why the AFCI kept tripping. New house, finishing up a few odd items today when the floor cleaners came to me and said "soon as we try to use our vacuum in the front bedroom the breaker trips" Huh, must be your vacuum, nobody else has tripped a breaker yet, so I reset the breaker and try my shop vac, trips almost immediately. This circuit has been up and running for months with no issues, lights working fine, plugs work fine except for the vacs. I swapped the breaker with another, problem stays with the circuit. Went on to do some other things so I could ponder on it a while.

Next job, owner wants the bath wall sconce flipped over in the bath that goes with this bedroom, go in there to do that when I noticed a faint humming coming from the 110 CFM exhaust fan which is COMPLETELY COVERED WITH BLUE TAPE AND CAN'T GET ANY AIR. Apparently the tilers covered it to keep dust out, or maybe it was the painters. Once the tape was removed all was well. So the fan must have been really over-amping and the vacs were enough to throw the circuit over the edge, of course first thoughts are always a wiring error or bad AFCI now days.

Just goes to show, I have learned over the years when troubleshooting not to just rush in and tear everything apart right away. It usually pays to think about it for a while and reason things out.

Last edited by BigB; 06/05/20 05:46 PM.