AFCI question

I recently inspected a new home, homeowner complained that every time she plugged in a clothes iron (1200 watt) into an upstairs bedroom the AFCI would trip, shutting off the power to bedroom and the downstairs Office/Den.
Usually I find only the bedrooms only are protected by AFCI’s. Is multiple use allowed by the NEC or is this just bad wiring practice, the builder did use the worst and I’m sure the cheapest Electric/Plumbing/HVAC all purpose contractor they could find.The builder is Stewart/Kret.

All opinions appreciated. Thanks, John

Early generations of the AFCI breakers have problems with a shared neutral or multiwire circuit. This condition causes nuisance tripping, which sounds to be what you have described.

The generally accepted remedy has been to wire (or re-wire) one circuit to one breaker (not necessarily one room).

I’m not sure if this issue has been addressed by the AFCI manufacturers in newer productions.

Also, if the power to the appliance is “on” when the plug is inserted, the AFCI will do its job and trip when an arc is detected.

AFCIs simply don’t work on a multiwire. They incorporate GF protection at the 30ma level.

Two-pole AFCI breakers DO work on multi-wire circuits.


To answer your question…AFCI’s can protect any 15A or 20A Branch Circuit the electrician chooses…As this question came up in the seminar I did this weekend as well…AFCI is not bound by the bedroom…while the bedroom has to be AFCI protected…it does not disallow other areas of the dwelling to also be on that same AFCI circuit.

The NEC does not " Specifically" tell you how many receptacles have to be on a circuit…but gives you the calculation guidelines to do it correctly.

So…can you have a bedroom on a AFCI and also pick up the receptacle in the hall lets say…or even another bedroom…Sure…nothing wrong with that…

Also as Greg has stated…when the 2008 NEC is adopted…look for AFCI’s on all 120V 15A and 20A Branch Circuits…

Hope this helps…

It may be that the AFCI part of the breaker is not the cause of the trip, but rather that the circuit is being overloaded. She is adding 10 amps to the circuit by plugging in the iron.
I hate that I wasn’t able to get to your seminar, I heard that it was very informative. Maybe next time.


Wish you could have attended, Hopefully I will be able to bring it back to SC at some point as it is always being “TWEEKED”

Very hard to keep it from going too far yet keeping it to the items the HI should be aware of. Some may find it too basic while others will find it very the seemed to be a balanced