Hi there,
Did the A/C guy actually state HOW the compressor was faulty?
Usually, the guy would need to put a megohm meter on it to check the winding resistances to ground and the actual winding resistances themselves, did he provide you with any test results after coming to that conclusion?
It isn't unusual for compressors to fail because of a voltage spike, no CB or fuse will ever protect against something like that, I've seen this happen quite a few times
You didn't state how old the A/C unit was in your OP?
I would find it pretty tenuous to blame an A/C unit failing because of a panel upgrade.
