[chenley]

Finished up a house about a week ago and I get a call about one of the AFCI breakers keeps tripping. Went and checked it out yesterday and it would automatically trip when turned on with no load on the circuit. Figured I would put the circuit on the AFCI that is installed above it. Waited about five minutes talking with the homeowner and it didn't trip. Decided it was a bad AFCI breaker, went and got another AFCI come back and it's tripped. Went ahead and replaced it and put the circuit on the new breaker. Flipped it on and all it well.

Got a call this morning that it is still tripping. Went out and wasn't going to mess around with this much more. I ended up taking the receptacle out that the homerun is on and wing-nutting the homerun wires. Flipped the AFCI back on and works fine. Went ahead and waited and got some work done on the laptop that needed to be done. 1.5 hours later the breaker trips about the time the GeoThermal Unit kicks on, which had kicked on/off about 4-5 times in that 1.5 hours. I reset it and get back to work, it ends up tripping about 45 minutes later.

I've checked the wiring in the panel and outlet box, neither are cut into the insulation. I'm just not really sure what to look for on this one, instead of running a new homerun which I'm really trying to avoid. Have any of you had this sort of problem? The only things on this circuit are 10 switched receptacles that go around a bedroom. Could it be the AFCI itself?

 

[JohnJ0906]

Was this tripping with the Home run removed from the receptacle, or had you replaced it?

Are you SURE there is nothing else on this circuit? Attic light, smokes, flood light, anything?

 

[itsunclebill]

Looks like it's time to put a Megger on the home run and see if you have a neutral-to-ground problem. It only takes one over driven metal staple to cause problems (and why I haven't used them for years).

I expect the advent of the AFCI requirements down the road will see more of some of the testing our buddies across the pond do on installations get to be a bit more common.

The house ropers that don't have time to unkink cable before pulling it through a hole are gonna have more issues too.

 

[chenley]

Thanks for the replies.

Yes, the homerun was isolated while being on the new AFCI breaker. All the staples are 1/2" GB insulated staples and I'm positive that it is just the ten receptacles on the circuit. I have been looking at purchasing a Megger have been waiting until this spring at some point.

Would this be enough to do what I need to do, instead of breaking the bank with one of the other ones? http://www.professionalequipment.com/extech-autoranging-digital-megohmmeter-380260/megohmmeter/

Also, I may go out and remove the load side wires from the breaker to see if it trips by itself. The HO is not to worried about it right now since it is just a guest room, but with Christmas coming up and his family coming I'd like to get it fixed ASAP.

 

[frank]

Chenley.
It's time to buy a Megger. If you had had one with you first trip back - you would have the problem sorted by now. Invaluable tool especially when RCD (GFI) is involved.

Without an instrument check my first guess would be neutral/earth fault someplace. But only time and testing will tell.

I checked the speck of the Megger you listed. Perfect for you. And a good price too.


Frank

 

[GREGNC]

i had a new construction once that had the same symptoms as yours.tried every thing including new brkr.finally out of desperation i moved brkr to another slot problem solved after a couple hours wasted.it was a brand new panel and breaker conection to bus was tight no sign of pitting or arcing.

 

[TOOL_5150]

Thanks for the replies.

Yes, the homerun was isolated while being on the new AFCI breaker. All the staples are 1/2" GB insulated staples and I'm positive that it is just the ten receptacles on the circuit. I have been looking at purchasing a Megger have been waiting until this spring at some point.

Would this be enough to do what I need to do, instead of breaking the bank with one of the other ones? http://www.professionalequipment.com/extech-autoranging-digital-megohmmeter-380260/megohmmeter/

Also, I may go out and remove the load side wires from the breaker to see if it trips by itself. The HO is not to worried about it right now since it is just a guest room, but with Christmas coming up and his family coming I'd like to get it fixed ASAP.

That is the exact megger I bought a few weeks ago! It works well. I am sure I dont know how to use it to its capabilities, but it will tell me if a cable is bad or a winding on a motor is shot. It really is not a bad price too. I bought mine delivered for 217.00

~Matt

 

[chenley]

Thanks for the information, going to get the Megger and test it instead of wasting more time fooling around with it.

 

[duckhunter]

I've had problems with AFI breakers in the past and most of the time it is neutral to ground. In fact, I just got done trouble shooting the same exact problem tonight at my sisters house that I'm trimming out. It was as simple as a ground touching the neutral terminals on one of the receptacles. I'd start ringing out your loop.

 

[JohnJ0906]

Would this be enough to do what I need to do, instead of breaking the bank with one of the other ones? http://www.professionalequipment.com/extech-autoranging-digital-megohmmeter-380260/megohmmeter/

Also, I may go out and remove the load side wires from the breaker to see if it trips by itself. The HO is not to worried about it right now since it is just a guest room, but with Christmas coming up and his family coming I'd like to get it fixed ASAP.

That's the one I have myself. I've only used it a couple of times, but Marc and Brian (2 members here with a lot of megger experience) both thought it was a good starter model.

 

[JohnJ0906]

Read this post, it has some good info on using a megger.

http://www.electriciantalk.com/showpost.php?p=7988&postcount=8

 

[aksparky]

I remember reading an artical in one of the electrical trade magazines where it talked about nuisance tripping of arc fault breakers, one of the things was having them directly above or below one another. If this is the case they should get cracking on a remedy before the new code change