 2: Where the insulation used is not available in thecolors required (e.g. high temperature insulation, chemicallyresistant insulation). Exception No. 3: Where multiconductor cable is used. Add 14.2.4.3 Exception No. 4 to subclause 12.2.4.3 after exceptionNo. 3 as follows: Exception No. 4: Where the identification of machine power andcontrol wiring is such that compliance with the mandatory colorcodes is too restrictive for specific applications, it shall bepermitted to use additional identification at selected locations asan alternative. This means of identification shall be permitted tobe by separate color coding, marking tape, tagging, or otherapproved means and shall be permanently posted on the inside ofthe main electrical control panel enclosure in a visible location.SUBSTANTIATION: The mandatory ungrounded power andcontrol wire color coding is used in the majority of metal workingmachine tools manufactured for use in the United States.However, some machine tool manufacturers have specificapplications for wire identification, such as different levels of acand dc voltages. In order to identify the wiring for these specialapplications, an exception is given to the mandatory color codes. This addition will harmonize the proposed NFPA 79-2002, IEC60204-1: 1997, and the proposed SAE HS1738. The addition ofexception No. 4 permits the use of the currently recognized colorcodes for power and control circuit wiring and allows an exceptionfor machines with special requirements.COMMITTEE ACTION: Accept.

The committee understands the submitters proposed action is toonly add a new exception 4 as stated in the proposal.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Committee Action on Proposal 79-122 (Log#55) [Clause 14].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 22 NEGATIVE: 3 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DROBNICK: I believe that straying from the current wire colorcodes which have been adhered to for years will compromise thesafety of electrical personnel. I believe that the first threeexceptions allow for current industry practice without the necessityfor Exception No. 4. GARVEY: The proposed new exception is unenforceable. Whodetermines when compliance is "too restrictive for specificapplications"? The exception effectively renders the generalrequirements of 14.2.4.3 useless. I do agree with the submitter’ssubstantiation that some limited exceptions are appropriate. KIIHR: I voted against the Acceptance of this proposal for thefollowing reasons: 1. The new exception #4 states that "Where the identification ofmachine power and control wiring is such that compliance withthe mandatory color codes is too restrictive for specificapplications, ..." There is no clear definition of ‘too restrictive’. 2. The substantiation given for acceptance of the proposal refersto a specific reason for utilizing different colors (to differentiatebetween different voltage levels). If this is the reason, then theexception should be for this particular application. 3. As the exception is currently worded, it essentially voids theentire subclause 14.2.4.3. A manufacturer can use any wire colorhe sees fit, and simply state that to use the colors prescribed in14.2.4.3 was too restrictive. 4. Any exception should be for very specific applications, whichcannot be accommodated by the basic language of the standard.This particular exception can be interpreted in a broad enoughsense that it cancels out the entire subclause.COMMENT ON AFFIRMATIVE: DOBROWSKY: I am concerned that the phrase "specificapplications" and the use of "additional identification at selectedlocations as an alternative" will not be consistently interpreted. FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55). SAUNDERS: 14.2.4.3 specifies the use of black, red, and blue forthe purpose of identification. The identification referred to is toprovide functional identification of conductors (i.e. ac or dccontrol) rather than individual identification of each conductor inthe circuit. However, subclause 14.2.1.1 requires individualidentification of each conductor and allows color to be permittedas one method to accomplish this identification. Therefore, it isimpossible to identify each individual conductor by color and stillmeet the requirements of 14.2.4.3. For example, if there are tenungrounded dc control conductors in the circuit, they would berequired to all be red per subclause 14.2.4.3. Although theproposed exception 4 may cover this, the statement "where …compliance with the mandatory color codes is too restrictive" lendsitself to interpretation of what is considered too restrictive. Recommendation: Add exception 5 to 14.2.4.3 "Where color isused for identification of each individual conductor."

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(Log #67)79- 130 - (16.1.3 [14.2.4.1]): Accept in PrincipleSUBMITTER: Heinrich Moedden, German Machine ToolBuilders Association (VDW)RECOMMENDATION: Revise text as follows: "Ungrounded circuit conductors that remain energized when themain disconnecting means is in the OFF position shall be eitherYELLOW or ORANGE (see 5.3.5 "Excepted circuits")."SUBSTANTIATION: The definition "ORANGE" is more precisethan the alternatives "YELLOW or ORANGE". Only one color typeshould be defined in order to avoid unnecessary conductorvariations for the machine tool builders.COMMITTEE ACTION: Accept in Principle. Revise text of the first sentence 14.2.4.1 to read as follow: "Ungrounded circuit conductors that remain energized when thesupply disconnecting means is in the OFF position shall beconsistantly applied as either ORANGE or YELLOW. Add a note to the end of this section to read as follows: Note: For further information on "Excepted Circuits", see 5.3.5. The remainder of the section is to remain unchanged.


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COMMITTEE STATEMENT: The committee desires to permiteither color as long as the requirement is applied consistantlywithin a machine. The cross reference to 5.3.5 was moved to anote to comply with the style manual. The committee understands that this proposal modifies theAction on Proposal 79-122 (Log #55).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARVEY: The color "Orange" is used to designate "Warning" byOSHA regulations. Often "white" wires turn "yellow" as theinsulation ages. Orange should be the preferred color.COMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55).

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(Log #16)79- 131 - (16.1.3, Note 1 [14.2.4]): Accept in PrincipleSUBMITTER: Melvin K. Sanders , TECo., Inc.RECOMMENDATION: Revise the Note to read as follows: NOTE: The international and European standards requirerecommends the use of the color ORANGE for this purpose whenidentification is by color . (See IEC 204-1 for specificrequirements.)SUBSTANTIATION: The note is in error. IEC 60204-1:199714.2.4. "Identification of other conductors shall by color (either solid orwith one or more stripes), number, alphanumeric, or acombination of color and numbers or alphanumeric. Whennumbers are used, they shall be Arabic; letters shall be Roman(either upper or lower case)." It is recommended that insulated conductors be color-coded asfollows: "ORANGE: interlock control circuits supplied from an externalpower source."COMMITTEE ACTION: Accept in Principle. Add a new note to 14.2.4.1 to read as follows: NOTE: IEC 60204-1 recommends the use of the color ORANGEfor this purpose where identification is by color.COMMITTEE STATEMENT: The concerns of the submitter arealready addressed in Proposal 79-122 (Log #55). The committeeunderstands that this proposal modifies the Committee Action onProposal 79-122 (Log #55).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: I am not opposed to adding the term but theproposed (revised) definition may be confusing. A safety controlcircuit may not necessarily be part of another control circuit. Thedefinition should be revised to remove the word "related". Theacceptance of Proposal 79-1 (Log #CP4) globally replaces "safetyrelated function" with "safety function". There may not be a needfor the definiton based on Proposal 79-63 (Log #153) beingrejected. FREUDENBERG: See my Comment on Affirmative on Proposal79-122 (Log #55).

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(Log #136)79- 133 - ([14.4.3.8]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Existing text: 14.4.3.8 Devices serving to guide and carry a cable with flexibleproperties, shall be so designed that the inner bending radius isnot less than the values given in the table XW, unless the smallerbending radius is agreed to by the cable manufacturer, taking intoaccount the permissible tension and the expected fatigue life. Revise text to read as follows: 14.4.3.8 Devices serving to guide and carry a cable with flexibleproperties, shall be so designed that the inner bending radius isnot less than the values given in table XW. Exception: The cable manufacturer, taking into account thepermissible tension and the expected fatigue life agrees to a smallerbending radius.

SUBSTANTIATION: The sentence is too long, retain meaningbut making a part of the sentence an exception and reword theexception from its existing passive voice.COMMITTEE ACTION: Accept in Principle. Revise 14.4.3.8 to read as follows: 14.4.3.8 Devices serving to guide and carry a cable with flexibleproperties, shall be so designed that the inner bending radius isnot less than the values given in table XW. Exception: A smaller bending radius shall be permitted if thecable is identified for the purpose.COMMITTEE STATEMENT: The exception was reworded tocomply with the NFPA Manual of Style. The committeeunderstands that this proposal modifies the Action on Proposal 79-122 (Log #55) [Clause 14].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #137)79- 134 - ([14.4.5.3]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Existing text: 14.4.5.3 Attachment plug and receptacle (plug/socket)combinations, shall be so designed that; a protective bonding(equipment grounding) circuit connection is made before any liveconnections are made; and the protective bonding (equipmentgrounding) circuit connection is not disconnected until all liveconnections in the plug are disconnected; except for connectionsused in PELV circuits, or the connectors used only to facilitateassembling / disassembling (multi-pole connectors). Revise text to read as follows: 14.4.5.3 Attachment plug and receptacle (plug/socket)combinations, shall be so designed that; (a) The protective bonding (equipment grounding) circuitconnection is made before any live connections are made. (b) The protective bonding (equipment grounding) circuitconnection is not disconnected until all live connections in theplug are disconnected. Exception: Connections used in PELV circuits, or the connectorsused only to facilitate assembling / disassembling (multi-poleconnectors).SUBSTANTIATION: The sentence is too long, retain meaningbut making it a list and an exception per NFPA MOS.COMMITTEE ACTION: Accept in Principle. Revise text to read as follows: 14.4.5.3 Attachment plug and receptacle (plug/socket)combinations, shall be so designed that; (a) The equipment grounding (protective bonding) circuitconnection is made before any current-carrying connections aremade, and (b) The equipment grounding (protective bonding) circuitconnection is not disconnected until all current-carryingconnections in the plug are disconnected. Exception: Connections used in PELV circuits, or the connectorsused only to facilitate assembling / disassembling (multi-poleconnectors) shall not be required to meet these requirements.COMMITTEE STATEMENT: The committee agrees that thesentence is too long and was reworded for clarity. The exceptionhas been revised to comply with the NFPPA Manual of Style. Thecommittee understands that this proposal modifies the Action onProposal 79-122 (Log #55) [Clause 14].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #110)79- 135 - (16.3.4 [14.4.2.5]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Revise text to read as follows: "Liquidtight flexible (metal or non-metallic) conduit..., and otherexternal mounded devices The exposed length of liquidtight flexible conduit or cablebetween connectors shall not exceed three and 1/3/ feet ( 1meter). Minimum wire size of cable shall be No. 16 AWG.


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Multiple-conductor cable is to be secured at each end with an oiltight connector. "SUBSTANTIATION: Liquidtight does not provide the impactresistance to damage as rigid conduit in typical harsh industrialenvironments which is likely in long runs typically found on largemachine tools. The outer plastic covering is susceptible to"brittling" (then breaking allowing fluids to penetrate) due toexposure to machine and process oils in atmospheric suspension.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This proposal is too restrictive.Lengths greater than those proposed are currently permitted in IEC60204-1 as well as in Proposal 79-122 (Log #55) 55, 14.4.2. The requirements in the new Proposal [79-122 (Log #55)]14.5.4.3 " Liquid-tight flexible conduit" limits its use to thoseidentified e.g.UL360. This proposal is more restrictive thanapplication limitations found in UL 360 and is appropriate to onlycertain limited applications of NFPA 79.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #135)79- 136 - ([14.1.2]): RejectSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Add paragraph to read as follows: 14.1.2 Conductor and cable runs 14.1.2.5 The equipment grounding (protective) conductor shallbe placed close as practicable to the associated live conductors inorder to decrease the impedance of the loop.SUBSTANTIATION: In conductor and cable runs the distancebetween the circuit conductors defines significant part of thecircuit impedance. The implicit design requirement forequipment grounding circuits is to have a low impedance pathshould a fault condition exist. Thus the need for the requirementto locate equipment grounding conductors as close as practicableto the associated live circuits that are likely to be a part of thecircuit loop during a fault condition that the equipment groundingconductor is intended to provide protection.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposed language is vague andunenforceable.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: SAUNDERS: The proposal should be accepted. Therequirement provides additional definition as to how toaccomplish the existing NEC requirement as stated in Article 250-2(d): "d) Performance of Fault Current Path. The fault current pathshall be permanent and electrically continuous, shall be capable ofsafely carrying the maximum fault likely to be imposed on it, andshall have sufficiently low impedance to facilitate the operation ofovercurrent devices under fault conditions."COMMENT ON AFFIRMATIVE: ANDERSON: The committee's statement in rejecting theproposal is true that the original proposal's approach does containlanguage that is unenforceable. But, given the desire of lowimpedance ground return paths, and given the physics that definethe variables that determine the impedance of a circuit, theconcept contained in the original proposal might still serve thesame useful purpose as a note to 14.1.2.1. Also, given that thecalculation of power circuit impedances is nominally done in thecourse of electrical power transmission systems engineering work,and rarely done in machine design work, the point in the notewould be helpful to an electrical designer of a machine. Thesubstantiation in the original proposal stands. The proposedrevised text to Log # 55 would become: 14.1.2 Conductor and cable runs 14.1.2.1 Conductors and cables shall be run from terminal toterminal without splices or joints.Exception No. 1: Splices shall be permitted to leads attached toelectrical equipment, such as motors and solenoids; such splicesshall be insulated with oil-resistant electrical tape or insulationequivalent to that of the conductors and installed in a suitableenclosure.

Exception No. 2: Where it is impracticable to provide terminals ina junction box (e.g. on mobile machines, on machines having longflexible cables) the use of splices or joints shall be permitted. Note: The equipment ground conductor should be placed asclose as practicable to their associated circuit conductors in orderto minimize the circuit impedance during the instance of a groundfault.

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(Log #99)79- 137 - ([14.1.2.2]): Accept in PrincipleSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to add new text to NFPA79-1997 as additional content for the newly proposed Clause 14which was reconciled with EN 60204-1 by Technical Committee onElectrical Equipment of Industrial Machinery action. Add text to read as follows: 14.1.2.2 Factory applied connectors molded onto cables shall bepermitted. Such connectors shall not be considered as splices orjoints.SUBSTANTIATION: Factory applied connectors molded ontocables are commonly utilized on the electrical equipment ofindustrial machinery. Such connectors are attached in a controlledenvironment where comprehensive quality assurance, test, andvalidation measures are applied. The robust design and successfulutilization history of such connectors indicate that such productsare not a safety risk. These connectors are not considered assplices or joints in cable runs for the purpose of this clause. Editorial organization of the material follows IEC 60204-1 1997Edition structure, and the Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: The concerns of the submitter arealready addressed in Proposal 79-122 (Log #55) (14.1.2.2).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: The word "Listed" should be inserted before"Factory" in the first sentence. Reason: This method should only be permitted if evaluated by aqualified testing laboratory, not installed at the "factory" where themachine is located.

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(Log #100)79- 138 - ([14.1.4]): Accept in PrincipleSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to add text to NFPA 79-1997 as additional content for the newly proposed Clause 14 whichwas reconciled with EN 60204-1 by Technical Committee onElectrical Equipment of Industrial Machinery action. Add text to read as follows: 14.1.4 Cables 14.1.4.1 Cables run exposed along the structure of the equipmentor system, or in the chases of the machinery shall be permitted.Exposed cables shall be installed to closely follow the surface andstructurel members of the machinery. 14.1.4.2 Cables shall be supported by the equipment or systemstructure as follows: (1) In such a manner that the cable will not be damaged bynormal equipment use (2) Every 12 in. in a non-vertical run Exception: Supporting distance may be increased up to 36 in.,whre the structure of the machine or system makes supportimpractical every 12 in. (3) Every 36 in. in a vertical run Exception: Supporting distance may be increased to 96 in., wherethe structure of the machine or system makes support impracticalevery 36 in. (4) When suspended in air spanning a distance up to 18 in. Exception: Span distance may be increased up to 36 in., wherethe structure of the machine or system makes support impracticalevery 18 in. 14.1.4.3 Cables shall not be supported by machinery guard worklikely to be removed for maintenance access. 14.1.4.4 Multiple cables can be supported and fastened togetherin a bundle provided the method of support and fastening is


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sufficient to support the mechanical weight and strain of thebundle. 14.1.4.5 Cables shall be fastened where supported. Exception No. 1: Where horizontal runs are inherently supportedby the machine or system structure, or by a floor or deck, fasteningis not required. Exception No. 2: Where run at not more than a 45 degree anglefrom horizontal, fastening is not required. 14.1.4.6 Cables shall be fastened with cable ties supported by anyof the following methods: (1) Screw-on cable tie mounts (2) Hammer-on cable tie mounting clips (3) Around the machine or system structural members (4) Through holes in the machine or system structural members (5) Cable mounting clamps (6) Other methods identified as acceptable for the purpose 14.1.4.7 The free ends of cable ties shall be cut flush after finaladjustment and fastening. Cable ties of the reusable or releasabletype shall not be permitted for use as a permanent fasteningmethod 14.1.4.8 Cables shall be protected from physical damage wherefollows: (1) By alternative routing (2) With additional guarding or railings (3) When supported by flooring or decking, with walk over ordrive over cable protective devices (4) By installation in a wire way (5) By installation in a floor or deck covering trapezoidal walkover raceway specifically designed for cable protection 14.1.4.9 Bends in cables shall be made so as not to cause unduestress. The radius of the curve of the inner edge of any bend shallnot be less than five times the diameter of the cable. 14.1.4.10 Where a cable is used in a length longer than optimallyrequired, the excess cable shall be coiled in loops at or near theload end. The coil shall be fastened to itself and to the machinerystructure. Exception: When an excess cable is associated with a horizontalcable run that is inherently and fully supported, the coil is notrequired to be fastened to the equipment or system structure.SUBSTANTIATION: As a common practice cables are extensivelyapplied as part of the electrical controls of industrial machinery.NFPA 79 and EN60201 are both silent on safe cable applicationmethodology, which forces industry to utilize a plethora of ad hoc,and sometimes questionable, measures. In order to facilitate thesafe and uniform utilization of cables, this text is proposed. It isthe intent of these paragraphs [14.1.4.x] to provide cableapplication methodology that is at least comprehensive as themethodology outlined for may wiring methods found in Chapter 3of NFPA 70. The purpose of this proposal is to clearly establishthe implementation requirements for cables used on the electricalequipment of industrial machinery. Editorial organization of the material follows IEC 60204-1 1997Edition structure, and the Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition. Substantiation for 14.1.4: As a common practice cables are extensively applied as part of theelectrical controls of industrial machinery. NFPA 79 and EN60201are both silent on safe cable application methodology, whichforces industry to utilize a plethora of ad hoc, and sometimesquestionable, measures. In order to facilitate the safe and uniformutilization of cables, this text is proposed. It is the intent of theseparagraphs [14.1.4.x] to provide cable application methodologythat is at least as comprehensive as the methodology outlined formany wiring methods found in Chapter 3 of NFPA 70. Section 14.1is divided into 4 subsections 1 General requirements, 2 Conductorand cable runs, 3 Conductors of different circuits, and 4 Cables.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition. Substantiation for 14.1.4.1: Specific application analysis will identify precisely how cablesneed to be run. In addition to conventional cable routingmethodology, the routing of cables along either the inside oroutside of the machine will at some point typically becomenecessary. Clause 14.1.4.1 recognizes and permits cables routedalong the exterior of the surface of the structural members of themachinery, as well as cables routed through chases inherent to themachinery structure, or through chases added to the machinerystructure for the purpose. Cables associated with a machine ormachinery system is an integral part of that machine or machinerysystem. Supporting cables by the equipment or system structureclearly indicates and maintains that association. Substantiation for 14.1.4.2: Provides information not in the present standard.

Some cable types may be more susceptible to physical damagethat others. Care should be taken to ensure that all applied cabalastype would not be subjected to physical damage under conditionsof normal use. Although this requirement may appear obvious tomost readers, Clause 14.1.4.2(a) codifies a requirement that theproper care be taken to ensure the integrity of the cableinstallation. Electrical, safety and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessupported at greater that 12 in. in a non-vertical run can make foran installation that would not satisfy a reasonable personsunderstanding of what constitutes “a neat and workman like”installation. Clause 14.1.4.2(b) helps ensure a conscientious“workman like” installation of cables. Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may beimpractical or undesirable to support cables in a non-vertical runat 12 in. intervals at all times. This exception to Clause 14.1.4.2(b)allows a reasonable extension of the support distance to cover suchcircumstances. Electrical, safety and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessupported at less than 36 in. in a vertical run can make for aninstallation that would not satisfy a reasonable personsunderstanding of what constitutes “a neat and workman like”installation. Clause 14.1.4.2(c) helps ensure a conscientious“workman like” installation of cables. Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may beimpractical or undesirable to support cables in a vertical run at 36in. intervals at all times. This exception to Clause 14.1.4.2(c)allows a reasonable extension of the support distance to cover suchcircumstances. Electrical, safety and application engineering evaluations ofindustrial machines and machinery systems indicate that cablessuspended in air spanning a distance greater that 18 in. can makefor an installation that would not satisfy a reasonable personsunderstanding of what constitutes a “neat and workman like”installation. Clause 14.1.4.2(d) helps ensure a conscientious“workman like” installation of cables. Electrical, safety, and application engineering evaluations ofindustrial machines and machinery systems indicate that it may bepractical or desirable for cables to span distances greater than 18in. at some times. This exception to Clause 14.1.4.2(d) allows areasonable extension of the span distance to cover suchcircumstances. Substantiation to 14.1.4.3: The supporting of cables on machinery guard work that is likelyto be removed for maintenance access would make for a potentiallyunsafe installation. The integrity of the installation would becompromised as soon as maintenance access to the equipmentbehind the guard work was required. Guard work likely to beremoved for maintenance access may be removed on a routinebasis. It is therefore reasonable to expect that the integrity of thecable installation will ultimately not be restored, and thereforeprohibited. Substantiation for 14.1.4.4: Where multiple cables are routed together, it is often commonpractice to fasten those cables together in a bundle so as to create aneat and workman like installation. Clause 14.1.4.4, recognizes thispractice, and requires that the fasteners and supports employed beof such construction so as to being substantial enough for theapplication. Substantiation for 14.1.4.5: In order to maintain a well managed, safe, installation effected ina neat and workman like manner, cables must be fastened wheresupported. Unfastened cables may be come a hazard if lefthanging around unfastened. Unfastened cables may cause aperson or object (e.g. tools) to hang up on the equipment causingpersonal injury or equipment damage. Exception 1 allows runs of cables where inherently supported bythe machine or machinery system structure, floor or deck, to laywhere supported without fastening. Fastening is not practical whencables are laying on the floor or dick within the structure of themachine or machinery system. Fasting is not warranted where theinherent design and natural construction of the machine ormachinery system naturally supports the cable runs. Exception 2 allows runs of cables at 45 degrees or less withoutfastening. Fastening is not practical when cables are lying withinthe structure of the machine or machinery system, and is notwarranted where the inherent design and natural construction ofthe machine or machinery system naturally supports the cable runs.At 45 degrees or less cables are not likely to move once in place. Substantiation for 14.1.4.6:


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Cable clamps and cables ties are a readily available, low cost andeffective method of fastening cables in place, and are used incommon practice for the purpose. Cable ties alone, however, arenot a complete fastening solution. In order to fasten a cable with acable ties additional hardware is required. That additionalhardware is defined in the text of 14.1.4.6. Cable tie mounts are a common usage item. A substantialmechanical fastening method for cable tie mounts is desirable inorder to maintain the integrity of the assembly. Screw fastening issuch a substantial method. The structural members of machinesare typically of substantial construction, and can serve as a safe andeffective fastening platform when cables are fastened with cable tiesaround the members or through holes in the members. Cable mounting clamps are common usage items that areexpressly intended for the purpose of fastening cables in place. Assuch, cable mounting clamps are acceptable means. Other methods of cable fastening may be deemed acceptablebased on the judgment of the applicable authority havingjurisdiction. Substantiation for 14.1.4.7: In order to maintain a neat and workman like assembly, cable tiesshould be cut flush once installed. Reusable cable ties have apropensity to loosen with time, and therefore do not maintain theintegrity of the assembly over time. Substantiation for 14.1.4.8: Cable must not be subjected to physical damage. Clause 14.1.4.8identifies methods by which physical damage to a cable can beavoided. Routing cables in such a way so as to ensure that cable runscannot be damaged, or using a commercially available walk ordrive over cable protective devices are acceptable and effectivemethods of protection. Routing cables in a cable trunk (wire way) or using a trapezoidalwalk over raceway can be specifically designed and constructed bythe machinery supplier for the purpose cable protection are alsoacceptable and effective. Substantiation for 14.1.4.9: Bends in cables should not be made in a manner that placesundue stress on the integrity of the cable. A requirement for ainner edge bend radius of not less than five times the diameter ofthe cable will ensure the integrity of the cable at bends in the cablerun. A typical cable manufacturer recommended minimumbending radius, for fixed installation of cables, is between 3 and 5times the cable diameter. Substantiation for 14.1.4.10: Cables, as typically applied for industrial machinery can be eitherof a perfect length, or longer than required. Clause 14.1.4.10provides requirements for the neat and workman like handling ofexcess cable lengths in a consistent, identifiable manner. Theexception to Clause 14.1.4.10 is consistent with the practicesoutlined in Exception 1 to Clause 14.1.4.5.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-122 (Log #55) (14.1.4) which meets the intent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: I am concerned that "flexible cords" will be usedwhere "cables" are intended. Specific cable types should bespecified. The exception to 14.1.4.5 should be deleted or modifiedbecause it literally permits cables to be on the floor.

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(Log #134)79- 139 - ([14.1.4.3]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: Add new text to read as follows: 14.1.4.3 Cables shall not be supported by machinery guard worklikely to be removed for maintenance access. Revise text to read as follows, adding exception: 14.1.4.3 Cables shall not be supported by machinery guard worklikely to be removed for maintenance access. Exception: Wiring for components that are an integral part of theguard and designed to remain on the guard when the guard isremoved for maintenance access. e.g. interlock switching schemes.

SUBSTANTIATION: The original proposal would exclude doormounted locking and interlocking which require cabling betweencomponents that are mounted on and removed with the removableguard. The circuits may function either through an on boardbattery system or a plug scheme that connects and disconnects withthe guard mounting or removal.COMMITTEE ACTION: Accept in Principle. Revise the proposed text to read as follows: 14.1.4.3 Cables shall not be supported by machinery guards thatare likely to be removed for maintenance access. Exception: Wiring for components that are an integral part ofthe guard and designed to remain on the guard when the guard isremoved for maintenance access shall be permitted to besupported by the guard.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on Proposal 79-122 (Log #55). Theexception has been modified to comply with the NFPA Manual ofStyle. In addition the word "work" has been removed for clarity anfthe example was removed because it is not necessary.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #107)79- 140 - (16.4 [14.1.1]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add new text to read as follows: 16.4.X Electrical connectors to motors, solenoids, and similardevices with integral leads, size 4 AWG and smaller, shall be madewith ring type pressure connectors. The connectors shall be boltedand taped. Soldered or insulation-piercing type connectors (lugs)are not acceptable. A connector device commonly known as a "wire nut" shall not beused for any connection.SUBSTANTIATION: Added text to better define connectionmethods. Have seen and needed to explain to equipment builders(OEM’s) both domestic and foreign the need to use such wiringpractice for maintenance and repair by the end user. Have foundwire-nuts used both on large solenoids (pre-mature failure) andalso motor connections (480/3/60), that have "broken down" andhave caused "single phasing" (on motors) conditions due to lack ofability to handle "inrush" current common with such devices.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Other termination devices areavailable that are suitable and have been sucessfully used. Thecommittee does not accept that there has been sufficient technicalsubstantiation to warrant this change.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: GARSIDE: I disagree with the complete rejection. The proposedexplict restriction on the use of "wire nuts" [exact wording mightneed editorial input] in industrial machinery would be a greatimprovement int he standard. (I agree with the committee thatspecifying only one kind of connection method would have beenunduly restrictive.)

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(Log #109)79- 141 - (Clause 17 [14.5.1.4(New)]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Revise text to read as follows: "All joints between lengths...designed for the purp Where conduit terminates in a threadless opening, a locknut shallbe provided both inside and outside the enclosure, and theconduit end shall be equipped with an insulating bushing. asuitable oiltight means (such as an oil-resistant synthetic rubber o- ring and a metal cup) shall be provided between the outsidelocknut and opening. When the conduit enters the openingthrough a conduit connector, the shoulder of the connector mayserve as the outside locknut. The o-ring assembly or an equivalentsealing device should also be furnished when a locknut is used as ajam nut on connectors fitted to threaded hubs. "SUBSTANTIATION: The lack of direction on the method toenter and connect raceway and conduit to boxes and enclosureshave caused a lack of sealing to liquids and debris that can causedetrimental effects to conductor insulation, the connections, andinsulation capability to "ground".COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The concept of this proposal isalready covered in Proposal 79-122 (Log #55), 14.5.3.1.3. There isinadequate substantiation to mandate a suitable oil tight, oilresistant, synthetic rubber O-ring termination.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #104)79- 142 - (17.4 [14.5.3]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Delete text as follows: " Intermediate metal (steel) conduit shall bepermitted....Provisions of 17.3.2 and 17.3.8"SUBSTANTIATION: Has been seen not to provide sufficientprotection in harsh industrial environment as encountered by themachine tools as described in the ANSI B11 series of standards.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This standard covers machinesbeyond the scope of the ANSI B11 series. Equipment must beselected to be suitable for the environment.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: There is no data as to what percentage ofmachines are installed in each of the wide range of environmentsfrom cleanroom, to office-like, to light industrial, to heavyindustrial, to extremely harsh environments including outdoorinstallations. The general statement "suitable for the intendedenvironment" is appropriate because one generic standard has tofit all industries and all environments for both machines covered byANSI B11 series and machines not covered by the ANSI B11series.The committee statement that "equipment must be selectedto be suitable for the environment" is absolutely necessary.

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(Log #105)79- 143 - (17.5 [14.5.3]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Delete text as follows: " Electrical metallic (steel) tubing shall be permitted....Provisions of 17.3.2 through 17.3.8. "SUBSTANTIATION: Has been seen not to provide sufficientprotection in harsh industrial environment as encountered by themachine tools as described in the ANSI B11 series of standards.COMMITTEE ACTION: Reject.

COMMITTEE STATEMENT: This standard covers machinesbeyond the scope of the ANSI B11 series. Equipment must beselected to be suitable for the environment.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-142 (Log #104)

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(Log #106)79- 144 - (17.6 [14.5.3]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Delete text as follows: " 17.6.1 Rigid nonmetallic conduit Schedule 80 and fittings shallbe listed... and all other sub sections."SUBSTANTIATION: Has been seen not to provide sufficientprotection in harsh industrial environment as encountered by themachine tools as described in the ANSI B11 series of standards.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This standard covers machinesbeyond the scope of the ANSI B11 series. Equipment must beselected to be suitable for the environment.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-142 (Log #104)

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(Log #108)79- 145 - (17.9.1 [14.5.4.2]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Delete text as follows: " 17.9.1 Flexible metal conduit shall consist of flexible metaltubing or woven wire armor... and all other sub sections. "SUBSTANTIATION: Conductor insulation damage has beenexperienced as machine lubrication oil, or process oils haveentered the conduit and has caused the insulation of theconductors to become brittle, break (when conduit is "flexed")and cause either conductor to conductor shorting or conductor toconduit (ground fault) shorting. Not suitable for environmentencountered by machine tools as identified by the ANSI B11 seriesof safety standards.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This standard covers machinesbeyond the scope of the ANSI B11 series. Equipment must beselected to be suitable for the environment.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: See my Comment on Affirmative on Proposal79-142 (Log #104)

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(Log #101)79- 146 - ([14.5.10]): Accept in PrincipleSUBMITTER: Gary J. Locke, Lockheed Martin SystemsIntegrationRECOMMENDATION: This proposal is to add new text to NFPA79-1997 as additional content for the newly proposed Clause 14which was reconciled with EN 60204-1 by Technical Committee onElectrical Equipment of Industrial Machinery action. Add text to read as follows: 14.5.10 Cord 14.5.10.1 Manufactured assemblies with factory applied moldedconnectors applied to cord shall be permitted. Note: Foradditional information on flexible cords, refer to ANSI/UL 62"Flexible cord and fixture wire"


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14.5.10.2 The use of cord shall be limited to individual exposedlengths of 50 ft or less. 14.5.10.3 Cord shall be installed in accordance with the provisionof clause 14.1.4. 14.5.10.4 Cord shall be permitted for use for flexible connectionsto pendant push-button stations. Chains or wire rope external tothe cord shall support the weight of pendant stations. 14.5.10.5 Cord shall be permitted for use for connectionsinvolving small or infrequent movements. Cord shall also bepermitted to complete the connection to normally stationarymotors, limit switches, and other externally mounted devices. 14.5.10.6 Connections to frequently moving parts shall be madewith conductors for flexing service in accordance with 13.7 Cordwith conductors for flexing service shall have vertical connectionsand shall be installed to avoid excessive flexing and straining. Exception: Horizontal connections shall be permitted where thecord is adequately supported.SUBSTANTIATION: As a common practice cords are extensivelyapplied as part of the electrical controls of industrial machinery.NFPA 79 and EN60201 are both silent on safe cord applicationmethodology, which forces industry to utilize a plethora of ad hoc,and sometimes questionable, measures. In order to facilitate thesafe and uniform utilization of cords, this text is proposed. It is theintent of these paragraphs [14.5.10.x] to provide cord applicationmethodology. The purpose of this proposal is to clearly establishthe implementation requirements for cords used on the electricalequipment of industrial machinery. Editorial organization of the material follows IEC 60204-1 1997Edition structure, and the Manual of Style for NFPA TechnicalCommittee Documents 2000 Edition. Substantiation for 14.5.10: Because the construction of cord is different than that of cable itsuse is limited. 14.5.10 was added for application purposes.Editorial addition to help organize the material and follow IEC60204-1 1997 Edition structure and Manual of Style for NFPATechnical Committee Documents 2000 Edition. Substantiation for 14.5.10.1: Adds cord to machine wiring practice. Factory appliedconnectors molded onto cord are commonly utilized on theelectrical equipment of industrial machinery. Such connectors areattached in a controlled environment where comprehensive qualityassurance, test, and validation measures are applied. Substantiation for 14.5.10.2: Adds cords to machine wiring practice for utilization of cord forconnection to the field I/O and similar. Length of a cord isrestricted to 50 ft to limit exposure to physical damage. Substantiation for 14.5.10.3: Provides reference for application methodology. Substantiation for 14.5.10.4: The first sentence revision will allow cords to be used. Substantiation for 14.5.10.5: Covers material not presently in this standard. The exception isdeleted as not pertinent to cord installations. Editorial change toNFPA 79 1997 Edition material location and add IECnomenclature, following IEC 60204-1 1997 Edition structure andManual of Style for NFPA Technical Committee Documents 2000Edition. Substantiation for 14.5.10.6: More logical topic location and better covers the anticipatedusage. NFPA 79 1997 Edition 16.3.5 has been relocated to theproposed 14.4.3.1 and 14.4.3.2 and 14.5.10.6. Paragraph 14.5.10.6address installation concerns for the use of cords.COMMITTEE ACTION: Accept in Principle. The committee understands that the only change made in thisproposal is to add a new exception to 14.5.10.4 to read as follows: Exception: Cords listed for the purpose shall be permitted to beused without an external chain or wire rope.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on Proposal 79-122 Log #55) [Clause14].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: DOBROWSKY: The word "Listed" should be inserted before"Manufactured". See my comment on Proposal 79-137 (Log #99). SAUNDERS: Subclause 14.4.2.2 requires external conductors tobe enclosed in raceway, which conflicts with the proposed14.5.10.2. Recommendation: Add cord and cord connectors to theexception for 14.4.2.2.

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(Log #130)79- 147 - (17.10.2 [14.5.6.6(New)]): Accept in PrincipleSUBMITTER: Glen Kampa, HoffmanRECOMMENDATION: Revise as follows: (Wireways) 17.10.2 Metal thickness and construction shall not be less thanNo. 14 MSG comply with UL 807.SUBSTANTIATION: The current metal thickness requirement isnot based on the size of the wireway. There is a need to point to adocument which offers a thickness requirement based on the widthof the wireway especially when 14 MSG is not adequate. UL 807 isa product standard which covers Wireways, Auxiliary Gutters andAssociated Fittings. This standard has a minimum thickness tablebased on the width of the wireway. This table also indicates thatlesser thickness than 14 MSG is permitted for smaller wireway (seeattached table). This standard also covers many additionalconstruction requirements for wireway which include protectionagainst corrosion, supports, expansion joints, hinges and latches. Note: Supporting material available for review at NFPAHeadquarters.COMMITTEE ACTION: Accept in Principle. Revise text to read: 14.5.6.6 Metal thickness and construction of wireways shall comply with UL 870, Wireways and Auxilary Gutters.COMMITTEE STATEMENT: The commttee understands that thetext only applies to wireways and has located the requirement in14.5.6.6. Editorially correct UL standard number. The committeeunderstands that this proposal modifies the Action on Proposal 79-122 (Log #55) [Clause 14].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #14)79- 148 - (17.11 [14.4.2]): Accept in PrincipleSUBMITTER: William E. Anderson, The Procter & GambleCompanyRECOMMENDATION: This proposal is to either revise theproposed NFPA 79, 2002 edition in which wiring practices,including raceways will be in Clause 14 or if that revision fails, toadd the proposed new text to the existing NFPA 79, 1997 edition,Clause 17 as follows: Revise the title for the proposed new 14.4.2 from "Externalraceways (ducts)" to: 14.4.2 External Raceways (Ducts) and Support Systems After the third paragraph add a new paragraph: "Cable trays shall be permitted to be used for cable or racewaysupport on industrial machines. Cable trays shall be permitted tosupport single conductors 1/0 or larger otherwise permitted onindustrial machines and, cables otherwise permitted on industrialmachines and, raceways functionally associated with industrialmanufacturing systems. Cables exposed to the direct rays of thesun shall be sunlight resistant." Or, if the 2000 edition does not accept the revisions that placeWiring and Raceways in Clause 14, then add the same paragraphabove as an addition to Clause 17 and it would become a newparagraph inserted after 17.10 to become: 17.11 Support Systems. Cable trays shall be permitted to be usedfor cable or raceway support on industrial machines. Cable traysshall be permitted to support single conductors 1/0 or largerotherwise permitted on industrial machines and, cables otherwisepermitted on industrial machines and, raceways functionallyassociated with industrial manufacturing systems. Cables exposedto the direct rays of the sun shall be sunlight resistant. Retain the remaining paragraphs and increase their number byone.SUBSTANTIATION: This addition reflects current practice inmany locations. Using cables already approved for use on machines in a cable traysupport system on the machine does not present an additional firehazard while providing a proven support system.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See Committee Action on Proposal79-122 (Log #55) (14.5.11) which meets the intent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #27)79- 149 - (Clause 18 [Clause 15]): Accept in PrincipleSUBMITTER: Melvin K. Sanders , TECo., Inc.RECOMMENDATION: Revise NFPA 79-1997 Clause 18 "Motorand motor compartments" and issue as new Clause 15 "Electricmotors and associated equipment" as follows: 15 Electric motors and associated equipment 15.1 General requirements Motors shall be suitable for the environment in which they areinstalled. NOTE 1: For additional information related to motor standards,refer to UL 1004, NEMA MG-1, IEEE 841 or IEC60034-1. NOTE 2: The protection requirements for motors and associatedequipment are given in 7.2 for overcurrent protection, in 7.3 foroverload protection, and in 7.6 for overspeed protection. 15.2 [Reserved] 15.3 Motor dimensions As far as is practicable, the dimensions of the motors shallcomply with those given in NEMA MG-1, IEC 60072-1 or IEC 60072-2 as appropriate. Note: For a comparison between kilowatt and horsepower size,see Annex X Tables X.1 and X.2 15.4 Motor mounting and compartments 15.4.1. Each motor and its associated couplings, belts andpulleys, or chains, shall be so mounted that they are adequatelyprotected from physical damage and are easily accessible forinspection, maintenance, adjustment and alignment, lubrication,and replacement. The motor mounting arrangement shall be suchthat all motor hold-down means can be removed and all terminalboxes are accessible. An adjustable base or other means shall beprovided when belt or chain drives are used. 15.4.2. Motors shall be mounted so that proper cooling isensured and the temperature rise remains within the limits of theinsulation class. 15.4.3. Motor compartments shall be clean and dry, and whenrequired, shall be ventilated directly to the exterior of the machine.The vents shall be such that ingress of swarf, dust, or water spray isat an acceptable level. 15.4.4. There shall be no opening between the motorcompartment and any other compartment that does not meet themotor compartment requirements. Where a raceway is run intothe motor compartment from another compartment not meetingthe motor compartment requirements, any clearance around theraceway shall be sealed. 15.5 Criteria for selection The characteristics of motors and associated equipment shall beselected in accordance with the anticipated service and physicalenvironment conditions (see 4.4). The points that shall beconsidered include: - type of motor; - type of duty cycle; - fixed speed or variable speed operation, (and consequentvariable influence of the ventilation); - mechanical vibration; - type of converter for motor speed control; - influence of the harmonic spectrum of the voltage and/orcurrent feeding the motor (when it is supplied from a converter)on the temperature rise; - method of starting and possible influence of the inrush currenton the operation of other users, taking into account possiblespecial considerations stipulated by the supply authority; - variation of counter torque load with time and speed; - influence of loads with large inertia; - influence of constant torque or constant power operations; - possible need of inductive reactors between motor and converter. 15.6 Protective devices for mechanical brakes Operation of the overload and overcurrent protective devices formechanical brake actuators shall initiate the simultaneous de-energization (release) of the associated machine actuators. NOTE – Associated machine actuators are those associated withthe same motion, for example cable drums and long-travel drives. 15.7 Direction Arrow. Where reverse rotation can produce an unsafe condition, adirection arrow shall be installed. The arrow shall be adjacent tothe motor and plainly visible. 15.8 Marking on Motors.Motors shall be marked in accordance with Section 430-7 of NFPA70.

SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738.Hi sto ri cal B ackgro u n d. In Mar ch o f 1998, t he NF P A 79 co mm itt ee p rep ared a stat emen to f wo rk. T he majo r elemen t s o f th e stat emen t o f w or k are: Harm on i zatio n - P u rp o se As th e us ers an d t h e man u fact u rers of i nd u st rial mach in es mo veto w ard a glo b al m anu f actu ri ng co mmu n ity , t h e n eed fo r ah armo n ized stan d ard af fecti n g i nd u st rial mach in ery b eco mes an eco n om ic n ecess ity . G en erall y, large u sers and man uf actu rers fi n dregu lat io n s b u rd en so me. Ho w ever, mu lt ip le regu lati o ns as wel l as co n fli cti ng regu lat io n s are an eco n o mic di sin cen ti ve t o glo b alexp an sio n . In o rd er t o ease th e b u rd en o f d iff erin g regu lati o n, an d at th e s ame t ime main tai n th e h igh st an dar d o f el ectri cal mach in esaf ety, th e NF P A 79 co mmi tt ee h as exp res sed th ei r d esi re, th ro u ghb all ot ed vo te, t o h armo n ize NF P A 79 w it h IE C- 60204-1. Imp o rt ance o f Is su e - Harm on i zatio n To d ay' s i n du st rial mach i ne s are very co mp lex an d exp en si ve. Asman u fact ur in g l in es b eco me mo d ul ar an d t ran sp o rtab le, i nd u st rial mach in es o rigi nal ly p ro du ced fo r a fo rei gn market may q ui ckly b etr ans po rt ed to th e d o mest ic market. T h e rever se i s al so tr ue. Di ff erin g el ectri cal stan d ard s add a lar ge co st to m ul ti nat io n alman u fact ur ers as th ey b ui ld and so meti mes m ov e man u fact ur in gfaci li ties .Harm on i zatio n - Ob j ective Th i s w o rk i s n ecessar y t o acco mp li sh th e goal o f all ow in g in d us tryto econ o mi cally b u ild on e in d u stri al mach in e cap ab le of p assi n g ad etai led el ectri cal s afety in sp ect io n u si ng eit her IE C 60204-1 o rNF P A 79 s tan d ard .B ot h th e NE C Tech n ical C o rrel atin g Co mmi tt ee an d th e Stan d ard sC ou n cil rev iew ed th e s tatem en t o f w or k in Ju ly of 1998. T he TC C u n ani mo u sly reco mmen d ed t he fo ll o wi ng acti on to t he Stan d ard sC ou n cil : "T he Tech n ical C o rrelat in g Co mmi tt ee agrees wi th t h e eff o rts o fth e NF P A 79 co mmi ttee to h ar mo ni ze t h e tech n ical req u ir emen tso f NF P A 79 an d IE C 60204, w her e feas ib le and wh ere in co n certw ith th e N EC an d i ts relat ed co d es an d s tan d ard s."R esu lt Th e NF P A Stan d ard s C o un ci l con si d ered an d co n cur red w ith th ereco mmen d ati o n. In Ju ne o f 1999, t h e NF P A 79 C o mmi ttee fo rmed 20 T ask Gro u p s. Each Task Gr ou p w as assign ed o n e p ro p o sed n ew clau se. T he Tas k Gr ou p co mp ared NF P A- 79-1997, C lau se 18 in i ts en tir etyan d w ith IE C 60204-1 C lau se 15. Th e Task Gro u p p resen t ed it sw or k to th e en ti re co mm itt ee o n s everal o ccasio n s f o r rev iew an d co mmen t. Th is p ro p os al i s a resu l t o f th at w or k. Th e Task Gro u p p ro p o ses to ren u mb er Cl aus e 18 o f NF P A 79-1997 t o co rresp o n d w ith IE C 60204-1. T he task gro u p p ro po ses th efo l lo wi n g ch an ges t o fu rt her i mp ro ve u sab il it y.15 Electric motors and associated equipment

Revise Clause 15 heading “18 Motors and motor compartments” toharmonize with IEC Clause 15 heading and because it addressesmore issues than just motors and motor compartments.


T he fi rst p apr agrap h rest ates fo r mo to rs, th e cur ren t N F PA 79- 1997,5.2, req ui rin g electr ical co mp o nen t s an d d evi ces t o b e su it ab le f o rth e env iro n men t in w h ich t h ey are in st alled . No t e 1 i s p ro vi d ed to assi st u sers in l ocat in g ap p ro p ri ate m ot o r st an dar ds , an d N o te 2p ermi ts us ers t o q u ickly access rel ated i nf o rmati o n. A glo b alch an ge p ro vid es n um ber s t o mu lt ip le p aragrap h clau ses an d n o testo assis t t h e u ser.

15.2 [Reserved]

Placeholder for future use.


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15.3 Motor dimensions

This subclause covers a subject not presently in NFPA 79-1997.This text is comparable with the requirements of IEC 60204-1,Clause 15. These motor dimensions were added to require the useof standard motor frame sizes where practicable.

A Note has been added to point users to additional information inthe Annex. The Annex and its two tables will be identified later.

15.4 Motor mounting and compartments

Replace ” NFPA 79-1997, 18.1 Access” and its paragraph as well as“18.2 Mounting arrangement“ and its paragraph 18.2.1 with “15.4Motor mounting and compartments” and paragraph 15.4.1.

This combines information into one paragraph and will provideadditional guidance as to the proper care of the motors, what isexpected and caution against damage exposure. Specific textconcerning sealed bearings is no longer necessary and is betteraddressed in motor standards.

The words “from physical damage” was inserted in 15.4.1 tospecifically state the type of protection desired.

NFPA 79-1997,18.2.3 and 18.2.4 text is adequately covered in theproposed 15.4.1 1st sentence.

NFPA 79-1997,18.2.2 text is adequately covered in the proposed15.4.2.

NFPA 79-1997, 18.4 is adequately covered by proposed 15.4.3 and15.4.4. “Raceway” is the more generic term, replacing “conduit”.“Pipe” incorrectly implies non-electrical fittings can be used.

15.5 Criteria for selection

There is no comparable NFPA 79 text, this will provide selectionguidance for motor applications and is intended to cover all typesof motors because of the proliferation of AC, DC, servomotors andthe like.

15.6 Protective devices for mechanical protection

There is no comparable NFPA 79 text. This new text enhancessafety by stopping the machine when the overcurrent deviceoperates provided the machine has a brake.

15. 7 Direction Arrow

Retained NFPA 79-1997 18.3 and renumbered for sequencing.

15.8 Marking on Motors

Retained NFPA 79-1997 18.5 and renumbered for sequencing.

Attachment C – Cross reference for clause number changesbetween NFPA 79-1997 Clause 18 and new Clause 15.

From1997 NFPA 79Edition

To 2002 NFPA 79 Edition

18 1515.115.215.3

18.1 15.418.2 15.418.2.1 15.4.118.2.3 15.4.118.2.4 15.4.118.2 15.4.118.2.2 15.4.218.4 15.4.318.4 15.4.4

15.515.6

18.3 15.718.5 15.8

From 2002 NFPA 79Edition

To 1997 NFPA 79 Edition

15 1815.1 New15.2 Reserved15.3 New15.4 18.115.4 18.215.4.1 18.2.115.4.1 18.2.315.4.1 18.2.415.4.1 18.215.4.3 18.415.4.4 18.415.8 18.515.4.4 18.415.5 New15.6 New15.7 18.315.8 18.5

COMMITTEE ACTION: Accept in Principle. Revise NFPA 79-1997 Clause 18 "Motor and motor compartments"and issue as new Clause 15 "Electric motors and associatedequipment" as follows: 15 Electric motors and associated equipment 15.1 General requirements Motors shall be suitable for the environment in which they areinstalled. NOTE 1: For additional information related to motor standards,refer to UL 1004, NEMA MG-1, IEEE 841 or IEC60034-1. NOTE 2: The protection requirements for motors and associatedequipment are given in 7.2 for overcurrent protection, in 7.3 foroverload protection, and in 7.6 for overspeed protection. 15.2 [Reserved] 15.3 Motor dimensions As far as is practicable, the dimensions of the motors shallcomply with those given in NEMA MG-1, IEC 60072-1 or IEC 60072-2 as appropriate. Note: For a comparison between kilowatt and horsepower size,see Annex X Tables X.1 and X.2 15.4 Motor mounting and compartments 15.4.1. Each motor and its associated couplings, belts andpulleys, or chains and sprockets, shall be so mounted that they areadequately protected from physical damage and are easilyaccessible for inspection, maintenance, adjustment and alignment,lubrication, and replacement. The motor mounting arrangementshall be such that all motor hold-down means can be removed andall terminal boxes are accessible. An adjustable base or othermeans of adjustment shall be provided when belt or chain drivesare used. 15.4.2. Motors shall be mounted so that proper cooling isensured and the temperature rise remains within the limits of theinsulation class. 15.4.3. Motor compartments shall be clean and dry, and whenrequired, shall be ventilated directly to the exterior of the machine.The vents shall be such that ingress of swarf, dust, or water spray isat an acceptable level. 15.4.4. There shall be no opening between the motorcompartment and any other compartment that does not meet themotor compartment requirements. Where a raceway is run intothe motor compartment from another compartment not meetingthe motor compartment requirements, any clearance around theraceway shall be sealed. 15.5 Criteria for selection The characteristics of motors and associated equipment shall beselected in accordance with the anticipated service and physicalenvironment conditions (see 4.4). The points that shall beconsidered include: - type of motor; - type of duty cycle; - fixed speed or variable speed operation, (and consequentvariable influence of the ventilation); - mechanical vibration; - type of converter for motor speed control; - influence of the harmonic spectrum of the voltage and/orcurrent feeding the motor (when it is supplied from a converter)on the temperature rise; - method of starting and possible influence of the inrush currenton the operation of other users, taking into account possiblespecial considerations stipulated by the supply authority; - variation of counter torque load with time and speed;


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- influence of loads with large inertia; - influence of constant torque or constant power operations; - possible need of inductive reactors between motor and converter. 15.6 Protective devices for mechanical brakes Operation of the overload and overcurrent protective devices formechanical brake actuators shall initiate the simultaneous de-energization (release) of the associated machine actuators. NOTE – Associated machine actuators are those associated withthe same motion, for example cable drums and long-travel drives. 15.7 Direction Arrow. Where reverse rotation can produce an unsafe condition, adirection arrow shall be installed. The arrow shall be adjacent tothe motor and plainly visible. 15.8 Marking on Motors.Motors shall be marked in accordance with Section 430-7 of NFPA70.COMMITTEE STATEMENT: Editorially revise 15.4.1 to includesprockets, and clarify that the "means" modifies "adjustment."Remove the cross reference in 15.5 as it was unnecessary.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: SANDERS:The ROP Editorial Review Task group reported at theROP meeting concerning the original substantiation provided andmade the following observations. See chart below.

The following is provided in response to the Editorial ReviewCommittee Report ROP meeting March 12-16, 2001.

This was originally submitted with the Proposal subsequentlyidentified as log 27 with Jack C. Sanders incorrectly identified asthe author, and is further revised to respond to the ER committeecomments.

15 Electric motors and associated equipment

Recommendation: Revise Clause 15 heading “18 Motors andmotor compartments” to harmonize with IEC Clause 15 heading.This proposal is part of the package of material submitted by theNFPA WG subcommittee derived from SAE HS-1738 review of IEC60204-1.

Substantiation: This clause addresses more than just motors andmotor compartments.


R ecom men dat io n : T hi s fi rst p aragrap h ret ain s th e p resen t text o fNF P A 79-1997 Secti o n 5.2. No t es 1 an d 2 h ave b een n ew. T hi sp ro p os al is p art o f th e p ackage o f mat erial su b mit ted b y th e NF P A WG su b co mmit tee d eriv ed fr om SA E HS- 1738 revi ew o f IE C 60204-1.

S u bs tan ti atio n : No t e 1 is p ro vid ed to assi st u sers in lo cat in gap p ro pr iate mo to r st and ard s, an d No t e 2 p ermi ts u sers to q u ickly access rel ated in f or mati on .

A glo b al ch an ge als o p ro vid es a n u mb erin g sys tem to mu lt ip lep aragrap h clau ses an d n o tes to fu rt h er assi st th e u ser.

15.2 [Reserved]

Recommendation: Retain reserved number.

Substantiation: This will serve as a placeholder for future use.

15.3 Motor dimensionsRecommendation: This new text provides information on asubject not presently in NFPA 79-1997. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.

Substantiation: This text is comparable to the requirements of IEC60204-1, Clause 15. The references will enable users to determinestandard motor frame sizes.

A Note has been added to direct users to additional information inAnnex G.

15.4 Motor mounting and compartments

Recommendation: Add title to the clause.

Substantiation: The title was added to follow the editingrequirements of the Manual of Style April 2000.

15.4.1

Recommendation: Combine ”NFPA 79-1997, 18.1 Access” and itsparagraph as well as “18.2 Mounting arrangement“ and its firstparagraph first sentence of 18.2.1 into “15.4 Motor mounting andcompartments” and paragraph 15.4.1. Delete the second sentenceof present 18.2.1. Section 18.2.3 is combined into clause 15.4.1 firstsentence. Section 18.2.4 is considered adequately covered by thegeneral requirements of the first sentence of clause 15.4.1. Thisproposal is part of the package of material submitted by the NFPAWG subcommittee derived from SAE HS-1738 review of IEC 60204-1.

Substantiation: This combines information from several sectionsinto one clause and provides additional guidance for the propermaintenance of the motors, what is expected, and cautions againstdamage exposure. Specific text concerning sealed bearings isbetter addressed within motor standards.

The words “from physical damage” is inserted in 15.4.1 tospecifically state the type of protection desired. The last sentence isadded to ensure means of adjustment are provided.

15.4.2

Recommendation: Incorporate present section 18.2.2 of presentNFPA 79-1997 into clause 15.4.2. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.

Substantiation: The proposed text provides additional clarity.This proposal is part of the package of material submitted by theNFPA WG subcommittee derived from SAE HS-1738 review of IEC60204-1.

15.4.3

Recommendation: Incorporate the first sentence of present NFPA79-197 section 18.4 into clause 15.4.3. This proposal is part of thepackage of material submitted by the NFPA WG subcommitteederived from SAE HS-1738 review of IEC 60204-1.

Substantiation: Present section 18.4 covered two separate issuesand separating them provides greater clarity. The proposedwording provides additional information concerning motorventilation.

[15.1] 15 18 Electric Motorsand associatedequipment

Substantiation is a technical statement explainingwhy a requirement has been added, deleted orchanged from the existing NFPA 79-1997. Thesubstantiation is almost non existent. Pleasefurnish the committee with technicalsubstantiation. Also, the committee is having ahard time understanding exactly what waschanged from the 1997 NFPA 79.

AIP

[15.2] 15.5 Delete the reference “(see 4.4)” ACC Stylemanual


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15.4.4

Recommendation: Move the second and third sentences of presentNFPA 79-1997 section 18.4 to clause 15.4.4. Replace “conduit orpipe” with “raceway”. This proposal is part of the package ofmaterial submitted by the NFPA WG subcommittee derived fromSAE HS-1738 review of IEC 60204-1.

Substantiation: “Raceway” is the more generic term, and “pipe”incorrectly implies non-electrical fittings can be used.

15.5 Criteria for selection

Recommendation: This new text provides selection guidance formotor applications. This proposal is part of the package ofmaterial submitted by the NFPA WG subcommittee derived fromSAE HS-1738 review of IEC 60204-1.

Substantiation: There is no comparable NFPA 79-1997 text and itis intended to cover all types of motors because of the proliferationof AC, DC, servomotors and the like.

15.6 Protective devices for mechanical protection

Recommendation: There is no comparable NFPA 79 text. Thisproposal is part of the package of material submitted by the NFPAWG subcommittee derived from SAE HS-1738 review of IEC 60204-1.

Substantiation: This new text enhances safety by positive stoppingof the machine in the event the overcurrent device operates and themachine relies upon a brake to halt operation.

15. 7 Direction Arrow

Recommendation: Retain present section 18.3 NFPA 79-1997 18.3and renumber as clause 15.7.

Substantiation: Retained by NFPA 79 Technical Committee action.Renumbered for correct sequencing.

15.8 Marking on Motors

Recommendation: Retain present section 18.5 NFPA 79-1997 andrenumber as clause 15.8.

Substantiation: Retained by NFPA 79 Technical Committee action.Renumbered for correct sequencing.

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(Log #92)79- 150 - (18.1, 18.2 [15.4.1]): Accept in PrincipleSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in rewrite of Clause 18 that is thenew Clause 15 in 15.4.1. Change the first sentence to read: "Each motor and its associated couplings, belts, pulleys and chainsshall...". Change the last sentence to read: "An adjustable base or other means of adjustment shall...".SUBSTANTIATION: This added change will improve the Englishin the first sentence, and provide clarification in the last sentence.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-149 (Log #27). This action meets theintent of the submitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #52)79- 151 - (Clause 19 [Clause 8]): Accept in PrincipleSUBMITTER: Paul Dobrowsky, Holley, NYRECOMMENDATION: Revise text as follows:8 Grounding

8.1 General

This clause provides for grounding, bonding and groundedconductor requirements.


8.1.1 Connections

Grounded conductors shall not be connected to the equipmentgrounding (protective) circuit except for at separately derivedsystems.

8.2 Equipment grounding (protective bonding) circuit

8.2.1 Grounding system

The equipment grounding (protective bonding) circuit consists of:(1) The equipment grounding (PE) terminal(s);(2) The conductive structural parts of the electrical equipment andthe machine;(3) The equipment grounding (protective) conductors andequipment bonding jumpers

All parts of the equipment grounding (protective bonding) circuitshall be capable of withstanding the highest thermal andmechanical stress that can be caused by fault currents which couldflow in that part of the circuit.



8.2.1.1 Equipment grounding

The machine and all exposed, noncurrent-carrying conductiveparts, material, and equipment likely to be energized shall beeffectively grounded. Where electrical devices are mounted onmetal mounting panels that are located within nonmetallicenclosures, the metal mounting panels shall be effectivelygrounded.

8.2.1.2 Equipment grounding terminal

(1) For each incoming supply, an equipment grounding (externalprotective ) conductor terminal shall be provided in the vicinity ofthe associated phase conductor terminals.


(3) T he ter min al sh all acco mmo d ate an eq u ip men t gro u n di n gco n du ct or si zed in acco rd an ce w ith T abl e XX .


8.2.1.2.1 Equipment grounding terminal marking





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8.2.2.3 Equipment grounding conductors and bonding jumpers ofthe wire type shall not be smaller than shown in Table XX.

Table XX — Size of equipment grounding conductors andbonding jumpers

Column “A,” Amperes Copper Conductor Size, AWGor kcmil

10 16 * or 18 *15 14, 16 *, or 18 *20 12, 14 *, 16 *, or 18 *30 1040 1060 10100 8200 6300 4400 3500 2600 1800 01000 2/01200 3/01600 4/02000 2502500 3503000 4004000 5005000 7006000 800



(2) It shall be permitted to use machine members or structuralparts of the electrical equipment in the equipment groundingcircuit provided that the cross-sectional area of these parts is atleast electrically equivalent to the minimum cross-sectional area ofthe copper conductor required.

8.2.3 Continuity of the equipment grounding (protective bonding)circuit








(2) An equipment (protective) bonding jumper shall connect theconductive door or cover to the equipment enclosure or to anequipment grounding (protective bonding) terminal within theenclosure.



8.2.4 Exclusion of switching devices

The equipment grounding (protective) circuit shall not containany switches or overcurrent protective devices. Links or plugs in thegrounding circuit shall be permitted if proper ly labeled orinterlocked with the control circuits.

8.2.7 Equipment grounding (protective) conductor connectingpoints


(2) The equipment grounding conductor connecting points, otherthan the equipment grounding terminal, shall be identified by agreen color or by use of the symbol that appears in 8.2.1.2.1.


8.3 Control circuits

Control circuits shall be permitted to be grounded or ungrounded.Where grounding is provided, that side of the circuit common tothe coils shall be grounded at the control transformer if alternatingcurrent or at the power supply terminal if direct current. Wheregrounding is not provided, an insulation monitoring system shallbe utilized as described in 9.4.2.1.

Exception No. 1: Exposed control circu its as permitted by 6.4 shall begrounded.



8.5 Lighting circuits



8.5.3 The grounded conductor, where run to a screw-shelllampholder, shall be connected to the screw-shell.S UB S TA NT IA TIO N: His to rical B ackgro u nd .

In M arch o f 1998, t h e NF P A 79 com mit tee p rep ared a st atemen t o fw or k. T h e maj o r el emen ts o f t h e st atemen t o f w o rk ar e:


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Har mon i zati on - P ur pose

A s t he u ser s an d t he m an u fact u rers of in du str ial mac hin es move to warda gl obal m anu f actu ri ng com mu n i ty, the n eed for a harm on iz ed st an dardaff ect in g i ndu st rial m achin er y b ecom es an econ om ic n eces sit y. Gen er ally ,lar ge u ser s an d m an u fact ur ers fi nd regu lat ion s bu rden som e. Ho weve r,m ul ti ple regu lat ion s as w ell as con f lic tin g regu lat ion s are an econ om icdis in cen ti ve t o gl obal expan si on . In orde r t o eas e t he bu rde n of dif feri n gregu l atio n, an d at t he sam e tim e mai n tain the high s tan dard o f e lect ric alm achin e safet y, the NFP A 79 com mi tt ee has expre ssed thei r des ire, thr ou gh bal lot ed vot e, to harm on ize N FPA 79 wi th IE C- 60204-1.

Im port anc e of Is su e - Har mon i zati on

T oday's in du st rial m achin es are very com plex an d expen si ve. As m anu f actu ri ng li ne s be com e m odu lar an d t ran sport able, i ndu st rial m achin es ori gin all y pro duc ed f or a fo reign marke t m ay qui ckly betr ans porte d to the dom est ic mar ket. T he re verse is also tr ue . D if fer in gel ectr ical st andar ds add a lar ge c ost to mu l tin at ion al man u fac tu rers asthe y bu i ld an d som eti mes m ove man u fact u rin g f acil it ies.

Har mon i zati on - Ob ject ive

T his wor k is n eces sary to accom pli sh t he go al o f al low in g in du stry to eco no mi call y bu i ld o ne in du st rial m achin e capabl e of pass in g a detai ledel ectr ical saf ety in spec tio n u sin g eit her I EC 60204-1 o r N FP A 79st andar d.

B ot h th e NE C Tech n ical C o rrel atin g Co mmi tt ee an d th e Stan d ard sC ou n cil rev iew ed th e s tatem en t o f w or k in Ju ly of 1998. T he TC C u n ani mo u sly reco mmen d ed t he fo ll o wi ng acti on to t he Stan d ard sC ou n cil :

"T he T echn ic al C or relat in g C o mm it tee agrees w ith the eff ort s of t he N FP A79 c omm it tee to harm on ize the t echn ical re qui rem en ts of NFP A 79 andIE C 60204, w here feasi ble an d w here in con cert w it h the N EC and it srel ated codes an d st an dards."

R esu lt

T he NF P A Stan d ard s C o u nc il co ns id ered an d co n cu rred w it h th ereco mmen d ati o n. In Ju ne o f 1999, t h e NF P A 79 C o mmi ttee fo rmed 20 T ask Gro u p s. Each Task Gr ou p w as assign ed o n e p ro p o sed n ew clau se.

T he Tas k Gr ou p co mp ared NF P A- 79-1997, C lau se 19 wi th I EC 60204-1 Cl au se 8. T he Tas k G ro up pr esen ted i ts wo rk to t he en tir eco mmi ttee o n several o ccasi o ns fo r revi ew and com men t. T h isp ro p os al i s a resu lt o f th at w or k.

T he Tas k Gr ou p p ro p o ses to r enu mb er Cl au se 19 of N FP A 79- 1997to cor resp o nd wi th IE C 60204- 1. Th e t ask gr ou p p ro p o ses th efo l lo wi n g ch an ges t o fu rt her i mp ro ve u sab il it y.

Clause 19 (1997 NFPA) has been proposed to be revised for thereasons provided according to each subdivision. The generalrequirements have been relocated to follow the format of IEC60204-1 to increase the ease of applying this standard on a globallevel. The numbering sequence may have gaps to continue tomatch IEC 60204-1 as much as possible. Editorial changes havebeen made to improve usability. Additional terms as used in theNEC have been added.

Proposed (new) reference numbers are used as a "base" tofacilitate an understanding of the intended concept.

Change the title of Clause 8 to Grounding The term grounding (asused in the NEC) includes requirements for bonding, groundingand grounded conductors. Equivelent terms were added inparenthesis throughout this clause to increase the ease of globalyusing this standard .

8.1 Revised existing NFPA79, 1997, subclause 19.1. The proposedlanguage provides a clear description of what this clause covers and

allows for a more global application. The figure will help the userwith the application of this Clause.

8.1.1 Connections. Inserted new text. This requirement has beenhighlighed in NEC Article 250 in sections 250-30 and 250-142(b)and needs to be in NFPA 79. Connections between groundedconductors and equipment grounding paths, at more than onelocation, allow objectionable current to flow and shouldspecifically be prohibited.

8.2. Provides more detail about what the subclause covers.

8.2.1 Provides the information from 19.1 in a list. The satisfactoryperformance of the equipment grounding path is necessary forsafety. Small parts that are not likely to become energized shouldnot have to be grounded.

8.2.1.1 The text from 19.3 was editorially improved .

8.2.1.2 The text from 19.5 was editorially improved and relocatedhere to provide a better organizational structure.

8.2.1.2 .1 Identification means for the equipment groundingterminal should be provided in the body ot the standard. Theproposed requirement corresponds with the NEC requirements.The appropriate new reference to replace 7.11. as used in 19.5 ofNFPA 1997 needs to be inserted here.

Table XX Revise existing Table 14 (in 1997 NFPA 79) asprovided. Overcurrent device sizes and corresponding conductorsizes are necessary for large machines. The information was copiedfrom Table 250-122 of the 1999 NEC.

8.2.2 Inserted new text and clarified the heading. A requirement,for identifying equipment grounding conductors, needs to be inthis Clause.

8.2.2.1 Relocated exixting text from 19.2.1.

8.2.2.2 Text from 19.2.2 was relocated here to increase the ease ofapplying this standard on a global level.

8.2.2.3 Revised and combined the exixting language from NFPA79, 1997 19.2.3 and 19.2.4 to improve usability. The table has beenrevised to include larger conductor size and is similar to NECSection 250-122. Bonding jumpers were added because sizerequirements are also applicable to them The replacementreference number for the exixting Table 14 in NFPA 79 needs to beincluded here.

8.2.3 Revised exixting NFPA 79, 1997, 19.6 by inserting the word“equipment” throughout entire 8.2.3.

8.2.3.2 Editorial revision to NFPA 79-1997, 19.6.6

8.2.3.3 Relocated from existing NFPA 79, 1997 19.6.2 andeditorially revised for clarity.

8.2.3.4 Relocated from existing NFPA 79, 1997 19.6.3

8.2.3.5 Relocated from existing NFPA 79, 1997 19.6.5 and insertedthe word “equipment.”

8.2.3.6 Where devices are located on doors suitable bonding mustbe provided. Covers can be removed rendering them ungroundedposing a shock hazard

8.2.3.7 Relocated from exixting NFPA 79, 1997 19.6.4

8.2.3.8 Added a new requirement. The continuity of theequipment grounding circuit is necessary for safety.

8.2.4 Relocated from exixting NFPA 79-1997, 19.4 and inserted theword “equipment.”

8.2.7 Added new text. The continuity of the equipment groundingconductor termination is important for safety and should not beused for an additional function. The note alerts the user of otherconcerns.

8.3 Relocated from exixting NFPA 79, 1997, 19.7. A sentence wasadded for insulation monitoring to correlate with 9.4.2.1.Exception No. 3 was added to permit ungrounded Class 2 circuitswithout insulation monitoring as provided in the NEC.


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8.5 Relocated from exixting NFPA 79, 1997, 19.8.

8.5.1 Relocated from exixting NFPA 79, 1997, 19.8.1. Theidentification requirement points to Clause 14 to provide allconductor identifiction requiremts in one location. The specificreference number is provided based on preliminary informationfrom the proposed Clausse 14 and needs verification of beingcorrect pending action on Clause 14.

8.5.2 Relocated from exixting NFPA 79, 1997, 19.8.2.

8.5.3 Relocated from exixting NFPA 79, 1997, 19.8.3.

NFPA 79 Grounding Cross Reference Chart

Clause 8 (NEW) Clause 19 (1997)

A. Cross Reference from Clause 8 (NEW) to Clause 19 (1997 NFPA 79)

8 Grounding 19 Grounded circuits and equipmentgrounding

Title Changed to match NEC

8.1 General 19.1 General Simplified the Clause statement

8.1.1 Connections No comparable text Added Text

8.2 Equipment grounding(protective bonding) circuit

No comparable text Added Heading

8.2.1 Grounding system 19.5 Grounding terminal

19.1

Listed the system components

8.2.1.1 Equipment grounding 19.3 Equipment grounding Editorial improvements

8.2.1.2 Equipment groundingterminal

19.5 Grounding terminal Editorial improvements

8.2.1.2.1 Equipment groundingterminal marking

19.5 Grounding terminal Simplified heading and added theidentification means

8.2.2 Equipment grounding(protective) conductors andbonding jumpers.

19.2 Grounding conductors Expanded heading

8.2.2.1 19.2.1 No change

8.2.2.2 19.2.2 No change

8.2.2.3

8.2.2.3(2)

19.2.3

19.2.4

Added bonding jumpers and combined text

8.2.3 Continuity of the equipmentgrounding (protective bonding)circuit

19.6 Continuity of the grounding circuit Inserted "equipment"

8.2.3.1 19.6.1 Inserted "equipment"


8.2.3.3 19.6.2 No change

8.2.3.4 19.6.3 No change


8.2.3.6 Doors or Covers No comparable text Added bonding requirement for devices ondoors.

8.2.3.7 19.6.4 No change


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A. Cross Reference from Clause 8 (NEW) to Clause 19 (1997 NFPA 79) (continued)

8.2.3.8 No comparable text Added continuity requirement

8.2.4 Exclusion of switching devices 19.4 Exclusion of switching devices Inserted "equipment"

8.2.7 Equipment grounding(protective) conductor connectingpoints

No comparable text Added Text

8.3 Control circuits 19.7 Control circuits Added Ex. No. 3

8.5 Lighting circuits 19.8 Lighting circuits No change

8.5.1 19.8.1 Added specific reference to 14

8.5.2 19.8.2 No change

8.5.3 19.8.3 No change

Table XX Table 14 Size of grounding conductors Added larger conductor sizes.

B. Cross Reference from Clause 19 (1997 NFPA 79) to Clause 8 (NEW).

19 Grounded circuits andequipment grounding

8 Grounding

19.1 General 8.1, 8.2.1

No comparable text 8.1.1 Connections (New)

19.2 Grounding conductors 8.2.2

19.2.1 8.2.2.1

19.2.2 8.2.2.2

19.2.3 8.2.2.3

19.2.4 8.2.2.3(2)

19.3 Equipment grounding 8.2.1.1

19.4 Exclusion of switching devices 8.2.4

19.5 Grounding terminal 8.2.1, 8.2.1.2, 8.2.1.2.1

Table 14 Size of groundingconductors

Table XX

19.6 Continuity of the groundingcircuit

8.2.3

19.6.1 8.2.3.1

19.6.2 8.2.3.3

19.6.3 8.2.3.4

19.6.4 8.2.3.7

19.6.5 8.2.3.5

19.6.6 8.2.3.2

19.7 Control circuits 8.3

19.8 Lighting circuits 8.5

19.8.1 8.5.1

19.8.2 8.5.2

19.8.3 8.5.3


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COMMITTEE ACTION: Accept in Principle. Revise to read as follows:8 Grounding.

8.1 General. This clause provides for grounding, bonding andgrounded conductor requirements.


8.1.1 Connections. Grounded conductors shall not be connectedto the equipment grounding (protective) circuit, except for, atseparately derived systems.

8.2 Equipment grounding (protective bonding) circuit.

8.2.1 Grounding system. The equipment grounding (protectivebonding) circuit consists of:(1) The equipment grounding (PE) terminal(s);(2) The conductive structural parts of the electrical equipment andthe machine;(3) The equipment grounding (protective) conductors andequipment bonding jumpers

All parts of the equipment grounding (protective bonding) circuitshall be capable of withstanding the highest thermal andmechanical stress that can be caused by fault currents which couldflow in that part of the circuit.



8.2.1.1 Equipment grounding. The machine and all exposed,noncurrent-carrying conductive parts, material, and equipmentlikely to be energized shall be effectively grounded. Whereelectrical devices are mounted on metal mounting panels that arelocated within nonmetallic enclosures, the metal mounting panelsshall be effectively grounded.

8.2.1.2 Equipment grounding terminal.

(1) For each incoming supply circuit , an equipment grounding(external protective ) conductor terminal shall be provided in thevicinity of the associated phase conductor terminals.


(3) T he ter min al sh all acco mmo d ate an eq u ip men t gro u n di n gco n du ct or si zed in acco rd an ce w ith T abl e XX .


8.2.1.2.1 Equipment grounding terminal marking.








8.2.2.3 Equipment grounding conductors and bonding jumpers ofthe wire type shall not be smaller than shown in Table XX.Equipment grounding conductors and bonding jumpers of thewire type shall not be smaller than shown in Table XX, but shallnot be required to be larger than the circuit conductors supplyingthe equipment.

8.2.2.3.1 (2) It shall be permitted to use machine members orstructural parts of the electrical equipment in the equipmentgrounding circuit provided that the cross-sectional area of theseparts is at least electrically equivalent to the minimum cross-sectional area of the copper conductor required. <<this was noteto table but was moved here according to Log #81>>

Table XX — Minimum Size of equipment groundingconductors and bonding jumpers

Column “A,” AmperesRating or setting ofautomatic overcurrentdevice in circuit ahead ofthe equipment

Copper Conductor Size, AWGor kcmil

10 16 or 1815 14, 16, or 1820 12, 14, 16, or 1830 1040 1060 10100 8200 6300 4400 3500 2600 1800 01000 2/01200 3/01600 4/02000 2502500 3503000 4004000 5005000 7006000 800



(2) It shall be permitted to use machine members or structuralparts of the electrical equipment in the equipment groundingcircuit provided that the cross-sectional area of these parts is atleast electrically equivalent to the minimum cross-sectional area ofthe copper conductor required. <<moved to precede tableaccording to Log #81>>

8.2.3 Continuity of the equipment grounding (protective bonding)circuit.



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(2) An equipment (protective) bonding jumper shall connect theconductive door or cover to the equipment enclosure or to anequipment grounding (protective bonding) terminal within theenclosure.



8.2.4 Exclusion of switching devices. The equipment grounding(protective) circuit shall not contain any switches or overcurrentprotective devices. Links or plugs in the grounding circuit shall bepermitted if properly labeled or interlocked with the controlcircuits.

8.2.7 Equipment grounding (protective) conductor connectingpoints.


(2) The equipment grounding conductor connecting points, otherthan the equipment grounding terminal, shall be identified by agreen color or by use of the symbol that appears in 8.2.1.2.1.


8.3 Control circuits. Control circuits shall be permitted to begrounded or ungrounded. Where grounding is provided, that sideof the circuit common to the coils shall be grounded at the controltransformer if alternating current or at the power supply terminal ifdirect current. Where grounding is not provided, an insulationmonitoring system shall be utilized as described in 9.4.2.1.Ungrounded control circuits shall be provided with an insulation- monitoring device that either indicates a ground (earth) fault orinterrupts the circuit automatically after a ground (earth) fault.

Exception No. 1: Exposed control circuits as permitted by 6.4 6.3 shall begrounded.



8.5 Lighting circuits.



8.5.3 The grounded conductor, where run to a screw-shelllampholder, shall be connected to the screw-shell.COMMITTEE STATEMENT: The reasons for editorially revisingClause 8 are as follows: 1) In 8.2.1.2, add the word "circuit" after the word "supply" as aneditorial correction. 2) Revise the text of 8.2.2.3 to clarity the requirement and removethe conflict with 13.6.1, exception. 3) Revise Table XX to add clarity to the requirements andremove a conflict with 13.6.1, exception. 4) In 8.3, Exception No. 1, add the missing cross reference to6.3, PELV.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: ANDERSON: In other chapters of this standard figures have beenincluded to help illustrate what is intended. NFPA 79 1997 edition,figures 1 and 2 represent system power distribution and systempower protection respectively. In IEC60204-1, figure 3 illustrates"examples of equipotential bounding (equipment grounding) forelectrical equipment of a machine".. Also, with additions forNorth American requirements, an illustration figure in the chapteron grounding is included in the new SAE HS1738. A similar figure is needed chapter 8 "Grounding", to helpillustrate the various requirements of section 8.2 "Equipmentgrounding (protective bounding) circuit". The figure is need helpnew machine designers and users outside of North America tocorrectly understand the terminology and the requirements inNFPA 79 for grounding. SAUNDERS: The existing IEC 204 document includes a Figurethat provides a reference for clarification of the terms used forgrounding and bonding. This figure should be included in theANNEX of the document. Revisions should be made to provide theNorth American and European terms for harmonization of termsand mutual understanding. (These revisions not made to theproposed figure but will be incorporated after review of the finalclause 8 material) ***Insert Figure Here***

___________________

(Log #81)79- 152 - (19.2.3 [8.2.2.3]): Accept in Principle in PartSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in rewritten Clause 8.2.2.3 thatreplaces 1997 NFPA 79 Clause 19.2.3. Place bullet (1) as a Note in Table XX, which is a part of newlyproposed clause 8 and delete it from the new 8.2.2.3. Make the sentence that had been identified as bullet (2) thesecond sentence of the paragraph of proposed clause 8.2.2.3 andremove the "(2)" numberSUBSTANTIATION: The proposed revision will make the nonemandatory sentence clearer as a note to the table. This will helpmake the information more immediately clear to the casualobserver the significance of column "A" of Table XX and maintainit in the text of the document.COMMITTEE ACTION: Accept in Principle in Part. The committee accepts the part that relocates Note 2 to thesection 8.2.2.3.1 preceding the Table XX. The committee acceptsthe remainder of the proposal in principle.COMMITTEE STATEMENT: See the Committee Action andStatement on Proposal 79-151 (Log #52) [Clause 8]. The action ofthis proposal has been incorporated into Proposal 79-151 (Log#52) [Clause 8].NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________


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(Log #2)79- 153 - (19.5 [8.2.1.2]): Accept in PrincipleSUBMITTER: Robert Ziller, Doboy Div., Sig Packaging Tech.RECOMMENDATION: Add to NFPA 79-1994, Section 19.5, thecomplete text of NFPA 70-1996, Section 250-119.SUBSTANTIATION: Identification of grounding terminal is notspecified in NFPA 79.COMMITTEE ACTION: Accept in Principle.COMMITTEE STATEMENT: This requirement is already in8.2.1.2.1 of Proposal 79-151 (Log #52) and meets the intent of thesubmitter.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #111)79- 154 - (19.6 [8.2.3]): RejectSUBMITTER: George M. Schreck , Komatsu America IndustriesLLCRECOMMENDATION: Add new text to read as follows: "Ground Bonding wire connection to either a terminal strip or toa "ground buss" shall have no more than two connections pertermination point."SUBSTANTIATION: Wire connection to either a terminal stripwith multiple blocks "commoned " or ground busses drilled andtapped for conductor connections that allow for single conductorruns to devices or other distribution points are typically notdisconnected at the bus for device removal or renewal. Exception: Devices that are pre-wired with multi-conductor cablecontaining a (grounding conductor" to be singly terminated ateither the ground buss or ground network connection distributionnetwork.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Multiple conductor terminations inone terminal are only permitted where the terminal is listed andmarked for use with more than one conductor.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #25)79- 155 - (Clause 20 [Clause 11]): Accept in PrincipleSUBMITTER: Jim F. Pierce, Intertek Testing ServicesRECOMMENDATION: Revise NFPA 79-1997 Clause 20"Electronic equipment" and issue as new Clause 11 "Electronicequipment" as follows:11 Electronic Equipment11.1 General11.1.1 This clause applies to all types of electronic equipmentincluding programmable electronic systems, subassemblies,printed circuit boards, electronic components, and othermiscellaneous solid state equipment.11.1.2 Electronic equipment used as part of an industrial machine,including subassemblies, printed circuit boards, devices, internalwiring and components need not be inspected at the time ofinstallation of the industrial machine, except to detect alterationsor damage, if the equipment has been listed by a qualifiedelectrical testing laboratory.11.1.3 Listed or labeled electronic equipment shall be permitted tobe used without modifications, on or with industrial machines,where approved for the location and use.11.2 Basic Requirements11.2.1 Equipment Grounding (Equipotential Bonding)11.2.1.1 All input/output racks (remote or local), processor racks,and conductive enclosures of power supplies shall be electricallybonded together in accordance with the supplier’s specificationsand connected to the equipment grounding (protective bonding)circuit.11.2.1.2 Where specified by the manufacturer, components andsubassemblies shall be effectively bonded to the equipmentgrounding (protective bonding) circuit in accordance with themanufacturer’s recommendations.11.2.2 SubassembliesSubassemblies shall be readily removable for inspection orreplacement.11.2.3 Electrical noise and transient suppression.

Transient Suppression, isolation or other appropriate means shallbe provided where the electronic equipment generates electricalnoise or transients, which can affect the operation of equipment.11.2.4 Output ProtectionOutputs controlled by programmable electronic systems shall beprotected from overload and short circuit conditions.11.3 Programmable Equipment11.3.1 Software ModificationProgrammable electronic systems shall be designed andconstructed so that the ability to modify the application programshall be limited to authorized personnel and shall require specialequipment or other means to access the program (e.g., accesscode, key operated switch).Exception: For reasons of safety, the manufacturer or supplier shallbe permitted to retain the right not to allow the user to alter theprogram.11.3.2 Memory Retention and Protection11.3.2.1 Means shall be provided to prevent memory alteration byunauthorized persons.11.3.2.2 Loss of memory shall not result in a hazardous condition.11.3.2.3 Power supplies for electronic units that require memoryretention shall have battery back-up of sufficient capacity to preventmemory loss for a period of at least 72 hours.11.3.3 Software Verification.Equipment using reprogrammable logic shall have means forverifying that the software is in accordance with the revelantprogram documentation.11.3.4 Use in Safety-related FunctionsSoftware and firmware-based controllers used in place of hardwarebased components with safety-related devices shall: (a) Be designed such that any single safety related component orfirmware failure shall: 1) Lead to the shutdown of the system in a safe state, and 2) prevent subsequent operation until the component failurehas been corrected: Note – Firmware is that executive control program in a non-volatile internal storage mode and is not changeable by the user. (b) Supply the same degree of safety achieved by usinghardwired/hardware components. Note: -- For example, this degree of safety may be achievedby using microprocessor redundancy, microprocessor diversity,and self-checking; (c) Be listed to an approved standard for safety-relatedfunctions such as IEC 61508, UL 991, UL 1998, or VDE 0801.11.4 Electronic Drives11.4.1 Electronic Drives SafeguardsWhere load conditions or reduced speeds can cause motoroverheating, embedded motor thermal protection (effective overthe motor speed range) shall be provided and interlocked with theelectronic drive system. See 7.3 for requirements regardingautomatic restarting of motors.SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738. His to rical B ackgro u nd : In M arch o f 1998, t h e NF P A 79co mmi ttee p rep ared a s tatem en t o f w or k. T h e maj o r el emen ts of th e stat emen t o f w or k are: Harm on i zatio n – P u rp os e: A s th e u sers an d th e man u fact ur ers o fin d u str ial mach in es mo ve to w ard a glo b al man u fact ur in gco mmu n it y, th e n eed fo r a h armo n ized st and ard aff ecti ngin d u str ial mach in ery b eco mes an eco n om ic n ecessi ty. Gen eral ly, lar ge u sers an d man u fact ur ers fi n d regu lat io n s b u rd ens om e.Ho w ever, mu lt ip le regu lat io n s as w ell as co n fli cti ng regu lat io n s arean eco n om ic d isi n cent ive to glo b al exp an sio n . In o rd er to ease th eb u rd en o f d if feri ng regu lat io n , an d at th e same ti me mai nt ain th eh igh st and ard o f elect rical mach in e saf ety, th e NF P A 79 co mmi tteeh as exp ressed th ei r d esir e, th ro u gh b all ot ed vo te, to h armo n izeNF P A 79 w ith IE C -60204-1. Imp o rt ance o f Iss ue – Harm on i zatio n : T od ay' s in d u str ialmach in es are very co mp lex an d exp en sive. A s man u fact ur in g li n esb eco me mo d u lar an d tr ans po rt ab le, in d u str ial mach in es o rigi n ally p ro d uced fo r a fo rei gn market may q u ickly b e tr ans po rt ed to th ed o mesti c market . T he rever se is als o tr ue. Di ff erin g elect ricalst and ard s ad d a lar ge co st to mu lt in ati o nal man u fact ur ers as th eyb u ild an d so met imes mo ve man u fact ur in g faci li ties . Harm on i zatio n – Ob ject ive: T hi s w or k is n ecessary to acco mp li sh th e go al o f all o wi ng in d u str y to eco n om icall y b u ild o n ein d u str ial mach in e cap ab le o f p assi ng a d etai led elect rical saf etyin sp ect io n u sin g eit h er IE C 60204-1 o r NF P A 79 st and ard .


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B ot h th e NE C T echn i cal C or relat in g C om mit tee an d th eStan d ard s C ou n cil revi ewed th e st atemen t o f w or k in Ju ly o f 1998.T he T CC u n ani mo u sly reco mmen d ed th e fo l lo wi n g acti o n to th eStan d ard s C ou n cil : "T h e T echn i cal C or relat in g C om mit tee agrees w ith th e eff o rts o fth e NF P A 79 co mmi ttee to h armo n ize th e tech n ical req u irem ent so f NF P A 79 an d IE C 60204, w her e feas ib le an d w her e in co n certw ith th e NE C an d it s rel ated co d es an d st and ard s. " R esu lt: T he NF P A Stan d ard s C ou n cil co n sid ered an d co n cur red w ith th e reco mmen d ati o n. In Ju n e o f 1999, th e NF P A 79C om mit tee fo rm ed 20 T ask Gr ou p s. E ach T ask Gr ou p w as assi gn edo n e p ro p os ed n ew clau se. T he T ask Gro u p co mp ared NF P A -79-1997, C lau se 20 w ith IE C 60204-1 C lau se 11. T he T ask Gr ou p p resen ted it s w or k to th een ti re co mmi ttee o n sever al o ccasio n s fo r revi ew an d co mmen t. T hi s p ro p os al is a resu l t o f th at w or k. T he T ask Gr ou p p ro p os es to ren u mb er NF P A 79-1997 C lau se 20to co rresp o n d w ith IE C 60204-1 C lau se 11. T he tas k gro u p p ro p os es th e fo l lo wi n g ch an ges to fu rt h er im pr ov e u sab il ity .

11 Electronic EquipmentRevision: No change except numbering; Clause 20 nowClause 11

11.1 GeneralRevision: No change except numbering; subclause 20.1

now subclause 11.111.1.1 Add IEC 60204-1 subclause 11.1.

Substantiation: This new explanatory textclarifies the intent of subclause 11.1.

11.1.2 New subclause. Substantiation: This new subclause covers asubject not presently in NFPA 79-1997 and itclarifies listed equipment used within industrialmachines need not be separately inspected iflisted by a qualified testing laboratory.

11.1.3 New subclause. Substantiation: This new subclause covers asubject not presently in NFPA 79-1997 and itclarifies listed equipment is to be used withoutmodification if approved for the location.

11.2 B asic req u irem ent s R evisi on : No ch an ge ex cep t n u mb erin g; su b clau se 20.2n o w su b clau se 11.2. 11.2.1 Equipment Grounding (Equipotential bonding) Add the IEC 60204-1 subclause 11.2.2 heading.

Substantiation: The new subclause headingclarifies the intent of the subclause.

11.2.1.1 Revision: NFPA 79 paragraph 20.3.2 split in twosubclauses.

Substantiation: This is old paragraph 20.3.2except it is split into two subclauses for clarity. 11.2.1.2 Addition: Second part of paragraph 20.3.2.

Substantiation: This paragraph is the other halfof 20.3.2. Split into two paragraphs to clarify the intent. 11.2.2 Subassemblies

Add new subclause heading. Substantiation: The new heading clarifies the

intent of the subclause.Revision: No change except numbering; subclause 20.2.2

now subclause 11.2.2. 11.2.3 Electrical noise and transient

Add new subclause heading. Substantiation: The new heading clarifies theintent of the subclause.

Revision: Change numbering from subclause 20.2.3 to11.2.3 and add “or other appropriate means”.

Substantiation: The revision clarifies othermeans may be used to achieve the samereduction in noise.

11.2.4 Output protection A dd n ew su b clau se h ead in g.

Substantiation: The new heading clarifies theintent of the subclause.

Revision: No change except numbering; subclause 20.2.6now 11.2.4. 11.3 Programmable equipment Add the IEC 60204-1 subclause 11.3 heading.

Substantiation: The new heading clarifies thecontent of the subclause.

11.3.1 Software Modification Add the IEC 60204-1 subclause 11.3.3 heading.

Substantiation: The new heading reads“modification” instead of “verification” whichclarifies the content of the subclause.

Revision: No change except numbering; subclause 20.3.1now 11.3.1. 11.3.2 Memory retention and protection

Add the IEC 60204-1 subclause 11.3.2 heading. Substantiation: The new heading clarifies thecontent of the subclause.

11.3.2.1 Add the IEC 60204-1 subclause 11.3.2 first paragraph. Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997 and is from IEC60204-1. It better addresses the issue ofprogrammable electronic systems in NFPA 7920.3.1 and clarifies the difference betweenmemory alteration and program verification.See 11.3.3.

11.3.2.2 Revise NFPA 79 paragraph 20.2.5 Substantiation: An editorial change. Intent of

requirement not changed.

11.3.2.3 Revision: No change except numbering; subclause 20.2.4now 11.3.2.3.11.3.3 Software Verification

Add the IEC 60204-1 subclause 11.3.3Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997. This text iscomparable with the requirements of IEC60204-1, Clause 11. This new subclauseaddresses the issue of being able to verify thesoftware after installation and use.

11.3.4 Use in Safety-related functions Add the IEC 60204-1 subclause 11.3.4 heading.

S u bs tan ti atio n : T he n ew h ead in g clar ifi es th eco n ten t o f th e su b clau se. Add new text from ANSI/RIA 15.06-1999.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997. This text issomewhat comparable with the requirementsfrom RIA and addresses the new technology inrobotics used in industrial machinery. IEC61508, UL 991, UL 1998 and VDE 0801 are theonly published standard known to thecommittee that may be used for listing of Safety-related function.

11.4 Electronic drives Add the IEC 60204-1 subclause 11.4 heading.

Substantiation: The new heading clarifies theintent of the subclause.

11.4.1 Add new requirements from the SAE/HS 1738 document.

Substantiation: This subclause covers a subjectnot presently in NFPA 79-1997. This text fromSAE/HS 1738 document clarifies the issuesrelated to automatic starting of motorscontaining embedded thermal protectors.


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COMMITTEE ACTION: Accept in Principle. Revise NFPA 79-1997 Clause 20 "Electronic equipment" and issueas new Clause 11 "Electronic equipment" as follows: 11 Electronic Equipment 11.1 General 11.1.1 This clause applies to all types of electronic equipmentincluding programmable electronic systems, subassemblies,printed circuit boards, electronic components, and othermiscellaneous solid state equipment. 11.1.2 Electronic equipment used as part of an industrialmachine, including subassemblies, printed circuit boards, devices,internal wiring and components need not be shall not be requiredto be inspected at the time of installation of the industrial machine,except to detect alterations or damage, if the equipment has beenlisted by a qualified electrical testing laboratory. 11.1.3 Listed or labeled electronic equipment shall be permittedto be used without modifications, on or with industrial machines,where approved for the location and use. 11.2 Basic Requirements 11.2.1 Equipment Grounding (Equipotential Bonding) 11.2.1.1 All input/output racks (remote or local), processorracks, and conductive enclosures of power supplies shall beelectrically bonded together in accordance with the supplier’sspecifications and connected to the equipment grounding(protective bonding) circuit. 11.2.1.2 Where specified by the manufacturer, components andsubassemblies shall be effectively bonded to the equipmentgrounding (protective bonding) circuit in accordance with themanufacturer’s recommendations. 11.2.2 Subassemblies. Subassemblies shall be readily removablefor inspection or replacement. 11.2.3 Electrical noise and transient suppression. TransientSuppression, isolation or other appropriate means shall beprovided where the electronic equipment generates electrical noiseor transients, which can affect the operation of equipment. 11.2.4 Output Protection. Outputs controlled by programmableelectronic systems shall be protected from overload and shortcircuit conditions. 11.3 Programmable Equipment 11.3.1 Software Modification. Programmable electronic systemsshall be designed and constructed so that the ability to modify theapplication program shall be limited to authorized personnel and

shall require special equipment or other means to access theprogram (e.g., access code, key operated switch).Exception: For reasons of safety, the manufacturer or supplier shallbe permitted to retain the right not to allow the user to alter theprogram. 11.3.2 Memory Retention and Protection 11.3.2.1 Means shall be provided to prevent memory alteration byunauthorized persons. 11.3.2.2 Loss of memory shall not result in a hazardouscondition. 11.3.2.3 Power supplies for electronic units that require memoryretention shall have battery back-up of sufficient capacity to preventmemory loss for a period of at least 72 hours. 11.3.3 Software Verification. Equipment using reprogrammablelogic shall have means for verifying that the software is inaccordance with the revelant program documentation. 11.3.4 Use in Safety-related Functions. Software and firmware-based controllers used in place of hardware based componentswith safety-related devices shall: (a) Be designed such that any single safety related component orfirmware failure shall: 1) Lead to the shutdown of the system in a safe state, and 2) Prevent subsequent operation until the component failurehas been corrected: Note – Firmware is that executive control program in a non-volatile internal storage mode and is not changeable by the user. (b) Provide protection equivelant to that of Supply the samedegree of safety achieved by using hardwired/hardwarecomponents. Note: For example, this degree of safety equivelancy may beachieved by using microprocessor redundancy, microprocessordiversity, and self-checking; (c) Be listed to an approved standard for safety-relatedfunctions such as IEC 61508, UL 991 or UL 1998, or VDE 0801. 11.4 Electronic Adjustable Speed Drives 11.4.1 Electronic Adjustable Speed Drives SafeguardsWhere load conditions or reduced speeds can cause motoroverheating, embedded motor thermal protection (effective overthe motor speed range) shall be provided and interlocked with theelectronic adjustable speed drive system. Note: See 7.3 for requirements regarding automatic restarting ofmotors.

CLAUSE NUMBERS: NFPA 79-1997 CROSS REF. TO PROPOSED NFPA 79-2002


Clause Heading (or topic) Clause Heading (or topic)20 Electronic equipment 11 Electronic equipment20.1 General 11.1 General

(new heading not in NFPA 79) 11.1.1 (Applies to all types of electronic equipment)(new subclause not in NFPA 79) 11.1.2 (Listed electronic eq need not be inspected)(new subclause not in NFPA 79) 11.1.3 (Listed/labeled eq permitted to be used)

20.2 Basic requirements 11.2 Basic requirements20.2.1 (Clause 5 applies to electronic)

(new heading not in NFPA 79) 11.2.2 Subassemblies20.2.2 (Subassemblies readily removable) (Subassemblies readily removable)

(new heading not in NFPA 79) 11.2.3 Electrical noise and transient suppression20.2.3 (Transient suppression) (Transient suppression)

(new heading not in NFPA 79) 11.3.2 Memory Retention and Protection(new subclause not in NFPA 79) 11.3.2.1 (Prevent memory alteration)

20.2.4 (Power supplies requiring memory) 11.3.2.3 (Power supplies requiring memory)20.2.5 (Loss of memory prohibit hazardous

conditions)11.3.2.2 (Loss of memory prohibit hazardous conditions)

(new subclause not in NFPA 79) 11.3.3 Software Verification(new heading not in NFPA 79) 11.2.4 Output Protection

20.2.6 (Outputs controlled shall be protected) (Outputs controlled shall be protected)20.3 Programmable electronic systems 11.3 Programmable equipment

(new subclause not in NFPA 79) 11.3.1 Software Modification20.3.1 (Ability to modify is limited) (Ability to modify is limited)

(new heading not in NFPA 79) 11.2.1 Equipment Grounding (Equipotential bonding)20.3.2 (Input/output racks bonded) 11.2.1.1 (Input/output racks bonded)

11.2.1.2 (Bonded to ground per manufacturers recommendations)(new heading not in NFPA 79) 11.3.4 Use in safety-related functions

(new subclause not in NFPA 79) (Proposed language from RIA)(new heading not in NFPA 79) 11.4 Electronic Drives

(new subclause not in NFPA 79) 11.4.1 Electronic Drives Safeguards(Motor overheating and embedded thermal protection)


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COMMITTEE STATEMENT: Editorial corrections andcorrections for consistancy were made to comply with the NFPAManual of Style. Changes to 11.3.4 were made to avoid the possibility of beingmisconstrued as allowing multiple levels of safety. References toIEC and VDE standards were deleted because they are notrecognized North American safety standards.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: BLOODGOOD: See my Explanation of Negative for Proposal 79-77 (Log #12). DOBROWSKY: Sections 11.1.2 and 11.1.3 should be expanded toinclude "electrical" equipment and relocated to a general chaptersuch as Chapter 4. The same issues apply to electrical equipment. FREUDENBERG: See my Comment on Affirmative on Proposal79-25 (Log #68).

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(Log #82)79- 156 - (20.x.x [9.2.5.4.2.4]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify in rewritten Clause 9 that replaces1997 NFPA 79 Clause 20 the following. Delete the wording of proposed clause 9.2.5.4.2.4 and itsassociated Note, and use instead the wording contained in IECstandard 60204-1, clause 9.2.5.4.2, which reads: "Where a category 0stop is used for the emergency stop function, it shall have onlyhard-wired electromechanical components. In addition, itsoperation shall not depend on electronic logic (hardware orsoftware) or on the transmission of commands over acommunications network or link."SUBSTANTIATION: Neither the current version 2000 of IEC60204-1, nor the current version 1997 of NFPA 79 allow the use ofelectronic logic systems to control a category 0 emergency stopfunction. The use of such systems for use in the stop function oflast resort is yet to be endorsed by many designers and users alike.Nor does there appear to be credible evidence that recognizedthird parties approve this provision for this specific purpose.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The new proposed Chapter 9[Proposal 79-62 (Log #46)] includes the existing requirementsfrom NFPA 79-1997 Clause 9. The new proposed Chapter 9 alsoincludes provisions to permit newer technologies. The NFPA 79-1997 Clause 20 material has been moved to the new proposedChapter 11.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #125)79- 157 - (20.1 [11.1.1]): RejectSUBMITTER: Richard Graham, Bridgeport MachinesLimited/Rep. CECIMO (European Committee for Co-operation ofthe Machine Tool IndustriesRECOMMENDATION: Retain current text, so that only 20.1General exists. In the committee’s proposal only 11.1.1 shouldremain and not 11.1.2 and 11.1.SUBSTANTIATION: The committee’s proposals to add 11.1.2and 11.1.3 does not clarify the situation with regard to listedequipment used within industrial machinery. If a piece ofelectronic equipment as listed in 11.1.2 of the new proposal is usedwithin a machine it would need to be inspected if the equipmenthas not been tested by a qualified electrical testing laboratory. Itdoesn’t make it clear who should do the inspecting and why itshould be necessary to inspect. Many manufacturers have facilitieswhere small printed circuit board assemblies are made. Theseoften are not inspected by a qualified electrical testing laboratorybut are utilized on the machine without a problem to machinesafety. This would place a great financial burden on manufacturersif the committee’s proposal was accepted.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: The proposed 11.1.2 and 11.1.3 donot require that electronic equipment be listed. The committeereaffirms the Substantiation of Proposal 79-155 (Log #25) for theseparticular sections.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26

VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: The definitions of listed, labeled, authorityhaving jurisdiction and other definitions have been extracted fromthe NFPA rules governing committee projects and inserted intoNFPA79 that will be extremely helpful in interpreting 11.1.2 and11.1.3 . These paragraphs do not require any additional testing orinspection where electronic equipment is NOT listed or labeled,however, where electronic equipment is listed or labeledparagraphs clarify that the equipment need not be inspected again.This is essentially the same provision in article 90-7 of the NEC.

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(Log #83)79- 158 - (20.x.x [9.2.7.4]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Delete the second sentence in proposednew clause 9.2.7.4.SUBSTANTIATION: Neither the current version of NFPA 79(1997), nor the current version of IEC 60204-1 (2000) require thecertification of serial data communication systems by a nationallyrecognized testing laboratory. This is an unwarranted burden onU.S. manufacturers.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Cable-less control of machinery isrelatively new, sub-subsection 9.2.7.4 allows for this new technologywith the necessary restrictions to improve the possibility of a safeapplication. On the substantiation statement: besides the NECrequirements; If the control is part of a safety related system a thirdparty certification is a requirement from the enforcementdocuments [e.g. European Community " machinery Directive"]NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #61)79- 159 - (Clause 21 (New) [Clause 19]): Accept in PrincipleSUBMITTER: Lynn F. Saunders, General Motors CorporationRECOMMENDATION: Revise text as follows:

19.1 General

The verification of the continuity of the equipment grounding(protective bonding) circuit shall be conducted (refer to 19.2).

When the electrical equipment is modified, the requirements statedin 19.7 shall apply.

A pp l icab le tes ts sh all b e p erfo rm ed w her e d eemed n ecessary in acco rd an ce w ith th e su b clau ses ref eren ced in th e fo l lo wi n g li st.

− verification that the electrical equipment is in compliance withthe technical documentation;

− insulation resistance test(refer to 19.3);− voltage test(refer to 19.4);− protection against residual voltages test (refer to 19.5);− functional test (refer to 19.6). It is recommended that they follow the sequence listed. Followingthis order will help ensure the accuracy of the tests results and thesafety of personnel.

19.2 Continuity of the Equipment Grounding (Protective Bonding)Circuit One of the following methods may shall be used to verify thecontinuity of the equipment grounding circuit:− Use an impedance measuring device, taking into account any

impedance in the measuring circuit. The measuredimpedance must be 0.1 ohms or less.

– Apply a current of at least 10 A, 50 Hz or 60 Hz, derived froma SELV source. The tests are to be made between theequipment grounding (PE) terminal (refer to 5.2) and


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relevant points that are part of the equipment grounding(protective bonding) circuit; the measured voltage betweenthe equipment grounding (PE) terminal and the points of testis not to exceed the values given in table 9 (refer to 8.2.2).

Note The concepts of SELV are further explained in UL XXX andin IEC 60364 411.1

Table 9 – Verification of Continuity Of The EquipmentGrounding ( Protective Bonding) Circuit

Minimum equipmentgrounding (protective)

conductorcross-sectional area ofthe branch under test

AWG

Maximum measured voltagedrop (values are given for a

test current of 10 A)

V

1 8 3 . 3

1 6 2 . 6

1 4 1 . 9

1 0 1 . 4

> 8 1 . 0

19.3 Insulation resistance tests The insulation resistance measured at 500 V d.c. between thepower circuit conductors and the equipment grounding (protectivebonding) circuit shall be 1 M Ω. The test may be made onindividual sections of the machine. EXCEPTIONFor certain parts of electrical equipment,incorporating for example busbars, collector wire or collector barsystems or slip-ring assemblies, a lower minimum value shall bepermitted, but that value must be 50 kΩ or greater] .

19.4 Voltage tests T he elect rical eq u ip men t sh all w ith st an d a tes t vo lt age ap p lied fo r ap erio d o f at leas t o n e seco n d b etw een th e co n du ct or s o f all cir cui tsan d th e eq u ip men t gro u n di n g (p ro tect ive b o nd i ng) cir cui t, excep tfo r th o se cir cui ts in t end ed to o p erate at o r b elo w 30 vo lt s (les s th an 42.4 vo lt s p eak). T he tes t vo lt age sh all :

− have a value of twice the rated supply voltage of the equipmentplus 1000 V

be supplied from an isolated power supply with a minimum ratingof 500 VA.

Components that are not rated to withstand the test voltage shall bedisconnected during testing.

19.5 Protection against residual voltages

Residual voltage tests shall be performed to ensure compliancewith 6.2.4.

19.6 Functional tests

The functions of electrical equipment shall be tested, particularlythose related to safety and safeguarding.

19.7 Retesting

Where a portion of the machine and its associated equipment ischanged or modified, that portion shall be reverified and retested,as is appropriate (see 19.1).

SUBSTANTIATION: This proposal is part of a package ofproposals to rewrite and harmonize NFPA 79, IEC 60204-1, andSAE HS-1738. 19.1 General. Testing is conducted on machinery to verify thesuitability of the grounding system and electrical insulation,especially in cases where a visual examination may not be adequate

19.2 Continuity of the Equipment Grounding (ProtectiveBonding) Circuit. It is normally difficult to clearly identify thesuitability of the grounding circuit with only a visual examination IEC 60364-6-61, clause 413.1.3.3 states: “The characteristics of protective devices (see subclause 413.1.3.8)and the circuit impedances shall be such that, if a fault ofnegligible impedance occurs anywhere in the installation between aphase conductor and a protective conductor or exposedconductive part, automatic disconnection of the supply will occurwithin the specified time, the following condition fulfilling thisrequirement: Z s x Ia ≤ U o, where: Z is the impedance of the fault loop comprising the source, the liveconductor up to the pint of the fault and the protective conductorbetween the point of the fault and the source. I is the current causing the automatic operation of thedisconnecting protective device within the time stated in Table 41Aas a function of the nominal voltage U or, under the conditionstated in subclause 413.1.3.5, within a conventional time notexceeding 5 s. U is the nominal a.c. r.m.s. voltage to earth. 19.3 Insulation resistance tests. This requirement defines alevel of insulation resistance which is greater than the levelrequired by the voltage tests 19.4 Voltage tests. In addition to verifying a level of insulationresistance, this test is also a check of proper wiring methods used.For example, loose strands of wire projecting from a terminal neara grounded part 19.5 Protection against residual voltages. Ensures theinclusion of testing requirements identified in clause 6.2.4“Protection against residual voltage” 19.6 Functional tests. This test would confirm the proper

operation of protective devices under all modes of operation,such as the interlock switch on a guard

19.7 Retesting. Provides a clear intent that after modificationsor changes are made, testing in accordance with the initialrequirements is required.COMMITTEE ACTION: Accept in Principle. Revise text as follows:19 Testing and Verification

19.1 General. The verification of the continuity of the equipmentgrounding (protective bonding) circuit shall be conducted anddocumented . (refer to 19.2).

When the electrical equipment is modified, the requirements statedin 19.7 shall apply.

A pp l icab le tes ts sh all b e p erfo rm ed w her e d eemed n ecessary in acco rd an ce w ith th e su b clau ses ref eren ced in th e fo l lo wi n g li st.

− verification that the electrical equipment is in compliance withthe technical documentation;

− insulation resistance test (refer to 19.3);− voltage test (refer to 19.4);− protection against residual voltages test (refer to 19.5);− functional test (refer to 19.6). It is recommended that they follow the sequence listed. Followingthis order will help ensure the accuracy of the tests results and thesafety of personnel.

Note: Refer to SEMI S9 for additional information on performingthe testing described in 19.1.

19.2 Continuity of the Equipment Grounding (Protective Bonding)Circuit. One of the following methods may shall be used to verifythe continuity of the equipment grounding circuit:− Use an impedance measuring device, taking into account any

impedance in the measuring circuit. The measuredimpedance must be 0.1 ohms or less.

– Apply a current of at least 10 A, 50 Hz or 60 Hz, derived froma SELV source. The tests are to be made between theequipment grounding (PE) terminal (refer to 5.2) andrelevant points that are part of the equipment grounding(protective bonding) circuit; the measured voltage betweenthe equipment grounding (PE) terminal and the points of testis not to exceed the values given in table 9 (refer to 8.2.2) .

–


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Note The concepts of SELV are further explained in UL 1950, UL3101-1, and IEC 60364-411.1.

Table 9 – Verification of Continuity Of The EquipmentGrounding ( Protective Bonding) Circuit

Minimum equipmentgrounding (protective)

conductorcross-sectional area of the

branch under test AWG

Maximum measured voltagedrop (values are given for a

test current of 10 A)

V 1 8 3 . 3 1 6 2 . 6 1 4 1 . 9 1 0 1 . 4 > 8 1 . 0

19.3 Insulation resistance tests. The insulation resistance measuredat 500 V d.c. between the power circuit conductors and theequipment grounding (protective bonding) circuit shall be 1 MΩ.The test may be made on individual sections of the machine. EXCEPTIONFor certain parts of electrical equipment,incorporating for example busbars, collector wire or collector barsystems or slip-ring assemblies, a lower minimum value shall bepermitted, but that value must be 50 kΩ or greater] .

19.4 Voltage tests. The electrical equipment shall withstand a testvoltage applied for a period of at least one second betweenthe conductors of all circuits and the equipment grounding(protective bonding) circuit, except for those circuitsintended to operate at or below 30 volts (less than 42.4 voltspeak). The test voltage shall:

− have a value of twice the rated supply voltage of the equipmentplus 1000 V

be supplied from an isolated power supply with a minimum ratingof 500 VA.

Components that are not rated to withstand the test voltage shall bedisconnected during testing.

19.5 Protection against residual voltages. Residual voltage testsshall be performed to ensure compliance with 6.2.4.

19.6 Functional tests. The functions of electrical equipment shallbe tested, particularly those related to safety and safeguarding.

19.7 Retesting. Where a portion of the machine and its associatedequipment is changed or modified, that portion shall be reverifiedand retested, as is appropriate (see 19.1).

COMMITTEE STATEMENT: 1) Remove all parantheticalreference notes to comply with the NFPA Manual of Style. 2) Require documentation of grounding continuity test in 19.1 inorder to show or prove a prior test had been made. 3) Add UL1950 and UL 3101-1 to the note for explaination ofSELV Circuits.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 21 NEGATIVE: 4 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DEFELICE: 1) AWG 12 wire does not appear in Table 9 of 19.2. 2) Calculations derived using data from Chapter 9, Table 8 ofNFPA 70-1999 show that the maximum permissible voltage dropsfrom Table 9 of 19.2 are exceeded at the following conductorlengths (values for test current of 10 amps, as per table):

AWG Resistance fromNFPA 70 Table

8

Rmax Length atwhich

Rmax isreached

18 .00795 ohms/ft .33 ohms 41.5 ft.16 .00499 ohms/ft .26 ohms 52.1 ft.14 .00314 ohms/ft .19 ohms 60.5 ft.10 .00124 ohms/ft .14 ohms 112.9 ft.8 .000778 ohms/ft .1 ohms 128.5 ft.

It is not unusual for large machines to exceed these lengths;thereby exceeding the limits permitted by Table 9 of 19.2. DOBROWSKY: The proposed test values are not practical forlarge machines. The phrase "where deemed necessary" is vagueand will not result in consistent interpretations. See also mycomments on Proposal 79-160 (Log #94). MONTEITH: The no vote is based upon the lack of panelsubstantiation for the departure in wording in the proposed NFPA79-2002 Clause 19.2 from IEC 60204-1 Clause 19.2. IEC 60204-1recommends tests that "may" be performed to verify the continuityof the grounding circuit. The proposed NFPA 79 Clause 19.2specifics the test and makes it mandatory. It is recommended thatClause 19.2 not mandate tests, but permit the builder to choose thetesting methods they determine appropriate (see Proposal 79-160(Log #94) for recommended wording). PADGETT: The no vote is based upon the lack of panelsubstantiation for the departure in wording in the proposed NFPA79-2002 Clause 19.2 form IEC 60204-1 Clause 19.2. IEC 60204-1recommends tests that "may" be performed to verify the continuityof the grounding circuit. The proposed NFPA 79 Clause 19.2specifics the test and makes it mandatory. It is recommended thatClause 19.2 not mandate tests, but permits the builder to choosethe testing methods they determine appropriate (see Proposal 79-160 (Log #94) for recommended wording). Defining testrequirements and procedures is not within the scope of NFPA 79.The scope of NFPA 79 is to define the requirement for the" application of electrical/electronic equipment, apparatus, orsystems supplied as part of industrial machines that will promotesafety" as stated in Clause 1.6. Testing is the subject matter forother documents and standards (example is the note in Clause 19.1referencing SEMI S9).

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(Log #94)79- 160 - (Chapter 21 (New) [19.1]): RejectSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modifying proposed new Clause 19. In Clause 19.1, change the first word of the first sentence to "A."In the same sentence delete all after the word "conducted" andthen add the word "periodically" as the final word. Sentence toread, "A verification of the continuity of the equipment grounding(protective bonding) circuit shall be conducted." Change the third sentence of proposed Clause 19.1 to read "Note:Applicable tests that can be performed include:" and make thissentence, and all that follows in clause 19.1, a Note. Delete all proposed clauses 19.2 through 19.6. Change thenumber of clause 19.7 to number 19.2 and delete all words afterthe word reverified." Change the reference number in the second sentence of proposedclause 19.1 from 19.7 to 19.2. Delete all of the "refer to_" parenthetical references in the bulletsof the newly created Note.SUBSTANTIATION: The many variables between different typesof industrial machinery, (Annex B of NFPA 79-1997 contains a nonexhaustive list of examples), and even between individual machinesof basically the same design, make the prescribed tests andincomplete test procedures of questionable merit. This makes itespecially inappropriate for Clause 19.2 to deem these to bemandatory techniques. The details of such testing and testmethods are better left to be specified for a given industrialmachine by the manufacturer’s individual design team and asdirected by company policies and procedures.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: Clause 19 has been sufficientlysubstantiated. There are methods and means to accomplish thetesting required by Clause 19. For example, the SemiconductorIndustry (See SEMI S9-1995, Electrical Test Methods forSemiconductor Manufacturing Equipment and S2-1993, SafetyGuidelines for Semiconductor Manufacturing Equipment) has fornine years, performed similiar tests on machines from table topsize to large integrated systems.


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NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 21 NEGATIVE: 4 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: DOBROWSKY: The proposal should be accepted or accepted inprinciple. The provided information is more suitable as a note.IEC 60204-1 uses the terms "may" and "can" when referring to thesetests. MONTEITH: See my Explanation of Negative Vote on Proposal79-159 (Log #61). PADGETT: See my Explanation of Negative for Proposal 79-159(Log #61). SAUNDERS: The Committee Action should be ACCEPT INPRINCIPLE with the following revisions being made to 19.2 and19.4 as follows. (19.3 as proposed in Proposal 79-159 (Log 61)remains unchanged). Revise 19.2 and 19.4 as follows:19.2 Continuity of the Equipment Grounding (Protective Bonding)CircuitVerification of the continuity of the equipment groundingconductor shall be completed in accordance with the requirementsSEMI S9 "Safety Guideline for Electrical Tests for SemiconductorManufacturing Equipment". The test described in the SEMI S9 standard basically requires thefollowing:- Use an impedance measuring device, taking into account anyimpedance in the measuring circuit. The measured impedancemust be 0.1 ohms or less. 19.3 Insulation resistance tests (NO CHANGE) 19.4 Voltage (Dielectric) tests Voltage (dielectric) tests shall be completed in accordance witthe requirements of SEMI S9 "Safety Guideline for Electrical Testsfor Semiconductor Manufacturing Equipment".The test described in the SEMI S9 standard basically requires theelectrical equipment power circuit wiring shall withstand adielectric withstand potential of 1500 Volts AC or 2121 Volts DCapplied for a period of at least one second between the conductorsof all circuits and the equipment grounding (protective bonding)circuit. Substantiation: The SEMI S9 standard provides the basicphilosophy of the test procedure, the safety precautions to use, thetest equipment required, and the procedures to be used includingthe acceptable results. Note: It is the intent that the reference to the SEMI S9 standardwill be updated to the latest version of the document. A version ofthe S9 standard is presently being modified and updated and theappropriate sections will be referenced. (A version of the DRAFTSEMI S9 Document is available at NFPA for review)

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(Log #140)79- 161 - (21.x [19.4]): Accept in PrincipleSUBMITTER: John Freudenberg , TeradyneRECOMMENDATION: Revise text as follows: 19.4 The machine shall withstand without breakdown a testvoltage gradually applied from zero to 1500Vac or 2121Vdc andheld at the maximum value for a period of at least one secondminute between the conductors of all primary circuits and theequipment grounding (protective bonding) circuit. The testvoltage shall be supplied from an isolated power supply with aminimum rating of 500 VA. Components that are not rated towithstand the test voltage shall be disconnected during testing. Note: Refer to SEMI S9 for additional information on performingthis dielectric withstand (hypot) test. SUBSTANTIATION: This is a proposal to modify a proposal thathas no basis in existing NFPA 79:1997 text. The proposal to applythis to ALL circuits is absolutely out of context and technicallyincorrect when applied to secondary circuits. During Type Listing of our 3 phase semiconductor tool required1960VAC (based on 2*480 plus 1000) or 1554Vac (based on 2*277plus 1000). The rating is 277 phase to ground & 480 Vac phase tophase. The hypot test is being applied to the phase to groundinsulation in the primary circuit. What the real problem that we faced was defining "rated voltage"for 3 phase equipment that was agreeable to all parties and hadmeaning in the international arena. We had very strong argumentsbacked by some IEC standards and interpretations that the "ratedvoltage" would be the working voltage applied line to groundacross the insulation so instead of 480 as the rated voltage it would

be 277. We also had strong arguments from the Japanese side thatthey have ungrounded 200 VAC systems so the "rated voltage"would have to be line to line. Not too surprising we had inputs from several NRETL’s *UL, ITSand ETI) and found that even within an organization there wasdisagreement on what "rated voltage" meant when discussing thesame standard such as UL 1950 (IEC950). To move forward and to try and stay away from defining "ratedvoltage" or creating tables with "non-standard" voltages that in factdo exist, we chose to go the route of one standard number anddebated a length a fixed value of 1000 VAC which equates to manyUS standards or 1500 VAC which in more international. We discussed the following methods to indicate the appropriatehipot test voltage: *a formula *a table *fixed value *a combination of the above Possible formulas included: *1000Vac plus twice rated input *1000Vac plus twice rated working voltage Note 1: A formula based on rated input voltage has shortcomingswith respect to 3 phase inputs where rated voltage input is definedas phase to phase voltage. Note 2: A formula based on working voltage was considered boththe most technically correct and the most complex. Both IEC60950/UL 1950 and IEC61010/UL 3111 determine hipot testvoltages based on "working voltage at rated input voltage". Possible fixed values included: *1000Vac, (min value per many USA only standards) *1240Vac, (consistent with 1000Vac + 2 * 120Vac rated input) *1500Vac, (basic insulation value per many IEC standards) *1760Vac (consistent with 1000Vac + 2 * 380Vac rated input) *1960Vac (maximum value consistent with 1000Vac + 2 * 480Vacrated input) The use of a table was discussed, however, there would beproblems covering all rated input voltages and/or all rated workingvoltages. How would all input voltages not covered beextrapolated. A table would not solve the concerns with technicaldifferences between rated input voltage and working voltage atrated input voltage unless the WG inconsistently used bothformulas in the table. Note: See IEC61010 Annex D for examples of over 20 tables inthe 1st edition. The IEC61010 2nd edition now has a single table ofbased appropriate hipot potentials for a required clearancedistance, however, the required clearance distance is still based onother tables of required clearance distances based on workingvoltage. The members of the working group preferred to go with one fixedhipot test potential of either 1000Vac or 1500Vac. The 1000Vacpotential is the least stigent value required anywhere in the worldwhere primary hipot testing is performed. The 1500Vac potentialwas considered an average value roughly consistent with 200 Vac to250 Vac rated input voltages (phase to phase) and roughlyconsistent with working voltages (phase to ground) at rated inputvoltages from 400 to 480 Vac. The majority of hipot test potentialsin various tables considered were 14XXVac. It was also felt that a1760Vac test potential for 380Vac rated input and a 1960Vac testpotential for 480Vac rated input was much higher than thatrequired based on working voltage and that USA only standardsbased on rated input voltage may not have been fully considering 3phase power distribution systems and/or power distributionsystems outside the United States.COMMITTEE ACTION: Accept in Principle.Revise text as follows: 19.4 The machine shall withstand without breakdown a testvoltage gradually applied from zero to 1500Vac or 2121Vdc andheld at the maximum value for a period of at least one secondbetween the conductors of all primary circuits and the equipmentgrounding (protective bonding) circuit. The test voltage shall be supplied from an isolated power supply with a minimum rating of500 VA. Components that are not rated to withstand the testvoltage shall be disconnected during testing. Note: Refer to SEMI S9 for additional information on performingthis dielectric withstand (hypot) test. COMMITTEE STATEMENT: The committee has editoriallycorrected the voltage to 2121 Vdc. In addition, the committee hasrevised the one minute to one second time duration because it isconsidered sufficient to evaluate the insulation integrety.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman


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COMMENT ON AFFIRMATIVE: FREUDENBERG: Using one simple applied voltage of 1500Vavor 2121Vdc will harmonize NFPA79 with SEMI S9such that thetesting requirement and test methods are identical. Thesemiconductor industry balloted 1000Vac plus twice rated inputand found major difference of opinion and confusion over whetherrated input for 3 phase machines was rated phase-to-phase voltageor rated phase-to-ground voltage.We felt that since hypot is a phase-to-ground test the phase-to-ground voltage was the moreappropriate voltage for the hypoy test but the phase-to-phasevoltage was the more common input voltage rating.Hence, onevalue of 1500Vac or 2121Vdc eliminated the confusion andcontroversy. GARVEY: The words "power and Class 1 circuits" should be usedinstead of "primary circuits". The term "primary circuits" is notcommonly used in this context in other NFPA standards such asthe NEC. SAUNDERS: Revise Committee Statement to be: See Action on Proposal 79-160 (Log #94) as suggested in mycomment on Negative ballot. Substantiation: Action for 19.4 meets the intent of the submitter.

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(Log #38)79- 162 - ([Annex A (new)]): Reject TCC NOTE: The TCC directs the committee to review the use ofall NOTES throughout the document. The TCC recognizes thatthe committee desire is in conflict with the NFPA Manual of Style.However, the TCC offers two possible directions for the TC toproceed for this edition of NFPA 79. Option 1: Convert all of the NOTES to FPN’s (as used in theNEC). However, in doing so the committee must review each ofthe notes and adhere to the strict FPN guidelines as used in theNEC. The FPN cannot contain any requirements, alternatives,interpretations of the requirement, or permissive statements.Examples of unacceptable NOTES are found in, but are notlimited to, 1.1 Note 1 (Proposal 79-8), 1.1 Note 2 (Proposal 79-8),3.5 NOTE (Proposal 79-11), 3.20 NOTE (Proposal 79-11), 3.87NOTE (Proposal 79-11), 4.4.2 NOTE (Proposal 79-24). If thematerial cannot be rewritten to comply with these rules, then itshould be deleted. The TCC would ask the NFPA Standards Council to allow thisoption for this edition of NFPA 79. Option 2: The TC is to relocate all explanatory NOTES toAnnex A of the document in accordance with the NFPA Manual ofStyle. In this arrangement, the required rules for the content ofthe NOTE is not as restrictive of the FPN concept used in theNEC. However, the explanatory material must not offerinterpretations of the text, provide alternatives to the mandatoryrules or contain requirements. This action will be considered by the committee as a publiccomment.SUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Add informative annex which contains thenotes from the proposed normative text.SUBSTANTIATION: This annex is in conformance with therequirements of the NFPA MOS which stipulates that all notes inthe normative text be transferred to the first annex of thedocument.COMMITTEE ACTION: Reject.

COMMITTEE STATEMENT: The committee does not believe thatthis Annex A as prescribed by the NFPA Manual of Style is userfriendly. The committee desires to retain all of the informative orexplanatory notes in the body of the normative text for thefollowing reasons: 1. The organization of the standard has been extensively revised. 2. Existing technical requirements have been reworded to effectharmonization. 3. There are a number of technical concepts that are bestexplained in informative language. 4. The value of the notes is far superior where the notes arelocated in the body of the text. Recognizing the Standards Councils authority in the matter, thecommittee respectfully requests that the committee be given theliberty to place the notes in the body of the document for the 2002document cycle.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: BLOODGOOD: I strongly support the Committee Action andCommittee Statement regarding this proposal. GARVEY: The users of the 2002 NFPA 79 will see a major changein the structure of the standard. In addition, the committee hasproposed several significant new technical changes. Many currentNFPA 79 requirements have been restated in language consistentwith both IEC text and the NFPA manual of style. The committeehas used the notes to assist the users of the document in findingand correctly applying the rules. Relocating the notes to an annexin the back of the book runs counter to the committee’s objectiveand will not facilitate the consistent and correct application of thestandard. FREUDENBERG: The value and meaning of the fine print note isoften lost when displaced from the normative text.

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(Log #39)79- 163 - ([Annex B ( New)]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Add informative annex to correspond tothe normative text, similar to Annex B in IEC 60204-1 as follows:

Annex B (informative) : Inquiry form for the electrical equipmentof machinesNFPA 79: 2002 (Proposed)

It is recommended that the following information is provided bythe intended user of the equipment. It facilitates an agreementbetween the user and supplier on basic conditions and additionaluser requirements to ensure proper design, application andutilization of the electrical equipment of the machine (see 4.1).See form on the following page.


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Name of manufacturer/supplier

Name of end user

Tender/Order No. Date

Type of Machine/Serial Number

1. Are there to be modifications as allowed for within this standard? YES ____ NO _____

Operating Conditions - Special requirements (see 4.4)

2. Ambient temperature range

3. Humidity range

4. Altitude

5. Environmental (e.g. corrosive atmospheres, particulate matter, EMC)

6. Radiation

7. Vibration, shock

8. Special installation and operation requirements (e.g. flame retardant requirements for cables and conductors )

Power supply(ies) and related conditions (see 4.3)

9. Anticipated voltage fluctuations (if more than ± 10 %)

10. Anticipated frequency fluctuations (if more than in 4.3.2)

Specification of short term value

11. Indicate possible future changes in electrical equipment that will require an increase in theelectrical supply requirements

12. Indicate for each source of electrical supply required:

Nominal Voltage (V) __________ AC ____ DC ____

If AC, number of phases _____ frequency ____ HzProspective short circuit current at the point of supply to the machine ______kA rms (see also question 15)

Fluctuations outside values given in 4.3.2 _________________________________________

13. Type of power supply earthing (see IEC 364-3-31):

- TN (System with one point directly earthed, with a protective conductor (PE) connected directly to that point) ____

- TT (System with one point directly earthed but the protective conductor (PE) not connected to that earth point of the system) ____

- IT (System that is not directly earthed) ____

14. Is the electrical equipment to be connected to a neutral (N) supply conductor? (See 5.1)

YES ____ NO ____

15. Does the user or the supplier provide the overcurrent protection of the supply conductors ? (see 7.2.2)

Type and rating of overcurrent protective devices

16. Supply disconnecting device

- Is the disconnection of the neutral (N) conductor required? YES ___ NO ____

- Is a link for the neutral (N) permissible? YES ____ NO ____

17. Type of disconnecting device to be provided

18. Limit of power up to which three-phase AC motors may be started directly across the incoming supply lines? HP(KW)

19. May the number of motor overload detection devices be reduced? (see 7.3)YES ____ NO ____

20. Where the machine is equipped with local lighting:

- highest permissible voltage V

- if lighting circuit voltage is not obtained directly from the power supply, state preferredvoltage V

Other Considerations

21. Functional identif ication (see 17.3)

22. Inscriptions/Special Markings

23. - Mark of Certification YES ____ NO ____ If YES, which one?

- on Electrical Equipment? In which language?

24. Technical documentation (see 18.1)

On what media _______ In which language?

25. Size, location, and purpose of ducts, open cable trays, or cable supports to be provided by the user (see 18.5) (additional sheets to beprovided where necessary)


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26. For which of the following classes of persons is access to the interior of enclosures required during normal operation of theequipment?

- Skilled persons

- Instructed persons

27. Are locks with removable keys to be provided for fastening doors or covers (see 6.2.2)?

28. Indicate if special limitations on the size or weight affect the transport of a particular machine or control equipment to theinstallation site:

- Maximum dimensions

- Maximum weight

29. In the case of machines with frequent repetitive cycles of operation dependent on manual control, how

frequently will cycles of operation be repeated? per hour

30. For what length of time is it expected that the machine will be operated at this ratewithout subsequent pause? min

31. In the case of specially built machines, is a certifi cate of operating tests with the loaded

machine to be supplied? YES ____ NO ____

32. In the case of other machines, is a certificate of operating type tests on a loaded prototypemachine to be supplied? YES ___ NO ____

33. For cable-less control systems, specify the time delay before automatic machine shutdown is

initiated in the absence of a valid signal (see 9.2.7.3)_______ seconds.

34. Do you need a specific method of conductor identification to be used for the conductors referred to in 14.2.4.

Yes__________ No__________ Type___________________________

SUBSTANTIATION: The inquiry form serves as the basis for abuyer-seller agreement for certain normative requirements in thestandard.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: FREUDENBERG: Annex B is NOT normative text, but may be aninformation tool for custom products. For volume products thesupplier manual or site prep guide would typically indicate similarinformation as part of the product specification. SANDERS: Annex B Inquiry form should be revised as follows:(See form on the following pages.)


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Annex B Inquiry form should be revised as follows (details of the proposed changes follow):

A n n e x B ( i n f o r m a t i v e ) : I n q u i r y f o r m f o r t h e e l e c t r i c a l e q u i p m e n t o f m a c h i n e s

N F P A 7 9 : 2 0 0 2 P r o p o s e d

I t i s r e c o m m e n d e d t h a t t h e f o l l o w i n g i n f o r m a t i o n i s p r o v i d e d b y t h e i n t e n d e d u s e r o f t h e e q u i p m e n t . I t f a c i l i t a t e s a n a g r e e m e n t b e t w e e n t h e u s e r a n d s u p p l i e r o n b a s i c c o n d i t i o n s a n d a d d i t i o n a l u s e r r e q u i r e m e n t s t o e n s u r e p r o p e r d e s i g n , a p p l i c a t i o n a n d u t i l i z a t i o n o f t h e e l e c t r i c a l e q u i p m e n t o f t h e m a c h i n e ( s e e 4 . 1 ) .

N a m e o f m a n u f a c t u r e r / s u p p l i e r

N a m e o f e n d u s e r

T e n d e r / o r d e r n o . D a t e

T y p e o f m a c h i n e / s e r i a l n u m b e r

1 . A r e t h e r e t o b e m o d i f i c a t i o n s a s a l l o w e d f o r w i t h i n t h i s s t a n d a r d ? Y E S N O

O p e r a t i n g c o n d i t i o n s – S p e c i a l r e q u i r e m e n t s ( s e e 4 . 4 )

2 . A m b i e n t t e m p e r a t u r e r a n g e

3 . H u m i d i t y r a n g e

4 . A l t i t u d e

5 . E n v i r o n m e n t a l ( e . g . c o r r o s i v e a t m o s p h e r e s , p a r t i c u l a t e m a t t e r , E M C )

6 . R N o n - i o n i z i n g r a d i a t i o n

7 . V i b r a t i o n , s h o c k

8 . S p e c i a l i n s t a l l a t i o n a n d o p e r a t i o n r e q u i r e m e n t s ( e . g . f l a m e - r e t a r d a n t r e q u i r e m e n t s f o r c a b l e s a n d c o n d u c t o r s )

P o w e r s u p p l y ( i e s ) a n d r e l a t e d c o n d i t i o n s ( s e e 4 . 3 )

9 . A n t i c i p a t e d v o l t a g e f l u c t u a t i o n s ( i f m o r e t h a n ± 1 0 % )

1 0 . A n t i c i p a t e d f r e q u e n c y f l u c t u a t i o n s ( i f m o r e t h a n i n 4 . 3 . 2 )

Specification of short-term value _______________________________________

1 1 . I n d i c a t e p o s s i b l e f u t u r e c h a n g e s i n e l e c t r i c a l e q u i p m e n t t h a t w i l l r e q u i r e a n i n c r e a s e i n t h e e l e c t r i c a l s u p p l y r e q u i r e m e n t s


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1 2 . I n d i c a t e f o r e a c h s o u r c e o f e l e c t r i c a l s u p p l y r e q u i r e d :

N o m i n a l v o l t a g e ( V ) A C DC

I f A C , n u m b e r o f p h a s e s fr e q u e n c y H z

P r o s p e c t i v e s h o r t - c i r c u i t c u r r e n t a t t h e p o i n t o f s u p p l y t o t h e m a c h i n e k A r m s ( s e e a l s o q u e s t i o n 1 5 )

F l u c t u a t i o n s o u t s i d e v a l u e s g i v e n i n 4 . 3 . 2

1 3 . T y p e o f p o w e r s u p p l y e a r t h i n g s y s t e m g r o u n d i n g ( s e e I E C 6 0 3 6 4 - 3 ) :

– T N ( s y s t e m w i t h o n e p o i n t d i r e c t l y e a r t h e d , w i t h a p r o t e c t i v e c o n d u c t o r ( P E ) c o n n e c t e d d i r e c t l y t o t h a t p o i n t )

– T T ( s y s t e m w i t h o n e p o i n t d i r e c t l y e a r t h e d b u t t h e p r o t e c t i v e c o n d u c t o r ( P E ) n o t c o n n e c t e d t o t h a t e a r t h p o i n t o f t h e s y s t e m )

– I T ( s y s t e m t h a t i s n o t d i r e c t l y e a r t h e d )

W y e p h a s e s m i d - p o i n t g r o u n d e d . De l t a p h a s e m i d - p o i n t g r o u n d e d .

D e l t a p h a s e s c o r n e r g r o u n d e d . Hi g h i m p e d a n c e g r o u n d e d .

W y e p h a s e s m i d - p o i n t u n g r o u n d e d . De l t a p h a s e s u n g r o u n d e d .

1 4 . I s t h e e l e c t r i c a l e q u i p m e n t t o b e c o n n e c t e d t o a n e u t r a l ( N ) s u p p l y c o n d u c t o r ? ( s e e 5 . 1 ) YE S N O

1 5 . D o e s t h e u s e r o r t h e s u p p l i e r p r o v i d e t h e o v e r c u r r e n t p r o t e c t i o n o f t h e s u p p l y c o n d u c t o r s ? ( s e e 7 . 2 . 2 )

T y p e a n d r a t i n g o f o v e r c u r r e n t p r o t e c t i v e d e v i c e s

1 6 . S u p p l y d i s c o n n e c t i n g d e v i c e

– I s t h e d i s c o n n e c t i o n o f t h e n e u t r a l ( N ) c o n d u c t o r r e q u i r e d ? Y E S N O

– I s a l i n k f o r t h e n e u t r a l ( N ) p e r m i s s i b l e ? Y E S N O

– T y p e o f d i s c o n n e c t i n g d e v i c e t o b e p r o v i d e d ?

1 7 . T y p e o f d i s c o n n e c t i n g d e v i c e t o b e p r o v i d e d .

1 8 . L i m i t o f p o w e r u p t o w h i c h t h r e e - p h a s e a . c . m o t o r s m a y b e s t a r t e d d i r e c t l y a c r o s s t h e i n c o m i n g s u p p l y l i n e s ? H P k W


1695

1 9 . M a y t h e n u m b e r o f m o t o r o v e r l o a d d e t e c t i o n d e v i c e s b e r e d u c e d ? ( s e e 7 . 3 )

Y E S N O

2 0 . W h e r e t h e m a c h i n e i s e q u i p p e d w i t h l o c a l l i g h t i n g :

– h i g h e s t p e r m i s s i b l e v o l t a g e V

– if l i g h t i n g c i r c u i t v o l t a g e i s n o t o b t a i n e d d i r e c t l y f r o m t h e p o w e r s u p p l y , s t a t e p r e f e r r e d v o l t a g e V

O t h e r c o n s i d e r a t i o n s

2 1 . F u n c t i o n a l i d e n t i f i c a t i o n ( s e e 1 7 . 3 )

2 2 . I n s c r i p t i o n s / s p e c i a l m a r k i n g s

2 3 . – M a r k o f c e r t i f i c a t i o n Y E S N O

I f Y E S , w h i c h o n e ?

– O n e l e c t r i c a l e q u i p m e n t ? I n w h i c h l a n g u a g e ?

2 4 . T e c h n i c a l d o c u m e n t a t i o n ( s e e 1 8 . 1 )

O n w h a t m e d i a ? I n w h i c h l a n g u a g e ?

2 5 . S i z e , l o c a t i o n , a n d p u r p o s e o f d u c t s , o p e n c a b l e t r a y s o r c a b l e s u p p o r t s t o b e p r o v i d e d b y t h e u s e r ? ( s e e 1 8 . 5 ) ( a d d i t i o n a l s h e e t s t o b e p r o v i d e d w h e r e n e c e s s a r y )

2 6 . F o r w h i c h o f t h e f o l l o w i n g c l a s s e s o f p e r s o n s i s a c c e s s t o t h e i n t e r i o r o f e n c l o s u r e s r e q u i r e d d u r i n g n o r m a l o p e r a t i o n o f t h e e q u i p m e n t ?

– S k i l l e d p e r s o n s

– I n s t r u c t e d p e r s o n s

2 7 . A r e l o c k s w i t h r e m o v a b l e k e y s t o b e p r o v i d e d f o r f a s t e n i n g d o o r s o r c o v e r s ? ( s e e 6 . 2 . 2 )

2 8 . I n d i c a t e i f s p e c i a l l i m i t a t i o n s o n t h e s i z e o r w e i g h t a f f e c t t h e t r a n s p o r t o f a p a r t i c u l a r m a c h i n e o r c o n t r o l e q u i p m e n t t o t h e i n s t a l l a t i o n s i t e :

– m a x i m u m d i m e n s i o n s

– m a x i m u m w e i g h t

2 9 . I n t h e c a s e o f m a c h i n e s w i t h f r e q u e n t r e p e t i t i v e c y c l e s o f o p e r a t i o n d e p e n d e n t o n m a n u a l c o n t r o l , h o w f r e q u e n t l y w i l l c y c l e s o f o p e r a t i o n b e r e p e a t e d ? p e r h o u r

3 0 . F o r w h a t l e n g t h o f t i m e i s i t e x p e c t e d t h a t t h e m a c h i n e w i l l b e o p e r a t e d a t t h i s r a t e w i t h o u t s u b s e q u e n t p a u s e ? m i n

3 1 . I n t h e c a s e o f s p e c i a l l y b u i l t m a c h i n e s , i s a c e r t i f i c a t e o f o p e r a t i n g t e s t s w i t h t h e l o a d e d m a c h i n e t o b e s u p p l i e d ? Y E S NO

3 2 . I n t h e c a s e o f o t h e r m a c h i n e s , i s a c e r t i f i c a t e o f o p e r a t i n g t y p e t e s t s o n a l o a d e d p r o t o t y p e m a c h i n e t o b e s u p p l i e d ? Y E S NO

3 3 . F o r c a b l e l e s s c o n t r o l s y s t e m s , s p e c i f y t h e t i m e d e l a y b e f o r e a u t o m a t i c m a c h i n e s h u t d o w n i s i n i t i a t e d i n t h e a b s e n c e o f a v a l i d s i g n a l ? ( s e e 9 . 2 . 7 . 3 ) : s e c o n d s

34. Do you need a specific method of conductor identification to be used for the conductors referred to in 14.2.1? YES NO Type


1696

Details of changes to Annex B.

1. Question 6 changed “Radiation” to “Non-ionizingradiation”.

2. Question 13 “earthing” changed to “system grounding” asmore appropriate, IEC reference deleted as unnecessary, and TN,IT, and TT systems are terms not used within this standard.However, it is useful to provide information based upon the systemto be encountered.

3. Question 18 “KW” changed to “HP” as term used in thisStandard.

4. Question 33 “s” changed to “seconds” for MOS.

___________________

(Log #40)79- 164 - (Annex B [Annex C]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Retain NFPA 79 -1997 Annex B but moveit to Annex C, as follows: NFPA 79: Annex C - Examples of industrial machines covered byNFPA 79 NFPA 79:2002 (Proposed) C.1 Machine tools 1) Metal cutting 2) Metal forming C.2 Plastics machinery 1) Injection molding machines 2) Extrusion machinery 3) Blow molding machines 4) Specialized processing machines 5) Thermoset molding machines 6) Size reduction equipment C.3 Wood machinery 1) Woodworking machinery 2) Laminating machinery 3) Sawmill machines C.4 Assembly machines C.5 Material handling machines 1) Industrial robots 2) Transfer machines C.6 Inspection/testing machines 1) Coordinate measuring machines 2) In-process gauging machines.

SUBSTANTIATION: None given.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

___________________

(Log #41)79- 165 - (Annex D [Annex D]): Accept in PrincipleSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Retain Annex D from NFPA 79-1997.SUBSTANTIATION: None given.

COMMITTEE ACTION: Accept in Principle.Replace Annex D from NFPA 79-1997 with a new Annex D. ***Insert ARTWORK Annex D Proposed SAE.doc***COMMITTEE STATEMENT: The committee agrees to update theannex material to that submitted by SAE.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanCOMMENT ON AFFIRMATIVE: ANDERSON: The present list of proposed illustrations is verycomplete, but does not include the vertical elementary drawing thatis common in Europe and becoming increasingly used in NorthAmerica. Examples showing a broad use of the style can be foundin the old IEC 60204-2, which is currently out of publication. Manyof the CAD packages used in machine electrical design utilize thevertical elementary style because of its ease in using drawinggeography for wire numbering schemes and cross referencing.

SANDERS:Details of Annex D review:IEEE 315 –1975 and 315A – 1986 Supplement (Reaffirmed 1993)Dod adopted 4 Sept 1975ANSI Y32.2 – 1975 (Reaffirmed 1989) Dod adopted 31 Oct 1975CSA Z99 – 1975

1. Figure D-17 titles “ANSI Y32.2 – IEE 315/315A SYMBOLTABLE” should be changed to “ANSI Y32.2 – IEE E 315/315ASYMBOL TABLE” for editorial purposes. (The reference numbersadded are for this discussion only and are not intended to beincluded in the final version of this Standard.)

The symbols in the left hand symbol table have been temporarilyidentified by numbering them from 1 through 15, top to bottom,along the left edge and the symbols in the right hand symbol tablehave been identified from 16 through 20, top to bottom, along theleft edge.

Number 7. The description is wrong, and should bechanged to:“TIMED CONTACT, N.C.T.C.” (Timed switch with TD closing.)

Number 8. The description is wrong, and should bechanged to:“TIMED CONTACT, N.O.T.O.” (Open switch with TD opening.)

Number 9 & 10.They are the same except for the number of contacts shown.Delete Number 9 as redundant.

Number 19. No IEEE standard number. It uses 4.15.5.1LIMIT SWITCH in a triangle; however, IEEE 315A Symbol number14.4.6 uses 2 vertical lines between the upper and lower points for aproximity (non-touching) indicator. The non-standard symbolshould be changed to the IEEE 14.4.6 type.

Number 20. Although this is a standard IEEE type for anindicator light, the IEEE version does not show lines emanatingfrom 45o, 135 o, 225 o, and 315 o and they should be deleted. A lettercan be used to show the color.

TemporaryAssignedNumber

IEEE Number Temporary AssignedNumber

IEEE Number

1 4.3.2 16 4.19.12 4.3.1 17 4.20.13 4.3.2 18 4.15.5.14 4.3.1 19 ------5 4.16.1 20 11.2.7.16 4.16.2 21 5.3.47 4.16.4 22 4.58 4.16.3 23 4.59 4.6.2 & 4.7.1 24 4.510 4.6.2 & 4.7.1 25 4.511 4.7.1 26 4.5.312 4.7.2 27 ---- -13 4.25.4 28 9.4.5 & 9.4.614 4.18.1 29 ---- -15 4.17.1 30 9.1.1


1697

Number 22. Although this is a standard IEEE type for acontrol relay coil, IEEE 4.5A requires a device designation insidethe circle (I.e. CR), with number assigned as needed.

Number 23. Although this is a standard IEEE type for acontactor coil, IEEE 4.5A requires a device designation inside thecircle (i.e. C1), with numbers assigned as needed.

Number 24. Although this is a standard IEEE type for amotor coil, IEEE 4,5A requires a device designation inside the coil(i.e. M1), with numbers assigned as needed.

Number 25. Although this is a standard IEEE type for atimer coil, IEEE 4.5A requires a device designation inside the circle(i.e. TR), with numbers assigned as needed.

Nu mb er 27. T hi s is n o t an IE E E st and ard fo r a co u nt ersym bo l . IE E E 12.2. 1 Gen eral is fo r mess agin g o n ly w hi le IE E E 12.2. 2 is u sed w ith a “make” co n tact.

Number 29. This is not an IEEE standard for a fusedterminal, and could not be found in the IEEE 315/315A document.This should be deleted, or if used marked as non-standard.

In addition, a review of Figure D-5 shows the following IEEEstandard symbols used and they should be included in Figure D-17.

1. IEEE 4.6.1 & 4.35.1 combined make up the mechanicalsingle throw polyphase disconnecting switch.

2. IEEE 2.2.1 Style 2 symbol for a capacitor should beincluded.

3. IEEE 4.30.5 Appendix D for a thermal relay should beincluded.

4. IEEE 5.1.1.1 wire terminals should be included.

___________________

(Log #5)79- 166 - (Annex E [Annex E]): Accept in PrincipleSUBMITTER: Steven Duritt, Empire Abrasive Equipment Co.RECOMMENDATION: Add the following "device and componentdesignations" to the list: OI = operator interface SSL = selector switch, illuminated SNSR = sensor or transducer.SUBSTANTIATION: "OI" is needed due to the use of interfacesconnected to programmable logic controllers. "SSL" would be acomplement to "PBL" which exists in the list. "SNSR" would beuseful for pressure transducers, media flow transducers, etc.COMMITTEE ACTION: Accept in Principle.Add the following "device and component designations" to the list: OIT = operator interface terminal SSL = selector switch, illuminated TSDR = transducer GUI = graphical user interface SNSR = sensor EMO = emergency (machine) off device ESTOP = emergency stop.COMMITTEE STATEMENT: These additional abreviations are anattempt to keep pace with the rapidly changing field of electricalcontrols. The committee understands that this action modifies theCommittee Action on Proposal 79-167 (Log #42).NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #42)79- 167 - (Annex E [Annex E]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Retain Annex E from NFPA 79-1997.Annex E (informative)Device and Component designations

The device and component designations given below are intendedfor use on diagrams in connection with the correspondinggraphical symbols to indicate the function of the particular device.These device and component designations are based on theassignment of a standard letter or letters to the fundamentalfunction that is performed by a component or device. Suitablenumbers (1,2,3, etc.) and letters (A, B, C, etc.) may be added tothe basic designation to differentiate between devices performingsimilar functions. The assignment of a designation to a device on specificequipment is governed by the function of that device on thatequipment and not by the type or nature of the device or itspossible use for other functions on other equipment. The sametype of device may perform different functions on differentequipment or even on the same equipment and, consequently, maybe identified by different designations.

Designation DeviceABE Alarm or Annunciator BellABU Alarm or Annunciator BuzzerAH Alarm or Annunciator HornAM AmmeterAT AutotransformerCAP CapacitorCB Circuit BreakerCI Circuit InterrupterCNC Computerized Numerical ControllerCON ContractorCOs Cable Operated (Emergency) SwitchCPU Central Processing UnitCR Control RelayCRA Control Relay, AutomaticCRH Control Relay, ManualCRL Control Relay, LatchCRM Control Relay, MasterCRT Cathode Ray Tube, Monitor or Video

Display UnitCRU Control Relay, UnlatchCS Cam SwitchCT Current TransformerCTR CounterD DiodeDISC Disconnect SwitchDISP DisplayDR DriveEND EncoderFLD FieldFLS Flow SwitchFS Float SwitchFTS Foot SwitchFU FuseGEN GeneratorGRD, GND GroundHM Hour MeterHTR Heating ElementIC Integrated CircuitINST InstrumentIOL Instantaneous OverloadI/O Input/Output DeviceL InductorLED Light Emitting DiodeLS Limit SwitchLT Pilot LightLVDT Linear Variable Differential

TransformerM Motor StarterMD Motion DetectorMF Motor Starter – ForwardMG Motor – GeneratorMR Motor Starter – ReverseMTR MotorOL Overload RelayPB PushbuttonPBL Pushbutton, IlluminatedPC Personal ComputerPCB Printed Circuit BoardPEC Photoelectric DevicePL PlugPLC Programmable Logic ControllerPOT PotentiometerPRS Proximity SwitchPS Pressure SwitchPWS Power Supply


1698

Q TransistorQTM ThermistorREC RectifierRECP ReceptacleRES ResistorRH RheostatS SwitchSCR Silicon Controlled RectifierSOL SolenoidSS Selector SwitchSSR Solid State RelayST Saturable TransformerSUP SuppressorSYN Synchro or ResolverT TransformerTACH Tachometer GeneratorTAS Temperature Actuated SwitchTB Terminal BlockT/C ThermocoupleTR Timer RelayTWS Thumbwheel SwitchV Electronic TubeVAR VaristorVM VoltmeterVR Voltage RegulatorVS Vacuum SwitchWLT WorklightWM WattmeterX ReactorZSS Zero Speed Switch

SUBSTANTIATION: None given.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #43)79- 168 - ([Annex F ( New )]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Add new annex which provides anoverview of IEC/IP ratings, as follows:Annex F (informative): Enclosure type rating vs. IP ratingF.1 Electrical enclosures are (NEMA 250 / UL 50 and UL 508)Type rated, and/or (IEC 60529) IP rated based upon the degree ofprotection provided. Type rated and IP rated electrical enclosures have only thefollowing in common: a degree of protection for persons fromhazardous components inside the enclosure; a degree of protectionfor equipment inside the enclosure from ingress of solid foreignobjects, including dust; and a degree of protection for equipmentinside the enclosure from ingress of water. The Type rating system, in a single electrical enclosure document,defines additional requirements that a Type rated enclosure mustmeet, which include: mechanical impact on enclosure walls; gasketaging and oil resistance; corrosion resistance (indoor andoutdoor); and door and cover latching requirements. The IEC 60529 designation consists of the letters IP followed bytwo numerals with optional letters. The first characteristic numeralindicates the degree of protection provided by the enclosure withrespect to persons and solid foreign objects entering the enclosure.The second characteristic numeral indicates the degree ofprotection provided by the enclosure with respect to the harmfulingress of water. The additional letter indicates the degree ofprotection for a person against access to hazardous parts. A briefdescription of the additional letter is as follows:

F.2 Arrangement of the IP CodeCode letters (International

Protection)IP

First characteristicnumeral

(numerals 0 to 6, orletter X)

N (or letter X)

Second characteristicnumeral

(numerals 0 to 8, orletter X)

N (or letter X)

Additional letter(optional)

(letters A, B, C, D) L

Supplementary letter(optional)

(letters H, M, S, W) L

Example: IP 23CH

Where a characteristic numeral is not required to be specified, itshall be replaced by the letter “X” (“XX” if both numerals areomitted). Additional letters and/or supplementary letters may beomitted without replacement.


1699

Where more than one supplementary letter is used, the alphabeticsequence shall apply.IPXXA Protected against access with the back of handIPXXB Protected against access with fingerIPXXC Protected against access with a toolIPXXD Protected against access with a wire These letter designations (A, B, C, D) can be used referencingthe protection of live parts while the enclosure is accessed. There isnot a comparable NEMA 250 rating to this application.

Electrical enclosures that carry only an IP rating have not beendesigned to the above additional Type rating requirements.Therefore, a Type rating cannot be assigned to an enclosure thathas only been IP rated because of the exclusion of the additionalrequirements of the Type rating system. However, because the IP requirements can be interpreted to beinclusive to the Type requirements, a conservative IP rating can beassigned to a Type rated enclosure by referencing Table H-1. As a practical matter thought, many electrical enclosures aretested to both the IP and Type requirements and carry both IP andType designations.

Table F.1 – Degrees of protection against access to hazardous parts indicated by the first characteristic numeralFirst

characteristicnumeral

Degree of protection

Brief description Definition0 Non-protected -1 Protected against access to hazardous parts

with the back of a handThe access probe, sphere of 50 mm Ø shall haveadequate clearance from hazardous parts

2 Protected against access to hazardous partswith a finger

The jointed test finger of 12 mm Ø, 80 mmlength, shall have adequate clearance formhazardous parts

3 Protected against access to hazardous partswith a tool

The access probe of 2,5 mm Ø shall not penetrate

4 Protected against access to hazardous partswith a wire

the access probe of 1,0 mm Ø shall not penetrate





Note. – In the case of the first characteristic numeral 3, 4, 5 and 6, protection against access to hazardous parts issatisfied if adequate clearance is kept. Due to the simultaneous requirement specified in Table II the definition “shallnot penetrate” is given in Table I.

Element Numerals orletters

Meaning for the protection ofequipment

Meaning for theprotection of persons

Code letters IP - -First characteristic

numeralsAgainst ingress of solid foreign

objectsAgainst access to

hazardous parts with

0 (non-protected) (non-protected)1 ≥ 50 mm diameter back of hand2 ≥ 12,5 mm diameter finger3 ≥ 2,5 mm diameter tool4 ≥ 1,0 mm diameter wire

5 dust-protected wire6 dust-tight wire

Second characteristicnumeral

Against ingress of water withharmful effects

-

0 (non-protected)1 vertically dripping2 dripping (15° tilted)3 spraying4 splashing5 jetting6 powerful jetting7 temporary immersion8 continuous immersion

Additional letter(optional)

- Against access tohazardous parts with:

A back of handB fingerC toolD wire

Supplementary letter(optional)

Supplementary informationspecific to:

-

H High-voltage apparatusM Motion during water testS Stationary during water testW Weather conditions


1700

A = The First Character Designation is the protection againstaccess to hazardous parts and solid foreign objects. The respectiveNEMA Enclosure Type meets the requirements for the EIC 520 IPFirst Character Designation. B = The IP Second Character Designation is the protectionagainst ingress of water. The respective NEMA Enclosure Typemeets the requirements for the IEC 529 IP second CharacterDesignation. Notes:1. Type rated enclosures for hazardous locations and potentiallyexplosive areas have been excluded from the table. The additionaland supplementary letters for IP ratings have also been excludedfrom the table. (See NEMA 250 / UL 50 and UL 508 and IEC 529 /IEC 60529.)2. Table H-1 shall only be used to assign an IP rating to a Typerated enclosure, and not to assign a Type rating to an IP ratedenclosure. Table H-1 assists in specifying enclosure ratings andshall not be used as a definitive guide. Example: If the conditions of installation require an IP 55, TableH-1 indicates that a Type 3, 3S, 4, 4X, 6, or 6P enclosure can beutilized. However, if the conditions of installation require a NEMAType 4, an enclosure that is only IP rated cannot be used as asubstitute. Note 3 – Although the corresponding NEMA Type ratings meet orexceed the corresponding IP rating as indicated in Table H-1, IECdoes not currently accept these ratings without further IEC testing.SUBSTANTIATION: Required for the understanding of IPdesignations.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE:

___________________(Log #71)

79- 169 - (Annex F1 [4.4.2]): AcceptSUBMITTER: John B. Deam, Rep. The Association forManufacturing TechnologyRECOMMENDATION: Modify rewrite of 1997 NFPA 79, AnnexF1 that is new Clause 4 in 4.4.2. In the last paragraph of proposed new clause 4.4.2 starting with"The effects of interference..." delete the last bullet and associatedwording. The bullet begins with the words "Europeanstandards...".SUBSTANTIATION: The standards noted areEuropean/International standards for which there are no identifieddomestic counterparts. This bullet does not provide U.S.requirements.COMMITTEE ACTION: Accept.COMMITTEE STATEMENT: The committee understands that thisproposal modifies the Action on Proposal 79-24 (Log #60) [Clause4]. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE:26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 Norman

EXPLANATION OF NEGATIVE:SAUNDERS: The references to the European Standards in ANNEXare for information only and are not a requirement, and thereforeshould remain as an appropriate reference.COMMENT ON AFFIRMATIVE: ANDERSON: I believe the committee action taken was doneunder the impression that the item to be deleted was part of astandard requirement. In reality all of subsection 4.4.2"Electromagnetic compatibility (EMC)" is a "note" and probablyshould be listed as a note similar to the long list of notes near theend of chapter 9 or an editor's note indicating all the informationunder 4.4.2 became a non mandatory note. The submitter is correct in that the bullet does not provide U.S.requirements, and maybe they should be added. But for machinebuilders using harmonized standards the offending bullet is goodintroduction to information about international requirements forEMC limits, should they wish to design to a broader market.Because the information is in a note form and not a requirement,those wishing to design and market to only the North Americanmarket are free to do so. I do not understand the proposer's objection to allowing theinformation to remain in the standard, unless he also mistakenlythought it was a requirement given the proposal's substantiation,and the fact later in the process all of the material became a notethat was placed under an apparent required sub section [4.4.2]. I believe the bullet should remain as part of the note materialdescribing EMC.

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(Log #44)79- 170 - ([Annex G (New)]): AcceptSUBMITTER: John F. Bloodgood, JFB EnterprisesRECOMMENDATION: Add new Annex G to assist with theunderstanding of certain text in Clause 15.Annex G (informative): Kilowatt Outputs with HorsepowerequivalentsG.1 Preferred kilowatt outputs with horsepower equivalents The kilowatt and horsepower values shown are not exactconversion values. They give the approximate relationships betweencountries employing the two different systems of units.Note:

1. IEC 60072-1 Annex D tables D.5.1 and D.5.2, Sixth Edition1991-2, are provided to assist with hp and kW r

2. The kW-hp conversions are approximately 1 hp = 720 W, notthe stated 746 W nor even the rounded off metric unitswhich result in 736 W.

kWPrimary Series Secondary Series

hp(746W)

0,06 1/120,09 1/80,12 1/60,18 1/40,25 1/30,37 1/20,55 3/40,75 11,1 1,51,5 1,8 22,2 33,7 3 5

Table F.2 – Assignment of IP ratings to type rated enclosuresA B

NEMA enclosure typeIPFirst

character1 2 3 3R 3S 4 4X 5 6 6P 12 12K 13

IPSecond

characterIP0_ AB AB AB AB AB AB AB AB AB AB AB AB AB IP_OIP1_ A AB AB AB AB AB AB AB AB AB AB AB AB IP_1IP2_ B AB B AB AB AB AB AB AB AB AB AB IP_2IP3_ AB B AB AB AB AB AB AB AB AB AB IP_3IP4_ AB B AB AB AB AB AB AB AB AB AB IP_4IP5_ AB AB AB AB A AB AB A A A IP_5IP6_ A A AB AB AB AB IP_6

B B IP_7B IP_8


1701

kW hp(746W)Primary Series Secondary Series

45,5 7,5

6,37,5 10

1011 15

1315 20

1718,5 25

2022 30

2530 40

3337 50

4045 60

5055 75

6375 100

8090 125

100110 150

125132 175150 200160 220185 250200 270220 300250 350280 375300 402315 422335 449355 476375 503400 536425 570450 603475 637500 670530 710560 750600 804630 845670 898710 952750 1005800 1072850 1139900 1206950 12731000 1340

G.2 Preferred horsepower with kilowatt equivalents

1)This value is introduced for use in certain countries that preferrounded off horsepower values.

The notes are to inform the user that additional information isnecessary in order to properly exchange motors.

SUBSTANTIATION: IEC 60072-1 Annex D tables D.5.1 and D.5.2Sixth Edition 1991-2 are provided to assist with hp and kW motorrelationships.COMMITTEE ACTION: Accept.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 25 NOT RETURNED: 1 Norman

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(Log #139)79- 171 - (Annex (New) [Annex X New]): RejectSUBMITTER: John Freudenberg , Teradyne/Rep. NortheastProduct Safety Society (NPSS)RECOMMENDATION: Add a complete copy of IEC60204 as anannex in the back of the NFPA 79 document.SUBSTANTIATION: The harmonization effort did not align allrequirements and rarely used identical text. Providing NFPA 79 &IEC60204 will provide one source for a complete superset ofelectrical machinery requirements suitable for use worldwide.Providing one source with both NFPA & IEC text would helpeducate users of similarities and differences.COMMITTEE ACTION: Reject.COMMITTEE STATEMENT: This is an admistrative decision tobe made by the Standards Administration apart from thecommittee process. The committee is concerned that by includingIEC 60204-1 in this document, it would substantially increase thecost of the document.NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 26VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 24 NEGATIVE: 1 NOT RETURNED: 1 NormanEXPLANATION OF NEGATIVE: FREUDENBERG: The committee should be on record aswanting to include a copy of IEC60204-1, otherwise, the StandardsAdministration has no reason to make a decision. The costs havenot been determined and the current NFPA viewpoint is aninternal perspective of costs. NFPA may be able to provide bothNFPA79 andIEC60204 as a set faster and cheaper than users ofNFPA79 can obtain one documents from NFPA and theinternational IEC60204-1 document from another source.COMMENT ON AFFIRMATIVE: DOBROWSKY: I do not support combining both standards intoone but would support the option of purchasing both standards(as a package of two separate standards) hopefully at a reducedcost.

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See the draft of NFPA 79 shown at the end of this book starting onpage 1835.

hp(746W) kW hp(746W) kW375 280 710 530400 298 750 560425 317 800 597450 336 850 634475 354 900 671500 373 950 709530 395 1000 746560 418 1060 791600 448 1120 836630 470 1180 880670 500 1250 930

7001) 522 1320 985

NFPA 79 — May 2002 ROP — DRAFT — Copyright 2001, NFPA

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NFPA 79

Electrical Standard for Industrial Machinery

2002 Edition

Chapter 1 Administration

1.1* Scope. 1.1.1 The provisions of this standard shall apply to the electrical/electronic equipment, apparatus, or systems of industrial machines operating from a nominal voltage of 600 volts or less, and commencing at the point of connection of the supply to the electrical equipment of the machine. 1.1.2 This standard shall not include the additional requirements for machines intended for use in hazardous (classified) locations. 1.2 Purpose. This standard shall provide detailed information for the application of electrical/electronic equipment, apparatus, or systems supplied as part of industrial machines that will promote safety to life and property. 1.3 Application. This standard shall not apply to the following:

(1) Fixed or portable tools judged under the requirements of a testing laboratory acceptable to the authority having jurisdiction

(2) Machines used in dwelling units

1.4 Specific Provisions Other Than NFPA 79. The size and overcurrent protection of the supply conductors to a machine shall be covered by NFPA 70, National Electrical Code , Article 670. The wiring between component machines of an industrial manufacturing system shall be covered by NFPA 70, National Electrical Code. Exception: Wiring of component machines of an industrial manufacturing system that is supplied by the manufacturer and is an integral part of the system, is adequately protected and supported, and meets the requirements of this standard. 1.5* Specific Provisions Not Made Relation to NFPA 70. On any point for which specific provisions are not made in this standard (e.g., some requirements for the application of Design E motors) the provisions of NFPA 70, National Electrical Code, shall be observed. 1.6 State of the Art. This standard shall not limit or inhibit the advancement of the state of the art. Each type of machine has unique requirements that shall be accommodated to provide adequate safety. [ROP 79-8 (Log 35)]

Chapter 2 Referenced Publications 2.1 General. 2.1.1 NFPA Publication. National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101.

NFPA 70, National Electrical Code®, 2002 edition. 2.1.2 Other Publications. 2.1.2.1 ANSI Publication. American National Standards Institute, Inc., 11 West 42nd Street, 13th floor, New York, NY 10036.

ANSI Z 535, Product Safety Signs and Labels, 1998. 2.1.2.2 ASTM Publications. American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

ASTM B 8, Standard Specification for Concentric - Lay - Stranded Copper Conductors Hard, Medium-Hard, or Soft, 1999.

ASTM B 174, Standard Specification for Bunch-Stranded Copper Conductors for Electrical Conductors, 1995.

ASTM B 286, Standard Specification for Copper Conductors for Use in Hookup Wire for Electronic Equipment, 1995. 2.1.2.3 IEC Publications. International Electrotechnical Commission, 3 rue de Varembe, P.O. Box 131, 1211 Geneva 20, Switzerland.

IEC 60072-1, Dimensions and output series for rotating electrical machines Part 1, 1991.

IEC 60072-2, Dimensions and output series for rotating electrical machines Part 2, 1990. 2.1.2.4 IEEE Publication. Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331.

IEEE 315, Graphical Symbols for Electrical and Electronics Diagrams, 1994. 2.1.2.5 NEMA Publications. National Electrical Manufacturers Association, 1300 N. 17th Street, Suite 1847, Rosslyn, VA 22209.

NEMA ICS 2, Industrial Control and Systems, Controllers, Contactors, and Overload Relays Rated Not More Than 2000 Volts AC or 750 Volts DC, 1993.

NEMA MG-1, Motors and Generators, 1998. 2.1.2.6 UL Publications. Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062.

UL 50, Standard for Safety Enclosures for Electrical Equipment, 1995. UL 508, Standard for Safety Industrial Control Equipment, 1999. UL 870, Standard for Safety Wire Ways, Auxiliary Gutters and

Associated Fittings, 1995. UL 991, Standard for Safety Tests for Safety-Related Controls Employing

Solid State Devices, 1995. UL 1063, Standard for Safety Machine - Tool Wires and Cables, 1998. UL 1998, Standard for Safety Software in Programmable, 1998.

Chapter 3* Definitions

3.1* General. The definitions contained in this chapter shall apply to the terms used in this standard. Where terms are not included, common usage of the terms shall apply. 3.2 NFPA Official Definitions. 3.2.1* Approved. Acceptable to the authority having jurisdiction. 3.2.2* Authority Having Jurisdiction. The organization, office, or individual responsible for approving equipment, materials, an installation, or a procedure. 3.2.3 Labeled. Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is


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acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner. 3.2.4* Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. 3.2.5 Shall. Indicates a mandatory requirement. 3.2.6 Should. Indicates a recommendation or that which is advised but not required. 3.3 General Definitions. 3.3.1 Accessible (as applied to equipment). Admitting close approach; not guarded by locked doors, elevation, or other effective means. [70:100] 3.3.2 Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections, without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, etc. [70:100] 3.3.3* Actuator. The part of the actuating system to which an external actuating force is applied. 3.3.3.1 Machine Actuator. A power mechanism used to effect motion of the machine. 3.3.4* Adjustable Speed Drives. An electrical device or group of electrical devices that alters the drive motor output speed over a range in a controlled manner. 3.3.5* Ambient Temperature. The temperature of the air or other medium where the equipment is to be used. 3.3.6 Ampacity. The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. [70:100] 3.3.7 Attachment Plug (Plug Cap) (Plug). A device that, by insertion in a receptacle, establishes a connection between the conductors of the attached flexible cord and the conductors connected permanently to the receptacle. [70:100] 3.3.8 Barrier. A physical obstruction that is intended to prevent contact with equipment or live parts or to prevent unauthorized access to a work area. [70E:I-2.1] 3.3.9* Bonding (Bonded). The permanent joining of metallic parts to form an electrically conductive path that will ensure electrical continuity and the capacity to conduct any current likely to be imposed. [70:100] 3.3.10 Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s). [70:100]

3.3.11 Cable Tray System. A unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways. [70:392.2] 3.3.12* Cable Trunking System. A system of enclosures comprised of a base and a removable cover intended for the complete surrounding of insulated conductors, cables, and cords. 3.3.13 Circuit Breaker. A device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating. [70:100] 3.3.14 Concurrent. Acting in conjunction; used to describe a situation wherein two or more control devices exist in an actuated condition at the same time (but not necessarily simultaneously). 3.3.15 Conduit. 3.3.15.1 Intermediate Metal Conduit. A listed steel raceway of circular cross-section with integral or associated couplings, connectors, and fittings approved for the installation of electrical conductors and used with listed fittings to provide electrical continuity. [70:342.2] 3.3.15.2 Rigid Metal Conduit. Rigid metal conduit is a listed metal raceway of circular cross section with integral or associated couplings, approved for the installation of electrical conductors and used with listed fittings to provide electrical continuity. [70:344.2] 3.3.15.3 Rigid Nonmetallic Conduit. A type of conduit and fittings of suitable nonmetallic material that is resistant to moisture and chemical atmospheres, flame retardant, resistant to impact and crushing, and resistant to distortion from heat or low temperatures under conditions likely to be encountered in service. [70:352.2] 3.3.16 Contact. 3.3.16.1 Direct Contact. Contact of persons with live parts. 3.3.16.2 Indirect Contact. Contact of persons with exposed conductive parts that have become live under fault conditions. 3.3.17* Control Circuit (of a machine). The circuit of a control apparatus or system that carries the electric signals directing the performance of the controller but does not carry the main power current. 3.3.18 Control Circuit Transformer. A voltage transformer utilized to supply a voltage suitable for the operation of control devices. 3.3.19 Control Circuit Voltage. The voltage utilized for the operation of control devices. 3.3.20 Control Device. A device connected into the control circuit and used for controlling the operation of the machine (e.g., position sensor, manual control switch, relay, magnetically operated valve). 3.3.21 Control Equipment. Operating elements, such as relays, contactors, circuit breakers, switches, solenoids, brakes, and similar types of components, intended to govern or perform a given function in the operation, including measuring, sensing, monitoring, protecting, and regulating of machinery.


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3.3.22 Controller. A device or group of devices that serves to govern, in some predetermined manner, the electric power delivered to the apparatus to which it is connected. [70:100] 3.3.23 Cord (Flexible). Cords that are constructed as described in and listed for use in accordance with Article 400 of NFPA 70, National Electrical Code. All conductors are stranded copper. 3.3.24 Device. A unit of an electrical system that is intended to carry but not utilize electric energy. [70:100] 3.3.25 Digital. Operated by the use of discrete signals to represent data in the form of numbers or other characters. 3.3.26 Disconnecting Means. A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply. [70:100] 3.3.27* Duct. An enclosed channel designed expressly for holding and protecting electrical conductors, cables, and bus bars. 3.3.28 Dwelling Unit. One or more rooms for the use of one or more persons as a housekeeping unit with space for eating, living, and sleeping, and permanent provisions for cooking and sanitation. [70:100] 3.3.29 Earth. See 3.3.46, Ground. 3.3.30 (Electrically) Instructed Person. A person adequately advised or supervised by an electrically skilled person to enable him or her to perceive risks and to avoid hazards that electricity can create. 3.3.31 (Electrically) Skilled Person. A person with relevant education and experience to enable him or her to perceive risks and to avoid hazards that electricity can create. 3.3.32 Electrical Operating Area. A room or location for electrical equipment to which access is intended to be restricted to skilled or instructed persons by the opening of a door or the removal of a barrier without the use of a key or tool, and that is clearly marked by appropriate warning signs. 3.3.33 Electromechanical. Any device in which electrical energy is used to magnetically cause mechanical movement. 3.3.34 Electronic Equipment. That part of electrical equipment containing circuitry mainly based on electronic devices and components. 3.3.35 Emergency Switching Off. An emergency operation intended to switch off the supply of electrical energy to all or a part of an installation where a risk of electric shock or another risk of electrical origin is involved. 3.3.36 Enclosed Electrical Operating Area. A room or location for electrical equipment to which access is intended to be restricted to skilled or instructed persons by the opening of a door or the removal of a barrier by the use of a key or tool, and that is clearly marked by appropriate warning signs. 3.3.37 Enclosure. A surrounding case constructed to provide a degree of protection against incidental contact with the enclosed equipment and to provide a degree of protection to the enclosed equipment against specified environmental conditions.

3.3.38 Energized. Electrically connected to a source of potential difference [70:100] 3.3.39 Equipment. A general term including material, fittings, devices, appliances, fixtures, apparatus, and the like used as part of, or in connection with, an electrical installation. [70:100] 3.3.40 Exposed (as applied to live parts). Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to parts not suitably guarded, isolated, or insulated. [70:100] 3.3.41* Failure (of equipment). The termination of the ability of an item to perform a required function. 3.3.42* Fault. The state of an item characterized by inability to perform a required function, excluding the inability, during preventive maintenance or other planned actions, or due to lack of external resources. 3.3.43 Feeder. All circuit conductors between the service equipment or the source of a separately derived system and the final branch circuit overcurrent device. [70:100] 3.3.44 Flame Retardant. So constructed or treated that it will not support flame. 3.3.45 Flexible Metal Conduit. A raceway of circular cross section made of helical wound, formed, and interlocked metal strip. 3.3.45.1 Liquidtight Flexible Metal Conduit. A raceway of circular cross section having an outer liquidtight, nonmetallic, sunlight-resistant jacket over an inner flexible metal core with associated couplings, connectors, and fittings and approved for the installation of electric conductors. 3.3.46 Ground. A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth. [70:100] 3.3.47 Grounded. Connected to earth or to some conducting body that serves in place of the earth. [70:100] 3.3.48 Grounded Conductor. A system or circuit conductor that is intentionally grounded. [70:100] 3.3.49 Grounding Conductor. A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes. [70:100] 3.3.50 Grounding Conductor, Equipment. The conductor used to connect the noncurrent-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or at the source of a separately derived system. [70:100] 3.3.51 Grounding Electrode Conductor. The conductor used to connect the grounding electrode to the equipment grounding conductor, to the grounded conductor, or to both, of the circuit at the service equipment or at the source of a separately derived system. [70:100] 3.3.52* Guard. Part of a machine specifically used to provide protection by means of a physical barrier.


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3.3.53 Hazard. A source of possible injury or damage to health. 3.3.54 Hazardous Condition. A circumstance in which a person is exposed to a hazard(s) that has the potential to result in harm immediately or over a long period of time. 3.3.55* Identified (as applied to equipment). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular code requirement. [70:100] 3.3.56 In Sight From, Within Sight From, Within Sight. Where this standard specifies that one equipment shall be "in sight from," "within sight from," or "within sight," etc., of another equipment, one of the equipments specified is to be visible and not more than 50 ft (15.24 m) distant from the other. [70:100] 3.3.57 Industrial Machinery (Machine). A power-driven machine (or a group of machines working together in a coordinated manner), not portable by hand while working, that is used to process material by cutting; forming; pressure; electrical, thermal, or optical techniques; lamination; or a combination of these processes. Machine can include associated equipment used to transfer material or tooling, including fixtures, to assemble/disassemble, to inspect or test, or to package. [The associated electrical equipment, including the logic controller(s) and associated software or logic together with the machine actuators and sensors, are considered as part of the industrial machine.] [70:670.2] 3.3.58 Industrial Manufacturing System. A systematic array of one or more industrial machines that is not portable by hand and includes any associated material handling, manipulating, gauging, measuring, or inspection equipment. [70:670.2] 3.3.59 Input. The terminals where current, voltage, power, or driving force may be applied to a circuit or device; the state or sequence of states occurring on a specific input channel; or the device or collective set of devices used for bringing data into another device. 3.3.60 Inrush Current (Solenoid). The inrush current of a solenoid is the steady-state current taken from the line at rated voltage and frequency with the plunger blocked in the rated maximum open position. 3.3.61 Inrush Locked Rotor Current (Motor). See 3.3.68 Locked Rotor Motor Current. 3.3.62 Interlock (for safeguarding). An arrangement that interconnects guard(s) or device(s) with the control system or all or part of the electrical energy distributed to the machine. 3.3.63* Interrupting Rating. The highest current at rated voltage that a device is intended to interrupt under standard test conditions. [70:100] 3.3.64 Jogging (Inching). The quickly repeated closure of the circuit to start a motor from rest for the purpose of accomplishing small movements of the driven machine. 3.3.65 Live Parts. Energized conductive components. [70:100] 3.3.66 Liquidtight Flexible Nonmetallic Conduit. A nonmetallic raceway of circular cross section of oil-, water-, and flame-resistant construction and fittings for the installation of electrical conductors.

3.3.67 Location. 3.3.67.1* Dry Location. A location not normally subject to dampness or wetness. [70:100] 3.3.67.2 Wet Location. Installations underground or in concrete slabs or masonry in direct contact with the earth; and in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather. [70:100] 3.3.68 Locked Rotor Motor Current. The steady-state current taken from the line with the rotor locked and with rated voltage (and rated frequency in the case of alternating-current motors) applied to the motor. 3.3.69 Marking. Signs or inscriptions attached by the manufacturer, for the identification of the type of a component or device. 3.3.70 Neutral Conductor. A conductor connected to the neutral point of a system and capable of contributing to the transmission of electrical energy. 3.3.71 Obstacle. A part preventing unintentional direct contact, but not preventing direct contact by deliberate action. 3.3.72 Output. The terminals where current, voltage, power, or driving force may be delivered by a circuit or device; the state or sequence of states occurring on a specific output channel; or the device or collective set of devices used for taking data out of another device. 3.3.73 Overcurrent. Any current in excess of the rated current of equipment or the ampacity of the conductor. It may result from overload, short circuit, or electrical fault. [70:100] 3.3.74* Overload. Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or a ground fault, is not an overload. [70:100] 3.3.75 Panel. An element of an electric controller consisting of a slab or plate on which various component parts of the controller are mounted and wired. 3.3.76 Plug/Socket Combination. A plug and socket outlet, a cable coupler, or an appliance coupler. 3.3.77 Point of Operation. The location in the (machine) where the material or workpiece is positioned and work is performed. 3.3.78 Positive Opening Operation (of a contact element). The achievement of contact separation as the direct result of a specified movement of the switch actuator through nonresilient members (e.g. not dependent upon springs). 3.3.79 Power Circuit. A circuit used for supplying power from the supply network to units of equipment used for productive operation and to transformers supplying control circuits. 3.3.80* Programmable Electronic System. A system based on one or more central processing units (CPUs), connected to sensors or actuators, or both, for the purpose of control or monitoring.


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3.3.81* Protective Bonding Circuit. The whole of the protective conductors and conductive parts used for protection against electric shock in the event of an insulation failure. 3.3.82 Protective Conductor. A conductor required by some measures for protection against electric shock for electrically connecting exposed conductive parts, extraneous conductive parts, or main earthing terminal. 3.3.83* Qualified Person. At a minimum, a qualified person shall be trained and knowledgeable of the construction and operation of equipment or a specific work method, and be trained to recognize and avoid the electrical hazards that might be present with respect to that equipment or work method. Such persons shall also be familiar with the proper use of special precautionary techniques, personal protective equipment, insulating and shielding materials, and insulated tools and test equipment. 3.3.84 Raceway. An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this standard. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways. [70:100] 3.3.85 Receptacle. A contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke. [70:100] 3.3.86 Redundancy. The application of more than one device or system, or part of a device or system, with the objective of ensuring that in the event of one failing to perform its function another is available to perform that function. 3.3.87 Reference Designation. A distinctive code that serves to identify an item in a diagram, list, chart, and on the equipment. 3.3.88 Relative Humidity. The ratio between the amount of water vapor in the gas at the time of measurement and the amount of water vapor that could be in the gas when condensation begins, at a given temperature. 3.3.89 Risk. A combination of the probability and the degree of possible injury or damage to health in a hazardous situation. 3.3.90 Safeguard. A guard or protective device used as a safety measure to protect persons from a present or impending hazard. 3.3.91 Safeguarding. Those safety measures consisting of the use of specific means called safeguards to protect persons from hazards that cannot reasonably be removed or are not sufficiently limited by design. 3.3.92 Safety Control Circuit. The part of the control circuit that incorporates safety related components. [ROP 79-16 (Log 154)] 3.3.93 Safety Distance. The distance between the pinch point or point-of-operation and the presence-sensing safety device (PSSD) sensing field that ensures that the operator cannot reach the danger point before the machine comes to a full stop.

3.3.94 Safety Function (Safety Measure). A means that eliminates or reduces a hazard. 3.3.95 Safe Working Procedure. A method of working that reduces risk. 3.3.96 Servicing Level. Location on which persons normally stand when operating or maintaining the electrical equipment. 3.3.97 Short-Circuit Current. An overcurrent resulting from a short circuit due to a fault or an incorrect connection in an electric circuit. 3.3.98 Socket. See 3.3.85 Receptacle. 3.3.99 Stop. 3.3.99.1 Controlled Stop. The stopping of machine motion, while retaining power to the machine actuators during the stopping process. 3.3.99.2 Uncontrolled Stop. The stopping of machine motion by removing power to the machine actuators, all brakes and/or other mechanical stopping devices being activated. 3.3.100 Subassembly. An assembly of electrical devices connected together that forms a simple functional unit. 3.3.101 Subplate. An internal metal surface separate from the walls of an enclosure or controller on which various component parts of the controller are mounted and wired. 3.3.102* Supplementary Overcurrent Protective Device. A device used where protection is required for lighting fixtures, appliances, and other equipment or for internal circuits and components of equipment. 3.3.103* Supplier. An entity (e.g., manufacturer, contractor, installer, integrator) that provides equipment or services associated with the machine. 3.3.104 Switching Device. A device designed to make or break the current in one or more electric circuits. 3.3.105 Tap Conductor. A conductor that has overcurrent protection ahead of its point of supply, that exceeds the value permitted for similar conductors that are protected as described elsewhere in this standard. [70:240-2] 3.3.106 Terminal. A conductive part of a device provided for electrical connection to circuits external to the device. 3.3.107 Tight (suffix). So constructed that the specified material is excluded under specified conditions. 3.3.108* Undervoltage Protection. The effect of a device that operates on the reduction or failure of voltage to cause and maintain the interruption of power. 3.3.109* User. An entity that utilizes the machine and its associated electrical equipment. [ROP 79-14 (Log 49)] 3.3.110 Ventilated. Provided with a means to permit circulation of air sufficient to remove excess heat, fumes, or vapors. [70:100]


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3.3.111 Voltage, Nominal. A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (e.g., 120/240 volts, 480Y/277 volts, 600 volts). The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment. [70:100] 3.3.112 Wireway. A sheet-metal or flame-retardant nonmetallic trough with hinged or removable covers for housing and protecting electric wires and cable and in which conductors are laid in place after the wireway has been installed as a complete system. [70:______] [ROP 79-11(Log 37)]

Chapter 4 General Operating Conditions 4.1* General Considerations. This chapter describes the general requirements and conditions for the operation of the electrical equipment of the machine. The risks associated with the hazards relevant to the electrical equipment shall be assessed as part of the overall requirements for risk assessment of the machine. 4.2 Electrical Components and Devices. Electrical components and devices shall be installed and used assuming the operating conditions of ambient temperature, altitude, humidity, and supply voltage outlined in this chapter, and within their design ratings, taking into account any derating stipulated by the component or device manufacturer. 4.3 Electrical Supply. 4.3.1* General. The electrical equipment shall be designed to operate correctly with the conditions of the supply as specified according to one of the following:

(1) The requirements in 4.3.2, 4.3.3, and 4.3.4 (2) The requirements specified by the user (3) The requirements specified by the supplier

4.3.2* Alternating Current (ac) Supplies. 4.3.2.1 Voltage. The electrical equipment shall be designed to operate correctly where the steady state supply voltage is from 90 percent to 110 percent of the nominal voltage. 4.3.2.2 Frequency. The electrical equipment shall be designed to operate correctly where the supply frequency is from 99 percent to 101 percent of the nominal frequency continuously. For short periods of time, the supply frequency shall be permitted to be from 98 percent to 102 percent of the nominal frequency. 4.3.2.3 Harmonics. The electrical equipment shall be designed to operate correctly where the harmonic distortion from the electric supply does not exceed 10 percent of the total voltage (rms value) between ungrounded conductors for the sum of the second through fifth harmonic. An additional percent of the voltage (rms value) between ungrounded conductors for the sum of the sixth through thirtieth harmonic shall be permitted. 4.3.2.4 Voltage Unbalance (in 3-Phase Supplies). The electrical equipment shall be designed to operate correctly where neither the voltage of the negative sequence component nor the voltage of the zero sequence component in 3-phase supplies exceeds 2 percent of the voltage of the positive sequence component.

4.3.2.5 Voltage Impulses. The electrical equipment shall be designed to operate correctly where the supply voltage impulses do not to exceed 1.5 milliseconds in duration with a rise/fall time between 500 nanoseconds and 500 microseconds. A peak supply voltage impulse shall not exceed more than 200 percent of the rated supply voltage (rms value). 4.3.2.6 Voltage Interruption. The electrical equipment shall be designed to operate correctly where the supply voltage is interrupted at zero voltage for not more than 3 milliseconds at any random time in the supply cycle. The time interval between successive voltage interruptions shall be more than 1 second. 4.3.2.7 Voltage Dips. The electrical equipment shall be designed to operate correctly where the supply voltage dips do not exceed 20 percent of the peak voltage of the supply for more than one cycle. The time interval between successive dips shall be more than 1 second. 4.3.3 Direct Current (dc) Supplies from Batteries. 4.3.3.1 Voltage. The electrical equipment shall be designed to operate correctly where the dc supply voltage of batteries is from 85 percent to 115 percent of the nominal voltage. A supply voltage from 70 percent to 120 percent of the nominal voltage shall be permitted for dc supplies to battery-operated vehicles. 4.3.3.2 Voltage Interruption. The electrical equipment shall be designed to operate correctly where the dc supply voltage of batteries is interrupted for a time interval not exceeding 5 milliseconds. 4.3.4 Direct Current (dc) Supplies from Converting Equipment. 4.3.4.1 Voltage. The electrical equipment shall be designed to operate correctly where the dc supply voltage of converting equipment is from 90 percent to 110 percent of the nominal voltage. 4.3.4.2 Voltage Interruption. The electrical equipment shall be designed to operate correctly where the dc supply voltage of converting equipment is interrupted for a time interval not exceeding 20 milliseconds. The time interval between successive voltage interruptions shall be more than 1 second. 4.3.4.3 Ripple (Peak-to-Peak). The electrical equipment shall be designed to operate correctly where the dc supply voltage ripple (peak-to-peak value) of converting equipment does not exceed 0.05 of the nominal voltage. 4.4* Physical Environment and Operating Conditions. 4.4.1* General. The electrical equipment shall be suitable for use in the physical environment and operating conditions specified in 4.4.3 to 4.4.6 and 4.4.8. When the physical environment or the operating conditions are outside those specified, an agreement between the supplier and the user shall be considered. 4.4.2* Electromagnetic Compatibility (EMC). 4.4.3* Ambient Operating Temperature. Electrical equipment shall be capable of operating correctly in the intended ambient air temperature. The ambient operating temperatures for correct operation of the electrical equipment shall be between air temperatures of 5°C and 40°C (41°F to 104°F). [For very hot environments (e.g., hot climates, steel mills, paper mills) and for cold environments, extra requirements may be necessary.]


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4.4.4* Relative Humidity. The electrical equipment shall be capable of operating within a relative humidity range of 20 to 95 percent (noncondensing). Harmful effects of relative humidity outside the permitted range shall be avoided by proper design of the equipment or, where necessary, by proper additional measures (e.g., built-in heaters, air conditioners, humidifiers). 4.4.5* Altitude. Electrical equipment shall be capable of operating correctly at altitudes up to 1000 m (3300 ft) above mean sea level. 4.4.6* Contaminants. Electrical equipment shall be adequately protected against the ingress of solid bodies and liquids (see Section 12.3). Equipment shall be suitable for the environment where contaminants (e.g., dust, acids, corrosive gases, salt) are present. 4.4.7* Nonionizing Radiation. 4.4.8 Vibration, Shock, and Bump. Undesirable effects of vibration, shock, and bump, including those generated by the machine and its associated equipment and those created by the physical environment shall be avoided by the selection of suitable equipment, by mounting it away from the machine, or by the use of antivibration mountings. 4.5 Transportation and Storage. The electrical equipment shall be designed to withstand storage and transportation temperatures within the range of -25°C to 55°C (-13°F to +131°F) and up to 65°C (149°F) for short periods not exceeding 24 hours. Suitable means shall be provided to prevent damage from excessive moisture, vibration, stress, and mechanical shock during shipment. 4.6 Provisions for Handling. Heavy and bulky electrical equipment that has to be removed from the machine for transport or that is independent of the machine shall be provided with suitable means for handling by cranes or similar equipment. 4.7 Installation and Operating Conditions. The electrical equipment shall be installed and operated in accordance with the manufacturer's instructions. Any conditions that are outside the operating conditions specified in Chapter 4 shall be permitted where acceptable to both the manufacturer and user. [ROP 79-24 (Log 60)]

Chapter 5 Incoming Supply Circuit Conductor Terminations and Devices for Disconnecting and Removing Power

5.1 Incoming Supply Circuit Conductor Terminations. 5.1.1* Where practicable, the electrical equipment of a machine shall be connected to a single power supply circuit . Where it is necessary to use another supply circuit for certain parts of the equipment (e.g., electronic circuits, electromagnetic clutches), that supply circuit shall, as far as is practicable, be derived from devices (e.g., transformers, converters) forming part of the electrical equipment of the machine. 5.1.2 Connections to guarded terminal blocks or other devices ahead of the disconnecting means shall be permitted for excepted circuits according to 5.3.5. Terminals for more than one conductor shall be so identified. 5.1.3* Where a grounded conductor is used it shall be clearly indicated in the technical documentation of the machine, such as in the installation diagram and in the circuit diagram. A separate insulated terminal shall be provided for the grounded conductor.

5.1.4 All terminals for the incoming supply circuit connection shall be legibly marked. 5.2* Grounding Terminal. A grounding terminal shall be provided for each incoming supply circuit. 5.3 Supply Circuit Disconnecting (Isolating) Means. 5.3.1 General. 5.3.1.1 A supply circuit disconnecting means shall be provided for the following:

(1) Each incoming supply circuit to a machine (2) The supply circuit to a feeder system using collector wires,

collector bars, slip-ring assemblies, or flexible cable systems (reeled, festooned) to a machine or a number of machines

(3) Each on-board power source (e.g., generator)

5.3.1.1.1 Each disconnecting means required by 5.3.1.1 shall be legibly marked to indicate its purpose. 5.3.1.1.2 Where a machine is supplied by more than one supply circuit, a marking shall be installed at each supply circuit disconnect location denoting the location of all other supply circuit disconnects. 5.3.1.2 The supply circuit disconnecting means shall disconnect (isolate) the electrical equipment of the machine, including all control circuits, from the supply circuit when required (e.g., for work on the machine, including the electrical equipment). Circuits that are not required to be disconnected by the supply circuit disconnecting means shall comply with 5.3.5. 5.3.1.3 The supply circuit disconnecting means other than attachment plugs and receptacles shall be mounted within the control enclosure or immediately adjacent thereto. Exception: Externally mounted supply circuit disconnecting means, whether interlocked or not interlocked with the control enclosure, supplying machines totaling 2 hp or less shall be permitted to be mounted up to 6.56 m (20 ft) away from the enclosure providing that the disconnecting means is in sight from and readily accessible to the operator.

Supply circuit disconnecting means mounted within or adjacent to the control enclosure shall be interlocked with the control enclosure in accordance with 6.2.3. Where the supply circuit disconnecting means is not adjacent to the control enclosure, or where the supply disconnecting means is an attachment plug and receptacle, a tool shall be required to open the control enclosure door. A label shall be attached to that door warning of dangerous voltage inside and advising disconnection of the power before opening. 5.3.1.4 Wire bending space shall be provided for the supply circuit disconnecting means in accordance with 430.10(B) of NFPA 70, National Electrical Code. Space shall be determined by maximum wire size of incoming lines or by maximum capacity of line lugs on the disconnecting means. Accidental contact with the line side live parts shall be inhibited. The supply circuit conductors to the disconnecting means shall be separated from other internal conductors by either of the following:

(1) Mounting the disconnect as near as practicable to the top of the enclosure while dedicating sufficient space between the top of the enclosure and the disconnect for the supply circuit conductors; or


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(2) Mounting the disconnect other than at the top of the enclosure and guarding its line side live parts against accidental contact, and by separating the supply circuit conductors from other internal conductors by the use of a barrier. 5.3.1.5 The supply circuit disconnecting means shall have no exposed live parts while in the open (off) position, except those associated with the circuits described in 5.3.5. 5.3.1.6 Where two or more disconnecting means are provided within the control enclosure for multiple supply circuits, they shall be grouped in one location where practicable. Protective interlocks for their correct operation shall be provided where a hazardous condition or damage to the machine or to the work in progress can occur. [ROP 79-35 (Log 142)] 5.3.2 Type. The supply circuit disconnecting device shall be one of the following types:

(1) A listed motor circuit switch (switch disconnector) rated in horsepower

(2) A listed, branch circuit-rated, molded case circuit breaker (3) A listed molded case switch (4) An instantaneous trip circuit breaker that is part of a listed

combination motor controller (5) A listed self-protected combination controller limited to

single motor applications (6) An attachment plug and receptacle (plug/socket

combination) for cord connection to motor loads totaling 2 hp or less [ROP 79-34 (Log 30)] 5.3.3 Requirements.

5.3.3.1 Where the supply circuit disconnecting device is one of the types in 5.3.2 (1) through (5), the device shall fulfill all of the following requirements:

(1) Isolate the electrical equipment from the supply circuit and

have one off (isolated) and one on position only. Circuit breakers are permitted to have a reset (tripped) position between off and on.

(2) Have an external operating means (e.g., handle). Exception: Power-operated switchgear need not be operable from outside the enclosure where there are other means to open it.

(3) Be provided with a permanent means permitting it to be

locked in the open (off) (isolated) position only (e.g., by padlocks) independent of the door position. When so locked, remote as well as local closing shall be prevented.

(4) Simultaneously disconnect all ungrounded conductors of the power supply circuit.

(5) Be operable, by qualified persons, independent of the door position without the use of accessory tools or devices.

(6) Be rated for the application as follows: a. The ampere rating shall be at least 115 percent of the sum

of the full-load currents required for all equipment that may be in operation at the same time under normal conditions of use.

b. Where rated in horsepower, the horsepower rating shall be at least equal that which is defined by Table 430.151(B) of NFPA 70, National Electrical Code, for a locked rotor equivalent equal to the largest sum resulting from the locked rotor currents of any combination of motors that can be started simultaneously and the

full-load currents of the remaining motor and nonmotor loads that can be operated at that time.

c. The voltage rating shall be at least equal to the nominal supply circuit voltage. [ROP 79-41 (Log 31)]

5.3.3.2 Where the supply circuit disconnecting device is one of the types in 5.3.2(1) through (6), the available fault current at the point of the supply to the machine shall not be greater than the short-circuit current rating of the disconnecting device. 5.3.3.3 When the supply circuit disconnecting device is an attachment plug and receptacle (plug/socket combination), it shall fulfill all of the following requirements:

(1) Have a load-break rating or be interlocked with a switching device that is load-break rated, capable of interrupting the locked rotor current of the largest motor plus the sum of the remaining load that is operating at that time

(2) Be of such a type and be so installed as to prevent unintended contact with live parts at any time even during insertion or removal of the connectors

(3) Have a first make, last break grounding (earthing) contact (4) Have a retaining means to prevent unintended or accidental

disconnection where rated at more than 20 amperes (5) Be located within sight from the operator station and be

readily accessible 5.3.3.4 In addition, a switching device on the machine shall be provided for switching the machine on and off. 5.3.4 Operating Handle. 5.3.4.1 The center of the grip of the operating handle of the disconnecting means, when in its highest position, shall be not more than 2.0 m (6 ft 7 in.) above the floor. A permanent operating platform, readily accessible by means of a permanent stair or ladder, shall be considered as the floor for the purpose of this requirement. 5.3.4.2 An operating handle of the disconnecting means shall meet the following criteria: (1) Be readily accessible with doors in the open or closed position (2) Maintain the environmental rating of the enclosure (3) Not be restricted by the enclosure door when the door is in the open position [ROP 79-41 (Log 31)] 5.3.5 Excepted Circuits. 5.3.5.1 The following circuits shall not be required to be disconnected by the main supply circuit disconnecting means:

(1) Lighting circuits for lighting needed during maintenance or

repair (2) Attachment plugs and receptacles (plug and socket outlets)

for the exclusive connection of repair or maintenance tools and equipment (e.g., hand drills, test equipment)

(3) Undervoltage protection circuits that are only used for automatic tripping in the event of supply circuit failure

(4) Circuits supplying equipment that are required to remain energized for satisfactory operation [e.g., temperature-controlled measuring devices, product (work in progress) heaters, program storage devices]


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5.3.5.2 Supply circuits for excepted circuits shall comply with all of the following conditions:

(1) Be a separate primary disconnecting means, isolating transformer, and secondary overcurrent protection furnished in an enclosure and mounted within the control enclosure, adjacent to the main disconnecting means

(2) Have line side (of the supply circuit disconnect) supply circuit connections internal to the control enclosure that are separate from and do not share a raceway with other conductors, and that are encased in rigid or flexible conduit if longer than 460 mm (18 in.) 5.3.5.3 The control interlocking circuits shall be capable of being disconnected at the control panel from which they are sourced. 5.3.5.4* Where circuits are not disconnected by the supply circuit disconnecting means, the following requirements shall be met:

(1) Permanent warning label(s) shall be placed adjacent to the supply circuit disconnecting means indicating that it does not de-energize all exposed live parts when it is in the open (off) (isolated) position

(2) A corresponding statement shall be included in the maintenance manual

(3) A permanent warning label shall be placed in proximity to each excepted circuit, or the excepted circuit shall be separated from other circuits or shall be identified by color.

5.4 Means for Removal of Power for Prevention of Unexpected Start-Up. 5.4.1 Means for removal of power shall be provided when prevention of unexpected start-up is required (e.g., during maintenance where the unexpected start-up of a machine can create a hazard). Such means shall be as follows:

(1) Appropriate for the intended use (2) Conveniently located (3) Readily identifiable (4) Provided with permanent means for locking in the off

position only 5.4.2 Removal of power can be accomplished by the use of the supply circuit disconnecting means, additional devices conforming to 5.3.2, or other means (e.g., a contactor switched off by a control circuit). 5.4.3 Where other means of removal of power are used, a single failure of any of its components shall not result in an inadvertent or unexpected start-up. 5.4.4 Other means of removal of power shall be employed only for situations that include the following:

(1) Routine exchange of parts, fixtures, and tools requiring no significant dismantling of the machine

(2) Work on the electrical equipment where all of the following conditions exist:

a. There is no hazard arising from electric shock (See Chapter

6) and burn. b. The switching off means cannot be negated by the work. c. The work is of a minor nature (e.g., replacement of plug-in

devices without disturbing existing wiring).

5.5 Devices for Disconnecting Electrical Equipment. 5.5.1 Devices shall be provided for disconnecting (isolating) electrical equipment to enable work to be performed without a risk from electric shock or burn. 5.5.2 The supply circuit disconnecting device (see Section 5.3) shall be permitted to fulfill this requirement where there is no need for isolating individual portions of the electrical circuit. 5.5.3 Where it is expected that it will be necessary to work on separately operable parts of a machine, a disconnecting means shall be permitted for the electrical equipment of each such part of the machine requiring separate isolation. 5.5.4 The following devices shall be permitted to fulfill the isolating function of 5.5.3:

(1) Devices described in 5.3.2 (2) A manual motor controller suitable for motor disconnecting

and compliant with UL 508 where located on the load side of the last short-circuit protective device (in the branch)

(3) A redundantly monitored, remotely operated contactor isolating system that incorporates control lockout provisions and is listed for isolation purposes 5.5.5 The devices in 5.5.4 shall be as follows:

(1) Readily accessible (2) Within sight of the part of the machine requiring isolation (3) Readily identifiable (4) For other than attachment plugs, provided with permanent

means for locking in the off position only

Chapter 6 Protection from Electric Shock 6.1 General. The electrical equipment shall provide protection of persons from electrical shock both in normal operation and during fault conditions. 6.2 Protection from Electric Shock During Normal Operation. Live parts operating at 50 volts rms ac or 60 volts dc or more shall be guarded against accidental contact by an enclosure or shall be a listed multiconductor cable or flexible cord. 6.2.1 Protection by Insulation of Live Parts. Live parts protected by insulation shall be completely covered with insulation that can only be removed by destruction. Such insulation shall be capable of withstanding the mechanical, chemical, electrical, and thermal stresses to which it can be subjected under normal operating conditions. Paints, varnishes, lacquers, and similar products are inadequate for protection against electric shock under normal operating conditions. 6.2.2 Protection by Enclosures. 6.2.2.1 Direct Contact from Outside an Enclosure. Live parts shall be located inside enclosures such that there cannot be any direct contact to live parts from the outside of an enclosure when using the test finger. The determination of the suitability of an enclosure as protection from electrical shock shall be determined by using a test finger as described in Figure 6.2.2.1. The test finger shall be applied, without appreciable force, in every opening in the enclosure after


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removal of all parts of the enclosure that can be removed without the use of a tool.

Figure 6.2.2.1 Jointed test finger. 6.2.3 Enclosure Interlocking. Enclosure interlocking as described in 6.2.3.1 through 6.2.3.4 shall be provided. 6.2.3.1 Each disconnecting means mounted within or adjacent to a control enclosure that contains live parts operating at 50 volts ac (rms value) or 60 volts dc or more shall be mechanically or electrically interlocked, or both, with the control enclosure doors so that none of the doors can be opened unless the power is disconnected. Interlocking shall be reactivated automatically when all the doors are closed. Exception No. 1: A disconnecting means used only for maintenance lighting circuits within control enclosures shall not be required to be interlocked with the control enclosure. A safety sign shall be provided that meets the requirements of 17.2.5. Exception No. 2: A disconnecting means used for power supply circuits within control enclosures to memory elements and their support logic requiring power at all times to maintain information storage shall not be required to be interlocked with the control enclosure doors. A safety sign shall be provided that meets the requirements of 17.2.5. 6.2.3.1.1 Means shall be permitted to be provided for qualified persons, using appropriate work practices, to gain access without removing power.

6.2.3.1.2 The interlocking means shall meet the following requirements:

(1) Utilize a device or tool as specified by the manufacturer of the interlock to allow qualified persons to defeat the interlock

(2) Be reactivated automatically when the door(s) is closed (3) Prevent closing of the disconnecting means while the

enclosure door is open, unless an interlock is operated by deliberate action

6.2.3.2 Where a qualified (skilled) person, using appropriate work practices, needs to enter an enclosure that does not have a disconnect, one of the following conditions shall be met:

(1) The use of a key or tool shall be required for opening the enclosure.

(2) An enclosure door shall be permitted to be opened without the use of a key or a tool and without disconnection of live parts only when all live parts inside are separately enclosed or guarded such that there cannot be any direct contact with live parts by a test finger. 6.2.3.3 Where the equipment has two or more sources of power or two or more independent disconnecting means, power wiring from each disconnecting means shall be run in separate raceway and shall not terminate in or pass through common junction boxes. 6.3 Protection by the Use of Protective Extra Low Voltage (PELV). 6.3.1* General Requirements. The use of PELV is to protect persons against electric shock from indirect contact and limited area direct contact. Where PELV circuits are used as control circuits, they shall also fulfill the relevant requirements of Chapter 5. PELV circuits shall satisfy all of the following conditions:

(1)* The nominal voltage shall not exceed the following: a. 30 volts ac (rms value) or 60 volts dc (ripple free) when the

equipment is used in normally dry locations and when large area contact of live parts with the human body is not expected

b. 6 volts ac (rms value) or 15 volts dc ripple free in all other cases

(2)* One side of the circuit or one point of the source of the supply of that circuit shall be connected to the equipment grounding (protective bonding) circuit.

(3) Live parts of PELV circuits shall be electrically separated from other live circuits. Electrical separation shall be not less than that required between the primary and secondary circuits of a safety isolating transformer.

(4) Conductors of each PELV circuit shall be physically separated from those of any other circuit. When this requirement is impracticable, the insulation provisions of 14.1.3 shall apply.

(5) Attachment plugs and receptacles (plugs and socket combinations) for a PELV circuit shall conform to the following:

a. Attachment plugs (plugs) shall not be able to enter receptacles (socket-outlets) of other voltage systems.

b. Receptacles (socket-outlets) shall not admit plugs of other voltage systems. 6.3.2 Sources for PELV. The source for PELV shall be one of the following:

(1) A safety isolating transformer (2) A source of current providing a degree of safety equivalent to

that of the safety isolating transformer (e.g., a motor generator with winding providing equivalent isolation)


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(3) An electrochemical source (e.g., a battery) or another source independent of a higher voltage circuit (e.g., a diesel-driven generator)

(4) An identified electronic power supply conforming to appropriate standards specifying measures to be taken to ensure that, even in the case of an internal fault, the voltage at the outgoing terminals cannot exceed the values specified in 6.3.1(1) 6.4 Protection Against Residual Voltages. 6.4.1 Live parts having a residual voltage greater than 60 volts after the supply has been disconnected shall be reduced to 60 volts or less within 5 seconds after disconnection of the supply voltage. Exception No. 1: Exempted from this requirement are components having a stored charge of 60 microcoulombs or less. Exception No. 2: Where such a provision would interfere with the proper functioning of the equipment, a durable warning notice drawing attention to the hazard and stating the delay required before entry to the enclosure is allowed, shall be displayed at an easily visible location on or immediately adjacent to the enclosure containing the capacitance. 6.4.2 The withdrawal of plugs or similar devices, which results in the exposure of conductors (e.g., pins), shall have a discharge time that does not exceed 1 second. Exception No. 1: Exempted from this requirement are components having a stored charge of 60 microcoulombs or less. Exception No. 2: Exempted from this requirement are conductors that are protected against direct contact. [ROP 79-25 (Log 68)]

Chapter 7 Protection of Equipment 7.1 General. Chapter 7 shall detail the measures to be taken to protect equipment against the effects of the following:

(1) Overcurrent arising from a short circuit (2) Overload currents (3) Ground faults (4) Overvoltages due to lightning and switching surges (5) Abnormal temperatures (6) Loss of or reduction in the supply voltage (7) Overspeed of machines/machine elements (8) Incorrect phase sequence

7.2 Overcurrent Protection. 7.2.1* General. Overcurrent protection shall be provided where the current in a machine circuit can exceed either the rating of any component in the circuit or the current carrying capacity of the conductors in the circuit, whichever is the lesser value. [ROP 79-46 (Log 75)] 7.2.2* Supply Conductors. Unless otherwise specified by the user, the supplier of the electrical equipment shall not be responsible for providing the overcurrent protective device for the supply conductors to the electrical equipment. The supplier of the electrical equipment shall state on the installation diagram the data necessary for selecting this overcurrent protective device.

7.2.3 Power Circuits. Devices for detection and interruption of overcurrent, selected in accordance with 7.2.10, shall be applied to each ungrounded phase conductor. Conductors shall be protected against overcurrent in accordance with their ampacities as specified in Section 13.5. [ROP 79-47 (Log 76)] 7.2.4 Control Circuits. 7.2.4.1 General. A control circuit tapped from the load side of the branch-circuit short-circuit and ground-fault protective device(s) and functioning to control the load(s) connected to that branch circuit shall be protected against overcurrent in accordance with 7.2.4.2. Such a tapped control circuit shall not be considered to be a branch circuit and shall be permitted to be protected by either a supplementary or branch-circuit overcurrent protective device(s). 7.2.4.2 Conductor Protection. 7.2.4.2.1 Conductors, other than flexible cords and fixture wires, shall be protected against overcurrent in accordance with their ampacities as specified in Section 13.5, unless otherwise permitted in 7.2.4.2.2 through 7.2.4.2.6. 7.2.4.2.2 Conductors sizes of 18, 16, and 14 AWG shall be considered as protected by an overcurrent device(s) of not more than a 20-ampere rating. 7.2.4.2.3 Conductors that do not extend beyond the control cabinet enclosure shall be considered protected by the load branch-circuit short-circuit and ground-fault protective device(s) where the rating of the protective device(s) is not more than 400 percent of the ampacity of the control circuit conductor for conductors 14 AWG and larger, or not more than 25 amperes for 18 AWG and 40 amperes for 16 AWG. 7.2.4.2.4 Conductors of 14 AWG and larger that extend beyond the enclosure shall be considered protected by the load branch-circuit short-circuit and ground-fault protective device(s) where the rating of the protective device(s) is not more than 300 percent of the ampacity of the control circuit conductors. 7.2.4.2.5 Conductors supplied by the secondary side of a single-phase transformer having a 2-wire (single-voltage) secondary shall be considered protected by overcurrent protection provided on the primary (supply) side of the transformer, if this protection is in accordance with 7.2.7 and does not exceed the value determined by multiplying the secondary conductor ampacity by the secondary-to-primary voltage ratio. Transformer secondary conductors (other than 2-wire) are not considered to be protected by the primary overcurrent protection. 7.2.4.2.6 Conductors of control circuits shall be considered protected by the motor branch-circuit short-circuit and ground-fault protective device(s) where the opening of the control circuit would create a hazard (e.g., the control circuit of a magnetic chuck). 7.2.5 Receptacle (Socket) Outlets and Their Associated Conductors. 7.2.5.1 Overcurrent protection shall be provided for the circuits feeding general purpose receptacle (socket) outlets intended primarily for supplying power to maintenance equipment. 7.2.5.2 Overcurrent protective devices shall be provided in the ungrounded phase conductors of each circuit feeding receptacle


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(socket) outlets. Overcurrent protection for these receptacle (socket) outlets shall not exceed 15 amperes. 7.2.6 Lighting Circuits. Overcurrent protection for lighting branch circuits shall not exceed 15 amperes. 7.2.7 Transformers. 7.2.7.1 Transformers for motor control circuits shall be protected in accordance with Article 430, Part VI, of NFPA 70, National Electrical Code. Transformers for other than motor control circuits shall be protected in accordance with of NFPA 70, National Electrical Code, Article 450, Part I. 7.2.8 Location of Overcurrent Protective Devices. An overcurrent protective device shall be located at the point where the conductor to be protected is connected to the supply except as follows:

(1) Overcurrent protection at the supply shall not be required if all of the following conditions are met:

a. The current carrying capacity of the conductors is at least equal to that required for the load.

b. Each connecting conductor to the overcurrent protective devices is no longer than 3 m (10 ft).

c. The conductor is suitably protected from physical damage. d. The conductor does not extend beyond the control panel

enclosure. e. The conductor terminates in a branch circuit rated circuit

breaker or set of fuses.

(2) Overcurrent protection at the supply shall not be required if all of the following conditions are met:

a. The conductor has an ampacity of at least one-third that of the conductor from which it is supplied.

b. The conductor is suitably protected from physical damage. c. The conductor is not over 7.5 m (25 ft) long and the

conductor terminates in a single circuit breaker or set of fuses. 7.2.9 Short-Circuit Interrupting Rating. The short-circuit interrupting rating shall be at least equal to the available fault current at the point of application. Where the short-circuit current to an overcurrent protective device can include additional currents other than from the supply (e.g., from motors, from power factor correction capacitors), these shall be taken into consideration. 7.2.10* Rating and Setting of Overcurrent Protective Devices. 7.2.10.1 Each motor controller and its associated wiring shall be protected as an individual branch circuit by a short-circuit protective device (SCPD) as specified by the controller manufacturer. The maximum rating of the designated SCPD shall be as shown in Table 7.2.10.1. Exception: Table 7.2.10.1 shall not apply to Design E motor circuits. The provisions of NFPA 70, National Electrical Code, shall be observed for Design E motor circuits.

Table 7.2.10.1 Maximum Rating1 or Setting of Fuse and Circuit Breakers: Motor, Motor Branch Circuit, and Motor Controller

Full-Load Current (%)

Fuse Class with Non-Time Delay

AC-2 AC-3 AC-4

R 300 300 300

J 300 300 300

CC 300 300 300

T 300 300 300

Fuse Class with Time Delay2 Type3 of Application AC-2 AC-3 AC-4

RK-54 150 175 175

RK-1 150 175 175

J 150 175 225

CC 150 300 300

Instantaneous trip circuit breaker5

800 800 800

Inverse trip circuit breakerb 150 250 250 1Where the values determined by Table 7.2.10.1 do not correspond to the standard sizes or ratings, the next higher standard size, rating, or possible setting shall be permitted. 2 Where the rating of a time-delay fuse (other than CC type) specified by the table is not sufficient for the starting of the motor, it shall be permitted to be increased but shall in no case be permitted to exceed 225 percent. The rating of a time-delay Class CC fuse and non-time-delay Class CC, J, or T fuse shall be permitted to be increased but shall in no case exceed 400 percent of the full-load current. [ROP 79-52 (Log 161)] 3 Types: AC-2: All light-starting duty motors, including slip-ring motors; starting, switching off,. AC-3: All medium starting duty motors including squirrel-cage motors; starting, switching off while running, occasional inching, jogging, or plugging but not to exceed 5 operations per minute or 10 operations per 10 minutes and all wye-delta and two-step autotransformer starting motors AC-4: All heavy starting duty motors including squirrel-cage motors; starting, plugging, inching, jogging. 4Unless a motor controller is listed for use with RK-5 fuses, Class RK-5 fuses shall be used only with NEMA-rated motor controllers.

5Instantaneous trip circuit breakers shall be permitted to be used only if they comply with all of the following:

(1) If they are adjustable, and (2) If part of a combination controller has motor-running

protection and also short-circuit and ground-fault protection in each conductor, and

(3) If the combination is especially identified for use, and (4) It is installed per any instructions included in its listing or

labeling and (5) If they are limited to single motor applications circuit

breakers with adjustable trip settings shall be set at the controller manufacturer's recommendation, but not greater than 1300 percent of the motor full-load current. 6Where the rating of an inverse time circuit breaker specified in Table 7.2.10.1 is not sufficient for the starting current of the motor, it shall be permitted to be increased but in no case exceed 400 percent for full-load currents of 100 amperes or less or 300 percent for full-load currents greater than 100 amperes.

[ROP 79-52 (Log 161)]


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7.2.10.2 Several motors each not exceeding 1 hp in rating shall be permitted on a nominal 120-volt branch circuit protected at not over 20 amperes or a 600-volt nominal or less branch circuit, protected at not over 15 amperes, where all of the following conditions are met:

(1) The full-load rating of each motor does not exceed 6 amperes.

(2) The rating of the branch-circuit short-circuit and ground-fault protective device marked on any of the controllers is not exceeded.

(3) Individual overload protection conforms to Section 7.3. 7.2.10.3 Where the branch-circuit, short-circuit, and ground-fault protective device is selected not to exceed that allowed by 7.2.10.1 for the smallest rated motor, two or more motors or one or more motors and other load(s), with each motor having individual overload protection, shall be permitted to be connected to a branch circuit where it can be determined that the branch-circuit short-circuit and ground-fault protective device will not open under the most severe normal conditions of service that might be encountered. 7.2.10.4 Two or more motors and their control equipment shall be permitted to be connected to a single branch circuit where short-circuit and ground-fault protection is provided by a single inverse time circuit breaker or a single set of fuses, provided both of the following conditions are met:

(1)* Each motor controller and overload device is listed for group installation with specified short-circuit current ratings.

(2) The rating or setting of the overcurrent device does not exceed the values in Table 7.2.10.4(2) for the smallest conductor in the circuit.

Table 7.2.10.4(2) Relationship Between Conductor Size and

Maximum Rating or Setting of Short-Circuit Protective Device for Power Circuits

Maximum Rating

Conductor Size (AWG)

Non-Time-delay Fuse or Inverse

Time Circuit Breaker (amperes)

Time Delay or Dual

Element Fuse (amperes)

14 12 10 8 6 4 3 2 1 0

2/0 3/0 4/0

60 80

100 150 200 250 300 350 400 500 600 700 800

30 40 50 80

100 125 150 175 200 250 300 350 400

7.2.11 Resistance Heating Branch-Circuit Overcurrent Protection. 7.2.11.1 If the branch circuit supplies a single nonmotor-operated load rated at 16.7 amperes or more, the overcurrent device rating shall not exceed 150 percent of the load rating.

7.2.11.2 Equipment employing resistance-type heating elements rated at more than 48 amperes shall have the heating elements subdivided. Each subdivided load shall not exceed 48 amperes and shall be protected at not more than 60 amperes. Exception: A single sheath-type heating element requiring more than 48 amperes shall be protected at not more than 125 percent of the load where the element is integral with and enclosed within the machine housing. 7.2.11.3 The supplementary overcurrent protective devices shall be as follows:

(1) Installed within or on the machinery or provided as a separate assembly

(2) Accessible but need not be readily accessible (3) Suitable for branch-circuit protection

The main conductors supplying these overcurrent protective devices shall be considered branch-circuit conductors. 7.2.12 Programmable Electronic System Power Supply Input Overcurrent Protection. Programmable electronic system power supply inputs shall be protected by overcurrent protective devices either externally or internally. The overcurrent protection size or rating shall be in accordance with the manufacturer’s instructions. 7.2.13 Control Devices. Pushbuttons, selector switches, sensors, and limit switches shall in no case be connected to a circuit rated larger than 10 amperes. 7.2.14 Common Overcurrent Device. The use of the same overcurrent device to provide the protection called for in 7.2.4, 7.2.6, and 7.2.7 shall be permitted. 7.3 Overload Protection of Motors. 7.3.1 General. Overload devices shall be provided to protect each motor, motor controller, and branch-circuit conductor against excessive heating due to motor overloads or failure to start. Motor overload protection shall be provided as follows:

(1) Motors in accordance with Article 430, Part III of NFPA 70, National Electrical Code.

(b) Adjustable speed drives (electronic drives) in accordance with Article 430.2 of NFPA 70, National Electrical Code. 7.3.2 Resetting. Resetting of the overload device shall not restart the motor. Exception: Where the machine has only a single motor of 2 hp or less, an overload reset operator mounted on the motor shall be permitted to restart the motor provided that the distance between the overload reset operator and the machine start pushbutton operator is 300 mm (12 in.) or less, and a suitable warning label is attached on or adjacent to the overload reset operator. 7.3.3 Number of Overloads. The minimum number and location of running overcurrent units shall be determined from Table 7.3.3. An overload unit in each phase shall not be required where overload protection is provided by other approved means.


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Note: For 2-phase power supply systems, see NFPA 70, National Electrical Code, Section 430.37. [ROP 79-44 (Log 45)]

Short-time-rated motors or high-reversing duty motors that cannot be adequately protected by external overload devices shall be protected by a thermal device mounted in the motor and sensitive to the temperature of the motor, or to both motor temperature and current. Motors that are an integral part of a refrigeration compressor of the hermetic or semihermetic type shall be protected per the compressor manufacturer's recommendations. 7.4* Abnormal Temperature Protection. Resistance heating or other circuits that are capable of attaining or causing abnormal temperatures and, therefore, can cause a hazardous condition shall be provided with suitable detection to initiate an appropriate control response. 7.5 Protection Against Supply Interruption or Voltage Reduction and Subsequent Restoration. 7.5.1 General. Where a supply interruption or a voltage reduction can cause a hazardous condition or damage to the machine or to the work in progress, undervoltage protection shall be provided (e.g., to switch off the machine) at a predetermined voltage level. 7.5.2 Undervoltage Protection. Where the operation of the machine can allow for an interruption or a reduction of the voltage for a short time period, delayed undervoltage protection shall be permitted to be provided. The operation of the undervoltage device shall not impair the operation of any stopping control of the machine. 7.5.3 Restarting. Upon restoration of the voltage or upon switching on the incoming supply, automatic or unintentional restarting of the machine shall be prevented when such a restart can cause a hazardous condition. Where only a part of the machine or of the group of machines working together in a coordinated manner is affected by the voltage reduction or supply interruption, the undervoltage protection shall initiate appropriate control responses to ensure coordination. 7.6 Overspeed Protection. 7.6.1* Motor Overspeed Protection. Unless the inherent characteristics of the motor or the controller, or both, are such as to limit the speed adequately, drive systems motors shall include protection against motor overspeed.

7.6.2 Equipment Overspeed Protection. Where the safe operating speed of the equipment is less than that of the drive motor, means shall be provided to limit the speed of the equipment. 7.7 (Reserved.) 7.8* Phase Sequence Protection. Where a phase loss or an incorrect phase sequence of the supply voltage can cause a hazardous condition or damage to the machine, protection shall be provided. 7.9 Protection Against Overvoltages Due to Lightning and Switching Surges. 7.9.1 Protective devices shall be permitted to be provided to protect against the effects of overvoltages due to lightning or switching surges. 7.9.2 Where provided, devices for the suppression of overvoltages due to lightning shall be connected to the incoming terminals of the supply disconnecting device. 7.9.3 Where provided, devices for the suppression of overvoltages due to switching surges shall be connected across the terminals of all equipment requiring such protection. 7.10 Power Factor Correction Capacitors. 7.10.1* Overcurrent Protection. Where capacitors are installed for motor power factor correction on circuits of 600 volts, nominal, and under, overcurrent protection for the conductors shall be provided. Each capacitor cell or capacitor bank shall be protected against rupture of the individual cells. Protection included as a part of the capacitor assembly shall be permitted. 7.10.2 Discharge of Stored Energy. Capacitors shall be provided with a means of discharging stored energy. [70:460.6] 7.10.2.1 Time of Discharge. The residual voltage of a capacitor shall be reduced to 50 volts, nominal, or less, within 1 minute after the capacitor is disconnected from the source of supply. [70:460.6] 7.10.2.2 Means of Discharge. The discharge circuit shall be either permanently connected to the terminals of the capacitor or capacitor bank, or provided with automatic means of connecting it to the terminals of the capacitor bank upon removal of voltage from the line. Manual means of switching or connecting the discharge circuit shall not be used. [70:460.6]

Table 7.3.3 Running Overcurrent Units

Kind of Motor Supply System

Number and Location of Overcurrent Units (Such as Trip Coils, Relays, or Thermal Cutouts)

1-phase, ac or dc 2-wire, 1-phase ac or dc ungrounded 1 in either conductor 1-phase, ac or dc 2-wire, 1-phase ac or dc, one conductor grounded 1 in ungrounded conductor 1-phase, ac or dc 3-wire, 1-phase ac or dc, grounded neutral 1 in either ungrounded conductor 3-phase, ac Any 3-phase * 3, one in each phase


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Chapter 8 Grounding 8.1* General. 8.1.1 Applicability. This chapter shall provide for grounding, bonding requirements, and grounded conductors. 8.1.2 Connections. Grounded conductors shall not be connected to the equipment grounding (protective) circuit, except for separately derived systems. 8.2 Equipment Grounding (Protective Bonding) Circuit. 8.2.1 Grounding System. The equipment grounding (protective bonding) circuit shall consist of the following:

(1) Equipment grounding (PE) terminal(s) (2) Conductive structural parts of the electrical equipment and

the machine (3) Equipment grounding (protective) conductors and

equipment bonding jumpers

All parts of the equipment grounding (protective bonding) circuit shall be capable of withstanding the highest thermal and mechanical stress that can be caused by fault currents flowing in that part of the circuit.

All exposed conductive parts of the electrical equipment and the

machine(s) shall be connected to the equipment grounding (protective bonding) circuit. Exception: Small parts such as screws, rivets, and nameplates that are not likely to become energized shall not be required to be grounded. 8.2.1.1 Equipment Grounding. The machine and all exposed, noncurrent-carrying conductive parts, material, and equipment likely to be energized shall be effectively grounded. Where electrical devices are mounted on metal mounting panels that are located within nonmetallic enclosures, the metal mounting panels shall be effectively grounded. 8.2.1.2* Equipment Grounding Terminal.

8.2.1.2.1 For each incoming supply circuit, an equipment grounding (external protective ) conductor terminal shall be provided in the vicinity of the associated phase conductor terminals. 8.2.1.2.2 All of the items in 8.2.1.1 shall be interconnected to the equipment grounding terminal.

8.2.1.2.3 The equipment grounding terminal shall accommodate an equipment grounding conductor sized in accordance with Table 8.2.2.3. 8.2.1.2.4* The equipment grounding terminal shall be identified with the word "GROUND," the letters "GND" or "GRD," the letter "G," the color GREEN, or the symbol in Figure 8.2.1.2.4. In addition to the required marking, the letters PE shall also be permitted to identify this terminal. Exception: Where an attachment plug and receptacle are used as the disconnecting means, 5.3.3.3 shall apply.

Figure 8.2.1.2.4 Grounding Symbol.

8.2.2 Equipment Grounding (Protective) Conductors and Bonding Jumpers. Equipment grounding (protective) conductors and bonding jumpers shall be identified in accordance with 14.2.2. 8.2.2.1 Conductors used for grounding and bonding purposes shall be copper. Stipulations on stranding and flexing as outlined in this standard shall apply. 8.2.2.2 Equipment grounding conductors and bonding jumpers shall be insulated, covered, or bare and shall be protected against physical damage. 8.2.2.3 Equipment grounding conductors and bonding jumpers of the wire type shall not be smaller than shown in Table 8.2.2.3, but shall not be required to be larger than the circuit conductors supplying the equipment. 8.2.2.3.1 Machine members or structural parts of the electrical equipment shall be permitted to be used in the equipment grounding circuit provided that the cross-sectional area of these parts is at least electrically equivalent to the minimum cross-sectional area of the copper conductor required. [ROP 79-152 (Log 81)]

Table 8.2.2.3 Minimum Size of Equipment Grounding Conductors and Bonding Jumpers

Rating or Setting of Automatic Overcurrent

Device in Circuit Ahead of the Equipment

(Not exceeding Amperes)

Copper Conductor Size

(AWG or kcmil)

10 16 15 14 20 12 30 10 40 10 60 10 100 8 200 6 300 4 400 3 500 2 600 1 800 1/0

1000 2/0 1200 3/0 1600 4/0 2000 250 2500 350 3000 400 4000 500 5000 700 6000 800

8.2.3 Continuity of the Equipment Grounding (Protective Bonding) Circuit.


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8.2.3.1 The continuity of the equipment grounding (protective bonding) circuit shall be ensured by effective connections through conductors or structural members. 8.2.3.2 Removing a device shall not interrupt the continuity of the equipment grounding (protective) circuit. 8.2.3.3 Bonding of equipment with bolts or other identified means shall be permitted where paint and dirt are removed from the joint surfaces or where the bonded members are effectively penetrated. 8.2.3.4 Moving machine parts, other than accessories or attachments, having metal-to-metal bearing surfaces shall be considered as bonded. Sliding parts separated by a nonconductive fluid under pressure shall not be considered as bonded. 8.2.3.5 Raceways, wireways, and cable trays shall not be used as equipment grounding or bonding conductors. 8.2.3.6 Doors or Covers. 8.2.3.6.1 Where electrical devices are mounted on conductive doors or covers, an equipment (protective) bonding jumper shall be installed. 8.2.3.6.2 An equipment (protective) bonding jumper shall connect the conductive door or cover to the equipment enclosure or to an equipment grounding (protective bonding) terminal within the enclosure.

8.2.3.7 Portable, pendant, and resilient-mounted equipment shall be bonded by separate conductors. Where multiconductor cable is used, the bonding conductor shall be included as one conductor of the cable. 8.2.3.8 Where equipment grounding conductors are subject to physical damage they shall be protected or monitored to ensure continuity. 8.2.4 Exclusion of Switching Devices. The equipment grounding (protective) circuit shall not contain any switches or overcurrent protective devices. Links or plugs in the grounding circuit shall be permitted if properly labeled or interlocked with the control circuits. 8.2.5* Equipment Grounding (Protective) Conductor Connecting Points. 8.2.5.1 All equipment grounding (protective) conductors shall be terminated in accordance with 14.1.1. The equipment grounding (protective) conductor connecting points shall have no other function. 8.2.5.2* The equipment grounding conductor connecting points, other than the equipment grounding terminal, shall be identified by the color GREEN or by use of the symbol in Figure 8.2.1.2.4. 8.3 Control Circuits. Control circuits shall be permitted to be grounded or ungrounded. Where grounding is provided, that side of the circuit common to the coils shall be grounded at the control transformer if alternating current or at the power supply terminal if direct current. Ungrounded control circuits shall be provided with an insulation monitoring device that either indicates a ground (earth) fault or interrupts the circuit automatically after a ground (earth) fault.

Exception No. 1: Exposed control circuits as permitted by Section 6.3 shall be grounded. Exception No. 2: Overload relay contacts shall be permitted to be connected between the coil and the grounded conductor where the conductors between such contacts and coils of magnetic devices do not extend beyond the control enclosure. Exception No. 3: Class 2 low-voltage circuits in Article 725 of NFPA 70, National Electrical Code shall not require insulation monitoring. 8.5 Lighting Circuits. 8.5.1 One conductor of all machine lighting and maintenance lighting circuits shall be grounded. The grounded conductor(s) shall be identified in accordance with Section 14.2. 8.4.2 Where the lighting circuit is supplied by a separate isolation transformer, the grounding shall occur at the transformer. Where the equipment maintenance lighting circuit is supplied directly from the plant lighting circuit, the grounding shall occur at the grounding terminal. 8.4.3 The grounded conductor, where run to a screw-shell lampholder, shall be connected to the screw-shell. [ROP 79-151 (Log 52)]

Chapter 9 Control Circuits and Control Functions 9.1 Control Circuits. 9.1.1 Control Circuit Supply. 9.1.1.1 Control transformers shall be used for supplying the control circuits. Control circuits shall not be derived from autotransformers. 9.1.1.2 Where dc control circuits are connected to the equipment grounding (protective bonding) circuit, they shall be supplied from a separate winding of the ac control circuit transformer or by another control circuit transformer or a listed dc power supply. 9.1.1.3 Transformers shall not be required if the supply voltage does not exceed 120 volts ac and the available short-circuit current does not exceed 1000 amperes rms.

9.1.1.4 The source of supply for all control circuits shall be taken from the load side of the supply disconnecting means. Exception: The power supply circuit to memory elements and their support logic requiring power at all times to maintain the storage of information shall be permitted to be taken from the line side of the supply disconnecting means or other power source. 9.1.1.5 The marking requirements of 17.2.4 shall apply. 9.1.2 Control Circuit Voltages. 9.1.2.1 AC Control Circuit Voltages. The ac voltage for control circuits shall not exceed 120 volts, ac single phase. Exception No 1: Other voltages shall be permitted, where necessary, for the operation of electronic, precision, static, or devices used in the control circuit. Exception No. 2: Any electromechanical magnetic device having an inrush current exceeding 20 amperes at 120 volts shall be permitted to be energized at


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line voltage through contactor or relay contacts. The contactor or relay contacts shall break both sides of the line voltage circuit to the magnetic device. The relay coil shall be connected to the control circuit. 9.1.2.2 DC Control Circuit Voltages. DC control voltage shall be 250 volts or less. 9.1.3 Protection. Control circuits shall be provided with overcurrent protection in accordance with Chapter 7. 9.1.4 Connection of Control Circuit Devices. 9.1.4.1 All operating coils of electromechanical magnetic devices and indicator lamps (or transformer primary windings for indicator lamps) shall be directly connected to the same side of the control circuit. All control circuit contacts shall be connected between the coil and the other side of the control circuit. Exception No. 1: Overload relay contacts where the wiring to these contacts does not extend beyond the control enclosure. Exception No. 2: Contacts of multipole control circuit switching devices that simultaneously open both sides of the control circuit. Exception No. 3: Ground test switching device contacts in ungrounded control circuits. Exception No. 4: Solenoid test switching device contacts in ungrounded circuits. Exception No. 5: Coils or contacts used in electronic control circuits where the wiring to these coils or contacts does not extend beyond the control enclosure. Exception No. 6: "Run" pushbuttons for two-hand operation, such as for presses having ground detection circuits and overcurrent protection in each conductor. 9.1.4.2 Contacts shall not be connected in parallel where the purpose is to increase ampacity. 9.2 Control Functions.

9.2.1 Start Functions. Start functions shall operate by energizing the relevant circuit. 9.2.2* Stop Functions. The three categories of stop functions shall be as follows:

(1) Category 0 is an uncontrolled stop by immediately removing power to the machine actuators.

(2) Category 1 is a controlled stop with power to the machine actuators available to achieve the stop then remove power when the stop is achieved.

(3) Category 2 is a controlled stop with power left available to the machine actuators.

9.2.3 Operating modes. 9.2.3.1 Each machine shall be permitted to have one or more operating modes (e.g., automatic, manual, normal, and bypass) determined by the type of machine and its application.

9.2.3.2 Where a hazardous condition results from mode selection, inadvertent selection shall be prevented from occurring (e.g., key-operated switch, access code). Mode selection by itself shall not

initiate machine operation. A separate action by the operator shall be required. [ROP 79-70 (Log 152)] 9.2.3.3* Safeguarding means shall remain effective for all operating modes. 9.2.3.4 Indication of the selected operating mode shall be provided (e.g., position of mode selector, provision of indicating light, visual display indication). 9.2.4 Overriding Safeguards. Where it is necessary to temporarily override one or more safeguards, a mode selection device or means capable of being secured (e.g,. locked) in the desired mode shall be provided to prevent automatic operation. The control circuit for the suspension of a safeguard shall have the same safety requirements as the suspended safeguard itself. In addition, one or more of the following measures shall be permitted to be provided:

(1) Initiation of motion by a hold-to-run or other control device. (2) A portable control station (e.g., pendent) with an emergency

stop device, and where appropriate, an enabling device. Where a portable station is used, motion shall only be initiated from that station.

(3) Limiting the speed or the power of motion. (4) Limiting the range of motion. [ROP 79-71 (Log 151)]

9.2.5 Operation.

9.2.5.1 General. 9.2.5.1.1 The necessary interlocks shall be provided for safe operation. 9.2.5.1.2 Measures shall be taken to prevent movement of the machine in an unintended manner after any stopping of the machine (e.g., locked-off condition, power supply fault, battery replacement, lost signal condition with cableless control). 9.2.5.2 Start. 9.2.5.2.1 The start of an operation shall be possible only where all of the safeguards are in place and functional except for conditions as described in 9.2.4. 9.2.5.2.2 On those machines where safeguards cannot be applied for certain operations, manual control of such operations shall be by hold-to-run controls together with enabling devices. 9.2.5.2.3 Interlocks shall be provided to ensure correct sequential starting. 9.2.5.2.4 On machines requiring the use of more than one control station to initiate a start, the following criteria shall be met:

(1) Each control station shall have a separate manually actuated start control device.

(2) All required conditions for machine operation shall be met. (3) All start control devices shall be in the released (off) position

before a start operation is permitted. (4) All start control devices shall be actuated concurrently.

9.2.5.3 Stop.

9.2.5.3.1 Each machine shall be equipped with a category 0 stop. 9.2.5.3.2 Category 0, Category 1, and/or Category 2 stops shall be provided where indicated by an analysis of the risk assessment and


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the functional requirements of the machine. Category 0 and Category 1 stops shall be operational regardless of operating modes, and Category 0 shall take priority. Stop function shall operate by de-energizing that relevant circuit and shall override related start functions.

9.2.5.3.3 Where required, provisions to connect protective devices and interlocks shall be provided. Where applicable, the stop function shall signal the logic of the control system that such a condition exists. The reset of the stop function shall not initiate any hazardous conditions. 9.2.5.4* Emergency Operations (Emergency Stop, Emergency Switching Off). 9.2.5.4.1 Emergency Stop. Where the emergency stop function is used, it shall be initiated by a single human action.

9.2.5.4.1.1 In addition to the requirements for stop, the emergency stop shall have the following requirements:

(1) It shall override all other functions and operations in all modes.

(2) Power to the machine actuators, which causes a hazardous condition(s), shall be removed as quickly as possible without creating other hazards (e.g., by the provision of mechanical means of stopping requiring no external power, by reverse current braking for a Category 1 stop).

(3) Reset of an emergency stop circuit shall not initiate a restart.

9.2.5.4.1.2 Where required, provisions to connect additional emergency stop devices shall be provided in accordance with Section 10.7. 9.2.5.4.1.3 The emergency stop shall function as either a Category 0 or a Category 1 stop (see 9.2.2). The choice of the category of the emergency stop shall be determined by the risk assessment of the machine.

9.2.5.4.1.4 Where a Category 0 stop is used for the emergency stop function, it shall have only hardwired electromechanical components. Exception: An electronic logic (hardware or software) system as well as the communication network or link that complies with 11.3.4 and is listed for Category 0 emergency stop function shall be permitted. The final removal of power shall be accomplished by means of electromechanical components. [ROP 79-77 (Log 12)] [ROP 79-72 (Log 150)] 9.2.5.4.1.5 Where a Category 0 or a Category 1 stop is used for the emergency stop function, final removal of power to the machine actuators shall be ensured and shall be by means of electromechanical components.

9.2.5.4.2 Emergency Switching Off. Where the emergency switching off function is used, it shall be initiated by a single human action.

9.2.5.4.2.1 Emergency switching off shall be permitted as follows:

(1) Where protection against direct contact (e.g., with collector wires, collector bars, slip-ring assemblies, control gear in electrical operating areas) is achieved only by placing out of reach or by obstacles.

(2) Where other hazards or damage caused by electricity are possible.

9.2.5.4.2.2 Emergency switching off shall be accomplished by disconnecting the incoming supply circuit of the machine effecting a Category 0 stop. Where the machine cannot tolerate the Category 0 stop, it shall be necessary to provide other protection, (e.g., against direct contact) so that emergency switching off is not necessary. 9.2.5.5 Hold-to-Run Controls. 9.2.5.5.1 Hold-to-run controls (e.g., jog, inch functions) shall require continuous actuation of the control device(s) to achieve operation.

9.2.5.5.2 Jog or inch functions shall operate only in the manual mode. Manual reverse shall be considered a jog function. The prevention of run or automatic operation during jog or inch shall be accomplished by an operator interface and a separate jog or inch selection method. 9.2.5.6* Two-Hand Control. All two-hand controls shall have the following features:

(1) The provision of two control devices shall require the concurrent actuation by both hands.

(2) It shall be necessary to actuate the control devices within a certain time limit of each other.

(3) Where the time limit of less than or equal to 0.5 seconds is exceeded, both control devices shall be released before operation is initiated.

(4) The control devices shall require continuous actuation during the hazardous conditions.

(5) Machine operation shall cease upon the release of either control device when hazardous conditions are still present and

(6) Require of the release of both control devices, before the machine operation is reinitiated. 9.2.5.7 Enabling Device. 9.2.5.7.1 An enabling device as used in this chapter is defined as an additional manually operated control device used in conjunction with a start control and, when continuously actuated, allows a machine to function. 9.2.5.7.2 When an enabling device is provided as a part of a system, it shall be designed to allow motion when actuated in one position only. In any other position motion shall be stopped. 9.2.5.7.3 Enabling devices shall have the following features:

(1) Connect to a Category 0 or a Category 1 stop (see 9.2.2) (2) Design follows ergonomic principles (3) For two-position types, the positions are as follows:

a. Position 1 is the off function of the switch (actuator is not operated)

b. Position 2 is the enabling function (actuator is operated) (4) For three-position types, the positions are as follows:

a. Position 1 is the off function of the switch (actuator is not operated)

b. Position 2 is the enabling function (actuator is operated in its mid position)

c. Position 3 is the off function of the switch (actuator is operated past its mid position)

A three-position enabling device shall require manual operation to reach position 3.


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9.2.5.7.4 When returning from position 3 to position 2, the function shall not be enabled. 9.2.5.7.5 An enabling device shall automatically return to its off function when its actuator is not manually held in the enabling position. 9.2.6 Combined Start and Stop Controls. A single pushbutton and other devices that alternately start and stop motion shall only be used for secondary functions where no hazardous condition arises when they are operated. 9.2.7 Cableless Control Functions. 9.2.7.1 General. 9.2.7.1.1 Means shall be provided to remove or disconnect the power supply of the operator control station. 9.2.7.1.2 Means (e.g., key-operated switch, access code) shall be provided, as necessary, to prevent unauthorized use of the operator control station. 9.2.7.1.3 Each operator control station shall carry an unambiguous indication of which machine(s) is intended to be controlled by that operator control station. 9.2.7.2 Control Limitation. 9.2.7.2.1 Measures shall be taken to ensure that control commands affect only the following:

(1) The intended machine (2) The intended functions

9.2.7.2.2 Measures shall be taken to prevent the machine from responding to signals other than those from the intended operator control station(s). 9.2.7.2.3 Means shall be provided so that the machine shall only be controlled from operator control stations in one or more predetermined zones or locations. 9.2.7.3 Stop Function. 9.2.7.3.1 Operator control stations shall include a separate and clearly identifiable means to initiate the stop function of the machine or of all the motions that causes a hazardous condition. The actuating means to initiate this stop function shall not be marked or labeled as an emergency stop device, even though the stop function initiated on the machine results in an emergency stop function. 9.2.7.3.2 A machine that has safety critical functions that are equipped with cableless control shall have a means of automatically initiating the stopping of the machine and preventing the initiation of potentially hazardous motions in the following situations:

(1) When a stop signal is received (2) When a fault is detected in the system (3) When a valid signal has not been detected within a specified

period of time 9.2.7.4* Serial Data Communication. In a machine where the control of safety critical functions relies on serial data transfer, correct communications shall be ensured by using an error detection

method that is able to cope with up to three error bits in any command sequence. The safety capability of the serial data communication system shall be listed to have the same degree of safety capability as hardware-based components installed in accordance with this standard. 9.2.7.5 Use of More Than One Operator Control Station. Where a machine has more than one operator control station, measures shall be taken to ensure that only one control station shall be enabled at a given time. Indication of which operator control station is in control of the machine shall be provided at locations where necessary for the safety requirements of the machine. Exception: A stop command from any one of the control stations shall be effective where necessary for the safety requirements of the machine. 9.2.7.6 Battery-Powered Operator Control Stations. A variation in the battery voltage shall not cause a hazardous condition. If one or more potentially hazardous motions are controlled using a battery-powered operator control station, a clear indication shall be given to warn the operator when a variation in battery voltage exceeds specified limits. Under those circumstances, the operator control station shall remain functional long enough to put the machine into a nonhazardous condition. 9.3 Protective Interlocks. 9.3.1 Reclosing or Resetting of an Interlocking Safeguard. The reclosing or resetting of an interlocking safeguard shall not initiate machine motion or operation that results in a hazardous condition. 9.3.2 Overtravel Limits. Where a machine overtravel causes a hazardous condition, a position sensor or limit switch shall be provided to initiate control action. 9.3.3 Operation of Auxiliary Functions. 9.3.3.1 Appropriate devices (e.g., pressure sensors) shall check the correct operation of the auxiliary functions. 9.3.3.2 Where the nonoperation of a motor or device for an auxiliary function (e.g., lubrication, coolant, swarf removal) causes a hazardous condition or causes damage to the machine or to the work in progress, interlocking shall be provided. 9.3.4 Interlocks Between Different Operations and for Contrary Motions. 9.3.4.1 All contactors, relays, and other control devices that control elements of the machine that cause a hazardous condition when actuated at the same time (e.g., those that initiate contrary motion) shall be interlocked against incorrect operation. 9.3.4.2 Motor contactors and starters that initiate opposing motion shall be both mechanically and electrically interlocked to prevent simultaneous operation. Relays and solenoids that are mechanically interlocked shall be electrically interlocked. [ROP 79-65(Log 84)] 9.3.4.3 Where certain functions on the machine are required to be interrelated for safety or for continuous operation, coordination shall be ensured by interlocks. For a group of machines working together in a coordinated manner and having more than one controller, provision shall be made to coordinate the operations of the controllers as necessary.


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9.3.4.4 Where a failure of a mechanical brake actuator results in the brake being applied when the associated machine actuator is energized and a hazardous situation results, interlocks shall be provided to switch off the machine actuator. 9.3.5 Reverse Current Braking. 9.3.5.1 Where reverse current braking is used on a motor, effective measures shall be taken to prevent the motor starting in the opposite direction at the end of braking where this reversal will cause a hazardous condition or damage to the machine or to the work in progress. For this purpose, the use of a device operating exclusively as a function of time shall not be allowed. 9.3.5.2 Control circuits shall be arranged so that rotation of a motor shaft, manually or otherwise, shall not result in a hazardous condition. 9.3.6 Protective Interlock. Where doors are interlocked, the interlocking devices shall be listed safety switches to prevent the operation of the equipment when the doors are open. [ROP 79-79 (Log 116)] 9.4 Control Functions in the Event of Failure. 9.4.1* General Requirements. Where failures or disturbances in the electrical equipment can cause a hazardous condition or damage to the machine or the work in progress, measures shall be taken to minimize the probability of the occurrence of such failures or disturbances. [ROP 79-67 (Log 85)] 9.4.2 Protection Against Unintended Operation Due to Ground (Earth) Faults and Voltage Interruptions. 9.4.2.1 Ground (Earth) Faults. Ground (earth) faults on any control circuit shall not cause unintentional starting or potentially hazardous motions, or prevent stopping of the machine. Grounded control circuits shall be in accordance with Sections 8.2 and 8.3. Ungrounded control circuits shall be provided with an insulation monitoring device that either indicates a ground (earth) fault or interrupts the circuit automatically after a ground (earth) fault. A restart of the machine with a detected ground (earth) fault shall be prevented. [ROP 79-69 (Log 147)] 9.4.2.2 Voltage Interruptions. 9.4.2.2.1 The requirements detailed in Section 7.5 shall apply. 9.4.2.2.2 Where a memory is used, its functioning in the event of power failure shall be ensured (e.g., by using a nonvolatile memory) where such loss of memory can result in a hazardous condition. [ROP 79-62 (Log 46)]

Chapter 10 Operator Interface and Control Devices 10.1 General. 10.1.1* Applicability. This chapter shall contain the requirements for devices mounted outside or partially outside control enclosures. 10.1.2 Location and Mounting. 10.1.2.1 Control Devices. As far as is practicable, control devices shall be as follows:

(1) Readily accessible for service and maintenance (2) Mounted in such a manner as to minimize the possibility of

damage from activities such as material handling

10.1.2.2 Hand-Operated Control Devices. The actuators of hand-operated control devices shall be selected and installed as follows:

(1) They are not less than 0.6 m (2 ft) above the servicing level and are within easy reach of the normal working position of the operator.

(2) The operator is not placed in a hazardous situation when operating them.

(3) The possibility of inadvertent operation is minimized. 10.1.3* Protection. Operator interface, control devices, and enclosures shall be suitable for the environment and shall withstand the stresses of expected use. 10.1.4 Position Sensors. 10.1.4.1 Position sensors (e.g., limit switches, position switches, proximity switches) shall be arranged so that they will not be damaged in the event of overtravel. 10.1.4.2* Position sensors used in circuits with safety-related functions either shall have positive (direct) opening operation or shall provide similar reliability. 10.1.5 Portable and Pendant Control Stations. 10.1.5.1 Portable and pendant operator control stations and their control devices shall be selected and arranged to minimize the possibility of inadvertent machine operations. 10.1.5.2 Pendant control stations that are vertically suspended from overhead shall comply with 14.4.2.4 or 14.5.10. 10.1.6 Operator Interface Devices. 10.1.6.1 Location of Operator Interface Devices. 10.1.6.1.1 Operator interface devices shall be mounted in locations that will minimize exposure to oil, coolant, and other contaminants. 10.1.6.1.2 Operator interface devices shall be within normal reach of the machine operator and shall be placed so that the operator is not exposed to hazards. 10.1.6.1.3 Operator interface devices shall be located so that unintentional operation by normal movement of the machine, operator, or work will be unlikely. 10.1.6.2 Arrangement of Operator Interface Devices. All start pushbuttons shall be mounted above or to the left of their associated stop pushbuttons. Exception No. 1: Start pushbuttons in series, such as operating pushbuttons on punch presses. Exception No. 2: Wobble-stick or rod-operated emergency stop pushbuttons mounted in the bottom of pendant stations. 10.1.7 Foot-Operated Switches. Foot-operated switches used for applications where accidental actuation could create a hazardous


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situation shall be protected to prevent accidental actuation by falling or moving objects and from unintended operation by accidental stepping onto the switch. Exception: Foot-operated switches used for emergency stop in accordance with 10.7.2.1 shall not be of the covered or hooded type. 10.2 Pushbutton Actuators and Color Graphic Interface Devices. 10.2.1 Pushbutton Actuators. Pushbutton actuators used to initiate a stop function shall be of the extended operator or mushroom-head types. 10.2.2 Colors. Pushbutton actuators and action initiating icons of color graphic interface devices shall be color coded in accordance with 10.2.2.1 through 10.2.2.6. 10.2.2.1 Start or On. The preferred color of start or on shall be GREEN, except that BLACK, WHITE, or GRAY shall be permitted. RED shall not be used for start or on. 10.2.2.2 Stop or Off. The preferred color of stop or off shall be RED, except that BLACK, WHITE, or GRAY shall be permitted. GREEN shall not be used for stop or off. Exception: Stop function operators of the wobble-stick or rod-operated types in the bottom of a pendant station need not be colored RED. 10.2.2.3 Emergency Stop. RED shall be used for emergency stop actuators in accordance with 10.7.4. 10.2.2.4 Alternate Action. Pushbuttons that, when pressed, act alternately as start and stop or on and off shall be BLACK, WHITE, or GRAY. RED or GREEN shall not be used. 10.2.2.5 Abnormal Conditions. The color YELLOW shall be used for actuators used to respond to abnormal conditions. 10.2.2.6 Hold to Operate. Pushbuttons that cause movement when pressed and stop movement when they are released (e.g., jogging) shall be BLACK, WHITE, GRAY, or BLUE with a preference for BLACK. 10.2.2.7 Reset. Reset pushbuttons shall be BLUE, BLACK, WHITE, or GRAY except when they also act as a stop or off button, in which case they shall be RED. 10.2.3 Legends. 10.2.3.1 A legend shall be provided for each operator interface device to identify its function and shall be located so that it can be easily read by the machine operator from the normal operator position. The legends shall be durable and suitable for the operating environment. Exception: Emergency stop devices require no legend if they meet the requirements of 10.7.4. [ROP 79-104 (Log 3)] 10.2.3.2 For illuminated pushbuttons, the function(s) of the light is separated from the function(s) of the button by a virgule (/). 10.3 Indicator Lights and Icons of Color Graphic Interface Devices. 10.3.1 Modes of Use. Indicator lights and icons of color graphic interface devices shall provide the following information:

(1) Indication to attract the operator's attention or to indicate that a certain task should be performed. The colors RED, YELLOW (AMBER), GREEN, and BLUE are normally used in this mode.

(2) Confirmation of a command or a condition, or the

termination of a change or transition period. The colors BLUE and WHITE are normally used in this mode. GREEN shall be permitted to be used in some cases. 10.3.2 Colors. Indicator lights and icons of color graphic interface devices shall be color-coded with respect to the condition (status) of the machine in accordance with Table 10.3.2. Alternate purposes shall be permitted to indicate machine or process status.

Table 10.3.2. Machine Indicator Lights and Icons Purposes

Color Safety of Persons or Environment

Condition of Process

State of Equipment



GREEN Safe Normal Normal BLUE Mandatory action

CLEAR WHITE GRAY

BLACK


10.3.3 Flashing Lights. Flashing lights shall be permitted to be used for any of the following purposes:

(1) Attract attention (2) Request immediate action (3) Indicate a discrepancy between the command and actual

states (4) Indicate a change in process (flashing during transition)

10.4 Illuminated Pushbuttons. Illuminated pushbutton actuators shall be color-coded in accordance with Table 10.3.2. The color RED for the emergency stop actuator shall not depend on the illumination source. 10.5 Rotary Control Devices. Devices having a rotational member, such as potentiometers and selector switches, shall be mounted in such a way as to prevent rotation of the stationary member. Friction alone shall not be relied upon to prevent rotation. 10.6 Start Devices. Actuators used to initiate a start function or the movement of machine elements (e.g., slides, spindles, carriers) shall be constructed and mounted to minimize inadvertent operation. Mushroom-type actuators for two-hand control initiation shall conform to 9.2.5.6. 10.7 Devices for Stop and Emergency Stop. 10.7.1 Location and Operation. 10.7.1.1 Stop and emergency stop pushbuttons shall be continuously operable and readily accessible. 10.7.1.2 Stop and emergency stop pushbuttons shall be located at each operator control station and at other locations where emergency stop is required.


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10.7.2 Types. 10.7.2.1 The types of devices for emergency stop shall include, but are not limited to the following:

(1) Pushbutton-operated switches in accordance with 10.7.4 (2) Pull cord-operated switches (3) Foot-operated switches without a mechanical guard (4) Push bar-operated switches (5) Rod-operated switches

10.7.2.2* Pushbutton-type devices for emergency stop shall be of the self-latching type and shall have positive (direct) opening operation. [ROP 79-101 (Log 121)] 10.7.3 Restoration of Normal Function After Emergency Stop. It shall not be possible to restore an emergency stop circuit until the emergency stop device has been manually reset. Where several emergency stop devices are provided in a circuit, it shall not be possible to restore that circuit until all emergency stop devices that have been operated have been reset. Exception: Where emergency stop devices of the momentary type are used in accordance with the exception of 10.7.2.2, the emergency stop circuit shall be manually reset. 10.7.4 Emergency Stop Actuators. Actuators of emergency stop devices shall be colored RED. The background immediately around pushbuttons and disconnect switch actuators used as emergency stop devices shall be colored YELLOW. The actuator of a pushbutton-operated device shall be of the palm or mushroom-head type. The RED/YELLOW color combination shall be reserved exclusively for emergency stop applications. Exception: The RED/YELLOW color combination shall be permitted for emergency stop actuators in accordance with 10.8.4. 10.7.5 Local Operation of the Supply Disconnecting Means to Effect Emergency Stop. 10.7.5.1 The supply disconnecting means shall be permitted to be locally operated to serve the function of emergency stop as follows:

(1) Where it is readily accessible to the operator (2) Where it is of the type described in 5.3.2(1), (2), or (3)

10.7.5.2 Where used as an emergency stop, the supply disconnecting means shall meet the color requirements of 10.7.4. 10.8 Devices for Emergency Switching Off. 10.8.1 Location. Emergency switching off devices as described in 9.2.5.4.3 shall be located as necessary for the given application. 10.8.2 Types. 10.8.2.1 The types of devices that initiate an emergency switching off operation shall be permitted to include, but are not limited to the following: (1) Pushbutton-operated switches (2) Pull-cord-operated switches 10.8.2.2 The pushbutton operated switch shall be permitted in a break-glass enclosure.

10.8.3 Restoration of Normal Function After Emergency Switching Off. It shall not be possible to restore an emergency switching off circuit until the emergency switching off circuit has been manually reset. 10.8.4 Actuators. 10.8.4.1 Actuators of emergency switching off devices shall be colored RED. The background immediately around the device actuator shall be permitted to be colored YELLOW. 10.8.4.2 Where the emergency switching off initiating device is separate from the emergency stop device, the emergency switching off initiating device shall be functionally identified. 10.8.5 Local Operation of the Supply Disconnecting Means to Effect Emergency Switching Off. Where the supply disconnecting means is to be locally operated for emergency switching off, it shall be readily accessible and shall meet the color requirements of 10.8.4.1. 10.9* Displays. Displays [e.g., visual display units, alarm annunciators, indicator lights and the action-initiating icons of human-machine interface (HMI) devices] shall be selected and installed in such a manner as to be visible from the normal position of the operator. [ROP 79-99 (Log 24)]

Chapter 11 Electronic Equipment [ROP 79-155 (Log 25)]

11.1 General. 11.1.1 This chapter shall apply to all types of electronic equipment including programmable electronic systems, subassemblies, printed circuit boards, electronic components, and other miscellaneous solid state equipment. 11.1.2 Electronic equipment used as part of an industrial machine, including subassemblies, printed circuit boards, devices, internal wiring, and components, shall not be required to be inspected at the time of installation of the industrial machine, except to detect alterations or damage, if the equipment has been listed by a qualified electrical testing laboratory. 11.1.3 Listed or labeled electronic equipment shall be permitted to be used without modifications, on or with industrial machines, where approved for the location and use. 11.2 Basic Requirements. 11.2.1 Equipment Grounding (Equipotential Bonding). 11.2.1.1 All input/output racks (remote or local), processor racks, and conductive enclosures of power supplies shall be electrically bonded together in accordance with the supplier’s specifications and connected to the equipment grounding (protective bonding) circuit. 11.2.1.2 Where specified by the manufacturer, components and subassemblies shall be effectively bonded to the equipment grounding (protective bonding) circuit in accordance with the manufacturer’s recommendations. 11.2.2 Subassemblies. Subassemblies shall be readily removable for inspection or replacement. 11.2.3 Electrical Noise and Transient Suppression. Transient suppression, isolation, or other appropriate means shall be provided


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where the electronic equipment generates electrical noise or transients, which can affect the operation of equipment. 11.2.4 Output Protection. Outputs controlled by programmable electronic systems shall be protected from overload and short-circuit conditions. 11.3 Programmable Equipment. 11.3.1 Software Modification. Programmable electronic systems shall be designed and constructed so that the ability to modify the application program shall be limited to authorized personnel and shall require special equipment or other means to access the program (e.g., access code, key-operated switch). Exception: For safety reasons, the manufacturer or supplier shall be permitted to retain the right not to allow the user to alter the program. 11.3.2 Memory Retention and Protection. 11.3.2.1 Means shall be provided to prevent memory alteration by unauthorized persons. 11.3.2.2 Loss of memory shall not result in a hazardous condition. 11.3.2.3 Power supplies for electronic units that require memory retention shall have battery backup of sufficient capacity to prevent memory loss for a period of at least 72 hours. 11.3.3 Software Verification. Equipment using reprogrammable logic shall have means for verifying that the software is in accordance with the relevant program documentation. 11.3.4 Use in Safety-Related Functions. Software and firmware-based controllers used in place of hardware-based components with safety-related devices shall meet the following requirements: (1) Be designed so that any single safety-related component or firmware failure shall operate as follows: a. Lead to the shutdown of the system in a safe state b.* Prevent subsequent operation until the component failure has been corrected c. Prevent unintended start-up of equipment upon correction of the failure (2)* Provide protection equivalent to that of hardwired/hardware components (3) Incorporate at least one passive, self-monitored electromechanical device as backup to ensure a line disconnect in case of a failure of the solid state components (4) Be listed to an approved standard for safety-related functions such as UL 991 or UL 1998 [ROP 79-74 (Log 88)] [ROP 79-73 (Log 155)] 11.4* Adjustable Speed Drives. Where load conditions or reduced speeds can cause motor overheating, embedded motor thermal protection (effective over the motor speed range) shall be provided and interlocked with the adjustable speed drive system. [ROP 79-155 (Log 25)]

Chapter 12 Control Equipment: Location, Mounting, and Enclosures [ROP 79-84 (Log 54)]

12.1 General Requirements.

12.1.1 All control equipment shall be located and mounted so as to facilitate the following: (1) Accessibility and maintenance of the equipment (2) Protection against the external influences or conditions under which the equipment is intended to operate (3) Operation and maintenance of the machine and its associated equipment 12.1.2 Minimum construction requirements shall comply with UL 508 and UL 50 for metallic and nonmetallic enclosures. [ROP 79-87 (Log 131)] 12.1.3 The depth of the enclosure or compartment including doors or covers shall not be less than the maximum depth of the enclosed equipment plus the required electrical clearances. 12.1.4 Any door(s) that permits access to live parts shall comply with 6.3.2.5. 12.2 Location and Mounting. 12.2.1 Accessibility and Maintenance. 12.2.1.1 All items of control equipment shall be placed and oriented so that they can be identified without moving them or the wiring. Where practicable, items that require checking or adjustment for correct operation or that are liable to need replacement, those actions shall be possible without dismantling other equipment or parts of the machine (except opening doors or removing covers). Terminals not associated with control equipment shall also conform to these requirements. 12.2.1.2 Terminal blocks shall be mounted to provide unobstructed access to the terminals and their conductors. 12.2.1.3 Exposed, nonarcing, bare, live parts within an enclosure or compartment shall have an air space of not less than 13 mm (1/2 in.) between them and the uninsulated walls of the enclosure or compartment, including conduit fittings. The air space for uninsulated doors of the enclosure shall be not less than 25 mm (1 in.). Where barriers between metal enclosures or compartments and arcing parts are required, they shall be of flame-retardant, noncarbonizing insulating materials. [ROP 79-98 (Log 133)] 12.2.1.4* All control equipment shall be mounted so as to facilitate its operation and maintenance. Where a special tool is necessary to remove a device, the tool shall be supplied. 12.2.1.5 Threaded fasteners with machine threads shall be used to attach components to a subplate and shall provide sufficient thread engagement to maintain secure mounting. 12.2.1.5.1 Steel subplate thickness shall provide engagement of at least 2 full threads. 12.2.1.5.2 Aluminum subplate thickness shall provide engagement of at least 3 full threads. 12.2.1.5.3 Thread cutting or thread forming screws shall be permitted if the thread engagement requirements of 12.2.1.5.1 and 12.2.1.5.2 are met. 12.2.1.5.4 Sheet metal screws, rivets, welds, solders, or bonding materials shall not be used to mount components to a subplate.


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Exception: Rivets shall be permitted to be used for attaching mounting rails and wiring channels. 12.2.1.6 Swing frames or swing out panels shall be permitted, provided the swing is more than 110 degrees. Wiring shall not inhibit swing. Panel-mounted components behind swing frames shall be accessible when open. 12.2.1.7* Where control devices are connected through plug-in arrangements, their association shall be made clear by type (shape), marking, or reference designation, singly or in combination. 12.2.1.8 Attachment plugs and receptacles (plug/socket) combinations that are handled during normal operation shall be located and mounted as to provide unobstructed access. 12.2.1.9 Test points, where provided, shall be mounted to provide unobstructed access, plainly marked to correspond with markings on the drawings, adequately insulated, and sufficiently spaced for connection of test leads. 12.2.2 Physical Separation or Grouping. 12.2.2.1 Machine compartments containing control equipment (built-in control) shall be completely isolated from coolant and oil reservoirs. The compartment shall be readily accessible and completely enclosed. The compartment shall not be considered enclosed where it is open to the floor, the foundation upon which the machine rests, or other compartments of the machine that are not clean and dry. 12.2.2.2 Pipelines, tubing, or devices (e.g., solenoid valves) for handling air, gases, or liquids shall not be located in enclosures or compartments containing electrical control equipment. Exception No. 1: Equipment for cooling electronic devices. Exception No. 2: Pipelines, tubings, or devices that are an integral part of listed equipment and are separated by suitable barriers. [ROP 79-95 (Log 10)] 12.2.2.3 Control devices mounted within the control enclosure and connected to the supply voltage, or to both supply and control voltages, shall be grouped separately from those connected only to the control voltages. 12.2.2.4 Terminals shall be separated into groups for power circuits, associated control circuits, and other control circuits, fed from external sources (e.g., for interlocking). 12.2.2.5 The groups shall be permitted to be mounted adjacently, provided that each group can be readily identified (e.g., by markings, by use of different sizes, by use of barriers, by colors). 12.2.3 Heating Effects. Heat-generating components (e.g., heat sinks, power resistors) shall be located so that the temperature of each component in the vicinity remains within the component manufacturer’s specified limits. 12.3 Degrees of Protection. 12.3.1* The protection of control equipment against ingress of solid foreign objects and of liquids shall be adequate taking into account the external influences under which the machine is intended to

operate (i.e., the location and the physical environmental conditions including dust, coolants, and swarf). 12.3.2 Enclosures of control equipment shall provide a degree of protection of at least NEMA Type 1. Exception: Where removable collectors on collector wire or collector bar systems are used and NEMA Type 1 enclosures are not practicable, suitable protection shall be provided (e.g., elevation, guarding). 12.4 Enclosures, Doors, and Openings. 12.4.1 Enclosures shall be constructed and finished using materials capable of withstanding the mechanical, electrical, and thermal stresses, as well as the effects of humidity and corrosion that are likely to be encountered in normal service. 12.4.2 Where corrosion protection beyond normal requirements is needed, nonmetallic enclosures identified for the purposes shall be permitted if they meet the requirements of UL 508. 12.4.3 Subplates having a surface area of more than 15,484 cm2 (2400 in.2) shall have supports provided in addition to the panel mounting means to aid in subplate installation. 12.4.4 Enclosures and subplates shall be free of burrs and sharp edges. 12.4.5 The exterior of the enclosure shall be of a material suitable for the intended environment, or include a protective finish suitable for the intended environment. 12.4.6 Fasteners used to secure doors shall be of the captive type. Windows provided for viewing internally mounted indicating devices should be of a material suitable to withstand mechanical stress and chemical attack [e.g., toughened glass, polycarbonate sheet of 3-mm (1/8-in.) thickness]. 12.4.7 Door fasteners on enclosures and compartments with door openings less than 1016 mm (40 in.) tall shall be designed to seal the door tightly around its perimeter with either captive fasteners or vault-type hardware that latch at the top and bottom. 12.4.8 Door fasteners on enclosures and compartments with door openings 1016 mm (40 in.) tall or more shall be designed to seal the door tightly around its perimeter with either captive fasteners or vault-type hardware that latch at the top, center, and bottom. 12.4.9 A print pocket sized to accommodate electrical diagrams shall be attached to the inside of the door of the control enclosure or compartment. Single-door and multi-door enclosures shall have at least one print pocket. 12.4.10 The joints or gaskets of doors, lids, covers, externally mounted accessories, interconnect panels, and enclosures shall withstand the deleterious effects of liquids, vapors, or gases used on the machine. The means used to maintain the enclosure’s degree of protection on doors, lids, and covers that require opening or removal for operation or maintenance shall be securely attached to either the door/cover or the enclosure and not deteriorate due to removal or replacement of the door or the cover, which would impair the degree of protection. 12.4.11 All openings in the enclosure, including those towards the floor or foundation or to other parts of the machine, shall be closed


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by the supplier(s) in a manner ensuring the protection specified for the equipment. Openings for cable entries shall be easily reopened on site. A suitable opening shall be permitted in the base of enclosures within the machine so that moisture due to condensation is allowed to drain. 12.4.12 Openings shall not be permitted between enclosures containing electrical equipment and compartments containing coolant, lubricating fluids, or hydraulic fluids, or compartments into which oil, other liquids, or dust can penetrate. This requirement shall not apply to electrical devices specifically designed to operate in oil (e.g., electromagnetic clutches) nor to electrical equipment in which coolants are used. 12.4.13 Where there are holes in an enclosure for mounting purposes, care shall be taken so that after mounting, the holes do not impair the required protection. 12.4.14 Equipment that, in normal or abnormal operation, can attain a surface temperature sufficient to cause a risk of fire or harmful effect to an enclosure material shall be as follows:

(1) Located within an enclosure that will withstand, without risk of fire or harmful effect, such temperatures as can be generated

(2) Mounted and located at a sufficient distance from adjacent equipment so as to allow safe dissipation of heat (see also 12.2.3); or

otherwise screened by material that can withstand, without risk of fire or harmful effect, the heat emitted by the equipment 12.5 Spaces Around Control Cabinets and Compartments. Access and working space for control cabinets and compartments operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the provisions of Chapter 12. Sufficient access and working space shall be provided and maintained around all control cabinets and compartments to permit ready and safe operation and maintenance of such control cabinets and compartments. 12.5.1 Working Space. The working space shall permit at least 90-degree opening of control cabinet and compartment doors or hinged panels. 12.5.1.1 The depth of the working space in the direction of access to live parts shall not be less than indicated in Table 12.5.1.1. Distances shall be measured from the control cabinet or compartment front or opening.

Table 12.5.1.1 Working Space Depth

Minimum Clear Distance Nominal Voltage to

Ground Condition 1 Condition 2 Condition 3

0–150 900 mm (3 ft) 900 mm (3 ft) 900 mm (3 ft) 151–600 900 mm (3 ft) 1 m (3 ½ ft) 1.2 m (4 ft)

Note: Where the conditions are as follows: Condition 1 — Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by insulating materials. Insulated wire or insulated busbars operating at not over 300 volts to ground shall not be considered live parts. Condition 2 — Exposed live parts on one side and a grounded surface on the other side. Concrete, brick, or tile walls shall be considered as grounded. Condition 3 — Exposed live parts on both sides of the working space (not guarded as provided in Condition 1) with the operator between.

Exception No. 1: Working space shall not be required in back or sides of control cabinets or compartments, where there are no renewable or adjustable parts on the back or sides and where all connections are accessible from locations other than the back or sides. Where rear access is required to work on de-energized parts on the back of enclosed control cabinet and compartment, a minimum working space of 762 mm (2 1/2 ft) horizontally shall be provided. Exception No. 2: By special permission, working space clearance depth of 762 mm (2 1/2 ft) or less shall be permitted where all uninsulated parts are at a voltage no greater than 50 volts rms ac or 60 volts dc. Exception No. 3: Condition 2 working clearance depth shall be permitted between control cabinets or compartments located across the aisle from each other or across from nonmachinery associated switchgear, panelboards, or motor control centers where conditions of maintenance and supervision ensure that written procedures have been adopted to prohibit the affected equipment doors on both sides of the aisle from being open at the same time and qualified persons who are authorized will service the installation. Exception No. 4: Condition 1 working clearance depth shall be permitted where control cabinets or compartments are located across the aisle from each other, or across from a grounded surface, and all associated control cabinet or compartment devices and equipment operating at greater than 50 volts rms ac or 60 volts dc are protected or rated IP20 or greater. Exception No. 5: A working space clearance depth of 762 mm (2 1/2 ft) shall be permitted where all of the following conditions are met: (a) The control cabinet or compartment is operating at not over 150 volts line-to-line or line-to-ground. (b) The conditions of maintenance and supervision ensure that only qualified persons will service the installation. (c) The door(s) of the control cabinet or compartment open at least 90 degrees or are removable. Exception No. 6: By special permission, working space clearance depth of less than 762 mm (2 1/2 ft) shall be permitted where all of the following conditions are met: (a) The control cabinet or compartment is operating at not over 150 volts line-to-line or line-to-ground. (b) The conditions of maintenance and supervision ensure that only qualified persons will service the installation. (c) The control cabinet and compartment requires a tool to open. (d) Where only diagnostic troubleshooting and testing on live parts is involved. (e) The door(s) of the control cabinet and compartment open at least 90 degrees or are removable. 12.5.1.2 The width of the working space in front of control cabinets and compartments shall be the width of the control cabinet or compartment, or 762 mm (2 1/2 ft), whichever is greater. 12.5.1.3 The working space height shall be clear and extend from the grade, floor, or platform to a height of 1.98 m (6 1/2 ft). Within the height requirements of Section 12.5, other equipment associated with the machine located above or below the control cabinet or compartment shall be permitted to extend not more than 153 mm (6 in.) beyond the front of the electrical control cabinet or compartment. 12.5.2 Access. At least one entrance of sufficient area shall be provided to give access to the working space around control cabinets or compartments. 12.5.2.1 Working space required by Section 12.5 shall not be used for storage.


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12.5.2.2 When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded. [ROP 79-32 (Log 96)] 12.5.3 Door in gangways and for access to electrical operating areas shall be at least 0.7 m (2 ft 4 in.) wide and 2.0 m (6 ft 7 in.) high, open outwards, and have a means (e.g., panic bolts or panic bars) to allow opening from the inside without the use of a key or tool. 12.6 Machine-Mounted Control Equipment. 12.6.1 Control equipment (e.g., limit switches, brakes, solenoids, position sensors) shall be mounted rigidly in a reasonably dry and clean location, shall be protected from physical damage, and shall be free from the possibility of accidental operation by normal machine movements or by the operator. Such equipment shall be mounted with sufficient clearance from surrounding surfaces to make its removal and replacement easy and shall have a suitable enclosure for the termination of conduit as well as provisions for making electrical connections. Exception No. 1: A solenoid sealed in an individual oil-filled container shall be permitted. Exception No. 2: Prewired devices (e.g., limit switches, proximity switches) provided with an identified cable need not be equipped with provisions for termination of conduit. 12.6.2 All limit switches or position sensors shall be installed so that accidental overtravel by the machine will not damage the limit switch or sensor. 12.6.3 Solenoids for operating devices shall be mounted so that liquids drain away from the electrical component enclosure. [ROP 79-84 (Log 54)]

Chapter 13 Conductors, Cables, and Flexible Cords [ROP 79-112 (Log 28)]

13.1 General Requirements. 13.1.1 General. Conductors, cables, and flexible cords shall be selected for the operating conditions (e.g., voltage, current, protection against electric shock, grouping of cables) and external influences (e.g., ambient temperature; presence of water or corrosive substances; mechanical stresses, (including stresses during installation, fire hazards) that can exist. Conductors, cables, and flexible cords shall be identified for their intended use. 13.1.2 Wire Insulation. Conductors shall be insulated. Exception No. 1: Bus bars shall not be required to be insulated. Exception No. 2: Bare conductors, such as capacitor or resistor leads and jumpers between terminals, shall be permitted where the method of securing provides electrical clearance. Exception No. 3: Equipment grounding conductors and bonding jumpers shall be permitted to be covered or bare.

13.1.3 Type MI Cable. Mineral-insulated, metal-sheathed cable, Type MI, shall be permitted. Temperature range shall be 85°C (185°F) for dry and wet locations. 13.1.4 Conductors and Static Control. Conductors smaller than 18 AWG used to connect electronic programmable control, input/output and static control shall be listed. 13.2 Conductors. 13.2.1 Conductor Material. Conductors shall be copper. Exception No. 1: Aluminum alloy busbars, located internal to the enclosure, shall be permitted where suitable for the application. Exception No. 2: The metal frame of the machine shall be permitted to be used as an equipment grounding (protective bonding) conductor. 13.2.2 Stranded Conductors. Conductors of sizes 22 through 4/0 AWG and sizes 250 through 1000 kcmil shall be only of stranded soft-annealed copper. Requirments for conductor cross-sectional area, dc resistance, and stranding shall be in accordance with Table 13.2.2. Exception No. 1: Conductors with stranding other than that specified in Table 13.2.2 shall be permitted on individual devices that are purchased completely wired (e.g., motor starters). Exception No. 2: Conductors subject to temperatures, voltages, environmental conditions, or flexing exceeding the ratings listed in this chapter shall have suitable characteristics. 13.2.3 Constant Flexing. Where constant flexing service is required, conductor stranding shall conform to Table 13.2.2. 13.2.4 Solid Conductors. Solid conductors 24 to 30 AWG of soft-annealed copper shall be permitted for use within control enclosures where not subject to flexing. 13.2.5 Printed Wire Assemblies. Printed wire assemblies of flame-retardant material shall be permitted in place of conductor assemblies provided they are within control enclosures and are mounted in such a way as to minimize flexing or stress. 13.2.6 Shielded Conductors. Where shielding is used around conductors in single or multiconductor cables, a foil shield shall be permitted for nonflexing applications. A continuous drain wire shall be provided for foil shield types. A braided shield shall be used where subject to longitudinal flexing. Torsional flexing applications (e.g., a robot arm) shall require shields designed specifically for their use. The shields and drain wire shall be covered with an outer jacket that is suitable for the environment. In all cases the shield shall provide a continuous conduction surface in the presence of bending and flexing. 13.2.7 Special Cables and Conductors. 13.2.7.1 Other listed conductors and listed cables shall be permitted. 13.2.7.2 Special conductors such as RG-/U transmission cable shall be permitted where necessary for the proper functioning of the equipment.


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13.3 Insulation. 13.3.1 The insulation and the finished wires and cables shall have flame-retardant properties and temperature limits and characteristics as follows: (1) MTW - Moisture-, Heat-, and Oil-Resistant Thermoplastic 60°C (140°F) Wet Locations 90°C (194°F) Dry Locations (2) THHN - Heat-Resistant Thermoplastic 90°C (194°F) Dry Locations

(3) THW - Moisture- and Heat-Resistant Thermoplastic 75°C (167°F) Dry and Wet Locations (4) THWN - Moisture- and Heat-Resistant Thermoplastic 75°C (167°F) Dry and Wet Locations 13.3.2 The average and the minimum thickness of the insulation in constructions A and B shall be in accordance with Table 13.3.2. 13.3.3 Construction B shall have a nylon jacket applied directly over the insulation. The jacket shall be snug on the insulation and shall be at least as thick as indicated in Table 13.3.2.

Table 13.2.2 Single Conductor Characteristics

Minimum Number of Strands

Wire Size or

(AWG/kcmil)

Cross-Sectional area, Nominal

(cm/mm2)

DC Resistance at

25oC

(ohms/1000 ft)

Nonflexing

(ASTM Class)

Flexing

(ASTM Class)

Constant Flex

(ASTM Class/AWG Size)

22 AWG 20 18 16 14 12 10 8 6 4 3 2 1

1/0 2/0 3/0 4/0

250 kcmil 300 350 400 450 500 550 600 650 700 750 800 900

1000

640/0.324 1020/0.519 1620/0.823 2580/1.31 4110/2.08 6530/3.31

10380/5.261 16510/8.367 26240/13.30 41740/21.15 52620/26.67 66360/33.62 83690/42.41 105600/53.49 133100/67.43 167800/85.01 211600/107.2

- /127 - /152 - /177 - /203 - /228 - /253 - /279 - /304 - /329 - /355 - /380 - /405 - /456 - /507

17.2 10.7 6.77 4.26 2.68 1.68 1.060

0.6663 0.4192 0.2636 0.2091 0.1659 0.1315 0.1042 0.08267 0.06658 0.05200 0.04401 0.03667 0.03144 0.02751 0.02445 0.02200 0.02000 0.01834 0.01692 0.01572 0.01467 0.01375 0.01222 0.01101

7(“) 10(K) 16(K) 19(C) 19(C) 19(C) 19(C) 19(C) 19(C) 19(C) 19(C) 19(C) 19(B) 19(B) 19(B) 19(B) 19(B) 37(B) 37(B) 37(B) 37(B) 37(B) 37(B) 61(B) 61(B) 61(B) 61(B) 61(B) 61(B) 61(B) 61(B)

7(“) 10(K) 16(K) 26(K) 41(K) 65(K) 104(K)

(\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\) (\)

19(M/34) 26(M/34) 41(M/34) 65(M/34) 41(K/30) 65(K/30)

104(K/30) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–) (–)

(B), (C), (K) — ASTM Class designation B and C per ASTM B 8-81, Class designation K per ASTM B 174-1971 (R1980). (‘)— A class designation has not been assigned to this conductor but is designated as size 22-7 in ASTM B286-1974 (R1979) and is composed of strands 10 mils in diameter (30 AWG). (\) — Nonflexing construction shall be permitted for flexing service. Per ASTM Class designation B 174-1971 (R1980) Table 3. (–)— Constant flexing cables are not constructed in these sizes.


1862

Table 13.3.2 – Thickness of Single Conductor

Unsulation (Mils)

Wire Size A B

(AWG or kcmil) Average/Minimum (Average/Minimum(Jacket)]

22 AWG 30/27 15/13(4) 20 30/27 15/13(4) 18 30/27 15/13(4) 16 30/27 15/13(4) 14 30/27 15/13(4) 12 30/27 15/13(4) 10 30/27 20/18(4) 8 45/40 0/27(5) 6 60/54 30/27(5)

4–2 60/54 40/36(6) 1–4/0 80/72 50/45(7)

250–500 Kcmil 95/86 60/54(8) 550–1000 110/99 70/63(9)

*UL 1063 Table 1.1 NEC Construction. A—no outer covering. B—nylon covering.

13.4 Wire Markings. 13.4.1 A durable legend printed on the outer surface of the insulation of construction A, on the outer surface of the nylon jacket of construction B, on the outer surface of the insulation under the jacket of construction B (only if clearly legible through the nylon), or on the outer surface of the jacket of a multiconductor cable shall be repeated at intervals of no more than 610 mm (24 in.) throughout the length of the single-conductor or the multiconductor cable. Exception: Sizes smaller than 16 AWG shall be permitted to be marked on the reel or on the smallest unit of the shipping carton. 13.4.2 The legend shall include the manufacturer's name or trademark, the wire type, voltage rating, and gauge or size. 13.4.3 Where the conductor size is 16 through 10 AWG and the stranding is intended for flexing service, the legend shall include "flexing" or "Class K." 13.4.4 Wire insulation shall be identified and adequate for the voltage on that conductor. 13.5 Conductor Ampacity. The continuous current carried by conductors shall not exceed the values given in Table 13.5. [ROP 79-120 [Log 90)]

Table 13.5 – Conductor Ampacity Based on Copper Conductors with 60°C and 75°C Insulation in an Ambient

Temperature of 30°C

Conductor

Size

(AWG)

Ampacity

60oC 75oC

30 – 0.5

28 – 0.8

26 – 1

24 2 2

22 3 3

20 5 5

18 7 7

16 10 10

14 15 15

12 20 20

10 30 30

8 40 50

6 55 65

4 70 85

3 85 100

2 95 115

1 110 130

0 125 150

2/0 145 175

3/0 165 200

4/0 195 230

250 215 255

300 240 285

350 260 310

400 280 335

500 320 380

600 355 420

700 385 460

750 400 475

800 410 490

900 435 520

1000 455 545 Notes: 1. Wire types listed in Section 13.3.1 shall be permitted to be used at the ampacities listed in this table 2. The sources for the ampacities in this table are Table 310-16 of NFPA 70, National Electrical Code.

13.5.1 Motor circuit conductors supplying a single motor shall have an ampacity not less than 125 percent of the motor full-load current rating. 13.5.2 Combined load conductors shall have an ampacity not less than 125 percent of the full-load current rating of all resistance heating loads plus 125 percent of the full-load current rating of the highest rated motor plus the sum of the full-load current ratings of all other connected motors and apparatus in operation at the same time.


1863

13.5.3 Where ampacity derating is required for ambient temperature correction for other than 30o C or adjusted for more than three current-carrying conductors in a raceway or cable, the factor(s) shall be taken from Tables 13.5.3(a) and 13.5.3(b). Sizing of conductors within control enclosures in wiring harnesses or wiring channels shall be based on the ampacity in cable or raceway. [ROP 79-120 (Log 90)] [ROP 79-121 (Log 91)]

Table 13.5.3(a) Correction Factors

Ambient Temp. (°°°°C)

Factor Ambient Temp. (°°°°F)

75OC 21-25 1.05 70-77 26-30 1.00 78-86 31-35 .94 87-95 36-40 .88 96-104 41-45 .82 105-113 46-50 .75 114-122 51-55 .67 123-131 56-60 .58 132-140 61-70 .33 141-158

[ROP 79-121 (Log 91)]

Table 13.5.3(b) Adjustment Factors for More Than Three Current-Carrying Conductors in a Raceway or Cable

Number of Current-Carrying Conductors

Percent of Values in Table 13.5.3(a) as Adjusted for Ambient Temperature if

Necessary 4 – 6 80 7 – 9 70

10 – 20 50 21 – 30 45 31 – 40 40

41 and above 35 [ROP 79-121 (Log 91)]

13.5.4 The maximum size of a conductor selected from Table 13.5 and connected to a motor controller shall not exceed the values given in Table 13.5.4. Exception: Where other motor controllers are used, the maximum conductor size shall not exceed that specified by the manufacturer.

Table 13.5.4 – Maximum Conductor Size for Given Motor Controller Size*

Motor Controller Size Maximum Conductor Size (AWG or Kcmil)

00

0

1

2

3

4

5

14 AWG

10

8

4

0

000

500 Kcmil

*See ANSI/NEMA ICS 2-[1993] table 2, 110-1.

13.5.5 Conductor/Terminal Compatibility. The conductor(s) shall be compatible with the device terminal(s), and the conductor size(s) shall not exceed the range recommended by the device manufacturer. 13.6 Conductor Sizing. 13.6.1 Conductors shall not be smaller than the following: (1) Power circuits 14 AWG Exception No. 1: 16 AWG shall be permitted where applicable as follows:

(a) For nonmotor power circuits of 8 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 16 AWG wire or Class CC, J, or T fuses rated at not more than 10 amperes or

(b) For motor loads with a full-load ampacity of 8 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 16 AWG wire or Class CC, J, or T fuses and Class 10 overload protection per UL 508, or

(c) For motor loads with a full-load ampacity of 5.5 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 16 AWG wire or Class CC, J, or T fuses and Class 20 overload protection per UL 508, and

(d) Where part of a jacketed multiconductor cable assembly or flexible cord, or as individual conductors, where used in a cabinet or enclosure. Exception No. 2: 18 AWG shall be permitted where applicable as follows:

(a) For nonmotor power circuits of 5.6 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 18 AWG wire or Class CC, J, or T fuses rated at not more than 7 amperes or

(b) For motor loads with a full-load ampacity of 5 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 18 AWG wire or Class CC, J, or T fuses and Class 10 overload protection per UL 508, or

(c) For motor loads with a full-load ampacity of 3.5 amperes or less, where protected in accordance with Chapter 7 using branch-circuit-rated circuit breakers listed for use with 18 AWG wire or with Class CC, J, or T fuses and Class 20 overload protection per UL 508 and

(d) Where part of a jacketed multiconductor cable assembly or flexible cord, or as individual conductors, where used in a cabinet or enclosure. [ROP 79-116 (Log 162)] (2) Lighting and control circuits conductors on the machine and in raceways shall not be smaller than 16 AWG. Exception: In a jacketed, multiconductor cable assembly, 18 AWG shall be permitted. (3) Control circuits within control enclosures or operator stations shall not be smaller than 18 AWG. (4) Electronic programmable control input/output and static control.

a. Conductors in raceways shall not be smaller than 24 AWG.


1864

Exception: In a jacketed, multiconductor cable assembly or cord, 30 AWG or larger shall be permitted.

b. Conductors within control enclosures shall not be smaller than 26 AWG. Exception: For jumpers and special wiring applications (e.g., solderless wrap or wire-clip-type connections or shielded conductors), conductors 30 AWG or larger shall be permitted. 13.6.2 Shielded Conductors. Shielded conductors shall consist of stranded, annealed copper of 25 AWG or larger for single conductors used in subassemblies and 22 AWG or larger for all other uses. 13.7 Conductors and Cables Used for Flexing Applications. 13.7.1 General. 13.7.1.1 Conductors and cables used for flexing applications shall be selected from Table 13.5. 13.7.1.2* Cables that are subjected to severe duties shall be of adequate construction to protect against the following: (1) Abrasion due to mechanical handling and dragging across rough surfaces (2) Kinking due to operation without guides (3) Stress resulting from guide rollers and forced guiding and being wound and rewound on cable drums 13.7.2* Mechanical Rating. The cable handling system of the machine shall be so designed to keep the tensile stress of the conductors as low as practicable during machine operations. Where copper conductors are used, the tensile stress shall not exceed 15 N/mm2 (2176 psi) of the copper cross-sectional area. 13.7.3* Current-Carrying Capacity of Cables Wound on Drums. Cables to be wound on drums (see Table 13.7.3) shall be selected with conductors of a cross-sectional area such that, when fully wound on and carrying the normal service load, the maximum allowable operating temperature is not exceeded. 13.8 Flexible Cords. 13.8.1 Multiconductor flexible cords shall be suitable for the intended use.

13.8.2 Ampacity of Flexible Cords. The continuous current by flexible cords shall not exceed the values given in Table 13.8.2.

Table 13.9.1 Allowable Ampacity for Flexible Cords and Cables [Based on Ambient Temperature of 30°°°°C (86°°°°F). See NFPA 70, National Electrical Code,

400.13 and 400.4].

Thermoset Type TS

Thermoset Types C, E, EO, PD, S, SJ, SJO, SJOW, SJOO, SJOOW,

SO, SOW, SOO, SOOW, SP-1, SP-2, SP-3, SRD, SV,

SVO, SVOO

Size (AWG)

Thermoplastic Types TPT, TST

Thermoplastic Types ET, ETLB, ETP, ETT, SE,

SEW, SEO, SEOW, SEOOW, SJE, SJEW,

SJEO, SJEOW, SJEOOW, SJT, SJTW, SJTO, SJTOW,SJTOO, SJTOOW, SPE-1, SPE-2, SPE-3, SPT-1, SPT-1W, SPT-2, SPT-2W, SPT-3, ST, SRDE, SRDT, STO, STOW, STOO, STOOW, SVE, SVEO, SVT, SVTO,

SVTOO

Types HPD, HPN,

HS, HSJ, HSO, HSJO,

HSOO, HSJOO

Aa Bb 27c 0.5 — — — 20 — 5d e — 18 — 7 10 10 17 — — 12 — 16 — 10 13 15 15 — — — 17 14 — 15 18 20 12 — 20 25 30 10 — 25 30 35 8 — 35 40 — 6 — 45 55 — 4 — 60 70 — 2 — 80 95 —

aThe allowable currents apply to 3-conductor cords and other multiconductor cords connected to utilization equipment so that only 3 conductors are currentcarrying. b The allowable currents apply to 2-conductor cords and other multiconductor cords connected to utilization equipment so that only 2 conductors are current carrying. c Tinsel cord. d Elevator cables only. e7 amperes for elevator cables only; 2 amperes for other types. Source: Table 13.9.1 is based on NFPA 70, National Electrical Code, Table 400.5(A). [ROP 79-112 Log 28)]

Table 13.7.3 Derating Factors for Cables Wound on Drums

Drum Type Number of Layers of Cable

Any Number 1 2 3 4 Cylindrical ventilated — 0.85 0.65 0.45 0.35 Radial ventilated 0.85 — — — — Radial nonventilated 0.75 — — — — Notes:

1. A radial-type drum is one where spiral layers of cable are accommodated between closely spaced flanges; if fitted with solid flanges, the drum is described as nonventilated and if the flanges have suitable apertures, as ventilated.

2. A ventilated cylinder drum is one where the layers of cable are accommodated between widely spaced flanges and the drum andsuitable ventilating apertures. 3. It is recommended that the use of derating factors be discussed with the cable and the cable drum manufacturers. This can resufactors being used.


1865

Chapter 14 Wiring Practices [ROP 79-122 (Log 55)]

14.1 Connections and Routing. 14.1.1 General Requirements. 14.1.1.1 All connections shall be secured against accidental loosening and shall ensure a thoroughly good connection. 14.1.1.2 The means of connection shall be identified for the cross-sectional areas and the type of conductors being terminated. 14.1.1.3 Terminals for more than one conductor shall be so identified. 14.1.1.4 A power distribution block designed for multiple tap conductors (e.g., single or multiple conductors “in” and multiple conductors “out”) shall be permitted for additional tap connections and circuit branching. 14.1.1.5 Soldered connections shall only be permitted where terminals are provided that are identified for soldering. 14.1.1.6 Terminals on terminal blocks shall be plainly identified to correspond with markings on the diagrams. 14.1.1.7 The installation of flexible conduits and cables shall be such that liquids drain away from the fittings. Where practicable, raceway connections shall enter the sides or bottom of an enclosure or box. 14.1.1.8 Means of retaining conductor strands shall be provided when terminating conductors at devices or terminals that are not equipped with this facility. Solder shall not be used for that purpose. 14.1.1.9 Shielded conductors shall be terminated so as to prevent fraying of strands and to permit easy disconnection. 14.1.1.10* Identification tags shall be readable, permanent, and identified for use in the physical environment. 14.1.1.11* Terminal blocks shall be mounted and wired so that the internal and external wiring does not cross over the terminals. 14.1.2 Conductor and Cable Runs. 14.1.2.1 Conductors and cables shall be run from terminal to terminal without splices or joints. Exception No. 1: Splices shall be permitted to leads attached to electrical equipment, such as motors and solenoids. Such splices shall be insulated with oil-resistant electrical tape or insulation equivalent to that of the conductors and installed in a suitable enclosure. Exception No. 2: Where it is impracticable to provide terminals in a junction box (e.g., on mobile machines, on machines having long flexible cables) the use of splices or joints shall be permitted. 14.1.2.2 Factory-applied connectors molded onto cables shall be permitted. Such connectors shall not be considered as splices or joints. 14.1.2.3 Where it is necessary to connect and disconnect cables and cable assemblies, an additional length shall be provided for that purpose.

14.1.2.4 The terminations of cables shall be supported to prevent mechanical stresses at the termination of the conductors. 14.1.3 Conductors of Different Circuits. Conductors of different circuits shall be permitted to be laid side by side and occupy the same raceway (duct) (e.g., wireway or cable trunking), or be in the same multiconductor cable assembly, provided that the arrangement does not impair the functioning of the respective circuit. Functionally associated circuit conductors including power, control, remote input/output, signaling, and communication cables shall be permitted in the same raceway or cable assembly regardless of voltage, provided all are insulated for the maximum voltage of any circuit within the raceway or cable assembly. Where those circuits operate at different voltages, the conductors shall be separated by barriers or shall be insulated for the highest voltage to which any conductor within the same raceway (duct) or cable assembly is subjected. Exception: Different voltage insulation levels or conductor properties shall be permitted in the same cable assembly, provided the cable assembly has been designed and tested to the identified application. 14.1.4 Cables. 14.1.4.1 Exposed cables intalled along the structure of the equipment or system or in the chases of the machinery shall be permitted. Exposed cables shall be installed to closely follow the surface and structural members of the machinery. 14.1.4.2 Cables shall be supported by the equipment or system structure as follows:

(1) In such a manner that the cable will not be damaged by normal equipment use

(2) Every 305 mm (12 in.) in a nonvertical run Exception: The supporting distance shall be permitted to be increased up to 914 mm (36 in.) where the structure of the machine or system makes support impractical every 305 mm (12 in.).

(3) Every 914 mm (36 in.) in a vertical run Exception: Supporting distance shall be permitted to be increased to 2.44 m (96 in.), where the structure of the machine or system makes support impractical every 914 mm (36 in.).

(4) When suspended in air spanning a distance up to 457 mm (18 in.) Exception: Span distance shall be permitted to be increased up to 914 mm (36 in.), where the structure of the machine or system makes support impractical every 457 mm (18 in.). 14.1.4.3 Cables shall not be supported by machinery guards that are likely to be removed for maintenance access. Exception: Wiring for components that are an integral part of the guard and designed to remain on the guard when the guard is removed for maintenance access shall be permitted to be supported by the guard. [ROP 79-139 (Log 134)] 14.1.4.4 Multiple cables shall be permitted to be supported and fastened together in a bundle, provided the method of support and fastening is sufficient to support the mechanical weight and strain of the bundle.


1866

14.1.4.5 Cables shall be fastened where supported. Exception No. 1: Where horizontal runs are inherently supported by the machine or system structure or by a floor or deck, fastening is not required. Exception No. 2: Where run at not more than a 45-degree angle from horizontal, fastening is not required. 14.1.4.6 Cables shall be fastened with cable ties supported by any of the following methods:

(1) Screw-on cable tie mounts (2) Hammer-on cable tie mounting clips (3) Around the machine or system structural members (4) Through holes in the machine or system structural members (5) Cable mounting clamps (6) Other methods identified as acceptable for the purpose

14.1.4.7 The free ends of cable ties shall be cut flush after final adjustment and fastening. Cable ties of the reusable or releasable type shall not be permitted for use as a permanent fastening method. 14.1.4.8 Cables shall be protected from physical damage as follows:

(1) By alternative routing (2) With additional guarding or railings (3) When supported by flooring or decking, with walk over or

drive over cable protective devices (4) By installation in a wire way (5) By installation in a floor or deck covering trapezoidal walk

over raceway specifically designed for cable protection 14.1.4.9 Bends in cables shall be made so as not to cause undue stress. The radius of the curve (measured from the inside edge of the bend) shall not be less than five times the diameter of the cable. 14.1.4.10 Where a cable is used in a length longer than optimally required, the excess cable shall be coiled in loops. The coil shall be fastened to itself and to the machinery structure. Exception: When an excess cable is associated with a horizontal cable run that is inherently and fully supported, the coil is not required to be fastened to the equipment or system structure. 14.2 Identification of Conductors. 14.2.1 General Requirements. 14.2.1.1 Conductors shall be identified at each termination by number, letter, color (either solid or with one or more stripes), or a combination thereof and shall correspond with the technical documentation. Exception No. 1: Internal wiring on individual devices purchased completely wired. Exception No. 2: Where the insulation used is not available in the colors required (e.g., high temperature insulation, chemically resistant insulation). Exception 3: Where multiconductor cable is used and other means of permanent identification is provided. 14.2.1.2 Where numbers are used, they shall be Arabic; letters shall be Roman (either upper or lower case).

14.2.2 Identification of the Equipment Grounding (Protective) Conductor. 14.2.2.1* The color GREEN (with or without one or more YELLOW stripes) shall be used to identify the equipment grounding conductor where insulated or covered. This color identification shall be strictly reserved for the equipment grounding (protective bonding) conductor. Exception No. 1: In multiconductor cable-connected assemblies where equipment grounding is not required, the solid color GREEN shall be permitted for other than equipment grounding. Exception No. 2: It shall be permitted to use conductors of other colors provided the insulation or cover is appropriately identified at all points of access. Exception No. 3: For grounded control circuits, use of a GREEN insulated conductor (with or without one or more YELLOW stripes) or a bare conductor from the transformer terminal to a grounding terminal on the control panel shall be permitted. 14.2.2.2 Where the equipment grounding (protective) conductor is identified by its shape, position, or construction (e.g., a braided conductor), or where the insulated conductor is not readily accessible, color coding throughout its length shall not be required. But the ends or accessible positions shall be clearly identified by Figure 8.2.1.2.4, the color GREEN (with or without one or more YELLOW stripes), or the bicolor combination GREEN and YELLOW. 14.2.3 Identification of the Grounded Circuit Conductor. 14.2.3.1* Where an ac circuit includes a grounded conductor, this conductor shall be WHITE, GRAY, or three continuous WHITE stripes on other than GREEN, BLUE, ORANGE, or YELLOW insulation along its entire length. 14.2.3.2 The use of other colors for the following applications shall be as follows:

(1) WHITE with BLUE stripe for grounded (current-carrying) dc circuit conductor.

(2) WHITE with ORANGE stripe or WHITE with YELLOW stripe for grounded (current-carrying) circuit conductor, which remains energized when the main disconnecting means is in the off position. The color choice of the stripe shall be consistent with the ungrounded conductor of the excepted circuit. 14.2.3.3 Where identification by color is used, bus bars used as grounded conductors shall be either colored by a stripe, 15 mm to 100 mm ((0.6 in. to 3.9 in.) wide in each compartment or unit or at each accessible position, or colored throughout their length. 14.2.4 Identification by Color for Other Conductors. 14.2.4.1* Ungrounded circuit conductors that remain energized when the supply disconnecting means is in the off position shall be consistently applied as either ORANGE or YELLOW. These color identifications shall be strictly reserved for this application only. Exception No. 1: Internal wiring on individual devices purchased completely wired.


1867

Exception No. 2: Where the insulation used is not available in the colors required (e.g., high temperature insulation, chemically resistant insulation). [ROP 79-130 (Log 67)] 14.2.4.2 Where color is used for identification, the color shall be used throughout the length of the conductor either by the color of the insulation or by color markers. Exception: Multiconductor cables shall be permitted to be permanently reidentified at the time of installation. 14.2.4.3 The use of other colors for the purpose of identification shall be as follows:

(1) BLACK for ungrounded line, load, and control conductors at line voltage

(2) RED for ungrounded ac control conductors at less than line voltage

(3) BLUE for ungrounded dc control conductors Exception No. 1: Internal wiring on individual devices purchased completely wired. Exception No. 2: Where the insulation used is not available in the colors required (e.g., high temperature insulation, chemically resistant insulation). Exception No. 3: Where multiconductor cable is used and other means of permanent identification is provided. Exception No. 4: Where the identification of machine power and control wiring is such that compliance with the mandatory color codes is too restrictive for specific applications, it shall be permitted to use additional identification at selected locations as an alternative. This means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved means and shall be permanently posted on the inside of the main electrical control panel enclosure in a visible location. [ROP 79-129 (Log 57)] 14.3 Wiring Inside Enclosures. 14.3.1* Panel conductors shall be supported where necessary to keep them in place. Nonmetallic ducts shall be permitted only when they are made with a flame-retardant insulating material. 14.3.2 Electrical equipment mounted inside enclosures shall be installed in such a way as to permit access to the wiring. 14.3.3 Conductors and cables used to connect devices mounted on doors or to other movable parts shall comply with flexing requirements of Section 13.7. Conductors and cables used for flexing applications shall be of sufficient length to permit full movement of the door or the moveable part. The conductors shall be anchored to the fixed part and to the movable part independently of the electrical connection. 14.3.4 Conductors that do not run in ducts shall be supported. 14.3.5 Multiple-device control panels shall be equipped with terminal blocks or with attachment plugs and receptacles for all outgoing control conductors. 14.3.6 The direct connection of power cables and cables of measuring circuits to the terminals of the devices for which the connections were intended shall be permitted.

14.3.7 Flexible cords, ac receptacles, ac plugs, appliance couplers and power cord sets shall be permitted inside enclosures for internal wiring and connections between assemblies with ac power where used in accordance with their listing. 14.4 Wiring Outside Enclosures. 14.4.1 General Requirements. The means of introduction of cables or ducts with their individual glands, bushings, and so forth into an enclosure shall ensure that the degree of protection is not reduced. 14.4.2 External Raceways (Ducts). 14.4.2.1 All conductors of the same ac circuit routed to the same location shall be contained in the same raceway (duct). 14.4.2.2 Conductors external to the electrical equipment enclosure(s) shall be enclosed in raceway (duct) described in Section 14.5. Exception: Cables and cable connectors need not be enclosed in a raceway where they are otherwise protected and supported. 14.4.2.3 Fittings used with raceways (ducts) or multiconductor cable shall be identified for use in the physical environment. 14.4.2.4 Flexible conduit or multiconductor cable with flexible properties shall be used where it is necessary to employ flexible connections to pendant pushbutton stations. The weight of the pendant stations shall be supported by means other than the flexible conduit or the multiconductor cable with flexible properties, except where the conduit or cable is specifically designed for that purpose. 14.4.2.5 Flexible conduit or multiconductor cable with flexible properties shall be used for connections involving small or infrequent movements. They shall also be permitted to complete the connection to stationary motors, position switches, and other externally mounted devices. Where prewired devices (e.g., position switches, proximity switches) are supplied, the integral cable shall not be required to be enclosed in a raceway (duct). 14.4.3 Connection to Moving Elements of the Machine. 14.4.3.1 Connections to moving parts shall be made using conductors in accordance with Section 13.7. Flexible cable and conduit shall have vertical connections and shall be installed to avoid excessive flexing and straining. Horizontal connections shall be permitted where the flexible cable or conduit is adequately supported. Cable with flexible properties and flexible conduit shall be so installed as to prevent excessive flexing and straining, particularly at the fittings. 14.4.3.2 Cables with flexible properties subject to movement shall be supported in such a way that there is neither mechanical strain on the connection points nor any sharp flexing. When this is achieved by the use of a loop, it shall provide for the cable with a bending radius of at least 10 times the diameter of cable. 14.4.3.3 Cable with flexible properties of machines shall be installed or protected so as to minimize the possibility of external damage due to factors that include the following cable use or potential abuse:

(1) Being run over by the machine itself (2) Being run over by vehicles or other machines


1868

(3) Coming into contact with the machine structure during movements

(4) Running in and out on cable baskets or on or off cable drums (5) Acceleration forces and wind forces on festoon systems or

suspended cables (6) Excessive rubbing by cable collector (7) Exposure to an excessive radiated heat source

14.4.3.4 The cable sheath shall be resistant to the wear from movement and the effects of atmospheric contaminants (e.g., oil, water, coolants, dust). 14.4.3.5 Where cables subject to movement are close to moving parts, precautions shall be taken to maintain a space of at least 25.4 mm (1 in.) between the moving parts and the cables. Where that distance is not practicable, fixed barriers shall be provided between the cables and the moving parts. 14.4.3.6 The cable handling system shall be so designed that lateral cable angles do not exceed 5 degrees, avoiding torsion in the cable when being wound on and off cable-drums and approaching and leaving cable guidance devices. 14.4.3.7 Measures shall be taken to ensure that at least two turns of flexible cables always remain on a drum. 14.4.3.8 Devices serving to guide and carry a cable with flexible properties shall be designed so that the inner bending radius is not less than the values given in Table 14.4.3.8. Exception: A smaller bending radius shall be permitted if the cable is identified for the purpose. [ROP 79-133 (Log 136)]

Table 14.4.3.8 Minimum Permitted Bending Radii for the Forced Guiding of Flexible Cables

Application

Cable Diameter or Thickness of Flat Cable (d)

(mm) d ≤ 8 8 < d ≤ 20 d > 20 Cable drums Guide rollers Festoon systems All others

6 d 6 d 6 d 6 d

6 d 8 d 6 d 6 d

8 d 8 d 8 d 8 d

For U.S. customary units, 8 mm = 0.315 in., 20 mm = 0.787 in.

14.4.3.9 The straight section between two bends in an S-shaped length and a bend into another plane shall be at least 20 times the diameter of the cable. 14.4.3.10 Where flexible conduit is adjacent to moving parts, the construction and supporting means shall prevent damage to the flexible conduit under all conditions of operation. Flexible metallic conduit shall not be used for rapid movements except when specifically designed for that purpose. 14.4.4 Interconnection of Devices on the Machine. Where practicable, machine-mounted switching devices (e.g., position sensors, pushbuttons) are connected in series or in parallel, and the connections between those devices shall be made through terminals forming intermediate test points. Such terminals shall be conveniently placed, protected from the environment, and shown on the relevant diagrams.

14.4.5 Attachment Plug and Receptacle (Plug/Socket) Combinations. 14.4.5.1 Where equipment is removable, connections to it through a polarized attachment plug and receptacle (plug/socket) combination shall be permitted. The male plug shall be connected to the load circuit. 14.4.5.2 Attachment plug and receptacle (plug/socket) combinations shall be listed for the intended use and shall be of the locking type where rated greater than 20 amperes. Where used on circuits of more than 300 volts to ground or 300 volts phase-to-phase, they shall be skirted and constructed to contain any arc generated when a connection is made or broken. 14.4.5.3 Attachment plug and receptacle (plug/socket) combinations shall be designed so that both of the following occurs: (1) The equipment grounding (protective bonding) circuit connection is made before any current-carrying connections are made. (2) The equipment grounding (protective bonding) circuit connection is not disconnected until all current-carrying connections in the plug are disconnected. Exception: Connections used in PELV circuits or the connectors used only to facilitate assembling and disassembling (multipole connectors) shall not be required to meet these requirements. [ROP 79-134 (Log 137)] 14.4.5.4 Attachment plug and receptacle (plug/socket) combinations used for carrying motor loads shall meet the conditions of 5.3.3.3 if the circuit is likely to be opened under load. 14.4.5.5 Where more than one attachment plug and receptacle (plug/socket) combination is used at the same location, they shall be mechanically coded to prevent incorrect insertion or be clearly identified. 14.4.5.6 Attachment plug and receptacle (plug/socket) combinations that are used for industrial power purposes or of a type used for domestic applications shall not be used for control circuits. 14.4.5.7 Means shall be provided to cover externally mounted receptacles (socket) when the plugs are removed. 14.4.6 Dismantling for Shipment. Where it is necessary that wiring be disconnected for shipment and where practicable, terminals or attachment plug and receptacle (plug/socket) combinations shall be provided at the sectional points. Such terminals shall be suitably enclosed and attachment plug and receptacle (plug/socket) combinations shall be protected from the physical environment during transportation and storage. Raceway and enclosure openings shall be sealed prior to shipment. 14.5 Raceways (Ducts), Support Systems (Cable Supports), Connection Boxes, and Other Boxes. 14.5.1 General Requirements. 14.5.1.1 Raceways (ducts) shall be identified for the environment. 14.5.1.2 All sharp edges, flash, burrs, rough surfaces, or threads that the insulation of the conductors can come in contact with shall be


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removed from raceways (ducts) and fittings. Where necessary, additional protection consisting of a flame-retardant, oil-resistant insulating material shall be provided to protect conductor insulation. 14.5.1.3 Drain holes shall not be permitted in raceways (ducts), junction boxes, and pull boxes where the holes would compromise the intended enclosure integrity. Drain holes of 6.4-mm (1/4-in.) diameter shall be permitted in wireways (cable trunking systems), connection boxes, and other boxes used for wiring purposes that are subject to accumulations of oil or moisture. 14.5.2* Percentage Fills of Raceways (Ducts). The combined cross-sectional area of all conductors and cables shall not exceed 50 percent of the interior cross-sectional area of the raceway (duct). The fill provisions shall be based on the actual dimensions of the conductors or cables used. 14.5.3 Rigid Conduit and Fittings. 14.5.3.1 General Requirements. 14.5.3.1.1 The minimum electrical trade size shall be metric designator 16 (trade size ½). 14.5.3.1.2* The maximum electrical trade size shall be metric designator 155 (trade size 6). 14.5.3.1.3 Where conduit enters a box or enclosure, a bushing or fitting providing a smoothly rounded insulating surface shall be installed to protect the conductors from abrasion, unless the design of the box or enclosure is such that it provides the same protection. Where conduit bushings are constructed entirely of insulating material, a locknut shall be provided both inside and outside the enclosure to which the conduit is attached. Exception: Where threaded hubs or bosses that are an integral part of an enclosure provide a smoothly rounded or flared entry for conductors. 14.5.3.1.4 Conduit bends shall be made in such a manner that the conduit shall not be damaged and the internal diameter of the conduit shall not be effectively reduced. The radius of the curve of any field bend shall be not less than shown in Table 14.5.3.1.4.

Table 14.5.3.1.4 Minimum Radii of Conduit Bends

Size of Conduit (in.)

Radius of Bend Done by Hand (in.)

Radius of Bend Done by Machine (in.)

1/2 4 4 3/4 5 4 1/2

1 6 5 3/4 11/4 8 7 1/4 11/2 10 8 1/4

2 12 9 1/2 21/2 15 10 1/2

3 18 13 31/2 21 15

4 24 16 41/2 27 20

5 30 24 6 36 30

For SI units, 25 mm = 1 in. Notes: 1. For field bends done by hand, the radius is measured to the inner edge of the bend. 2. For a single-operation (one-shot) bending machine designed for the purpose, the radius is measured to the centerline of the conduit.

14.5.3.1.5 A run of conduit shall contain not more than four-quarter bends or a combination of bends totaling 360 degrees between pull points. 14.5.3.2 Metal-Type Nonflexible Conduit. 14.5.3.2.1 General Requirements. 14.5.3.2.1.1 Conduits shall be securely held in place and supported at each end. 14.5.3.2.1.2 Fittings shall be compatible with the conduit and identified for the application. Fittings and conduits shall be threaded using an electrical conduit die unless structural difficulties prevent assembly. Running threads shall not be used on conduit for connection at couplings. Metallic tubing shall not be threaded. Where threadless fittings are used, the conduit shall be securely fastened to the equipment. 14.5.3.2.2* Rigid Metal Conduit and Fittings. Rigid metal conduit and fittings shall be of galvanized steel or of a corrosion-resistant material identified for the conditions of service. 14.5.3.2.3* Intermediate Metal Conduit. Intermediate metal conduit shall be a steel raceway of circular cross section with integral or associated couplings, approved for the installation of electrical conductors and used with approved fittings to provide electrical continuity. 14.5.3.2.4* Electrical Metallic Tubing. Electrical metallic (steel) tubing shall be a metallic tubing of circular cross section approved for the installation of electrical conductors when joined together with approved fittings. The maximum size of tubing shall be the 4-in. electrical trade size. 14.5.3.3 Rigid Nonmetallic Conduit (PVC Schedule 80). 14.5.3.3.1* Rigid nonmetallic conduit (PVC Schedule 80) shall be of suitable nonmetallic material approved for the installation of electrical conductors and identified for use where subject to physical damage. 14.5.3.3.2 Conduit shall be securely held in place and supported as specified in Table 14.5.3.3.2. In addition, conduit shall be securely fastened within 900 mm (3 ft) of each box, enclosure, or other conduit termination. Table 14.5.3.3.2 Support of Rigid Nonmetallic Conduit (RNC)

Conduit Size Maximum Spacing Between Supports

Metric Designator

Trade Size

Mm or m

ft

16 – 27 ½ – 1 900 mm 3 35 – 53 1 ¼ – 2 1.5 m 5 63 – 78 2 ½ – 3 1.8 m 6

91 – 129 3 ½ – 5 2.1 m 7 155 6 2.5 m

14.5.3.3.3* Expansion fittings shall be installed to compensate for thermal expansion and contraction. 14.5.3.3.4 All joints between lengths of conduit and between conduit and couplings, fittings, and boxes shall be made with fittings approved for the purpose.


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14.5.4 Flexible Metal Conduit and Fittings. 14.5.4.1 General Requirements. 14.5.4.1.1 Flexible metal conduit and liquidtight flexible metal conduit, minimum electrical trade size shall be metric designator 12 (trade size 3/8). Exception: Thermocouples and other sensors. 14.5.4.1.2* The maximum size of flexible metal conduit and liquidtight flexible metal conduit shall be metric designator 103 (trade size 4). 14.5.4.1.3 Flexible metal conduit and liquidtight flexible metal conduit shall be installed in such a manner that liquids will tend to run off the surface instead of draining toward the fittings. 14.5.4.1.4 Fittings shall be compatible with the conduit and identified for the application. Connectors shall be the “union” types. 14.5.4.2 Flexible Metal Conduit. Flexible metal conduit shall be identified for use in the expected physical environment. 14.5.4.3 Liquidtight Flexible Metal Conduit. Liquidtight flexible metal conduit shall be identified for use in the expected physical environment. 14.5.5 Flexible Nonmetallic Conduit and Fittings. 14.5.5.1 Liquidtight flexible nonmetallic conduit is a raceway of circular cross section of the following types:

(1) A smooth, seamless inner core and cover that is bonded together and has or more reinforcement layers between the core and cover

(2) A smoother inner surface with integral reinforcement within the conduit wall

(3) A corrugated internal and external surface with or without integral reinforcement within the conduit wall 14.5.5.2 A flexible nonmetallic conduit shall be resistant to kinking and shall have physical characteristics of the sheath of multiconductor cables. 14.5.5.3 The conduit shall be identified for use in the expected physical environment. 14.5.5.4 Liquidtight flexible nonmetallic conduit minimum electrical trade size shall be 3/8 in. 14.5.5.5* The maximum size of liquidtight flexible nonmetallic conduit shall be 4-in. trade size. 14.5.5.6 Fittings shall be compatible with the conduit and identified for the application. 14.5.5.7 Flexible conduit shall be installed in such a manner that liquids will tend to run off the surface instead of draining toward the fittings. 14.5.6 Wireways (Cable Trunking Systems).

14.5.6.1 Wireways (cable trunking systems) external to enclosures shall be rigidly supported and clear of all moving or contaminating portions of the machine. 14.5.6.2 Covers shall be shaped to overlap the sides; gaskets shall be permitted. Covers shall be attached to wireways by hinges or chains and held closed by means of captive screws or other suitable fasteners. On horizontal wireway, the cover shall not be on the bottom. Hinged covers shall be capable of opening at least 90 degrees. 14.5.6.3 Where the wireway is furnished in sections, the joints between sections shall fit tightly but shall not be required to be gasketed. 14.5.6.4 The only openings permitted shall be those required for wiring or for drainage. 14.5.6.5 Wireways shall not have opened but unused knockouts. 14.5.6.6 Metal thickness and construction of wireways shall comply with UL 870, Wireways and Auxiliary Gutters. [ROP 79-147 (Log 130)] 14.5.7* Machine Compartments and Wireway. The use of compartments or wireways within the column or base of a machine to enclose conductors shall be permitted provided the compartments or wireways are isolated from coolant or oil reservoirs and are entirely enclosed. Conductors run in enclosed compartments or wireways shall be secured and arranged so that they are not subject to damage. 14.5.8 Connection Boxes and Other Boxes. 14.5.8.1 Connection boxes and other boxes used for wiring purposes shall be readily accessible for maintenance. Those boxes shall provide protection against the ingress of solid bodies and liquids, taking into account the external influences under which the machine is intended to operate. 14.5.8.2 Those boxes shall not have opened but unused knockouts or any other openings and shall be constructed so as to exclude materials such as dust, flyings, oil, and coolant. 14.5.9 Motor Connection Boxes. 14.5.9.1 Motor connection boxes shall enclose only connections to the motor and motor-mounted devices (e.g., brakes, temperature sensors, plugging switches, tachometer generators). 14.5.9.2 Electrical connections to motors, solenoids, and other devices with integral leads, sizes 14 AWG through 4 AWG, shall be made with ring-type pressure connectors (pressure-tool applied) and bolted. 14.5.9.3 Connectors shall be insulated with a material that will not support combustion. 14.5.9.4 Soldered or insulation-piercing-type connectors (lugs) shall not be used. 14.5.10 Cord. 14.5.10.1* Manufactured assemblies with factory-applied molded connectors applied to cord shall be permitted.


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14.5.10.2 The use of cord shall be limited to individual exposed lengths of 15 m (50 ft) or less. 14.5.10.3 Cord shall be installed in accordance with the provision of 14.1.4. 14.5.10.4 Cord shall be permitted for use with flexible connections to pendant pushbutton stations. Chains or wire rope external to the cord shall support the weight of pendant stations. Exception: Cords listed for the purpose shall be permitted to be used without an external chain or wire rope. [ROP 79-146 (Log 101)] 14.5.10.5 Cord shall be permitted for use with connections involving small or infrequent movements. Cord shall also be permitted to complete the connection to normally stationary motors, limit switches, and other externally mounted devices. 14.5.10.6 Connections to frequently moving parts shall be made with conductors for flexing service in accordance with Section13.7. Cord with conductors for flexing service shall have vertical connections and shall be installed to avoid excessive flexing and straining. Exception: Horizontal connections shall be permitted where the cord is adequately supported. 14.5.11 Cable Trays. Cable trays to be used for cable or raceway support on industrial machines shall be permitted. Cable trays shall be permitted to support single conductors 1/0 or larger that are otherwise permitted on industrial machines, cables that are otherwise permitted on industrial machines, and raceways functionally associated with industrial manufacturing systems. [ROP 79-122 (Log 55)]

Chapter 15 Electric Motors and Associated Equipment [ROP 79-149

(Log 27)] 15.1* General Requirements. Motors shall be suitable for the environment in which they are installed. 15.2 (Reserved) 15.3* Motor Dimensions. As far as is practicable, the dimensions of the motors shall comply with those given in NEMA MG-1, IEC 60072-1, or IEC 60072-2 as appropriate. 15.4 Motor Mounting and Compartments. 15.4.1 Each motor and its associated couplings, belts and pulleys, or chains and sprockets shall be mounted so that they are adequately protected from physical damage and are easily accessible for inspection, maintenance, adjustment and alignment, lubrication, and replacement. The motor mounting arrangement shall be so that all motor hold-down means can be removed and all terminal boxes are accessible. An adjustable base or other means of adjustment shall be provided when belt or chain drives are used. 15.4.2 Motors shall be mounted so that proper cooling is ensured and the temperature rise remains within the limits of the insulation class. 15.4.3 Motor compartments shall be clean and dry, and when required, shall be ventilated directly to the exterior of the machine. The vents shall be so that ingress of swarf, dust, or water spray is at an acceptable level.

15.4.4 All openings between the motor compartment and any other compartment shall meet the motor compartment requirements. Where a raceway is run into the motor compartment from another compartment not meeting the motor compartment requirements, any clearance around the raceway shall be sealed. 15.5 Criteria for Selection. The characteristics of motors and associated equipment shall be selected in accordance with the anticipated service and physical environment conditions. The points that shall be considered include the following:

(1) Type of motor (2) Type of duty cycle (3) Fixed speed or variable speed operation (and consequent

variable influence of the ventilation) (4) Mechanical vibration (5) Type of converter for motor speed control (6) Influence of the harmonic spectrum of the voltage and/or

current feeding the motor (when it is supplied from a converter) on the temperature rise

(7) Method of starting and possible influence of the in-rush current on the operation of other users, taking into account possible special considerations stipulated by the supply authority

(8) Variation of counter torque load with time and speed (9) Influence of loads with large inertia (10) Influence of constant torque or constant power operations (11) Possible need of inductive reactors between motor and

converter 15.6* Protective Devices for Mechanical Brakes. Operation of the overload and overcurrent protective devices for mechanical brake actuators shall initiate the simultaneous de-energization (release) of the associated machine actuators. 15.7 Direction Arrow. Where reverse rotation can produce an unsafe condition, a direction arrow shall be installed. The arrow shall be adjacent to the motor and plainly visible. 15.8 Marking on Motors. Motors shall be marked in accordance with Section 430.7 of NFPA 70, National Electrical Code. [ROP 79-149(Log 27)]

Chapter 16 Accessories and Lighting [ROP 79-105 (Log 26)]

16.1 Accessories. 16.1.1 Where the machine or its associated equipment is provided with receptacle outlets to be used for accessory equipment (e.g., hand-held power tools, test equipment), the following conditions shall apply:

(1) Receptacles shall be of the grounding type, 125-volt, single-phase, 15-ampere configuration and listed for the applied voltage.

(2) Receptacles with their associated attachment plugs (plug/sockets) shall be in accordance with 14.4.5.3.

(3) The continuity of the equipment grounding (protective bonding) circuit to the receptacle outlet shall be verified by Section 19.2.

Exception: Verification is not required for PELV circuits in accordance with Section 19.2.

(4) All ungrounded (unearthed) conductors connected to the receptacle outlet shall be protected against overcurrent in


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accordance with the provisions of 7.2.5 and these circuits shall not be connected to other machine circuits.

(5) Where the power supply to the receptacle outlet is not disconnected by the supply disconnecting device for the machine or section of the machine, the warning and marking requirements of 5.3.5.4 shall apply.

(6) Shall be suitable for the environment. Receptacles mounted external to the enclosure shall be provided with a means to cover the receptacle when the plug is removed. [ROP 79-106 (Log 169)] 16.1.2 Receptacles, which are part of the industrial machine, either internal or external to the control cabinet and intended for use by maintenance personnel, shall have Ground-Fault Circuit-Interrupter(GFCI) protection for personnel. 16.2 Local Lighting of the Machine and Equipment. 16.2.1 General. 16.2.1.1 Lighting circuits shall comply with the provisions of Section 8.5. 16.2.1.2 Machine work lights shall not contain switches or receptacles where exposed to liquids or condensing mists unless identified for the purpose. Lampholders shall not incorporate a switch or receptacle. Work lights used in wet locations shall be provided with ground fault protection. [ROP 79-110 (Log 124)] 16.2.1.3 The conductors to stationary lights used as an integral part of the machine shall be Type MTW, and the conductors within the fixtures shall be not smaller than 18 AWG. 16.2.1.4 Flexible cords shall be Type SO, STO, or STOW or Type SJO, SJOW, or SJTO and shall not incorporate in-line switches. 16.2.1.5 Stroboscopic effects from lights shall be avoided. 16.2.2 Supply. 16.2.2.1 The lighting circuit voltage shall not exceed 150 volts between conductors. 16.2.2.2 Lighting circuits shall have overcurrent protection in accordance with 7.2.6 and shall be supplied from one of the following sources:

(1) A separate isolating transformer connected to the load side of the supply disconnecting means. Overcurrent protection shall be provided in the secondary circuit.

(2) A separate isolating transformer connected to the line side of the supply disconnecting means shall be permitted for the supply of a maintenance lighting circuit in control enclosures only. Overcurrent protection shall be provided in the secondary circuit.

(3) A grounded machine circuit that has separate overcurrent protection and does not exceed 150 volts to ground shall be permitted.

(4) An isolating transformer connected to the line side of the supply disconnecting device when a separate primary disconnecting means and secondary overcurrent protection are provided and mounted within the control enclosure adjacent to the supply disconnecting device.

(5) An externally supplied lighting circuit (e.g., factory lighting supply). This shall be permitted in control enclosures and for the

machine work light(s) where the total power rating does not exceed 3 kW. 16.2.3 Protection. Local lighting circuits shall be separately protected with overcurrent protection and shall not exceed 15 amperes. 16.2.4 Lighting Fixtures. 16.2.4.1 Adjustable lighting fixtures shall be suitable for the physical environment. 16.2.4.2 The lampholders shall be as follows:

(1) Rated for the voltage and wattage of the lamp (2) Constructed with an insulating material protecting the lamp

so as to prevent unintentional contact, except where fixed lighting is out of reach of operators during normal operations, the provisions of this subsection do not apply. 16.2.4.3 Reflectors and protectors shall be supported by a bracket and not the lampholder. [ROP 79-105 (Log 26)]

Chapter 17 Marking and Safety Signs [ROP 79-18 (Log 23)] 17.1 General. 17.1.1 The electrical equipment shall be marked with the supplier's name, trademark, or other identifying symbol. 17.1.2 Safety signs, nameplates, markings, and identification plates shall be of sufficient durability to withstand the physical environment involved. 17.2 Safety Signs for Electrical Enclosures. [ROP 79-92 (Log 6)] 17.2.1 Enclosures that do not clearly show that they contain electrical devices shall be marked with a safety sign in accordance with ANSI Z535 series, which deal with product safety signs. [ROP 79-93 (Log 20)] 17.2.2 Safety signs shall be plainly visible on the enclosure door or cover. [ROP 79-92 (Log 6)] 17.2.3 It shall be permitted to omit safety signs on the following:

(1) An enclosure equipped with a supply disconnecting device (2) An operator-machine interface or control station (3) A single device with its own enclosure (e.g., position sensor)

[ROP 79-92 (Log 6)] 17.2.4 A safety sign shall be provided adjacent to the disconnecting operating handle(s) where the disconnect(s) that is interlocked with the enclosure door does not de-energize all exposed live parts when the disconnect(s) is in the open (off) position. 17.2.5 Where an attachment plug is used as the disconnecting means, a safety sign shall be attached to the control enclosure door or cover indicating that power shall be disconnected from the equipment before the enclosure is opened. 17.2.6 Where the disconnecting means is remote from the control enclosure, a safety sign shall be attached to the enclosure door or


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cover indicating that the power shall be disconnected from the equipment before the enclosure is opened and that the enclosure shall be closed before the power is restored. 17.3* Function Identification. Control devices, visual indicators, and displays used in the operator-machine interface shall be clearly and durably marked with regard to their functions either on or adjacent to the unit. 17.4 Machine Nameplate Data. 17.4.1 Control equipment shall be legibly and durably marked in a way that it is plainly visible after the equipment is installed. A nameplate giving the following information shall be attached to the enclosure:

(1) Name or trademark of supplier (2) Serial number, where applicable (3) Rated voltage, number of phases and frequency (if ac), and

full-load current for each supply (4) Ampere rating of the largest motor or load (5) Maximum ampere rating of the short-circuit and ground-fault

protective device, where provided (6) Electrical diagram number(s) or the number of the index to

the electrical drawings 17.4.2 The full-load current shown on the nameplate shall not be less than the full-load currents for all motors and other equipment that can be in operation at the same time under normal conditions of use. Where unusual loads or duty cycles require oversized conductors, the required capacity shall be included in the full-load current specified on the nameplate. 17.4.3 Where more than one incoming supply circuit is to be provided, the nameplate shall state the information in 17.4.1 for each circuit. 17.4.4 Where only a single motor or motor controller is used, the motor nameplate shall be permitted to serve as the electrical equipment nameplate where it is plainly visible. 17.4.5 Where overcurrent protection is provided in accordance with 7.2.3, the machine shall be marked "overcurrent protection provided at machine supply terminals." A separate nameplate shall be permitted to be used for this purpose. 17.5 Equipment Marking and Identification. 17.5.1 Where equipment is removed from its original enclosure or is placed so that the manufacturer's identification plate is not easily read, an additional identification plate shall be attached to the machine or enclosure. 17.5.2 Where a motor nameplate or connection diagram plate is not visible, additional identification shall be provided where it can be easily read. 17.5.3 Nameplates, identification plates, or safety signs shall not be removed from the equipment. 17.5.4 All control panel devices and components shall be plainly identified with the same designation as shown on the diagram(s). This identification shall be adjacent to (not on) the device or component.

Exception No. 1: Where the size or location of the devices makes individual identification impractical, group identification shall be used. Exception No. 2: This requirement shall not apply to machines on which the equipment consists only of a single motor, motor controller, pushbutton station(s), and work light(s). 17.5.5 All devices external to the control panel(s) shall be identified by a nameplate with the same designation as shown on the diagram(s) and mounted adjacent to (not on) the device. Exception: Devices covered by Section 17.3. 17.5.6 Terminations on multiconductor plugs and receptacles shall be plainly marked. The markings on the plug and receptacles and on drawings shall correspond. 17.5.7 Where group protection as provided for in 7.2.10 is used, information specifying the short-circuit protective device for each group protected motor branch circuit shall be included with the equipment.

Chapter 18 Technical Documentation [ROP 79-19 (Log 53)] 18.1 General. 18.1.1 The information necessary for installation, operation, and maintenance of the electrical equipment of a machine shall be supplied in the form of drawings, diagrams, charts, tables, and instructions as appropriate. The information provided shall be permitted to vary with the complexity of the electrical equipment. For very simple equipment, the relevant information shall be permitted to be contained in one document provided this document shows all the devices of the electrical equipment and enables the connections to the supply network to be made. 18.1.2 The machinery supplier shall ensure that the technical documentation specified in this chapter is provided with each machine. 18.1.3 Technical documentation shall be permitted to be supplied in an agreed upon format. 18.2 Information to Be Provided. The following information shall be provided with the electrical equipment:

(1) Clear, comprehensive description of the equipment, installation and mounting, and the connection to the electrical supply(ies)

(2) Electrical supply circuit(s) requirements (3) Overview (block) diagram(s) where appropriate (4) Schematic diagram(s) (5) Information (where appropriate) on the following:

a. Programming b. Sequence of operation(s) c. Frequency of inspection d. Frequency and method of functional testing e. Adjustment, maintenance, and repair f. Interconnection diagram g. Panel layouts h. Instruction and service manuals i. Physical environment (e.g., lighting, vibration, noise levels,

atmospheric contaminants)


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(6) A description (including interconnection diagrams) of the safeguards, interacting functions, and interlocking of guards with potentially hazardous motions

(7) A description of the safeguarding means and methods provided where the primary safeguards are overridden (e.g., manual programming, program verification)

(8) Information for safety lockout procedure (9) Explanation of unique terms (10) Part’s list and recommended spare part’s list (11) Maintenance instructions and adjustment procedures (12) Reference information (where appropriate) on the following:

a. Lubrication diagram b. Pneumatic diagram c. Hydraulic diagram d. Miscellaneous system diagrams (e.g., coolant, refrigerant)

18.3 Requirements Applicable to All Documentation. 18.3.1 The documents shall be prepared in accordance with the requirements of Sections 18.4 through 18.10. 18.3.2 For referencing of the different documents, the supplier shall select one of the following methods: (1) Each of the documents shall carry as a cross-reference the document numbers of all other documents belonging to the electrical equipment (2) All documents shall be listed with document numbers and titles in a drawing or document list. The first method shall be used only where the documentation consists of four or less documents. 18.3.3 Where appropriate, a table of contents shall appear prominently on the first sheet and shall refer to all major sections of the electrical drawings. 18.4* Basic Information. The technical documentation shall contain, as a minimum, information on the following:

(1) Normal operating conditions of the electrical equipment

including the expected conditions of the electrical supply, and where appropriate, the physical environment

(2) Handling, transportation, and storage (3) Inappropriate use(s) of the equipment

The technical documentation shall be permitted to be presented as a separate document or as part of the installation or operation documentation. 18.5 Installation Diagram. 18.5.1* The installation diagram shall provide all information necessary for the preliminary work of setting up the machine. 18.5.2 The specified position of the electrical supply to be installed on site shall be clearly indicated. 18.5.3* The data necessary for choosing the type, characteristics, rated currents, and setting of the overcurrent protective device(s) for the supply circuit conductors to the electrical equipment of the machine shall be stated. 18.5.4* Where necessary, the size, purpose, and location of any raceways (ducts) in the foundation that are to be provided by the user shall be detailed.

18.5.5* The size, type, and purpose of raceways (ducts), cable trays, or cable supports between the machine and the associated equipment that are to be provided by the user shall be detailed. 18.5.6* Where necessary, the diagram shall indicate where space is required for the removal or servicing of the electrical equipment. 18.5.7* Where it is appropriate, an interconnection diagram or table shall be provided. That diagram or table shall give full information about all external connections. Where the electrical equipment is intended to be operated from more than one source of electrical supply, the interconnection diagram or table shall indicate the modifications or interconnections required for the use of each supply. 18.6* Block (System) Diagrams and Function Diagrams. Where it is necessary to facilitate the understanding of the principles of operation, a system diagram shall be provided. For the purposes of this chapter, a block diagram shall symbolically represent the electrical equipment together with its functional interrelationships without necessarily showing all of the interconnections. 18.7 Circuit Diagrams. 18.7.1* Diagrams, including machine schematics, of the electrical system shall be provided and shall show the electrical circuits on the machine and its associated electrical equipment. Electrical symbols shall be in accordance with IEEE 315 where included therein. Any electrical symbols not included in IEEE 315 shall be separately shown and described on the diagrams. The symbols and identification of components and devices shall be consistent throughout all documents and on the machine. Exception: Wiring schematics shall not be required for commercially available or field replaceable components. 18.7.2* Pertinent information such as motor horsepower, frame size, and speed shall be listed adjacent to its symbol. 18.7.3* Where appropriate, a diagram showing the terminals for interface connections shall be provided. Switch symbols shall be shown on the electromechanical diagrams with all supplies turned off (e.g., electricity, air, water, lubricant) and with the machine and its electrical equipment in the normal starting condition and at 20°C (68°F) ambient. Control settings shall be shown on the diagram. 18.7.4 Conductors shall be identified in logical order in accordance with Section 14.2. 18.7.5* Circuit Characteristics. [ROP 79-21 (Log 118)] 18.7.5.1 Circuits shall be shown in a way so as to facilitate the understanding of their function as well as maintenance and fault location. 18.7.5.2 A cross-referencing scheme shall be used in conjunction with each relay, output device, limit switch, and pressure switch so that any contact associated with the device can be readily located on the diagrams. 18.7.6 Control circuit devices shall be shown between vertical lines that represent control power wiring. The left vertical line shall be the control circuit’s common and the right line shall be the operating coil’s common, except where permitted by Chapter 9 design requirements. Control devices shall be shown on horizontal lines


1875

(rungs) between the vertical lines. Parallel circuits shall be shown on separate horizontal lines directly adjacent to (above or below) the original circuit. 18.7.7 An interconnection diagram shall be provided on large systems having a number of separate enclosures or control stations. It shall provide full information about the external connections of all of the electrical equipment on the machine. 18.7.8 Interlock wiring diagrams shall include devices, functions, and conductors in the circuit where used. 18.7.9 Plug/receptacle pin identification shall be shown on the diagram(s). 18.8 Operating Manual. 18.8.1* The technical documentation shall contain an operating manual detailing proper procedures for set-up and equipment use. 18.8.2 Where the operation of the equipment can be programmed, detailed information on methods of programming, equipment required, program verification, and additional safety procedures (where required) shall be provided. 18.9 Maintenance Manual. 18.9.1* The technical documentation shall contain a maintenance manual detailing proper procedures for adjustment, servicing and preventive inspection, and repair. 18.9.2 Where methods for the verification of proper operation are provided (e.g., software testing programs), the use of those methods shall be detailed. 18.10 Part’s List. 18.10.1 The part’s list shall comprise, as a minimum, information necessary for ordering spare or replacement parts (e.g., components, devices, software, test equipment, technical documentation) required for preventive or corrective maintenance including those that are recommended to be carried in stock by the equipment user. 18.10.2 The part’s list shall show the following for each item:

(1) Reference designation used in the documentation (2) Its type designation (3) Supplier and alternative sources where available (4) Its general characteristics where appropriate (5) Quantity of items with the same reference designation

[ROP 79-19 (Log 53)]

Chapter 19 Testing and Verification [ROP 79-159 (Log 61)]

19.1* General. The verification of the continuity of the equipment grounding (protective bonding) circuit shall be conducted and documented. When the electrical equipment is modified, the requirements in Section 19.7 shall apply. Applicable tests shall be performed where deemed necessary in accordance with the references in the following list:

(1) Verification that the electrical equipment is in compliance with the technical documentation (see Chapter 18) (2) Insulation resistance test (see Section 19.3) (3) Voltage test (see Section 19.4) (4) Protection against residual voltages test (see Section 19.5) (5) Functional test (see Section 19.6) 19.2* Continuity of the Equipment Grounding (Protective Bonding) Circuit. One of the following methods shall be used to verify the continuity of the equipment grounding circuit: (1) Use an impedance measuring device, take into account any impedance in the measuring circuit. The measured impedance shall be 0.1 ohms or less. (2) Apply a current of at least 10 amperes, 50 Hz or 60 Hz, derived from a SELV source. The tests are to be made between the equipment grounding (PE) terminal and relevant points that are part of the equipment grounding (protective bonding) circuit; the measured voltage between the equipment grounding (PE) terminal and the points of test is not to exceed the values given in Table 19.2.

Table 19.2 Verification of Continuity of the Equipment Grounding (Protective Bonding) Circuit

Minimum Equipment Grounding (Protective Bonding) Conductor

Cross-sectional Area of the Branch Under Test

(AWG)

Maximum Measured Voltage Drop*

(V) 18 3.3 16 2.6 14 1.9 10 1.4 >8 1.0

*Values are given for a test current of 10 amperes. Exception: For certain parts of electrical equipment, incorporating busbars, collector wire or collector bar systems, or slip-ring assemblies, a lower minimum value of 50,000 ohms shall be permitted. 19.4* Voltage Tests. The machine shall withstand without breakdown a test voltage gradually applied from 0 to 1500 volts ac or 2121 volts dc and held at the maximum value for a period of at least 1 second between the conductors of all primary circuits and the equipment grounding (protective bonding) circuit. The test voltage shall be supplied from an isolated power supply with a minimum rating of 500 volt amperes. Components that are not rated to withstand the test voltage shall be disconnected during testing. [ROP 79-161 (Log 140)] 19.5 Protection Against Residual Voltages. Residual voltage tests shall be performed to ensure compliance with 6.2.4. 19.6 Functional Tests. The functions of electrical equipment, particularly those related to safety and safeguarding, shall be tested. 19.7 Retesting. Where a portion of the machine and its associated equipment is changed or modified, that portion shall be reverified and retested as appropriate. [ROP 79-159 (Log 61)]


1876

Annex A Explanatory Material [ROP 79-162 (Log 38)] Annex A is not a part of the requirements of this NFPA document but is included for informational purposes only. This annex contains explanatory material, numbered to correspond with the applicable text paragraphs. A.1.1 In this standard, the term electrical includes both electrical and electronic equipment. Requirements that apply only to electronic equipment shall be so identified. [ROP 79-8 (Log 35)] The general terms machine and machinery as used throughout this standard mean industrial machinery. [ROP 79-8 (Log 35)] See Annex C for examples of industrial machines covered by this standard. [ROP 79-8 (Log 35)] A.1.5 Motor design letter designations are found in ANSI/NEMA MG 1 and ANSI/IEEE 100. [ROP 79-8 (Log 35)] [ROP 79-10 (Log 36)] A.3.1 Chapter 3 contains only those definitions essential to the proper application of this standard. It is not intended to include commonly defined general terms or commonly defined technical terms from related codes and standards. In general, only those terms that are used in two or more places are defined. Spelling and definitions of general words and terms follow Webster’s Collegiate Dictionary, 10th edition. The terms in parenthesis used throughout this standard are from the English version of IEC 60204-1 and are based on the Oxford English dictionary. [ROP 79-11 (Log 37)] A.3.2.1 Approved: The National Fire Protection Association does not approve, inspect, or certify any installations, procedures, equipment, or materials nor does it approve or evaluate testing laboratories. In determining the acceptability of installations or procedures, equipment, or materials, the “authority having jurisdiction” may base acceptance on compliance with NFPA or other appropriate standards. In the absence of such standards, said authority may require evidence of proper installation, procedure, or use. The “authority having jurisdiction” may also refer to the listings or labeling practices of an organization that is concerned with product evaluations and is thus in a position to determine compliance with appropriate standards for the current production of listed items. A.3.2.2 Authority Having Jurisdiction: The phrase “authority having jurisdiction” is used in NFPA documents in a broad manner because jurisdictions and approval agencies vary, as do their responsibilities. Where public safety is primary, the authority having jurisdiction may be a federal, state, local, or other regional department or individual such as a fire chief; fire marshal; chief of a fire prevention bureau, labor department, or health department; building official; electrical inspector; or others having statutory authority. For insurance purposes, an insurance inspection department, rating bureau, or other insurance company representative may be the authority having jurisdiction. In many circumstances, the property owner or his or her designated agent assumes the role of the authority having jurisdiction; at government installations, the commanding officer or departmental official may be the authority having jurisdiction. [ROP 79-11 (Log 37)] A.3.2.4 Listed. The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless it is also labeled. Use of the system employed by the listing organization allows the authority having jurisdiction to identify a listed product. [ROP 79-11 (Log 37)]

A.3.3.3 Actuator. The actuator can take the form of a handle, knob, pushbutton, roller, plunger, and so forth. There are some actuating means that do not require an external actuating force but only an action. See also 3.3.3.1 Machine Actuator. [ROP 79-11 (Log 37)] A.3.3.4 Adjustable Speed Drives. This includes ac and dc voltage modes and frequency mode controls. Belt, chain, or roller shifting controllers are not included. [ROP 79-14 (Log 49)] A.3.3.5 Ambient Temperature. Ambient air temperature as applied to an enclosure or housing is the average temperature of the surrounding air that comes in contact with the enclosure or housing. Ambient air temperature as applied to a component or device within the enclosure is the average temperature of the surrounding air that comes in contact with the component. [ROP 79-11 (Log 37)] A.3.3.9 Bonding (Bonded). See 3.3.81, Protective Bonding Circuit. [ROP 79-11(Log 37)] A.3.3.12 Cable Trunking System. See 3.3.112, Wireway. [ROP 79-11(Log 37)] A.3.3.17 Control Circuit (of a machine). Power circuit protection can be provided by control shunt-tripping. A.3.3.27 Duct. Conduits, cable trunking systems (see 3.3.12) and underfloor channels are types of duct. See 3.3.84, raceway. [ROP 79-11(Log 37)] A.3.3.41 Failure (of Equipment). After failure the item has a fault. “Failure” is an event, as distinguished from “fault,” which is a state. This concept as defined does not apply to items consisting of software only. [ROP 79-11(Log 37)] A.3.3.42 Fault. A fault is often the result of a failure of the item itself, but can exist without prior failure. [ROP 79-11(Log 37)] A.3.3.52 Guard. Depending on its construction, a guard may be called casing, cover, screen, door, enclosing guard. A.3.3.55 Identified (as applied to equipment). Suitability of equipment for a specific purpose, environment, or application can be determined by a qualified testing laboratory, inspection agency, or other organization concerned with product evaluation. Such identification can include labeling or listing. [ROP 79-11(Log 37)] A.3.3.63 Interrupting Rating. Equipment intended to interrupt current at other than fault levels can have its interrupting rating implied in other ratings, such as horsepower or locked motor current. [ROP 79-11(Log 37)] A.3.3.67.1 Dry Location. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction. [ROP 79-11(Log 37)] A.3.3.74 Overload. Overload should not be used as a synonym for overcurrent. [ROP 79-11(Log 37)] A.3.3.80 Programmable Electronic System. This term includes all elements in the system extending from sensors to other input devices via data highways or other communication paths to the actuators or other output devices. [ROP 79-11(Log 37)]


1877

A.3.3.81 Protective Bonding Circuit. See 3.3.9, Bonding. [ROP 79-11(Log 37)] A.3.3.83 Qualified Person. See 3.3.30, (Electrically) Instructed Person and 3.3.31, (Electrically) Skilled Person. [ROP 79-11(Log 37)] A.3.3.85 Receptacle. See 3.3.98, Socket. [ROP 79-11(Log 37)] A.3.3.102 Supplementary Overcurrent Protective Device. The device cannot be used as a substitute for power circuit overcurrent devices in place of the power circuit protection. A.3.3.103 Supplier. The user can also act in the capacity of a supplier to him or herself. [ROP 79-11(Log 37)] A.3.3.108 Undervoltage Protection. The principal objective of this device is to prevent automatic restarting of the equipment. Standard undervoltage or low-voltage protection devices are not designed to become effective at any specific degree of voltage reduction. [ROP 79-11(Log 37)] A.4.1 A sample inquiry form is provided in Annex B for use in facilitating an agreement between the supplier and the user. Hazards can include, but are not limited to, the following: (1) Failures or faults in the electrical equipment resulting in the possibility of electrical shock or electrical fire (2) Failures or faults in control circuits (or components and devices associated with these circuits) resulting in malfunctioning of the machine (3) Disturbances or disruptions in power sources as well as failures or faults in the power circuits resulting in the malfunctioning of the machine (4) Loss of continuity of circuits that depend upon sliding or rolling contacts resulting in a failure of a safety function (5) Electrical disturbances (e.g., electromagnetic, electrostatic, or radio interference) either from outside the electrical equipment or internally generated (6) Stored energy (either electrical or mechanical) (7) Audible noise at levels that cause health problems to persons Safety measures are a combination of the measures incorporated at the design stage and those measures required to be implemented by the user. Design and development should be the first consideration in the reduction of risks. Where this is not possible, safeguarding should be considered. Safeguarding includes the use of safeguards, awareness means, and safe working procedures. A.4.3.1 See Annex B. [ROP 79-24 (Log 60)] A.4.3.2 The short time value for the frequency can be specified by the user (see Annex B). [ROP 79-24 (Log 60)] A.4.4 In addition, refer to Annex B for 4.4.3 through 4.4.6. A.4.4.1 See Annex B for a sample inquiry form that will facilitate an agreement between the user and the supplier. A.4.4.2 The electrical interferences generated by the equipment itself should not exceed levels specified in the relevant equipment standards and others dealing with electromagnetic compatibility (EMC) levels. The levels allowed should be determined for the specific application. Generated interference signals can be kept to a minimum by the following: (1) Suppression at the source by using capacitors, inductors, diodes, Zener diodes, varistors, or active devices, or a combination of these

(2) Equipment screening in a bonded electrically conductive enclosure to provide segregation from other equipment Undesirable effects of electrostatic discharge, radiated electromagnetic energy, and supply conductor (mains borne) interference should be avoided (e.g., use of appropriate filters and time delays, choice of certain power levels, suitable wiring types and practices). The effects of interference on equipment can be reduced by the following: (1) Reference potential circuit or common connections. Each common connection treated as a single circuit and connected to one of several central reference points that are connected to ground (wired to earth) by insulated conductors of large cross-sectional area (2) Frame Connections. In each piece of equipment all frame connections are to be taken to a common point with a conductor of large cross-sectional area (e.g., braided conductors, foil strips having a width much greater than the thickness) used between slides and enclosures. The connections to the frame are to be as short as possible (3) Transmission of signals. Electrostatic screens, electromagnetic shields, twisted conductors, and orientation (i.e., crossing cable runs at as near to 90 degrees as practicable) as necessary to ensure that the low level signal wiring is not affected by interference from control or power cables, or running the connections parallel to the ground plane as necessary (3) Separation of equipment. Separating and/or shielding sensitive equipment (e.g., units working with pulses and/or at low signal levels) from switching equipment (e.g., electromagnetic relays, thyristors). Separation of low level signal wiring from control and power cables [ROP 79-169 (Log 71)] [ROP 79-24 (Log 60)] A.4.4.3 See Annex B. A.4.4.4 For extremely dry or moist environments, extra requirements may be necessary to prevent static discharge. A.4.4.5 See Annex B. A.4.4.6 See Annex B. A.4.4.7 Where equipment is subject to radiation (e.g., microwave, ultraviolet, lasers, x-rays), additional measures should be taken to avoid malfunctioning and accelerated deterioration of the insulation. [ROP 79-24 (Log 60)] A.5.1.1 For large complex machinery comprising of a number of widely spaced machines working together in a coordinated manner, more than one incoming supply circuit might be needed depending upon the site supply circuit arrangements (see 5.3.1). [ROP 79-33 (Log 59)] A.5.1.3 See question 14 in Annex B. [ROP 79-33 (Log 59)] A.5.2 For additional information on the grounding terminal, see 8.2.1.2. [ROP 79-33 (Log 59)] A.5.3.5.4(3) For additional information on color identification for other conductors, see 14.2.4. [ROP 79-33 (Log 59)] A.6.3.1(1) Ripple-free is conventionally defined for a sinusoidal ripple voltage as a ripple content of not more than 10 percent rms. [ROP 79-25 (Log 68)] A.6.3.1(2) For additional information on isolating transformers, refer to IEC 60742 and IEC 61558-1. [ROP 79-25 (Log 68)] A.7.2.1 General. Figures A.7.2.1(a) and A.7.2.1(b) show typical circuits acceptable for the protection of current-carrying and current-consuming electrical machine components. Protective interlocks are not shown.


1878

Line Reference Single motor(main SCPD)

Multiple motors(main and branch SCPD)

Multiple motors(main SCPD only)

Disc

O.L

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M M

O.L

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M

O.L

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M

O.L

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M

O.L

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M

O.L

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M

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M

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SeeFigure 2

SeeFigure 2

Disc

O.L

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M

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M

O.L

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O.L

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Disc

SeeFigure 2

Several motorsunder 1 hp



Two motors1 hp to 5 hp

Each motorover 5 hp

These applications may not provide type–2 protection for all devicesSymbolShort circuitprotection device (SCPD)

Motor and resistiveloadsChapter 15

Disconnect(if used)

Overload protection7.3

Motor control

Control circuit andspecial purposecontrol protectioncond: 7.2.4trans. 7.2.7undervoltage 7.5

Branch overcurrentprotection (whensupplied) 7.2.10

Disconnectingmeans; Chapter 5

SupplyNEC, Article 670A

B

C

D

E

F

G

H

Disc

MTR

Disc

MTR

Disc

MTR

Disc

MTR

Disc

MTR

Disc

MTR

Disc

MTR

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MTR

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MTR

Disc

MTR

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MTR

Disc

MTR

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MTR

Main overcurrent protec-tion (when supplied)7.2.2; 7.2.3; 7.2.10

Figure A.7.2.1(a)

MotorChapter 15

Remote location drive unitinternally or externallyprotected

Internally protected drive unit

Externally protected drive unit

Control circuit and specialcontrol protectioncond., 7.2.4trans., 7.2.7undervoltage, 7.5power supply, 7.2.12

Overcurrent protection,7.2.10

Main overcurrent protection (whensupplied) 7.2.2; 7.2.3; 7.2.10

Disconnecting meansChapter 5

SupplyNEC 70, Article 670

Line Reference Control circuit connections Misc. drive connections

A

B

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E1

E2

E3

F

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Disc Disc Disc

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Figure A.7.2.1(b) [ROP 79-44 (Log 45)]


1879

A.7.2.2 See 7.2.10 and 18.5. [ROP 79-44 (Log 45)] The size and overcurrent protection of the supply conductors to a machine are covered by Article 670 of NFPA 70, National Electrical Code . [ROP 79-44 (Log 45)] A.7.2.10.1, Table 1, Note 6. IEC 947-4 defines the terms Type 1 and Type 2 coordinated protection as follows. Type 1 Protection: Under short-circuit conditions the contactor or starter may not be suitable for further use without repair or replacement. Type 2 Protection: Under short-circuit conditions the contactor or starter shall be suitable for further use. The maximum allowable values in Table 7.2.10.1 do not guarantee Type 2 protection. Type 2 protection is recommended for use in applications where enhanced performance and reliability are required. [ROP 79-44 (Log 45)] A.7.2.10.4(1) The short-circuit current rating includes the following: (1) The class and rating of the short-circuit protective device (2) The maximum nominal application voltage (3) The maximum available fault current [ROP 79-44 (Log 45)] A.7.4 An example could be a resistance heating circuit that is short-time rated or that loses its cooling medium. A.7.6.1 Overspeed protection means include, but are not necessarily limited to, the following: (1) A mechanical overspeed device incorporated in the drive to remove armature voltage upon motor overspeed. (2) An electrical overspeed detector that will remove armature voltage upon motor overspeed. (3) Field loss detection to remove armature voltage upon the loss of field current. (4) Voltage-limiting speed-regulated drives that operate with constant full field. In this case, protection is obtained individually for the loss of field or tachometer feedback; however, protection against simultaneous loss of field and tachometer is not provided. [ROP 79-44 (Log 45)] A.7.8 Conditions of use that can lead to an incorrect phase sequence include the following: (1) A machine transferred from one supply to another (2) A mobile machine with a facility for connection to an external power supply [ROP 79-44 (Log 45)] A.7.10.1 See 7.2.1 and 7.2.10. [ROP 79-44 (Log 45)] A.8.1 The terms protective earthing conductor, protective bonding conductor, protective conductor, neutral, and earth are used in other countries. [ROP 79-151 (Log 52)] A.8.2.1.2 The minimum cross-sectional area of the external protective copper conductor can be required to be larger for IEC applications. See Table 1 in IEC 60204-1 for these requirements. [ROP 79-151 (Log 52)] A.8.2.1.2.4 Some other standards require the letters PE for the connection to the external protective earthing system. A.8.2.5.2 The letters PE or the bicolor GREEN and YELLOW is used in some countries. [ROP 79-151 (Log 52)

A.9.2.2 With the exception of emergency stop and depending upon the risk assessment, removal of power can be accomplished by the use of either electromechanical or solid-state components. [ROP 79-62 (Log 46)] A.9.2.3.3 See 9.2.4 for overriding of safeguards under special conditions. [ROP 79-62 (Log 46)]

A.9.2.5.4.1 For other safety-related stop functions, see 11.3.4. A.9.2.5.6 See Annex B. A.9.2.7.3.2(3) A valid signal also includes the signal that confirms communication is established and maintained. (See Annex B.) [ROP 79-62 (Log 46)] A.9.2.7.4 One way to determine applicable error detection methods is to refer to IEC 60870-5-l, “Telecontrol equipment and systems.” [ROP 79-62 (Log 46)] A.9.4.1 The measures and the extent to which they are implemented, either individually or in combination, depend on the safety requirements associated with the respective application. [ROP 79-67 (Log 85)] Measures to reduce these risks include but are not limited to the following:

(1) Protective devices on the machine (e.g., interlock guards, trip devices)

(2) Protective interlocking of the electrical circuit (3) Use of proven circuit techniques and components (see 9.4.2.1) (4) Provisions of partial or complete redundancy (see 9.4.2.2) or

diversity (see 9.4.2.3) (5) Provision for functional tests (see 9.4.2.4)

In general, only single failures are to be regarded. In the event of higher levels of risk, it can be necessary to ensure that more than one failure cannot result in a hazardous condition.

Measures to minimize risk in the event of failure include the use of proven circuit techniques and components. These measures include but are not limited to the following:

(1) Bonding of control circuits for operational purposes (see 9.4.2.1)

(2) One terminal of the control device (i.e., the operating coil) connected to the bonded conductor and all switching elements (e.g., contacts) connected to the nonearthed (grounded) side of the control supply (see 9.1.4)

(3) Stopping by de-energizing (see 9.2.2) (4) Switching of all live conductors to the device being controlled

(see 9.4.2.1) (5) Use of switching devices having positive opening operation (see

IEC 60947-5-1) (6) Circuit design to reduce the possibility of failures causing

undesirable operations By providing partial or complete redundancy it is possible to minimize the probability that one single failure in the electrical circuit can result in a hazardous condition. Redundancy can be effective in normal operation (i.e., on-line redundancy) or designed as special circuits that take over the protective function (i.e., off-line redundancy) only where the operating function fails. Where off-line redundancy that is not active during normal operation is used, suitable measures should be taken to ensure that these control circuits are available when required. [ROP 79-66(Log 86)]


1880

The use of control circuits having different principles of operation or differing types of devices can reduce the probability of faults and failures giving rise to hazards. Examples include the following:

(1) The combination of normally open and normally closed contacts operated by interlocking guards.

(2) The use of different types of control circuit components in the circuit.

(3) The combination of electromechanical and electronic circuits in redundant configurations.

(4) The combination of electrical and nonelectrical systems (e.g., mechanical, hydraulic, pneumatic) can perform the redundant function and provide the diversity. Functional tests can be carried out automatically by the control system, or manually by inspection or tests at start-up and at predetermined intervals, or a combination as appropriate (see also Sections 18.2 and 19.6). [ROP 79-66(Log 86)] [ROP 79-62 (Log 46)] A.10.1.1 For further information on device selection, mounting, identification, and coding, see IEC 60073 and IEC 60447. [ROP 79-99 (Log 24)] A.10.1.3 For further information on degrees of protection, see UL 50, UL 508, Annex F and IEC 60529. [ROP 79-99 (Log 24)] A.10.1.4.2 For further information on positive (direct) opening operation, see IEC 60947-5-1. A.10.7.2.2 For further information on positive (direct) opening operation, see IEC 60947-5-1. [ROP 79-99 (Log 24)] A.10.9 Displays intended to be warning devices are recommended to be of the flashing or rotary type and be provided with an audible warning device. [ROP 79-99 (Log 24)] A.11.3.4(1)(b) Firmware is an executive control program in a nonvolatile internal storage mode and is not changeable by the user. [ROP 79-155 (Log 25)] A.11.3.4(2) For example, equivalency can be achieved by using microprocessor redundancy, microprocessor diversity, and self-checking. [ROP 79-155 (Log 25)] A.11.4 See Section 7.3 for requirements regarding automatic restarting of motors. [ROP 79-155 (Log 25)] A.12.2.1.4 Where access is required for regular maintenance or adjustment, the location of relevant devices is recommended to be between 0.4 m (15.75 in.) and 2.0 m (78.75 in.) above the servicing level to facilitate maintenance. The location of the terminals is recommended to be at least 0.2 m (7.88 in.) above the servicing level and be so placed that conductors and cables can be easily connected to them. [ROP 79-84 (Log 54)] A.12.2.1.7 For additional information on attachment plug and receptacle (plug/socket) combinations, see 14.4.5. [ROP 79-84 (Log 54)] A.12.3.1 The degrees of protection against ingress of water and other liquids are covered by NEMA 250. See also Annex H. [ROP 79-84 (Log 54)] A.13.7.1.2 Cables for such conditions are specified in relevant national standards. The operational life of the cable will be reduced where unfavorable operating conditions such as high tensile stress, small radii, bending

into another plane, and/or where frequent duty cycles coincide. [ROP 79-112 (Log 28)] A.13.7.2 Where the demands of the application exceed the tensile stress limit of 15 N/mm2, cables with special construction features should be used. The allowed maximal tensile strength should be agreed upon with the cable manufacturer. The allowed maximum stress of conductors of flexible cables with material other than copper should be agreed upon with the cable manufacturer. The following conditions affect the tensile stress of the conductors: (1) Acceleration forces (2) Speed of motion (3) Dead (hanging) weight of the cables (4) Method of guiding (5) Design of cable drum system [ROP 79-112 (Log 28)] A.13.7.3 Where cables of circular cross-sectional area are installed on drums, the maximum current-carrying capacity in free air should be derated in accordance with Table 13.7.3. For additional information, also refer to clause 44 of IEC 60621-3. [ROP 79-112 (Log 28)] A.14.1.1.10 A single tag bearing the complete identification is preferred. [ROP 79-122 (Log 55)] A.14.1.1.11 For additional information on terminal blocks, refer to IEC 60947-7-1, “Low-voltage switchgear and control gear.” [ROP 79-122 (Log 55)] A.14.2.2.1 The international standards reserve the use of bicolor combination GREEN and YELLOW for this purpose. The bicolor combination is such that on any 15-mm (0.6-in.) length, one of the colors covers at least 30 percent and not more than 70 percent of the surface of the conductor, and the other color covers the remainder of the surface. [ROP 79-122 (Log 55)] A.14.2.3.1 IEC 60204-1 reserves the use of the color LIGHT BLUE for the neutral conductor and requires its use when identification is by color. [ROP 79-122 (Log 55)] [ROP 79-126 (Log 17)] A.14.2.4.1 IEC 60204-1 recommends the use of the color ORANGE for this purpose where identification is by color. For further information on excepted circuits, see 5.3.5. [ROP 79-130 (Log 67)] [ROP 79-131 (Log 16)] A.14.3.1 For additional information on flame-retardant materials, refer to IEC 60332-1, Tests on electric cables under fire conditions. [ROP 79-122 (Log 55)] A.14.5.2 It should be recognized that, for certain conditions, a larger size raceway or a lesser raceway fill should be considered. A.14.5.3.1.2 Metric trade numerical designations for rigid metal conduit are the same as those found in IEC 981-1989 Extra-heavy duty rigid steel conduits for electrical installations, namely: ½ = 16, ¾ = 21, 1 = 27, 1¼ = 35, 1½ = 41, 2 = 53, 2½ = 63, 3 = 78, 3½ = 91, 4 = 103, 5 = 129, and 6 = 155. [ROP 79-122 (Log 55)] A.14.5.3.2.2 The use of dissimilar metals in contact that can cause galvanic action should be avoided. [ROP 79-122 (Log 55)] A.14.5.3.2.3 The use of dissimilar metals in contact that can cause galvanic action should be avoided. [ROP 79-122 (Log 55)] A.14.5.3.2.4 The use of dissimilar metals in contact that can cause galvanic action should be avoided. [ROP 79-122 (Log 55)] A.14.5.3.3.1 For additional information about rigid nonmetallic conduit, refer to UL 651. [ROP 79-122 (Log 55)]


1881

A.14.5.3.3.3 For additional information see Table 347-9(A).of NFPA 70, National Electrical Code, 1999, Expansion Characteristics of PVC Rigid Nonmetallic Conduit Coefficient of Thermal Expansion = 3.38 × 10-5 in./in./º F. A.14.5.4.1.2 Metric trade numerical designations for flexible metal conduit and liquidtight flexible metal conduit are 3/8 = 12, ½ = 16, ¾ = 21, 1 = 27, 1¼ = 35, 1½ = 41, 2 = 53, 2½ = 63, 3 = 78, 3½ = 91, and 4 = 103. [ROP 79-122 (Log 55)] A.14.5.5.5 Metric trade numerical designations for liquidtight flexible nonmetallic conduit are 3/8 = 12, ½ = 16, ¾ = 21, 1 = 27, 1¼ = 35, 1½ = 41, 2 = 53, 2½ = 63, 3 = 78, 3½ = 91, and 4 = 103. [ROP 79-122 (Log 55)] A.14.5.7 See Section 17.2 for information on warning marking and signs. [ROP 79-122 (Log 55)] A.14.5.10.1 For additional information on flexible cords, refer to ANSI/UL 62, Flexible Cord and Fixture Wire. [ROP 79-122 (Log 55)] A.15.1 For additional information related to motor standards, refer to UL 1004, NEMA MG-1, IEEE 841, or IEC 60034-1. The protection requirements for motors and associated equipment are given in Section 7.2 for overcurrent protection, in Section 7.3 for overload protection, and in Section 7.6 for overspeed protection. [ROP 79-149(Log 27)] A.15.3 For a comparison between kilowatt and horsepower size, see Annex G Tables G.1 and G.2. [ROP 79-149(Log 27)] A.15.6 Associated machine actuators are those associated with the same motion (e.g., cable drums and long-travel drives). [ROP 79-149(Log 27)] A.17.3 Such markings can be as agreed between the user and the supplier of the equipment. See Annex B for additional information. For further information on symbols, see IEC 60417 and ISO 7000. Consideration should be given to the use of IEC symbols for pushbuttons.

Figure A.17.3(a) Symbol that represents start or on - IEC symbol

number 5007.

Figure A.17.3(b) Symbol that represents stop or off - IEC symbol number 5008.

Figure A.17.3(c) Symbol that represents alternatively act as start and stop or on and off - IEC symbol number 5010.

Figure A.17.3(d) Symbol that represents movement when pressed and stop movement when released (jogging) - IEC symbol number 5011.

A.18.4 The technical documentation should also contain, where appropriate, information regarding load currents, peak starting currents, and permitted voltage drops. That information should be contained in either the system or circuit diagram(s). [ROP 79-19 (Log 53)] A.18.5.1 In complex cases, it can be necessary to refer to the assembly drawings for details. [ROP 79-19 (Log 53)] A.18.5.3 For further information regarding supply circuit conductors, see 7.2.2. [ROP 79-19 (Log 53)] A.18.5.4 For recommendations concerning supplier agreements, see Annex B. [ROP 79-19 (Log 53)] A.18.5.5 For recommendations concerning supplier agreements, see Annex B. [ROP 79-19 (Log 53)] A.18.5.6 Examples of installation diagrams can be found in IEC 61082-4. [ROP 79-19 (Log 53)] A.18.5.7 Examples of interconnection diagrams/tables can be found in IEC 61082-3. [ROP 79-19 (Log 53)] A.18.6 Examples of block diagrams can be found in IEC 61082-1-2. Further rules and examples can be found in IEC 61082-2-3. [ROP 79-19 (Log 53)] Function diagrams can be used as either part of, or in addition to, the block diagram. Examples of function diagrams can be found in IEC 61082-1-2 and in IEC 61082-2-4. [ROP 79-19 (Log 53)] A.18.7.1 See Annex D for examples of electrical diagrams. [ROP 79-20 (Log 119)] A.18.7.2 Examples of circuit diagrams can be found in IEC 61082-1 and in IEC 61082-2-5. [ROP 79-19 (Log 53)] A.18.7.3 The diagram showing the terminals for interface connections can be used in conjunction with the circuit diagram(s) for simplification. The diagram should contain a reference to the detailed circuit diagram of each unit shown. [ROP 79-19 (Log 53)] A.18.7.5 See Annex E for examples of devices and component designations. [ROP 79-21 (Log 118)] A.18.8.1 Particular attention should be given to the safety measures provided and to the improper methods of operation that are anticipated.


1882

A.18.9.1 Recommendations on maintenance/service records should be part of that manual. Troubleshooting information and suggestions for locating and replacing faulty components, suggested preventative maintenance schedules, and related data should be included. [ROP 79-19 (Log 53)]

Name of manufacturer/supplier Name of end user Tender/Order No. Date Type of Machine/Serial Number 1. Are there to be modifications as allowed for within this standard? YES ____ NO _____ Operating Conditions - Special requirements (see Section 4.4) 2. Ambient temperature range 3. Humidity range 4. Altitude 5. Environmental (e.g., corrosive atmospheres, particulate matter, EMC) 6. Radiation 7. Vibration, shock 8. Special installation and operation requirements (e.g., flame-retardant requirements for cables and conductors) Power supply(ies) and related conditions (see Section 4.3) 9. Anticipated voltage fluctuations (if more than ±10 %) 10. Anticipated frequency fluctuations (if more than in 4.3.2) Specification of short-term value 11. Indicate possible future changes in electrical equipment that will require an increase in the electrical supply requirements 12. Indicate for each source of electrical supply required: Nominal Voltage (V) __________ ac ____ dc ____ If ac, number of phases _____ frequency ____ Hz Prospective short-circuit current at the point of supply to the machine ______kA rms (see also question 15) Fluctuations outside values given in 4.3.2 _________________________________________ 13. Type of power supply earthing (see IEC 364-3-31): - TN [System with one point directly earthed, with a protective conductor (PE) connected directly to that point] ____ - TT [System with one point directly earthed but the protective conductor (PE) not connected to that earth point of the system] ____ - IT (System that is not directly earthed) ____ 14. Is the electrical equipment to be connected to a neutral (N) supply conductor? (see Section 5.1) YES ____ NO ____ 15. Does the user or the supplier provide the overcurrent protection of the supply conductors? (see 7.2.2) Type and rating of overcurrent protective devices 16. Supply disconnecting device - Is the disconnection of the neutral (N) conductor required? YES ___ NO ____ - Is a link for the neutral (N) conductor permissible? YES ____ NO ____ 17. Type of disconnecting device to be provided


1883

A.19.1 It is recommended that the sequence listed is followed. Following this order will help ensure the accuracy of the tests results and the safety of personnel. Refer to SEMI S9 for additional information on performing the testing described in Section 19.1. A.19.2 The concepts of SELV are further explained in UL 1950, UL 3101-1, and IEC 60364-411.1. A.19.4 Refer to SEMI S9 for additional information on performing this dielectric withstand (hypot) test. [ROP 79-161 (Log 140)]

Annex B Inquiry Form for the Electrical Equipment of Machines [ROP 79-163 (Log 39)]

This annex is not a part of the requirements of this NFPA document but is included for informational purposes only. B.1 It is recommended that the following information is provided by the intended user of the equipment. It facilitates an agreement between the user and supplier on basic conditions and additional user requirements to ensure proper design, application, and utilization of the electrical equipment of the machine (see Section 4.1).

Annex C Examples of Industrial Machines Covered by NFPA 79 [ROP 79-164 (Log 40)]

This annex is not a part of the requirements of this NFPA document but is included for informational purposes only. C.1 Machine Tools. Examples of machine tools are as follows:

(1) Metal cutting (2) Metal forming

C.2 Plastics Machinery. Examples of plastics machinery are as follows:

(1) Injection molding machines (2) Extrusion machinery (3) Blow molding machines (4) Specialized processing machines (5) Thermoset molding machines (6) Size reduction equipment

C.3 Wood Machinery. Examples of wood machinery are as follows:

(1) Woodworking machinery (2) Laminating machinery (3) Sawmill machines

18. Limit of power up to which three-phase ac motors can be started directly across the incoming supply lines? ____ HP ____ KW 19. Can the number of motor overload detection devices be reduced? (see Section 7.3) YES ____ NO ____ 20. Where the machine is equipped with local lighting: - Highest permissible voltage V - If lighting circuit voltage is not obtained directly from the power supply, state preferred voltage V Other Considerations 21. Functional identification (see Section 17.3) 22. Inscriptions/special markings 23. -Mark of certification YES ____ NO ____ If YES, which one? - On electrical equipment? In which language? 24. Technical documentation (see Section 18.1) On what media? _______ In which language? 25. Size, location, and purpose of ducts, open cable trays, or cable supports to be provided by the user (see Section 18.5) (additional sheets to be provided where necessary) 26. For which of the following classes of persons is access to the interior of enclosures required during normal operation of the equipment? - Skilled persons - Instructed persons 27. Are locks with removable keys to be provided for fastening doors or covers? (see Section 6.2.2) 28. Indicate if special limitations on the size or weight affect the transport of a particular machine or control equipment to the installation site: - Maximum dimensions - Maximum weight 29. In the case of machines with frequent repetitive cycles of operation dependent on manual control, how frequently will cycles of operation be repeated? per hour 30. For what length of time is it expected that the machine will be operated at this rate without subsequent pause? minutes 31. In the case of specially built machines, is a certificate of operating tests with the loaded machine to be supplied? YES ____ NO ____ 32. In the case of other machines, is a certificate of operating-type tests on a loaded prototype machine to be supplied? YES ___ NO ____ 33. For cableless control systems, specify the time delay before automatic machine shutdown is initiated in the absence of a valid signal (see 9.2.7.3)_______ seconds. 34. Do you need a specific method of conductor identification to be used for the conductors referred to in 14.2.4? Yes__________ No__________ Type___________________________


1884

C.4 Assembly Machines. C.5 Material-Handling Machines. Examples of material-handling machines are as follows:

(1) Industrial robots (2) Transfer machines

C.6 Inspection/Testing Machines. Examples of inspection/testing machines are as follows:

(1) Coordinate measuring machines (2) In-process gauging machines

Annex D Technical Documentation [ROP 79-164 (Log 40)]

This annex is not a part of the requirements of this NFPA document but is included for informational purposes only. Figures D.1(a) through D.1(q) are not intended to be (design) guidelines. They are included only to illustrate documentation methods.

Annex E Device and Component Designations

[ROP 79-167 (Log 42)] This annex is not a part of the requirements of this NFPA document but is included for informational purposes only.

E.1 Device and Compound Designations. The device and component designations given in Table E.1 are intended for use on diagrams in connection with the corresponding graphical symbols to indicate the function of the particular device. These device and component designations are based on the assignment of a standard letter or letters to the fundamental function that is performed by a component or device. Suitable numbers (1, 2 ,3, etc.) and letters (A, B, C, etc.) can be added to the basic designation to differentiate between devices performing similar functions. The assignment of a designation to a device on specific equipment is governed by the function of that device on that equipment and not by the type or nature of the device or its possible use for other functions on other equipment. The same type of device can perform different functions on different equipment or even on the same equipment and, consequently, can be identified by different designations.

Table E.1 Device and Component Designations Designation Device ABE Alarm or Annunciator Bell ABU Alarm or Annunciator Buzzer AH Alarm or Annunciator Horn AM Ammeter AT Autotransformer CAP Capacitor CB Circuit Breaker CI Circuit Interrupter CNC Computerized Numerical Controller CON Contractor COs Cable-Operated (Emergency) Switch CPU Central Processing Unit CR Control Relay CRA Control Relay, Automatic CRH Control Relay, Manual CRL Control Relay, Latch CRM Control Relay, Master CRT Cathode Ray Tube, Monitor or Video Display Unit CRU Control Relay, Unlatch CS Cam Switch CT Current Transformer CTR Counter D Diode DISC Disconnect Switch DISP Display DR Drive

EMO Emergency (Machine) Off Device END Encoder ESTOP Emergency Stop FLD Field FLS Flow Switch FS Float Switch FTS Foot Switch FU Fuse GEN Generator GRD, GND Ground GUI Graphical User Interface HM Hour Meter HTR Heating Element IC Integrated Circuit INST Instrument IOL Instantaneous Overload I/O Input/Output Device L Inductor LED Light Emitting Diode LS Limit Switch LT Pilot Light LVDT Linear Variable Differential Transformer M Motor Starter MD Motion Detector MF Motor Starter - Forward MG Motor - Generator MR Motor Starter - Reverse MTR Motor OIT Operator Interface Terminal OL Overload Relay PB Pushbutton PBL Pushbutton, Illuminated PC Personal Computer PCB Printed Circuit Board PEC Photoelectric Device PL Plug PLC Programmable Logic Controller POT Potentiometer PRS Proximity Switch PS Pressure Switch PWS Power Supply Q Transistor QTM Thermistor REC Rectifier RECP Receptacle RES Resistor RH Rheostat S Switch SCR Silicon Controlled Rectifier SOL Solenoid SNSR Sensor SS Selector Switch SSL Selector Switch, Illuminated SSR Solid State Relay ST Saturable Transformer SUP Suppressor SYN Synchro or Resolver T Transformer TACH Tachometer Generator TAS Temperature-Actuated Switch TB Terminal Block T/C Thermocouple TR Timer Relay TSDR Transducer TWS Thumbwheel Switch V Electronic Tube VAR Varistor VM Voltmeter VR Voltage Regulator VS Vacuum Switch WLT Worklight WM Wattmeter X Reactor ZSS Zero Speed Switch

[ROP 79-166(Log 5)]


1885

Figure D.1(a) Cover sheet and sheet index.


1886

Figure D.1(b) System layout and intallation diaagram.


1887

Figure D.1(c) Block (system) diagram.


1888

Figure D.1(d) Interconnection diagram.


1889

Figure D.1(e) Elementary schematic.


1890

Figure D.1(f) PLC input diagram.


1891

Figure D.1(g) PLC output diagram.


1892

Figure D.1(h) Sample enclosure layout.


1893

Figure D.1(i) Sample enclosure layout.


1894

Figure D.1(j) Sequence of operations – graphical.


1895

Figure D.1(k) Sequence of operations – descriptive graphical.


1896

Figure D.1(l) Sample servo diagram.


1897

Figure D.1(m) Sample PLC network — station layout.


1898

Figure D.1(n) Sample operator station.


1899

Figure D.1(o) Sample parts list.


1900

Figure D.1(p) ISO (A2) drawing standard framework.


1901

Annex F Enclosure Type Rating Versus IP Rating

[ROP 79-168(Log 43)] Thes annex is not a part of the requirements of this NFPA document but is included for informational purposes only. F.1 Rating for Electrical Enclosures. Electrical enclosures are type rated (NEMA 250 / UL 50 and UL 508) and/or IP rated (IEC 60529) based upon the degree of protection provided.

Type-rated and IP-rated electrical enclosures have only the following in common: (1) A degree of protection for persons from hazardous components inside the enclosure

(2) A degree of protection for equipment inside the enclosure from ingress of solid foreign objects, including dust (3) A degree of protection for equipment inside the enclosure from ingress of water

Figure D.1(q) (Selected) ANSI Y32.2/IEEE315/315A symbol table.


1902

F.1.1 Type Rating System. The type rating system, in a single electrical enclosure document, defines additional requirements that a type-rated enclosure must meet, which include the following: (1) Mechanical impact on enclosure walls (2) Gasket aging and oil resistance (3) Corrosion resistance (indoor and outdoor) (4) Door and cover latching requirements F.1.2 IP Rating System. The IEC 60529 designation consists of the letters IP followed by two numerals with optional letters (e.g., IP 23CH). The first characteristic numeral indicates the degree of protection provided by the enclosure with respect to persons and solid foreign objects entering the enclosure. The second characteristic numeral indicates the degree of protection provided by the enclosure with respect to the harmful ingress of water. The additional letter indicates the degree of protection for a person against access to hazardous parts. A brief description of the additional letter is in Table F.1.2. Table F.1.2 Arrangement of the IP Code Code letters (International

Protection) IP

First characteristic numeral

(numerals 0 to 6, or letter X)

N (or letter X)

Second characteristic numeral

(numerals 0 to 8, or letter X)

N (or letter X)

Additional letter (optional)

(letters A, B, C, D) L

Supplementary letter (optional)

(letters H, M, S, W)

L

Example: IP 23CH Where a characteristic numeral is not required to be specified, it shall be replaced by the letter “X” (“XX” if both numerals are omitted). Additional letters and/or supplementary letters may be omitted without replacement.

Table F.1 - Degrees of Protection Against Access to Hazardous Parts indicated by the First Characteristic Numeral

First characteristic numeral

Degree of protection

Brief description Definition 0 Nonprotected - 1 Protected against access

to hazardous parts with the back of a hand

The access probe, sphere of 50 mm Ø shall have adequate clearance from hazardous parts

2 Protected against access to hazardous parts with a finger

The jointed test finger of 12 mm Ø, 80 mm length shall have adequate clearance form hazardous parts

3 Protected against access to hazardous parts with a tool


4 Protected against access to hazardous parts with a wire

the access probe of 1,0 mm Ø shall not penetrate





Note: In the case of the first characteristic numeral 3, 4, 5, and 6, protection against access to hazardous parts is satisfied if adequate clearance is kept. Due to the simultaneous requirement specified in Table II, the definition shall not penetrate is given in Table I.

Table X.X Element Numerals or letters Meaning for the protection of equipment Meaning for the protection of

persons Code letters IP - - First characteristic numerals Against ingress of solid foreign objects Against access to hazardous parts

with: 0 (non-protected) (non-protected)

1 • 50 mm diameter back of hand 2 • 12,5 mm diameter finger 3 • 2,5 mm diameter tool 4 • 1,0 mm diameter wire 5 dust-protected wire 6 dust-tight wire Second characteristic numeral Against ingress of water with harmful

effects -

0 (non-protected) 1 vertically dripping 2 dripping (15° tilted) 3 spraying 4 splashing 5 jetting 6 powerful jetting 7 temporary immersion 8 continuous immersion Additional letter (optional) - Against access to hazardous parts

with: A back of hand B finger C tool D wire Supplementary letter (optional) Supplementary information specific to: - H High-voltage apparatus M Motion during water test S Stationary during water test W Weather conditions


1903

Where more than one supplementary letter is used, the alphabetic sequence shall apply.

IPXXA Protected against access with the back of hand IPXXB Protected against access with finger IPXXC Protected against access with a tool IPXXD Protected against access with a wire

These letter designations (A, B, C, D) can be used referencing the protection of live parts while the enclosure is accessed. There is not a comparable NEMA 250 rating to this application. Electrical enclosures that carry only an IP rating have not been designed to the above additional type rating requirements. Therefore, a type rating cannot be assigned to an enclosure that has only been IP rated because of the exclusion of the additional requirements of the type rating system. Because the IP requirements can be interpreted to be inclusive to the type requirements, a conservative IP rating can be assigned to a type-rated enclosure by referencing Table H-1. As a practical matter thought, many electrical enclosures are tested to both the IP and type requirements and carry both IP and type designations.

Table F.2 Assignment of IP ratings to type rated enclosures A NEMA enclosure type B First Character

1 2 3 3R 3S 4 4X 5 6 6P 12 12K 13 Second Character

IP0_ AB AB AB AB AB AB AB AB AB AB AB AB AB IP_O IP1_ A AB AB AB AB AB AB AB AB AB AB AB AB IP_1 IP2_ B AB B AB AB AB AB AB AB AB AB AB IP_2 IP3_ AB B AB AB AB AB AB AB AB AB AB IP_3 IP4_ AB B AB AB AB AB AB AB AB AB AB IP_4 IP5_ AB AB AB AB A AB AB A A A IP_5 IP6_ A A AB AB AB AB IP_6 B B IP_7 B IP_8

A - The first character designation is the protection against access to hazardous parts and solid foreign objects. The respective NEMA enclosure type meets the requirements for the IEC 520 IP first character designation. B - The IP second character designation is the protection against ingress of water. The respective NEMA enclosure type meets the requirements for the IEC 529 IP second character designation. Notes: 1. Type-rated enclosures for hazardous locations and potentially explosive areas have been excluded from the table. The additional and supplementary letters for IP ratings have also been excluded from the table. (See NEMA 250 / UL 50 and UL 508 and IEC 529 / IEC 60529.) 2. Table H-1 shall only be used to assign an IP rating to a Type rated enclosure, and not to assign a Type rating to an IP rated enclosure. Table H-1 assists in specifying enclosure ratings and shall not be used as a definitive guide. Example: If the conditions of installation require an IP 55, Table H-1 indicates that a Type 3, 3S, 4, 4X, 6, or 6P enclosure can be utilized. If the conditions of installation require a NEMA Type 4, an enclosure that is only IP rated cannot be used as a substitute. Although the corresponding NEMA type ratings meet or exceed the corresponding IP rating as indicated in Table H-1, IEC does not currently accept these ratings without further IEC testing.


1904

Annex G Kilowatt Outputs with Horsepower Equivalents [ROP 79-170(Log 44)]

This annex is not a part of the requirements of this NFPA document but is included for informational purposes only. G.1 Preferred Kilowatt Outputs with Horsepower Equivalents. The kilowatt and horsepower values shown in Tables G.1 and G.2 are not exact conversion values. They give the approximate relationships between countries employing the two different systems of units.

Table G.1 Preferred kW Outputs with HP Equivalents kW hp(746W) Primary Series Secondary

Series

0,06 1/12 0,09 1/8 0,12 1/6 0,18 1/4 0,25 1/3 0,37 1/2 0,55 3/4 0,75 1 1,1 1.5 1,5 1,8 2 2,2 3 3,7 3 5 4 5,5 7.5 6,3 7,5 10 10 11 15 13 15 20 17 18,5 25 20 22 30 25 30 40 33 37 50 40 45 60 50 55 75 63 75 100 80 90 125 100 110 150 125 132 175 150 200 160 220 185 250 200 270 220 300 250 350 280 375 300 402 315 422 335 449 355 476 375 503 400 536 425 570

450 603 475 637 500 670 530 710 560 750 600 804 630 845 670 898 710 952 750 1005 800 1072 850 1139 900 1206 950 1273 1000 1340 Source: IEC 60072-1 Annex D Tables D.5.1 and D.5.2, Sixth Edition 1991-2, are provided to assist with hp and kW r Note: The kW-hp conversions are approximately 1 hp = 720 W, not the stated 746 W nor even the rounded off metric units which result in 736 W.

G.2 Preferred Horsepower Outputs with Kilowatt Equivalents.

Table G.2 Preferred Horsepower Outputs with Kilowatt Equivalents. hp (746W) kW hp

(746W) kW

375 280 710 530 400 298 750 560 425 317 800 597 450 336 850 634 475 354 900 671 500 373 950 709 530 395 1000 746 560 418 1060 791 600 448 1120 836 630 470 1180 880 670 500 1250 930 700* 522 1320 985 *This value is introduced for use in certain countries that prefer rounded off horsepower values. Note: The kW-hp conversions are approximately 1 hp = 720 W, not the stated 746 W nor even the rounded off metric units which result in 736 W. Source: IEC 60072-1 Annex D tables D.5.1 and D.5.2, Sixth Edition 1991-2, are provided to assist with hp and kW r

The notes are to inform the user that additional information is necessary in order to properly exchange motors.


1905

Annex H NFPA 79-1997 Cross Reference [ROP 79-172 (Log CP3)] H.1 NFPA 79-1997 Cross Referenced to NFPA 79-2002

Text to follow H.2 NFPA 79-2002 Cross Referenced to NFPA 79-1997

Text to follow