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Joined: Feb 2008
Posts: 6
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I know this is an old thread but, the OP sked for AFCI horror stories. I'm in the middle of one.

Wired new home Master bd rm, bath on one AFCI, 2 bed rms and bath on another.

No problems after wiring house
A couple months later hm owner says Mst bd.rm. tripping intermitantly.

Swapped the two AFCI positions.

A few weeks later the 2 bd. rms. breaker is tripping, but not the mstr. bd. rm.

Replaced both breakers.

2 bd. rms. trip anytime you turn on more than one light.

Checked the next day, could not get brker to trip.

Went back in the evening after hm. owner called could not get breaker to hold.

I've wired many AFCIs in the past and have had a problem with tripping but never this intermittant stuff.
Used two wire home runs, and GE brkrs

Any ideas
Thanks Mark

Joined: Jul 2007
Posts: 1,335
The only thing I can think of is see if the home owner is using a piece of equipment that was moved from the other circuit. A hair dryer, or vaccum, etc.

"Live Awesome!" - Kevin Carosa
Joined: Dec 2000
Posts: 4,291
Originally Posted by markb

Wired new home Master bd rm, bath on one AFCI, 2 bed rms and bath on another.

By the NEC, the bathrooms cannot be wired to the bedrooms.

210.11(C)(3) Bathroom Branch Circuits.
In addition to the number of branch circuits required by other parts of this section, at least one 20-ampere branch circuit shall be provided to supply bathroom receptacle outlet(s). Such circuits shall
have no other outlets.

Joined: Feb 2008
Posts: 6
New Member
Bathroom receptacle is on seperate 20a. cir.
Lights and fan only on AFCI.

Joined: Jul 2008
Posts: 98
Likes: 1
This is only a guess, but could the fan motor be arcing internally?
Perhaps only not everybody uses the fan when they shower.
Try unplugging the fan for a few days and see if the problem goes away.


Joined: Feb 2008
Posts: 6
New Member
Thanks Bruce good idea.
I went over yesterday and checked all sw. and plug connection.

Checked voltage at panel 255v. A-B 127to N.
Maybe a fluckuation triggering AFCI?

It may be days before any tripping.

When I was checking connections, I drew a visable-audible arc several times but AFCI didn't trip. I've experienced this on other houses I've wired, but without the problems of this house.

Find it interesting that it wouldn't trip.

Last edited by markb; 11/26/09 01:59 PM.
Joined: Jul 2004
Posts: 9,788
Likes: 14
This may be an off the wall idea but how about swapping the AFCI out for a GFCI to figure out if this is a ground fault problem or an arc problem. It might help you narrow it down.

Greg Fretwell
Joined: Mar 2004
Posts: 947
twh Offline
If ever a technology encouraged extension cords between rooms, this is it. We've had problems with lights, but usually related to the switch or a bulb that burns out. Plug-in devices that trip an AFCI are appliances with built-in switches or thermostats, like irons, heaters and vacuums.

Since you had a problem in the evening, it makes me wonder about light bulbs. Are any CFL lamps or fluorescent ballasts involved?

twh #190616 11/27/09 04:05 AM
Joined: Jul 2002
Posts: 8,432
Likes: 3
I would have to ask the question:
Why is it that only the US use this sort of device, when no other electrical people around the rest of the world, feel the need to?

Joined: Nov 2006
Posts: 23
It is because the powers that be in America allow manufacturers and their reps to sit on the code council. Now the manufacturers just dream up something like arc fault breakers, then get them written into the code, no worries about selling them. Basically the same story as it always is in USA, if you need an answer for anything just follow the money trail.

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