Dennis said:
I will say that the use of afci on new construction has made many electricians go back and find fault with their installs. Personally I have found them to work fairly well and have just a few issues with them. The main problem is vacuums, TV's (and accessories) and ceiling fans but usually only the cheaper fans.
I would agree. I think that many of the complaints were due to actual problems. Here is a case in point:
A lady was referred to be due to her frustration over a tripping AFCI circuit for the master bedroom. It was a new house recently C/O'd and the electrician had 3 call backs for nuisance tripping AFCI. He eventually gave up and said that this was a problem with the AFCI's and they should not be required and this was a perfect example. In total frustration, she called my office and I agreed to go out and troubleshoot the problem by the hour.
The circuit in question was the master bedroom that also fed the fan/light combo in the master bathroom. In the master bedroom, it ran the lighting and receptacles.
There was only 1 light off a switch directly over the bedroom, the rest were plugged in lamps along the side of the bed
There was 1 small television plugged in. No other equipment other than an alarm clock was plugged into this circuit.
Whenever you plugged in a simple tester to a receptacle, it tripped the AFCI breaker.
You could turn the light on and off without tripping it most of the time but if there was a load on one of the receptacles, it would trip the AFCI.
I started with the basics and swapped AFCI units with no change in results.
I then disconnected the master bath light/fan with no change.
I pulled every single receptacle and switch out of the wall with no change.
I then painstakingly megged the hot and neutral wires by methodically removing devices from the circuit. All was good.
I also ran resistance checks from hot to neutral, ground, etc. with all normal results.
I was sure that there was going to be a staple behind a wall somewhere that was damaging NM but none of the tests could determine that.
Finally, there was one last box that I needed to access. The light above the bed. It was a large, heavy, oak king bed with little room to move it anywhere. After moving all of the furniture I was able to access the light fixture. It was a porcelain single incandescent temporarily in place until they decided what ceiling fan they wanted. This is where I found the problem.
The electrician did not ground the ceiling fan rated box and the equipment ground wire was hanging down, almost touching the exposed neutral terminal on the back of the fixture. It was not touching it but close enough to create an arc when there was enough load coming through the neutral which was a pass through for other parts of the system. This explains why all of the megger and resistance checks looked good. That was it. I grounded the box and pushed the ground up and out of the way and the problem was solved.
So yes, I agree that AFCI's have discovered problems from electrician mistakes.