480/277v sub panel

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Welcome to the forum.

You're asking about running a neutral. For 480v only, no; for 480/277v, absolutely.
 
infinity said:
Yes but the question is do I need to pull one the answer is that for a sub-panel it is not required by the NEC. A service is a different story.
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If the sub-panel has 1 pole loads, how would you plan to support the 277V without a neutral. Irrespective of the service needing the neutral to its disconnect.
 
ron said:
If the sub-panel has 1 pole loads, how would you plan to support the 277V without a neutral. Irrespective of the service needing the neutral to its disconnect.
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The OP makes no mention of single pole 277 volt loads it only asks if the panel requires a neutral. If there are 277 volt loads then yes obviously a neutral in the feeder is required. I mentioned the service because I have heard eletricians say that a sub-panel always requires a neutral which is not true.
 
infinity said:
I mentioned the service because I have heard eletricians say that a sub-panel always requires a neutral which is not true.
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I once failed an inspection because I ran a feeder and panel with no neutral, and I asked him to call his supervisor whom I know, and backed up the inspector. I knew I was right and we were still discussing it when his boss called back and said I was correct, and he passed me.
 
LarryFine said:
I once failed an inspection because I ran a feeder and panel with no neutral, and I asked him to call his supervisor whom I know, and backed up the inspector. I knew I was right and we were still discussing it when his boss called back and said I was correct, and he passed me.
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That was the reason I mentioned the difference between a sub-panel and a service. I've heard it many times from various people including inspectors who have said that a neutral is required. In commercial work we install 3Ø, 3-wire feeders and switchboards all of the time.

I'm glad you were able to somewhat painlessly resolve your problem.
 
I would read the phrase '480/277V subpanel' as implying that the panel be capable of supporting 480V and 277V loads, and thus requiring a neutral.

But as others have noted above, the neutral is not required unless 277V ('single pole') loads are served. This includes MWBC circuits on multiple pole breakers.

If any circuit supplied by this subpanel requires a neutral, then the subpanel requires a neutral.

Jon
 
infinity said:
I'm glad you were able to somewhat painlessly resolve your problem.
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It wasn't a problem for me; I like being right. :giggle: I have challenged inspection failures four times, and "won" every time. I don't give in when I'm sure.

It's always polite and friendly. I don't see inspectors as the enemy. We really have the same goals: a safe, compliant, and well-performing installation.
 
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