480/277V panelboard instead of 208/120V

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rose1981

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How can we use a 480/277V square d NF panelboard instead of a 120/208V panelboard. I specified 120/208V panelboard in the drawing. But square D shipped 480/277V panelboard, and the electricians installed it.
 
I assume you mean 208/120V.

While the panel and breakers for a 480/277V are going to be more expensive than 208/120V equipment, the 480/27V could be used for 208/120V. A bit funky but the equipment is certainly rated for the lesser voltage.

I believe you would need signage posted that states a different voltage is being supplied.
 
jumper said:
I assume you mean 208/120V.

While the panel and breakers for a 480/277V are going to be more expensive than 208/120V equipment, the 480/27V could be used for 208/120V. A bit funky but the equipment is certainly rated for the lesser voltage.

I believe you would need signage posted that states a different voltage is being supplied.
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Will anything happen in the long run? Will the breaker trip on time?
 
jumper said:
While the panel and breakers for a 480/277V are going to be more expensive than 208/120V equipment, the 480/27V could be used for 208/120V. A bit funky but the equipment is certainly rated for the lesser voltage.
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Those breakers are going to be real expensive compared to 208/120.

I think I would make the supplier send the correct panel and swap it out. May be able to just swap out the guts. The difference in price of a 277V, 20 amp breakers and a 120V 20 amp breaker starts to add up quick if you have a panel full of breakers.
 
growler said:
Those breakers are going to be real expensive compared to 208/120.

I think I would make the supplier send the correct panel and swap it out. May be able to just swap out the guts. The difference in price of a 277V, 20 amp breakers and a 120V 20 amp breaker starts to add up quick if you have a panel full of breakers.
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Agreed.
 
Swap it out. It may have been indicated wrong but you'd think the installer would catch that


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rose1981 said:
How can we use a 480/277V square d NF panelboard instead of a 120/208V panelboard. I specified 120/208V panelboard in the drawing. But square D shipped 480/277V panelboard, and the electricians installed it.
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I have the same thing at my plant. 480/277V panelboard running 208/120V service. I brought it up after substantial completion and basically everyone said that it as long as it was not a violation of the NEC we were going to have to live with it.

If you decide to leave it installed, it should be very clearly labeled as 208/120V.
 
Saturn_Europa said:
I have the same thing at my plant. 480/277V panelboard running 208/120V service. I brought it up after substantial completion and basically everyone said that it as long as it was not a violation of the NEC we were going to have to live with it.

If you decide to leave it installed, it should be very clearly labeled as 208/120V.
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Presumably by that time the money had been spent for the overspec breakers, so no financial gain from changing it.
 
The NF panelboard is UL listed for use on all AC voltage systems up to 480V Line-Line and 277V Line-Ground. There is no need for 'special signage', the maximum equipment rating and the applied voltage are rarely the same thing, that is why standards like the NEC and NFPA70E requires 'field applied' labeling.

The use of the NF panels is one way to achieve fully rated systems where the available fault current is greater than 22kA. Maybe this why it was supplied in the first place?
 
rose1981 said:
But square D shipped 480/277V panelboard, and the electricians installed it.
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rose1981 said:
The only reason I can think of is that the manufacturer shipped a wrong panelbaord
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Who has to pay for the more expensive panel and breakers ? If they shipped it for free (same as the less expensive panel ) that's one thing but if they charge for it that's another.

Have them check the invoice and see what you were billed for.
 
We have used 480Y/277 volt panels for 208Y/120 volt circuits when the engineer wanted 65 KA interrupting rating circuit breakers. GE Type TEY CB's are rated for 65 KA @120 volts.
 
infinity said:
We have used 480Y/277 volt panels for 208Y/120 volt circuits when the engineer wanted 65 KA interrupting rating circuit breakers. GE Type TEY CB's are rated for 65 KA @120 volts.
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Interesting. I'm sure that must throw some people for a loop when they see it. :lol:
 
peter d said:
Interesting. I'm sure that must throw some people for a loop when they see it. :lol:
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The first time I saw it, I opened up the panel board looked at the single pole 277 volt breakers, pulled the panel schedule out of its sleeve and was very, very concerned. Once I tested all the outlets on the panel schedule and found 120 v, I calmed down a little bit. But yes, it threw me for a loop for about 10 minutes.
 
Saturn_Europa said:
The first time I saw it, I opened up the panel board looked at the single pole 277 volt breakers, pulled the panel schedule out of its sleeve and was very, very concerned. Once I tested all the outlets on the panel schedule and found 120 v, I calmed down a little bit. But yes, it threw me for a loop for about 10 minutes.
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277 volt office outlets. They have powerful computers. :D
 
If you're stuck with it, it may be cheaper to put a subpanel right next to it so you only have to buy one breaker for the 480v panel.
 
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