afcicircuit breaker
I am installing 120v wiring for a dorm-type setting, and some of the rooms are over 70 feet from the breaker panel. The NEC says that the home run may not exceed 50 feet for 14 AWG and 70 feet for 12 AWG conductors. If it does the first receptacle in the branch circuit has to be an AFCI receptacle.
So, in the case where the 1st receptacle is more than 70 feet from the panel do I need both (an AFCI breaker and an ACFI Receptacle)?
I've had some issues with AFICs in the past, and one quick thing you should check (which ended up being my problem): Is the insulation on the wire coming into the outlet box pinched and causing a loose/flaky connection? That will still give power to the outlet (under a normal breaker) and won't trip a normal breaker, but it'll drive an AFCI nuts.
Another technique you can try to debug this is by swapping in a GFCI breaker, and see if that trips too. If the GFCI trips, it's a grounding problem. If it only trips on the AFCI, then there's arcing somewhere along the circuit. Check junction boxes, the outlet boxes and the connections to the plugs in the boxes.
Happy & Safe Debugging!
Some surge protectors work by "redirecting" surges to the equipment ground, which is pretty much the definition of a ground fault. In this case, it's definitely possible that surge suppressors could be tripping GFCI receptacles/breakers (given a large enough surge).
As for the AFCIs... When electrical contacts separate, they often create an arc between the contacts. This arc spans the gap until the contacts are too far apart, and the arc can no longer be sustained. It's possible (in theory) that the GFCI tripping could create a large enough arc, for long enough to cause the AFCI to trip. It's not likely that a properly functioning GFCI would do this, but if the GFCI was old and worn it could be opening the contacts slow enough that a detectable arc is being produced.
Determining if the GFCI tripping is causing the AFCI to trip, is a simple test. Simply press the test button on the GFCI. If the AFCI trips, you'll have figured out half the problem. If the ACFI does not trip, you could repeat the test using a receptacle tester with a GFCI test function.
If it's determined that the GFCI is causing the AFCI breaker to trip, replacing the GFCI receptacle may resolve that part of the issue.
Figuring out if the surge suppressor is tripping the GFCI, is a more difficult proposition. It will likely require you to monitor the supply voltage over some time, to identify and document possible surges.
Best Answer
I could be wrong here, but the way the code is written, the circuit length should only matter if...
210.12(A)(1) allows the circuit to be protected by a "combination-type arc-fault circuit interrupter", without any mention of the length of the circuit. So I would expect as long as you're installing a combination-type AFCI, and not a "supplemental arc protection circuit breaker". Then there should be no problem. But I've been known to misinterpret code from time to time.