Is that a 200A panel with a 200A main breaker and a feedthrough lug kit on the busbars? If so, all the breakers on your lug kit as well as those in the panel must be counted and the total of the ratings must be less than 200A.Does this comply with the code section listed in the subject title if the label is added? (See the attached sketch)
I don't see how the busbar would ever see more than 200As.
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That's a 2017 NEC reference to the 'sum of all breakers rule"? If I recall correctly feed through lugs were something of a loophole to this rule before the 2020 NEC.Does this comply with the code section listed in the subject title if the label is added? (See the attached sketch)
I don't see how the busbar would ever see more than 200As.
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I know you know we have other rules besides the 120% rule.
His reference is to the sum of all breakers rule in the 2017 NEC. You can't get around it by putting some of the breakers on feedthrough lugs. If he were to use a breaker rather than the lugs he would be limited to an 80A breaker.
The breakers connected to the lug kit are thereby connected to the busbar of the panel and must be considered in the sum of all breakers rule. That's my opinion, of course.
That doesn't address the question.
Since (c) does not apply based on the code language, you cannot even look at (c) for this installation.
You'll have to explain how you think it doesn't apply. I disagree.
But it could. What's to prevent someone exploiting this loophole from installing 400A of PV connected to the lugs? IMO, 705.12(B)(2)(3)(b) applies because anything connected to the lugs is connected to the bus. But, whatever; it's not my problem, so do whatever you think you can get away with. I certainly would not put my PE seal on it.
With 72A output? How?
In the 2017 NEC, the definition of an inverter output circuit would require all the conductors to the service, including the busbar, to be rated 400A. What's to prevent any installation from being modified to be no longer compliant? The 90A of output (after 125% factor) is compliant IMO.
It could be compliant with both (b) and (c). Or neither. (b) doesn't affect whether the installation is compliant with (c). It's not either/or.
I am aware of what the code says and doesn't say. As you said it's a loophole, and I don't do loopholes; he has 210A of breaker ratings connected to that 200A bus just as surely as if that 90A OCPD were landed directly on the bus. I would not stamp it as NEC compliant unless his AHJ does not consider the grid battery sense breaker to be either a source or a load.
Because, as you pointed out, breakers connected on the load side of the feed through connection are not "overcurrent devices on panelboards," If you don't have that condition, (c) does not apply. Maybe it should, but the language in the 2017 does not permit it.
Yes, the overcurrent devices on the load side of the feed through connection aren't on the panelboard, so therefore they don't need to be summed. I don't see how that disqualifies (c) from applying the situation. There is still 120A of breakers that is on the panelboard needs to be summed. But if that were zero it would still comply with (c). Can't follow you at all here.
What is the difference, electrically speaking, between a 90A breaker in a panel and 90A of OCP on the other end of a conductor set connected to feedthrough lugs on that same panel? There is none that I can see; the NEC's silence on this point is, as you say, a loophole. If that battery sensor, whatever it is, were on a 10A instead of a 20A breaker, I'd stamp it.
