100% Rule on meter-main with feed through panel

[ryangittens]

Ref. NEC 2020

Per 705.12(B)(3)(3) as I understand it the feed through panel needs to be counted. If the feedthrough has a 200A main that would make adding any size breaker to meter-main panel non-compliant. However if you place the solar/source breaker at the end of the meter main I don't see any way of overloading the bus bars and everything seems properly protected. There is no code section for this but wanted to see what your thoughts were.

Under 2020 this may not fly but 2023 705.12(B)(6) allows for engineering calculations.

 

[jaggedben]

I think it's a loophole in the code language, and the AHJ may have any interpretation of it.

We have discussed this a few times. The code language doesn't really call it out properly, but it makes no real sense for 200A breaker in the sub not to be counted. At the same time, the rules are quite conservative so the installation is probably safe. So in my opinion the installation is compliant by the letter of the code. That said the subsection on feed through lugs is worded weirdly enough to be interpreted to say this design is not allowed.