Arc Fault circuit breakers

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vilasman

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I took over an unfinished electrical job, and I know how many of you feel about that...

Anyway the person before me wired the bedrooms in 3 wire. I get there the walls are closed up. I pull new 2 wire feeders to the attic and hook into the circuit but cutting and splicing a wire and then I went into the house found where the 3 wire junction boxes were, disconnected the hot from the 3 wire and disconnected the hot and the neutral from the two wire that was going off to the plugs in the bedrooms and capped all of that off. The arc faults hold and they test ok and I passed inspection.
But when ever you plug anything into the circuit the arc faults trip.

so whats the problem? This is my first expierence with arc faults. They are homeline
 
Re: Arc Fault circuit breakers

Your problem is, the circuit protected by the AFCI has another path for neutral. Check for boxes that the bedroom circuit shares with another circuit, and see if the neutrals are tied together.

If there's nothing obvious, try turning the power off, disconnecting the neutral from the breaker and testing for continuity from ground to neutral.

The reason it only trips under load is that it senses say, 1 amp leaving on the hot wire, and only .4 amps returning on the neutral. The ground-fault portion of the AFCI is reacting to what it percieves as a ground fault. ;)
 
Re: Arc Fault circuit breakers

thank you!
thank you very much!
I thought I had cleared all the neutrals, but it appears that i havent
 
Re: Arc Fault circuit breakers

Bear in mind, I wasn't 100% clear on the most common problem: a ground wire touching a neutral on a receptacle is usually the other path to neutral. :)
 
Re: Arc Fault circuit breakers

YOu may have installed two 2-wire circuits, however, there may still be some 3-wire cable suppying the down stream loads. If the AFCI breaker supplies one circuit of a 3-wire cable, the neutral current is not the same a the current on one circuit and it will trip.
 
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