[RE-wrenches] Busbar rating with multiple main breakers

[Chris Mason]

The 120% rule refers to source breakers, not load breakers.


On Thu, Dec 19, 2013 at 3:16 PM, SunHarvest <eric at harvesthesun.com> wrote:

>  Hi guys -
>
> Concerning the 120% rule: I've encountered several circumstances recently
> where a 400A nameplate-rated (listed on inside label) main panel has two
> 200A main breakers. One of the breakers will be feeding the busbar in the
> main and the other will feed a subpanel. I had previously thought the main
> busbar is rated at the nameplate rating (400A in this case) regardless of
> quantity of main breakers. My lead electrician says the main busbar in
> these types of panels is derated to 200A because of the split. However, I
> have two other reliable electrician friends who disagree with my lead
> electrician. One of my C10 buddies says it depends on whether or not the
> busbar in the main is broken up into 2 sections (200A) or it is continuous
> (400A). Can anyone clear up, beyond doubt, our disagreement?
>
> Thanks!
>
> Eric Stikes
> SunHarvest
>
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-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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