I have frequently come across breakers that will buzz or hum when a load is applied.

Most frequently,it's associated with an air handler ckt. for heat pumps.The auxillary heat or heat strips as we call them here,may not do this. It's usually when the heat pump/air handler starts.

I've seen it in different makes of loadcenters,different size ckts,have tried moving breakers around with not much improvement.

Now these are almost always ckts. in which the terminations are tight,wire sized properly,everything seems to be done correctly,but sometimes there's a slight buzz no matter what is done.

It seems to drive homeowners nuts,something isn't done right,"you're going to burn my house down" etc.

Any thoughts as to how to avoid/stop this?
Am I doing something wrong?

Russell