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#77085 - 04/20/01 07:52 AM Code Enforcement Overkill?
Pete Offline
Junior Member

Registered: 04/20/01
Posts: 1
Built a metal building, with office inside with metal studs. No wood anywhere. Bldg & studs are grounded. Each receptacle has its own grounding lead. Our code enforcement inspector says each junction box must also have a grounding lug. Further, any rigid metal conduit with more than 3 load carrying conductors, conductors must be derated. So, if a 2" conduit has 4 conductors, the wire must be oversized. I'd appreciate comments.

2014 / 2011 NEC & Related Books and Study Guides
#77086 - 04/20/01 08:03 AM Re: Code Enforcement Overkill?
resqcapt19 Offline

Registered: 11/10/00
Posts: 2209
Loc: IL
250-148(a) requires the EGC to be connected to the box. Table 310-15(b)(2)(a) requires derating of conductors for more than 3 current carrying conductors. Remember that is you are using THHN you can use the 90°C ampacity for derating purposes.

#77087 - 04/20/01 03:47 PM Re: Code Enforcement Overkill?
Tom Offline

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA

Don's reply is right on the money. With THHN insulation in a dry location, you usually don't have a derating problem (at least in the smaller sizes) until you get to the 10th conductor.

Few things are harder to put up with than the annoyance of a good example.


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