Electrical rooms provide safe and secure spaces for the operation and maintenance of electrical equipment. While electrical equipment types and ratings can have significant impacts on electrical room requirements, distributing the electrical power to the rest of the building via wiring, busways, and raceways can also affect electrical room design. Switchboards, switchgear, transformers, generators, and UPSs require space for installation, maintenance, heat dissipation, and possible future expansion. And the wiring, busways, and raceways that distribute the electrical power must be accounted for—now, and in the future. Documentation and monitoring of electrical system’s equipment and how it connects to the rest of the facility must be accurately maintained. The design of electrical rooms requires an integrated approach among disciplines. Architects and structural, mechanical, and fire protection engineers should work as a team in designing these rooms. NFPA 70: National Electrical Code (NEC) is the main source for electrical room requirements, but other codes, good practices, and recommendations should be considered. The result will be a room that is safe and secure, and provides for the functional operation and maintenance of the specific electrical equipment located within.

1. Electrical Systems:
Designing electrical rooms
Join the discussion about this Webcast on Twitter at #CSEelectricalroom
Sponsored by:

2. Brian Martin, PE, Portland Electrical Department Manager
CH2M Hill
Portland, Ore.
Brian Rener, PE, LEED AP, Associate
SmithgroupJJR,
Chicago, Ill.
Moderator: Jack Smith,
Consulting-Specifying Engineer and Pure Power,
CFE Media, LLC
Presenters:

3. Electrical Systems: Designing
electrical rooms
Brian Martin, PE, Portland Electrical
Department Manager
CH2M Hill
Portland, Ore.
Brian Rener, PE, LEED AP, Associate
SmithgroupJJR ,
Chicago, Ill.

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

5. Electrical room design
• Needs a coordinated team:
• Electricals
• Architects
• Structural
• Mechanicals
• Fire protection

6. Room types
• Primary service rooms
• Electrical rooms
• UPS or battery rooms
• Generator rooms
• Computer rooms
• Utility vaults

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

8. Working vs. dedicated spaces
• Different spaces
– Worker vs. equipment

9. Working vs. dedicated spaces
• Different spaces
– Worker vs. equipment

10. 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

11. Working space: table

12. Working space: elevations

13. 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

14. 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

15. 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

16. Foreign systems (MP)
• NEC: above, if protected
• What about sprinklers?
• NEC: okay in dedicated space

17. 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

18. Primary equipment
• Switchboard vs. switchgear
• Switchboards: UL 891
– Front access
– Rear access
– Primarily fixed mounted

19. Primary equipment
• Switchboard Vs Switchgear
• Switchgear - ANSI C37
– Rear Access
– Primarily Drawout Construction

20. 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

21. Access: plan examples

22. 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
Workplace - arc flash zones
• Arc flash gear, venting
• Height above switchboards
• Space planning: work with your architect

23. 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

24. 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

25. 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

26. 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

27. 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

28. Structural
• Often overlooked
– Switchboards and switchgear
– Generators
– Vibration isolation
– Computer rooms
– Raised floors
– Miscellaneous
• Pads
• Penetrations
• Fire sealing
• Path of delivery

29. Lighting
• Recommended lighting levels
– IES and NFPA 70E: 30 foot-candles
• Emergency lighting
– 1 foot-candle is not enough
• Switching
– Must include nonautomatic means

30. Miscellaneous room issues
• EMI
• Noise

31. 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
Workplace
• NFPA 110
• IES

32. Brian Martin, PE, Portland Electrical Department Manager
CH2M Hill
Portland, Ore.
Brian Rener, PE, LEED AP, Associate
SmithgroupJJR,
Chicago, Ill.
Moderator: Jack Smith,
Consulting-Specifying Engineer and Pure Power,
CFE Media, LLC
Presenters:

33. Webcasts and Research
• Smart Electrical Systems: Meters, submeters
and smart meters
• 2013 Electrical and Power study

34. Electrical Systems:
Designing electrical rooms
Join the discussion about this Webcast on Twitter at #CSEelectricalroom
Sponsored by: