Big shocker here (pun intended), I've got an afci tripping. The circuit is in a living room and only has 5 outlets. 20amp cutler-hammer afci breaker. Tv, cable box, dvd, speaker system all plugged in -- breaker trips from time to time. Was fine for a few weeks, then started tripping again. Can't figure out the cause, it isn't always when one component is turned on. Any thoughts?

AFCI devices, such as smoke detectors and other safety deivecs, can be a pain.

First, the breaker can be defective.

If you have another AFCI breaker, try swapping it for a few days.

There can be a loose connection at any one of the outlets on the circuit.

It may be by any one of your plugged in devices. Try keeping them unplugged to see if the CB continues to trip, to either confimr or deny one of the devices are the reason.

As TK noted, any kind of loose wire will cause an AFCI to trip. If the breaker itself isn't bad, then it is doing it's job. If this is in a living room, it must be a fairly new house or was retrofitted as AFCI's in living rooms are a fairly recent code addition. My house is 4 yrs old and only has them in BR's.

As TK mentions, Swapping AFCI's is a good, cheap, fast way to help narrow down.
This should help tell if it is the Breaker or Circuit.
Take note of what is plugged in when it trips, Unplug one item at at time for a while to determine which piece of equipment is causing/not causing the trip.

Thanks for the help. It was a complete removal and new install of wiring, so yeah the afci was mandated by inspector.

Will try swapping out the breaker tomorrow... if that doesn't work I'll check all the boxes next week. Will let all know of the resolution... maybe it'll help someone

I am not clear as to why an inspector would require an arc fault in a living room or why your receptacles are 20 amp.

Twp wanted arc fault in all rooms not gfci protected. Breaker is 20, wire is 12ga, outlets are 15

Just wondering, the outlets aren't back-stabbed are they? Because this could cause a loose connection which might in turn trip the breaker.

Which code does the two claim to follow?

I don't know for sure... didn't care - twp wanted it, 2011 NEC requires it, why not be most up to date.

replaced with a new afci... been about a week now, so far so good... not convinced yet since the other one would go similar stretches working fine -- but that one also randomly wouldn't trip when hitting the test button, so I'm hoping that's all it is. Will update if it changes.

thanks for the advice

Ballenger, down here they now require all circuits, except appliances to be Arc Fault Protected if not GFI Protected.
A remodel job I just got is a level/class 3? And it requires Arc If not Gfi, in a 3 story house that is all multicurcuits, Which means An additional neutral need to be pulled to numerous locations and can be tricky withmultiple 3 way and circuits that are spread out, Not a problem, just a lot more work, Some of these codes helped generate work but can be expensive for the Homeowner, I think the codes were written previous to the Real estate market collapsing, an additional cost for the homeowner that remodels, I suppose they are not one of the Poor or financially strapped.