600 amp breaker in a 400a panelboard - Electrician Talk - Professional Electrical Contractors Forum

Electron_Sam78 · 03-08-2011, 03:59 PM

I was looking at the work of a fellow electrician who did a job for our company and found that a 600 amp circuit breaker, serving as the service disconnect, was installed in a Square D I-line panel. The kicker was that the data plate (sticker) rated the panelboard at 450 amps max.

Am I missing something? That would be a violation of the UL listing and the amperage rating of the equipment. That's at least 2 code violations there. Could there be another explanation?

mcclary's electrical · 03-08-2011, 04:09 PM

Quote:

Originally Posted by Electron_Sam78

I was looking at the work of a fellow electrician who did a job for our company and found that a 600 amp circuit breaker, serving as the service disconnect, was installed in a Square D I-line panel. The kicker was that the data plate (sticker) rated the panelboard at 450 amps max.

Am I missing something? That would be a violation of the UL listing and the amperage rating of the equipment. That's at least 2 code violations there. Could there be another explanation?

did it say 450 amp breaker?
was the bus rating 450 amps?
or was the main 450 amps?
Don't quite have enough info, but I can think of a few scenarios that it would be legal.

**Dennis Alwon** · 03-08-2011, 04:12 PM

I am not familiar very much with I Line panels but was the 450amps the rating of the panel or the rating of the max. busbar breaker sizes?

LOL Or what McClary said.

Electron_Sam78 · 03-08-2011, 04:52 PM

on the tag it is identified as an I-line panelboard, gives the cat no., voltage rating, and the box labeled "MAX Amps" contains the pre-printed numbers: 450 A.

BBQ · 03-08-2011, 04:59 PM

Sam, if you had a 450 amp panel and wanted a 450 amp breaker you would have to use a 600 amp frame size breaker with a 450 amp 'rating plug' or 450 amp setting.

Look at the breaker carefully for a setting or rating plug.

HARRY304E · 03-08-2011, 05:07 PM

Quote:

Originally Posted by Electron_Sam78

on the tag it is identified as an I-line panelboard, gives the cat no., voltage rating, and the box labeled "MAX Amps" contains the pre-printed numbers: 450 A.

Whats the cat,#

If it is on the name plate 450Amps max then a 600Amp main is too big.

A 600 amp and 400 amp ILine breaker would fit in an ILine panel..

Im sure that if you get that cat # you will be able to get the exact rating of that panel...

jwjrw · 03-08-2011, 05:09 PM

Quote:

Originally Posted by HARRY304E

Whats the cat,#

If it is on the name plate 450Amps max then a 600Amp main is too big.

A 600 amp and 400 amp ILine breaker would fit in an ILine panel..

Im sure that if you get that cat # you will be able to get the exact rating of that panel...

I think BBQ nailed it......