In 2017, I had a new 20 amp circuit (with dedicated GFCI outlet and AFCI breaker) installed by an electrician, which is right below my then two-year-old Square D electrical panel box (with aluminum bus). I run my .62 amp air purifier 24/7. But often, I also run my 1/2 amp fan and my 12 amp space heater at the same time. I have the space heater plugged directly into the outlet, while the other two appliances are plugged into a 3 in 1. The space heater runs for no longer than two hours at a time. But I would leave the fan on for hours.
Lately, this circuit has tripped twice. I don’t believe I’m overloading the circuit. And appliances with a ground fault would trip the circuit immediately upon being plugged in. So I’m wondering if it’s an arc fault trip. How can I tell the difference between a real arc fault trip and a nuisance arc fault trip? Also, could the aluminum bus circuit breaker be a factor (as opposed to a copper bus)?