I've been chasing an arc fault breaker nuisance tripping problem for months. My son in law is an electrician and advised me on how to do it. It's basically trial and error. Hope it's not in the walls and start replacing outlets and switches. I replaced or rewired all the outlets and switches on the circuit. The control pad for my security system was on the circuit with the breaker that tripped a lot. Last weekend I moved the control box to a different circuit just so I wouldn't have the inconvenience of resetting the system when the breaker tripped. Within 12 hours, the breaker on the new circuit tripped. I also noticed that a can light on the same circuit was flickering when it never had before. My wife and I shared a light bulb moment. We both said, "Maybe it's the control box for the security system." The nuisance tripping started shortly after we had the security system installed.
I called Comcast and explained my problem. The tech scheduled a service call. A couple of hours later I got a call from someone who identified himself as a second level support tech. He asked me if the breaker had tripped again. I told him it hadn't. He then told me that the service call wasn't necessary because the equipment was working correctly. I insisted on having the service call anyway and he backed down. He said they would call me back in 3 or 4 hours to check how things were going. Another "second level" tech told me the same thing. I insisted on the service call, pointing out that less than 12 hours of uninterrupted service was hardly proof that the box or its power supply wasn't defective. We wrangled for about 15 minutes before he gave up. The next morning a tech came with a new control box. He replaced the old one and agreed with me that what I'd concluded was reasonable and replacing the control box might be the answer. It's now been 24 hours. Lights that flickered, 2 cfls not on the circuit with the control box, and mini floods in a display cabinet on the circuit, don't flicker. We moved the control box back to the original circuit because it was closest to the door to the garage. As yet no breaker trip. I'm not 100% sure that the problem is solved, but all of the obvious flaky electrical stuff has stopped.
I'm concerned that Comcast would go to the effort of having 2 people call me to try cancel the service call. OK, Comcast had to pay for the tech's time and the cost of the new control box. OTOH they also had to pay 2 people to call me to no avail. Side note: the people who called me clearly weren't familiar with arc fault breakers and how non catastrophic events can cause a breaker to trip. They seemed confident that the lack of recurrance of an intermittent problem in less than 12 hours was proof that there was no problem. One of the less frequent causes of nuisance trips is switching power supplies. There also could have been something resembling a loose connection in the control box. It's rare but hardly impossible. The benefit to me from this experience is that I learned more than I ever wanted to know about arc fault breakers. <g> The internet is wonderful. My son in law was a big help too.
Thanks for reaching out and sharing your experience. I'm happy that we were finally able to send a tech out who was able to help identify what could have been causing your problem as well as taking the extra time to troubleshoot and swap the equipment to see if he was able to find a resolution. I'd also like to thank you for your patience while trying to get this taken care of. If there's anything we can assist you with in the future, please feel free to reach out to us.