Question

[mydamcomputer]

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]

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)

 

[mcclary's electrical]

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

 

[iwire]

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.

 

[augie47]

"all I had on the truck !! ":grin:
that works for a lot of the "why in the world" stuff I see.

 

[LarryFine]

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

That only means that the 200a main would pop first. As long as no conductor is unprotected, it's cool.

 

[Dennis Alwon]

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]

. . . 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]

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]

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

 

[Power Tech]

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?:

200 amp, 42 circuit panel. I am sure there is a manufacturer that has something weird. I think the largest 3 phase plug ion I have seen is 100 amp.

 

[LarryFine]

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]

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]

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.

 

[LarryFine]

Dennis, we're convinced the OQ in the OP was aking about load breakers. He even had "(load)" in the post.