I wish it was that simple … I probably wasn’t clear enough, the lights aren’t all on the same switch. In fact, they are split between 10 different switched circuits. The most lights on any of the switches in 4. And again, I have not been able to discern any pattern of a particular switch, or group of switches, that trip the breaker. Sometimes nearly all the lights were on when it happened. Last winter it happened multiple times in a row w/just a couple of lights on, and it didn’t matter which ones.
Oh, and as far as I’ve experienced it, it’s not happening when you turn on a switch, but some time after. So you turn on some lights, and then at some point the breaker will just trip. Usually, when it does this, it will keep doing it multiple times in short order.
I just read an article about why AFCI’s trip and it mentioned “lighting controls with LED’s”. Two of the switches are Leviton dimmers that have a small 'finder" LED in them. Could that be it? Note there are not any smart devices in the circuit anywhere.
This would mean putting both circuits that connect to the 14/3 on the black wire; I have been hoping I could separate them out onto two different breakers to reduce the load. Is there a way I can safely do this or am I stuck unless I pull new wire now?
I like the way you think …