Harold:
From your comments..."She said the EC who just got done wiring her new reno work said that it was the AFCI's fault. She asked me if that was true, and all I can say to her was that I have heard of such problems, but I haven't seen or heard of any cures yet. I didn't know if it was an appliance problem or a wiring problem."
The ECs comment that it is the fault of the AFCI is (IMHO) a not correct. He should have explained the function of AF and then proceeded try another appliance in the tripping circuit(s), as you mentioned.
A recent new SFD had two (2) tripped AFCIs when I walked to the panel. One reset, one immediatley tripped. The trim carpenter had a small miter saw that tripped the one I reset. It worked fine in a countertop 20 amp GFI outlet. Plug the same saw into an AFCI outlet...trip. The second circuit that immediatley tripped had a wayward nail thru the NM, HG&N straight thru.
There have been a few others (AFCI) issues, bad splices, bad AFCI cb, & the fateful...MWBC! We all learn by experience!
