[RE-wrenches] Busbar rating with multiple main breakers

[SunHarvest]

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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20131219/3d552a15/attachment-0003.html>