The quoted statement is correct if the calculated load is 180A or less. Do you have a statement from them say the allowable load is 200A on each 4/0 Al feeder in your situation? That would be incorrect.
If your question to them was about that distinction, then I would respond that they haven't actually answered the question.
Cheers, Wayne
It's a good point.
Here is the scenario I presented:
"Single family dwelling with 320A service. Meter enclosure (no disconnect) feeds two 200A main breaker panels. Load calculations show the 4/0 Al feeders between meter socket and the (2) 200A disconnects will see greater than 180A."
So, I think I can ask for clarity that they are allowing a
load calc up to 200A on each of the feeders, but not allowable ampacity per-se. Personally, I don't know how they could justify their stance without use of the 83% rule.
I have multiple permits open with the county currently, so I have to be thoughtful about not aggravating the inspector and becoming a target. I think he did do his due diligence by taking it to discussion with the other electrical inspectors, and probably could have chosen to blow me off and tell me that was his ruling, so I have to give him credit for that - even if they didn't come to the right conclusion. I think my next point of contact can be clarifying and presenting information that is not meant to press them further, but be more information sharing.
Do I understand correctly that as AHJ, they can effectively override the code? Of course, he is indicating they believe it is meeting NEC, and not that they are overriding.
I think my only real shot at getting the county aligned with the code is if I get guidance from a more superior authority that it is not to code. In my head, that means either something directly from NEC or from the state electrical board. Does that sound right, or is there someone else who would influence them?
My intent would be to get confirmation if that authority that it does or does not meet code, and if not, then notify the inspector I intend to upgrade my conductors, and by the way, here is a letter from 'authority' that says I'm not to code, FYI.
In the bigger picture, do I understand correctly that if I use EMS to limit the feeder loads (between meter and each of the two disconnects), that I cannot have a set point > 160A?
Is there a section of code that deals with lockouts of particular equipment that works in that manner? i.e. 'if you have Appliance A on, Appliance B cannot run, so consider the load the greater of Appliance A or B'. e.g. the scenario where I use the steam shower generator to lockout the makeup air heater. I'm just making sure I can justify to an inspector using only the larger of the two loads from my calculation, though I am not finding NEC references this directly.
Edit to add: In my county, their documentation indicates they follow state electrical codes (which are simply 2023 NEC)