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

Plastic box, Cutler Hammer Breaker, no room overhead without cutting ceiling joist in to for MC cable, ohm check ok with no readings between neutral and ground, or hot to ground or hot to neutral. Once I take the wire loose from the circuit the breaker holds. The breaker I switched to test it was a 15 amp AFCI and done the same way. No way the contractors going to tear down the wall When I fished the new wire down the wall, it tore some of the insulation off the "pull" wire, but I didn't see any "nicks" in the conductors. The inspector told me a few months ago, they may change the rule for AFCI's again that would only include the bedrooms again. I may have to let it fall under that

Does the AFCI trip when anything else is plugged into that receptacle, or just the wet/dry vac? Does it trip when the wet/dry vac is plugged in, or turned on?

If the cable was nicked and seeing a parallel short, it should be arcing as soon as the circuit is energized; plugging something in wouldn't make a difference. I don't think the cable is your problem. AFCIs aren't supposed to trip on series shorts, either, but it wouldn't hurt to double-check the wirenuts and other splices.

First, though, I'd replace this receptacle, regardless of how it tests. My gut feeling is there's crap loose in this receptacle and it's shorting out when you plug your wet/dry vac in.

Steve:

You said.."If the cable was nicked and seeing a parallel short, it should be arcing as soon as the circuit is energized; plugging something in wouldn't make a difference. I don't think the cable is your problem. AFCIs aren't supposed to trip on series shorts, either, but it wouldn't hurt to double-check the wirenuts and other splices."

I'm under the understanding that a combo AFCI sees series and parallel faults, hence the 'combo' designation. I don't profess to be an AFCI maven as AFCI are 'new' here in NJ as of 10/6/2009, and resi is still slow. I garnered my info from various mfg sites & info, and from a lot of guys here that have AFCI experience.

sparkync,

That is a real heard scratcher of an issue!!!

Keep us informed on the progress.

I cannot think of anything, not already covered so far, which could be tried.

Does the AFCI Breaker trip if another type of load is plugged in to the Receptacle in question? (other than the Wet Vacuum Sweeper).

Scott

To create a series fault, you'd have to not only nick the wire, but actually break it. I think you'd have noticed this during installation.

Have you checked the tightness of the breaker and neutral terminals in the panel? And other connection points? An untightened terminal with nothing but the spring tension of the wire can cause arcing that might trip it.

Did you try a GFCI breaker as a test?
That will decide whether this is an arc fault or a ground fault.

I never even noticed this comment until now.
Are you saying that the last NM cable out of this device box is also supplying a gas log fireplace?
If so, does the fireplace have a variable speed universal blower motor mounted below it?
Or possibly an electronic ignition module?
If so, then that may be the problem. Either that or the wiring in the gas log itself could have a problem.