electrical systems: designing electrical rooms

Electrical Systems: Designing electrical rooms

Join the discussion about this Webcast on Twitter at #CSEelectricalroom

Sponsored by:

Brian Martin, PE, Portland Electrical Department ManagerCH2M HillPortland, Ore.

Brian Rener, PE, LEED AP, AssociateSmithgroupJJR,Chicago, Ill.

Moderator: Jack Smith, Consulting-Specifying Engineer and Pure Power, CFE Media, LLC

Presenters:

Electrical Systems: Designing electrical rooms

Brian Martin, PE, Portland Electrical Department Manager

CH2M HillPortland, Ore.

Brian Rener, PE, LEED AP, AssociateSmithgroupJJR ,

Chicago, Ill.

Presentation scope

• NFPA 70 (NEC) 2014• International Building Code (IBC)• 800 A and Above • Primary services• No hazardous locations• Good engineering practices

Electrical room design

• Needs a coordinated team:• Electricals• Architects• Structural• Mechanicals• Fire protection

Room types

• Primary service rooms• Electrical rooms• UPS or battery rooms• Generator rooms• Computer rooms• Utility vaults

Design issues

• Working vs. dedicated spaces• Dedicated spaces and foreign systems• Fire protection• Fire ratings• Ventilation• Structural• Building occupancy• Lighting

Working vs. dedicated spaces

• Different spaces– Worker vs. equipment

Working vs. dedicated spaces

• Different spaces– Worker vs. equipment

Working space• Applies to:

– “Equipment operating at 600 V, nominal, or less, to ground and likely to require examination, adjustment, servicing, or maintenance while energized.” NEC Article 110.26(A)

• Switchboards• Switchgear (Added in 2014)• Motor control centers• Panelboards• Disconnect switches• Circuit breakers• Controllers• Controls for HVAC equipment• Transformers sometimes fall into this category

Working space: table

Working space: elevations

Nonelectrical parts

“Where rear access is required to work on nonelectrical parts on the back of enclosed equipment, a minimum horizontal working space of 30 in. shall be provided.” NEC Article 110.26(A)(1)a

Dedicated spaces• Applies to:

• “All switchboards, switchgear, panelboards, and motor control centers shall be located in dedicated spaces and protected from damage.” NEC Article 110.26(E)

• Switchboards• Switchgear (Added in 2014)• Panelboards• Motor control centers

Dedicated spaces and foreign systems

• Can you have foreign systems (mechanical ducts and/or plumbing) in your electrical room? – Yes and no

• Understand dedicated space

Foreign systems (MP)

• NEC: above, if protected

• What about sprinklers?• NEC: okay in dedicated space

2014 NEC change• Outdoor spaces

– New requirement now calls for the same basic dedicated equipment or electrical space for outdoor installations that has been in effect for indoor installations

– This space above and below the electrical equipment should be dedicated

Primary equipment

• Switchboard vs. switchgear• Switchboards: UL 891

– Front access – Rear access– Primarily fixed mounted

Primary equipment

• Switchboard Vs Switchgear• Switchgear - ANSI C37

– Rear Access– Primarily Drawout Construction

Access

• 1200 amps & 6 feet in width– Two doors on opposite ends– Doors 6’ 1/2’’ x 24”– One door if working clearance

doubled– Doors Swing Out

• 800 A (New to NEC 2014)– Listed Panic Hardware on Doors

Access: plan examples

Beyond NEC: working space and access

• Doors: at least 36 in. wide or double 36 in., 9 ft. high• Access to drawout devices• Would you want to work in only 3½ ft?• Breaker truck access• NFPA 70E: Standard for Electrical Safety in the Workplac

e - arc flash zones

• Arc flash gear, venting• Height above switchboards • Space planning: work with your architect

Fire protection

• Sprinklers– NFPA 13: yes, or 2 hr rating– Some cities: preaction

• Fire detection– Smoke detectors in electrical rooms– Recommend heat and flame detection in generator

rooms

Fire ratings

• Do electrical rooms need to be fire rated?– NEC

• Not if sprinklered– What about dry type transformers?

• 112.5 kVA, 155 C or higher insulation

• Emergency systems (NEC Article 700)– NEC high rise or high occupancy

• Approved fire suppression• 2-hr systems

Fire ratings

• NFPA 110– EPS installed in a separate room for Level 1 systems– Room must have a 2-hr rating

• Know your local codes– Example: City of Chicago

• Generator room rating: 3 hr• Fuel storage: 550-gal limit• Not located more 2 floors up or down from grade.

• Insurance carrier requirements

Ventilation

• Required?• General rating of equipment: 104 F• Recommend: 86 F• Electrical rooms

– Without transformer: 1 cfm/sq. ft. – With transformer: 1.0% to 2.0% of kVA (3 cfm/kVA)

• Generator rooms– Cooling vs. combustion air– After engine shuts down– Remote radiator – 2,500 Btu/hr/kVA

Ventilation

• Battery/UPS rooms– Keep temperature around 77 F– What about hydrogen?

• Flooded (vented) batteries• Valve regulated, sealed• Conflicting codes: NEC, UFC, IFC

– Safe rules• 1 cfm/sq. ft. • Fan failure relay

Structural

• Often overlooked– Switchboards and switchgear – Generators– Vibration isolation– Computer rooms– Raised floors– Miscellaneous

• Pads • Penetrations• Fire sealing• Path of delivery

Lighting

• Recommended lighting levels– IES and NFPA 70E: 30 foot-candles

• Emergency lighting– 1 foot-candle is not enough

• Switching– Must include nonautomatic means

Miscellaneous room issues

• EMI• Noise

Codes and Standards References from Today’s Webcast

• NFPA 70 (NEC) 2014• International Building Code (IBC)• UL 891• ANSI C37• NFPA 70E: Standard for Electrical Safety in the Workplac

e• NFPA 110• IES

Brian Martin, PE, Portland Electrical Department ManagerCH2M HillPortland, Ore.

Brian Rener, PE, LEED AP, AssociateSmithgroupJJR,Chicago, Ill.

Moderator: Jack Smith, Consulting-Specifying Engineer and Pure Power, CFE Media, LLC

Presenters:

Webcasts and Research

• Smart Electrical Systems: Meters, submeters and smart meters

• 2013 Electrical and Power study

Electrical Systems: Designing electrical rooms

Join the discussion about this Webcast on Twitter at #CSEelectricalroom

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