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
Sponsored by:
