Need some help here. Whenever the A/C's on, my electric panel would be buzzing, sometimes continuously. But sometimes it buzz at that initial running of the A/C.

The breakers are Siemens. Thermostat is RiteTemp, not sure if the wiring of that has anything to do with it.

Electrician came out once to look at it, puzzled, changed the breaker out with something old he had on the truck but does the same thing. He tested the amp is within tolerance, find no other cause or major "issue," and called it a day....

He was able to isolate the buzzing to the A/C breakers though.

Anything I can test myself before getting another company to look at it? Like buying a identical matching breaker to swap out? I can't feel any heat from touching the panel and breakers.