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mydamcomputer

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What would be the largest single 3 phase size Breaker (load) allowed to be installed in a 3 phase 200a branch panel? where in the NEC does the refrence exist?:
 

iwire

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As long as the calculated load is correct you can install any size breaker in any size panel. (Assuming the manufacturer lists that breaker for that panel)
 

iwire

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I would disagree and say the largest is a 200. I don't see how you could put anything bigger than that if the feeder is not rated for it
There would be no violation in supplying say a 160 amp load from a 400 amp breaker installed in a panel supplied by 200 amp feeder.

That said ............ why anyone would choose to do that is beyond my imagination.
 

Dennis Alwon

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I think the op is asking what size breaker is allowed to be installed in a 200 amp panel. I think he may be talking about branch circuit rather than a main feeder. If this is the case I believe a 125 amp breaker is as large as one can put on a 200 amp panel buss for branch circuits on most brand panels. This is in the manufacturers info not the NEC
 

LarryFine

Master Electrician Electric Contractor Richmond VA
. . . I believe a 125 amp breaker is as large as one can put on a 200 amp panel buss for branch circuits on most brand panels. This is in the manufacturers info not the NEC
That is, of course, manufacturer-dependent, and we've seen multi-contact take-off blocks that get around the usual per-stab current limitations. They're lug-only terminals that install like breakers, but make contact with more than one lug per phase.
 

iwire

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I think the op is asking what size breaker is allowed to be installed in a 200 amp panel.
Yes that is what they asked.


I think he may be talking about branch circuit rather than a main feeder.
That really does not matter.


If this is the case I believe a 125 amp breaker is as large as one can put on a 200 amp panel buss for branch circuits on most brand panels. This is in the manufacturers info not the NEC
I kind of mentioned that already but he asked for the NEC reference. :smile:

where in the NEC does the reference exist
 

Dennis Alwon

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What I was trying to say was that I thought he was talking about a branch circuit and not the main breaker. If it is a 200 amp panel then, of course the max. main breaker in that panel will not be greater than 200 amps.

I think I answered the question on where in the NEC it is found when I stated it was not in the NEC
 

LarryFine

Master Electrician Electric Contractor Richmond VA
However, one could have a panel with, say, a 60a main, and install a 100a breaker.

It's only useful function would be that of a switch, but it could be done.

Plus, its conductors would need not be larger than those of the feeder, IINM.
 

iwire

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What I was trying to say was that I thought he was talking about a branch circuit and not the main breaker.
I agree, I am sure he is asking about branch or feeder breakers.


If it is a 200 amp panel then, of course the max. main breaker in that panel will not be greater than 200 amps
.

I do not understand what the main breaker has to do with it at all.

I could have a 30 amp main breaker and a 100 amp feeder breaker as long as the calculated load was under 30.
 

Dennis Alwon

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I agree, I am sure he is asking about branch or feeder breakers.


.

I do not understand what the main breaker has to do with it at all.

I could have a 30 amp main breaker and a 100 amp feeder breaker as long as the calculated load was under 30.
I am not certain what the OP is asking but if the panel is rated 200 amps you cannot have a main breaker in the panel greater than 200 amps-- that would be the max. Sure you could use a 30 or a 100amp but the op was asking for the max size. ML panels have conversion kits for MB but you cannot use a 225amp MB in the panel if the panel is rated 200 amps.
 
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