What could be causing AFCI breaker and GFCI receptacle nuisance tripping?
I have a new house. During the last couple of months I will find that multiple breakers will have tripped at the same time. I can't find any info on multiple breakers tripping together. It isn't always the same breakers, or the same number of breakers, but it is always AFCI breakers. A group of them will trip about once every two weeks, but at random times/days but never in the middle of the night. They have no problem being reset. It almost always happens when we are away from the home. There is nothing on that would make me suspect it is the problem. The The non-AFCI breakers don't trip.
The most common breaker to trip is in a area where I installed an extra outlet (and has an alarm system plugged in to it). Although this is the most common brekaer to trip it doesn't always trip when a group of them trip. The second most common breaker to trip is one that I put a chandelier in (the house was already wired for it, I just had to hook the wires up to the ceiling).
Although I mention my two additions, I don't know for sure that this is the problem, but maybe. I find it strange that a group of them trip, but not always the same group, or even a common breaker that always trips. I had an electrician come out to take a look but he was confussed and just tightened all the connections in the breaker panel, but we are still seeing the problem (although maybe less severe). What should I check? What could cause this? If I have the electrician come out again what should I have them do?