Hey I have an arch fault that trips over night.New home not occupied yet. I used meter on meg ohm scale to grounding and grounded wire no cont. to the hot wire.Should I replace it or look for trouble. I did move it to a circuit other than the bedroom and it didn`t trip last night.I did put the bed room on a regular CB and it didn`t trip last night.Can I run a megger on it and if it`s clear then can I sleep tonight.Really has me wandering..

First of all, don't use a megger to test the circuit while the AFCI is connected. It could be damaged.

I would suggest trying another AFCI on the circuit. If two different AFCIs trip on that circuit, but not when connected to other circuits, there is probably something wrong with the circuit.

The AFCI may be doing what it was designed to do. There may be intermittent arcing in a damaged cable that only occurs at line voltage, and that won't show on a meter.

You could pull and inspect the fixtures and receptacles, and try loosening the cable clamps in the boxes, if they are used.

Ed

R-B

If you have access to a megger I would give it a shot. As Ed said make sure you disconnect the AFCI from the circuit. Also make sure you remove any GFCI's, dimmers or other electronic devices from the circuit. If you don't have access to a megger then try replacing the AFCI. I have not had to use AFCI's yet but have had circuit breakers intermittently trip for no apparent reason and know what you mean about not being able to sleep. I have used a megger several time to successfully find problems. Not to long ago we had a 15 amp breaker feeding the kitchen lights would trip once every day or two. I opened all of the boxes to try and find the problem and even used a multi-meter but nothing showed up. The next day I came back with the megger and the problem showed up right away. I narrowed the problem down to a piece of 14-3 between two three way switches. Since most of this piece wire was run in the crawl space under the house I carefully examined it and found one staple was pounded a little too hard.

Good luck with the search.

Curt

Also, keep in mind that the AFCI also provides GFCI protection. My guess: it is tripping due to a ground fault rather than arcing. I assume that it is not a multi-wire circuit.
I had an AFCI that tripped often. It was dedicated to the receptacles of a bedroom but one of the receptacles was switched via a switch loop to a box that housed a switch to a ceiling fan as well. Since the ceiling fan was on a seperated circuit, the shared grounds between the fan and receptacle cables caused the AFCI to trip.

AFCI's run hot, especially when racked up together, the thermal trip is then lowered....barring this , look for a leak to ground.

Help Afci kicking my a$$.Guys what Is going on I replaced the breaker and now the new one trips.Ok I took the breaker out of the box installed it on the bedroom cir. and tripped.Then I took A OUtdoor light and hooked it up at the panel box it trips I tried on several other circuits it trips whats going on??This is a subpanel 4 wire the whole bit.Just to make it clear the test light I hooked neutral to neutral bar and black to breaker didn`t do a switch.Ran a megger on the cir. no problems hooked a large heater to it and watched for current spikes. Pulled every outlet out and checked.

It's not clear to me when this is tripping, but if you replace it with a GFCI breaker and it trips that will point to a ground-Fault rather than an Arc-Fault and you can take it from there. Test for connections between a ground and Neutral and look at items being used on the circuit.

Bill

Guys:
I can't believe that New Jersey did something to make life easier. They did not adopt the AFCI requirement! (Yet)
Also, we are working on the '99 NEC, the '02 will be adopted "soon".....so they say.

I read everyones problems with AFCI, and sooner or later they will be here, I guess.

John

Let me make sure I read your post correctly:
Did you wire and outdoor light directly to the breaker with no other load? In other words, install breaker, wire one side of light to breaker hot side and the other side to the breaker neutral side with no ground and the breaker still trips?
Sounds like the breaker is defective or not installed correctly.
If the hot and neutral are wired to the correct spots on the breaker and the neutral pigtail is connected to the neutral bar, my guess is the breaker is defective. I can't think of any other way the neutral current and ground current can be unequal. And there obviously is no arc pattern.
Bill's suggestion is a good one - try a GFCI breaker to make sure that it is a ground fault problem.

Reel-Break,

Forgive me for asking the question. . .just to be certain. Are you connecting the branch circuit neutral to the AFCI breaker or to the neutral bar?

Respectfully,
Al

I can relate to your problems with the AFCI. I had an AFCI that was installed in new construction that would trip as soon as any load was applied on the circuit. I immediately started thinking through the possibilities of Hot to neutral arcing or even neutral to ground connection, but thankfully before I started taking everything apart, I checked the panel and found that I had connected the wrong neutral wire to the AFCI breaker. Thus whenever a load was applied, the breaker was sensing a ground fault since there was no equal current returning on the neutral wire. Needless to say, I was humbled and was reminded that sometimes it is the simple things.

P.S. Please forgive me for saying neutral instead of ungrounded conductor

I'm with Al on this. It sounds like you are connecting your load neutral to the neutral buss instead of the breaker. It must be connected to the breaker!

Curt

Yes the the neutral went to breaker I read the post I did write it wrong..Sorry It was in fact a bad breaker and the local supply gave me no trouble in replacement.But I did waste several hours.and dollars.Thanks I guess it would pay to proof read.Thanks again.Wander how many will be late for work when storm causes the afci`s to trip?and the clock don`t work....just a thought.

Another selling point for battery back-up alarm clocks.