ECN Forum Forums General Topics of the Trade General Discussion Area AFCI breakers

From the troubles you're having with these things I'm glad they haven't appeared over here. It's probably only a metter of time though.

When the manufacturers got their "current signatures" of typical fault arcing, I wonder if they bothered to compare these with those obtained from a motor which is sparking slightly at the brushes?

it might be interesting to compare the signatures and see how close they are. If sparking commutators is going to cause problems with AFCIs, I see you having a lot of calls if/when they start to be used on circuits feeding power tools etc.

I have a new custom home to wire in the next month. I plan on meeting the AFCI requirement for this house so I ordered 4 AFCI breakers a couple of weeks ago from the one and only supply house in this county. The only line they sell is ITE. I got my 4 Q120-AF breakers yesterday($30.63ea.)and after reading nesparky's post about the EE's house I decided to run some tests on one in my shop.Here's what I did: My shop is all in EMT so I dropped a foot of 3/8" flex out of the bottom of my panel to a handybox. I ran 3 #12 THHNs(black, white & green)to a Hubbell CR-20 duplex receptacle. I have plugged everything I could find into this receptacle trying to trip it. Blow dryers, circular saw, air compressor, old electric blanket(and ran over it with my truck while plugged in), Milwaukee Holehawg(badly in need of new brushes),and an old B&D drill that you have to shake to keep it running. I took an old 16ga. extension cord and cut the ungrounded conductor then twisted just 2 strands of copper conductor back together and plugged a Milwaukee 1800W heat gun into the cord. It ran until the strands got hot and burned in two but none of this tripped the AFCI breaker! The only thing I had that would trip it was my Ideal GFCI plug-in tester. It tripped it instantly. Does anyone have any other experiment suggestions? I would also like to know what brand nesparky had trouble with.

Good man Fred!
it is interesting that a GFI tester would trip an AFCI. I wonder if the 10ma?? is close to 75W ??