I reread your OP twice just to make sure i didnt miss it however you did not state this in your OP at all
since this is a new build youre paying for, the electrician should be the one worrying about the issue and fixing it. if he cant, then he needs to find another electrician who can.
I wouldnt be touching any of it as the homeowner...
its a new build NOT a renovation
It is technically a renovation. We kept the outer walls, and stripped everything back to the outside walls, new electrical, plumbing, inside walls, Insulation, kitchen, etc.
so how does the disposal get turned on and off?
The breaker was tripping before he installed the switch for the disposer. That is when he started checking things and found the problem. I was told about the problem by the carpenter. After talking to the electrician this afternoon, he told me that the problem breaker was swapped with the one above it, and that it "popped" in that position. When that happened, he thought it was still in the same slot, but it wasn't. I guess that is an easy mistake to make in a panel with 21 breakers on each side. We were short on breakers, so I bought 3 additional from Amazon, but they didn't come in an original box, but in a foam bag. These are Square D QO breakers, and all the rest I purchased came packed in Square D cardboard boxes. I don't know if Square D sells breakers in bulk boxes or not.
I wanted him to get everything in the kitchen done because if there were a problem after the backsplash was installed, there would be no way to troubleshoot it once the granite was glued in place, such as a sheetrock screw hitting a wire.
so he had TWO defective breakers? In the OP you stated another arc fault breaker was tried with the same results.
Thats some really bad odds.
what is the brand and model?
Only one defective breaker, and the brand is Square D. As for the electrician, he is working for me as a favor, since he has a job with an electrical contractor who doesn't always have work for him. My only complaint about his work is that he wasted a lot of wire. There is no doubt in my mind that he doesn't have as much experience as some of you do, but everyone has to learn every day on the job. I don't know anyone who starts off as an expert on day one.