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NEMA EN P1-2020

NEMA 250 Enclosure Types Published by National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org © 2020 National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American Copyright Conventions.

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NEMA EN P1-2020

© 2020 National Electrical Manufacturers Association

Disclaimer

The guidelines presented in a NEMA Standards publication are considered technically sound at the time they are approved for publication. They are not a substitute for a product seller’s or user’s own judgment with respect to the particular product referenced in the Standard or guideline, and NEMA does not undertake to guarantee the performance of any individual manufacturer’s products by virtue of this Standard or guide. Thus, NEMA expressly disclaims any responsibility for damages arising from the use, application, or reliance by others on the information contained in these Standards or guidelines.

NEMA EN P1-2020


Foreword

This NEMA white paper is completely based on NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum). In the preparation of this white paper, input of users and other interested parties has been sought and evaluated. This publication will be periodically reviewed by the Enclosures Section of the NEMA Building Infrastructure Division.

Proposed or recommended revisions should be submitted to:

NEMA Technical Operations Department National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209

This Standard was developed by the NEMA Enclosure Section of the Building Infrastructure Division. Section approval of the Standard does not necessarily imply that all section Members voted for its approval or participated in its development. At the time it was approved, the Enclosure Section was composed of the following Members:

ABB, Inc. Memphis, TN Allied Moulded Products, Inc. Bryan, OH AmeriTex Machine and Fabrication, LLC. Willis, TX Arlington Industries, Inc. Scranton, PA Atkore International Harvey, IL Boltswitch, Inc. Crystal Lake, IL Eaton Cleveland, OH Emerson Automation Solutions Rosemont, IL Hubbell Incorporated Shelton, CT IPEX USA, LLC. Pineville, NC Legrand, North America West Hartford, CT Millbank Manufacturing Company Kansas City, MO nVent, Hoffman Enclosures Inc. St. Louis Park, MN Rittal North America LLC Urbana, OH Robroy Industries, Inc. Verona, PA Schneider Electric Boston, MA Siemens Industry, Inc. Norcross, GA Snake Tray Bay Shore, NY Space Age Electronics Sterling, MA

NEMA EN P1-2020


Scope The purpose of this document is to provide general information on the definitions of NEMA enclosure types, a guide for comparing specific applications of enclosures, and a comparison between NEMA enclosure type numbers, and ANSI/IEC enclosure classification designations. The document is intended for use by architects, engineers, installers, inspectors, and other interested parties. For more detailed and complete information, please refer to NEMA 250-2018 Enclosures for Electrical Equipment (1000 Volts Maximum).

NEMA Type Ratings The following definitions have been taken from the NEMA 250.

In non-hazardous locations, the specific enclosure types, their applications, and the environmental conditions they are designed to protect against when completely and properly installed are as follows:

Type 1 Enclosures constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts and provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt).

Type 2 Enclosures constructed for indoor use to provide a degree of protection for personnel

against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); and, provide a degree of protection from harmful effects on the equipment due to the ingress of water (dripping and light splashing).

Type 3 Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); and, that will be undamaged by the external formation of ice on the enclosure.

Type 3R Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); and, that will be undamaged by the external formation of ice on the enclosure.

Type 3S Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); and, for which the external mechanism(s) remain operable when ice-laden.

Type 3X Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); that provides an increased level of protection against corrosion and that will be undamaged by the external formation of ice on the enclosure.

Type 3RX Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the

NEMA EN P1-2020


equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); that will be undamaged by the external formation of ice on the enclosure that provides an increased level of protection against corrosion.

Type 3SX Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow); that provides an increased level of protection against corrosion; and for which the external mechanism(s) remain operable when ice-laden.


for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose-directed water); and, that will be undamaged by the external formation of ice on the enclosure.

Type 4X Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); provide a degree of protection from harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); that provides an increased level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure.


against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and settling dust, lint, fibers, and flyings); and, provide a degree of protection from harmful effects on the equipment due to the ingress of water (dripping and light splashing).


forpersonnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide a degree of protection from harmful effects on the equipment due to the ingress of water (hose directed water and the entry of water during occasional temporary submersion at a limited depth); and, that will be undamaged by the external formation of ice on the enclosure.

Type 6P Enclosures constructed for either indoor or outdoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); provide a degree of protection from harmful effects on the equipment due to the ingress of water (hose directed water and the entry of water during prolonged submersion at a limited depth); that provides an increased level of protection against corrosion and that will be undamaged by the external formation of ice on the enclosure.

Type 12 Enclosures constructed (without knockouts) for indoor use to provide a degree of protection

for personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings); provide a degree of protection from harmful effects

NEMA EN P1-2020


on the equipment due to the ingress of water (dripping and light splashing) and provide a degree of protection against light splashing and seepage of oil and non-corrosive coolants.

Type 12K Enclosures constructed (with knockouts) for indoor use to provide a degree of protection for

personnel against access to hazardous parts; provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings); and, provide a degree of protection from harmful effects on the equipment due to the ingress of water (dripping and light splashing) and provide a degree of protection against light splashing and seepage of oil and non-corrosive coolants.


against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings); to provide a degree of protection from harmful effects on the equipment due to the ingress of water (dripping and light splashing); and, to provide a degree of protection against the spraying, splashing, and seepage of oil and non-corrosive coolants.

In hazardous locations, when completely and properly installed and maintained, Type 7 enclosure is designed to contain an internal explosion without causing an external hazard. Type 9 enclosures are designed to prevent the ignition of combustible dust.

Table 2-1, NEMA 250-2018

Comparison of Specific Applications of Enclosures for Indoor Locations

Type of Enclosure

Provides a Degree of Protection against the Following Conditions 1 2 4 4X 5 6 6P 12 12K 13

Access to hazardous parts X X X X X X X X X X Ingress of solid foreign objects (falling dirt) X X X X X X X X X X Ingress of water (dripping and light splashing)

… X X X X X X X X X

Ingress of solid foreign objects (circulating dust, lint, fibers, and flyings **)

… … X X … X X X X X

Ingress of solid foreign objects (settling dust, lint, fibers, and flyings **)

… … X X X X X X X X

Ingress of water (hosedown and splashing water)

… … X X … X X … … …

Oil and coolant seepage … … … .. … … … X X X

Oil or coolant spraying and splashing … … … … … … … … … X

Corrosive agents ... ... ... X ... ... X ... ... ... Ingress of water (occasional temporary submersion)

... ... ... ... ... X X ... ... ...

Ingress of water (occasional prolonged submersion)

... ... ... ... ... ... X ... ... ...

NEMA EN P1-2020


Type 7 Explosion-proof enclosures demonstrating compliance with the requirements of ANSI/UL 1203 for use in hazardous (classified) locations classified as Class I, Division 1, Groups A, B, C, or D as defined in ANSI/NFPA 70.

Type 9 Dust-ignition-proof enclosures demonstrating compliance with the requirements of ANSI/UL

1203 for use in hazardous (classified) locations classified as Class II, Division 1, Groups E, F, or G as defined in ANSI/NFPA 70.

Specific Type Ratings The following tables are guides for comparing specific applications of enclosures. ** These fibers and flyings are not considered Class III type ignitable fibers or combustible flyings. For

Class III type ignitable fibers or flyings, see the NEC, Article 500.5(D).

Table 2-2, NEMA 250-2018 Comparison of Specific Applications of Enclosures for Indoor & Outdoor Locations

Provides a Degree of Protection Against the Following Conditions

Type of Enclosure

3 3X 3R 3RX 3S 3SX 4 4X 6 6P Access to hazardous parts Ingress of solid foreign objects (falling dirt) Ingress of water (dripping and light splashing)

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

X X X

Ingress of water (rain, snow, and sleet**) X X X X X X X X X X Sleet*** ... ... ... ... X X ... ... ... ... Ingress of solid foreign objects (windblown dust, lint, fibers, and flyings****)

X X ... ... X X X X X X

Ingress of water (hosedown and splashing water)

... ... ... ... ... ... X X X X

Corrosive agents ... X ... X ... X ... X ... X Ingress of water (occasional temporary submersion)

... ... ... ... ... ... ... ... X X

Ingress of water (occasional prolonged submersion)

... ... ... ... ... ... ... ... ... X

** External operating mechanisms are not required to be operable when the enclosure is ice covered. *** External operating mechanisms are operable when the enclosure is ice covered. See subsection 5.6 of NEMA 250-2018. **** These fibers and flyings are not considered Class III type ignitable fibers or combustible flyings. For

Class III type ignitable fibers or flyings see the NEC, Article 500.5(D).

NEMA EN P1-2020


Ancillary Ratings In addition to type designations, the following ancillary conditions can be evaluated and marked. The ancillary ratings are optional add-ons to the basic type ratings.

Pressure Wash (PW) Enclosures constructed for exterior cleaning with high-pressure power washers and tested in accordance with Section 5.15 of NEMA 250. The PW ancillary rating may be appended only to the following ratings: 3, 3X, 3S, 3SX, 4, 4X, 6, 6P, 12, 12X, 13. §

nema 250 enclosure types - emotors direct

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