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Designing a 480 V panel

Designing a 480 V panel

Designing a 480 V panel

(OP)
I designed a 480 V panel that will have total connected load of 160 A. The main breaker I specified for this panel was 250 A. But my supplier for the panel replied to me saying the minimum size of the main breaker in that panel that he can give is 400 A. On the other side, this 480 V panel will be fed by a 200 A CB which will be 225' away. I want to know if I supply a 400 A main breaker with a 200 A CB, am I violating the NEC ?

RE: Designing a 480 V panel

Not a violation, but why do you have a main breaker in your panel if adequate protection is provided on the upstream side of the panel feeder?

Best to you,

Goober Dave

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RE: Designing a 480 V panel

(OP)
DRWeig,

Thanks for your feedback. I cannot use a main lug only panel since the 200 A breaker is 225 feet away. Locking out the equipment will be hard in this case.

RE: Designing a 480 V panel

Ah, so the main breaker is just serving as a local disconnect switch. Not a problem then.

Best to you,

Goober Dave

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RE: Designing a 480 V panel

(OP)
Exactly. Well, I would go with MLO panel and have a 200 A fused disconnect. Thanks for your help DrWeig.

RE: Designing a 480 V panel

Your supplier is a dolt by the way. Maybe the minimum FRAME size of the main breaker will be 400A based on the number of pole spaces in your panelboard, but you can get a 400AF/250AT breaker anywhere.

You need a new supplier that knows what he is doing...


"Will work for salami"

RE: Designing a 480 V panel

Quote:

I would go with MLO panel and have a 200 A fused disconnect.

Why fused? You have a 200A breaker upstream for protection. Use a solid blade disconnect.

RE: Designing a 480 V panel

(OP)
Thanks all for your comments. Appreciate your help.

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