# Need circuit troubleshooting help, Arc fault breaker keeps tripping.



## sparky250 (Aug 28, 2012)

Hey guys I'm looking for some insight to a problem Im having at a house I recently wired and am now finishing. Ill explain the circuitry and situation as best as I can and things I have already tested to troubleshoot.

14/2 HR to a switch box-switch box is a 3 way going out to a 4way, and another 4 way, and a 3way at the end of the line with a switch leg. Power then jumps out of the switch box where home run is to a bedroom light switch box, 14/3 to the ceiling box, then 14/2 drops to power 6 plugs and a sensor light.

The issue is with all the circuit wiring connected as intended and on an arc fault, every time 1 of the 4 hallway switches ( 3way or 4 way ) is hit, the circuit trips. Lights go on momentarily but circuit trips. The breaker can then be reset right away and does not trip right away until switch is hit again. The switch leg wire has been tested with an extension cord on an arc fault and the lights work so I assume no shorts there. 

Then I split the circuit up, took out the 14/2 jumper wire that takes power to the bedroom light and with that wire out the 3way 4way switches work and do not trip the circuit. Once the 14/2 jumper is added back into the circuit, there is no instantaneous trip but once one of the 3way/4way switches is hit arc fault breaker trips.

If I swap out the arc fault for a normal 15A breaker, the circuit does NOT trip at all when one of the 3way/4way switches is hit.

I have used a continuity tester on my fluke T5 with all end of the wiring open and have found no shorts. I am going to megger the wiring once I find access to one but cant afford to buy one at the moment.

Im pretty confident that there is some wire damage which is leaking a small amount of current, explained by an arc fault tripping but not a regular 15A breaker. What I find confusing though is why the circuit only trips when a 3way/4way switch is hit, with the 14/2 jumper to power bedroom....if there is wiring damage wouldnt the arc fault breaker trip right away....


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## erics37 (May 7, 2009)

sparky250 said:


> Then I split the circuit up, took out the 14/2 jumper wire that takes power to the bedroom light and with that wire out the 3way 4way switches work and do not trip the circuit. Once the 14/2 jumper is added back into the circuit, there is no instantaneous trip but once one of the 3way/4way switches is hit arc fault breaker trips.


Well you're on the right track with your dividing & conquering. If you can eliminate a portion of the circuit along with the problem then you know where to begin scrutinizing. If the AFCI does not trip with the bedroom power feed disconnected, then the problem is in the bedroom power feed.

What is the "sensor light" you mentioned? Like an occupancy sensor thing?


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## HARRY304E (Sep 15, 2010)

sparky250 said:


> Hey guys I'm looking for some insight to a problem Im having at a house I recently wired and am now finishing. Ill explain the circuitry and situation as best as I can and things I have already tested to troubleshoot.
> 
> 14/2 HR to a switch box-switch box is a 3 way going out to a 4way, and another 4 way, and a 3way at the end of the line with a switch leg. Power then jumps out of the switch box where home run is to a bedroom light switch box, 14/3 to the ceiling box, then 14/2 drops to power 6 plugs and a sensor light.
> 
> ...




First thing is try GFCI breaker on that circuit,If it trips then you have a ground fault, If not it may be an arc fault.
Do you have more than one circuit in your switch boxes?
If so you need to make sure your neutrals and grounds are separate and contained in their own circuit if they are mixed up in any way that will cause the AFCI'S to trip.
What type of lamps are you using CFL's led's ?
Are you using dimmer switches?
If you are using CFL's OR led's make sure that the lamps what ever type are dimmable and make sure the switches are rated for dimming led"s and CFL's.


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## sparky250 (Aug 28, 2012)

HARRY304E said:


> First thing is try GFCI breaker on that circuit,If it trips then you have a ground fault, If not it may be an arc fault.
> Do you have more than one circuit in your switch boxes?
> If so you need to make sure your neutrals and grounds are separate and contained in their own circuit if they are mixed up in any way that will cause the AFCI'S to trip.
> What type of lamps are you using CFL's led's ?
> ...


I will definately try a GFCI breaker tomorrow. If there is a ground fault, the GFCI breaker will trip instantly.... 

There is only one circuit in 3 of the boxes, one of the 4ways is ganged with a 3way from another circuit. I checked before but I will make sure neutrals/3wires are not crossed. Say the neutral of a 3wire is crossed wouldn't the breaker trip instantly....

The 3way/4ways control hallway pots with Par20's. All bulbs have been tested and that whole string of lights worked when the switch leg is directly given Hot & Neutral from a different arc fault used for testing.

No dimmers.

Thanks for the quick response. Hopefully I can get the issue solved quickly in the morning or theres gonna be another wasted day :001_huh:


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## sparky250 (Aug 28, 2012)

erics37 said:


> Well you're on the right track with your dividing & conquering. If you can eliminate a portion of the circuit along with the problem then you know where to begin scrutinizing. If the AFCI does not trip with the bedroom power feed disconnected, then the problem is in the bedroom power feed.
> 
> What is the "sensor light" you mentioned? Like an occupancy sensor thing?


Eric : Thats exactly what I am thinking is the problem. But once I add the bedroom power feed back into the circuit, it doesnt trip right away.. it trips only when one of the 3way/4way switches is hit in the other half of the circuit.

Ive attached my crude one line diagram to help.


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## D-Bo (Apr 15, 2012)

sparky250 said:


> I will definately try a GFCI breaker tomorrow. If there is a ground fault, the GFCI breaker will trip instantly....
> 
> There is only one circuit in 3 of the boxes, one of the 4ways is ganged with a 3way from another circuit. I checked before but I will make sure neutrals/3wires are not crossed. Say the neutral of a 3wire is crossed wouldn't the breaker trip instantly....
> 
> ...


This should be an easy troubleshoot. What a waste of time to replace an afci breaker with a gfci breaker. A fault is a fault and its your responsibility to find it. Wasting a day on this is bad, wasting 2 would be disturbing


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## sparky250 (Aug 28, 2012)

Then with the detail ive given, were to you think it is D-Bo. I think its in the 14/2 jumper out to the bedroom, but dont understand why the breaker only trips when a switch is hit.


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## TimChaput69 (Nov 14, 2011)

Are you using the same switch each time to try the circuit when it trips, if so try a different switch and maybe you have a bad switch.


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## D-Bo (Apr 15, 2012)

sparky250 said:


> Then with the detail ive given, were to you think it is D-Bo. I think its in the 14/2 jumper out to the bedroom, but dont understand why the breaker only trips when a switch is hit.


I would double check all the switch boxes and make sure they are made up correctly if you haven't yet I.e. travellers not crossed or tied to nuetral. If you think its your feed did you isolate both ends and measure resistance? What happens when you refeed the bedroom from a known working afci circuit. If everything checks out and nothing reveals itself id refeed and move on


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## Stickshaker (Jun 29, 2012)

I've had ground wires touching the neutral screws on receptacles, and they wouldn't trip until a load was put on the circuit elsewhere...


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## MikePEC (Jun 23, 2012)

What h e said^^^


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## Sparky J (May 17, 2011)

Just jumping in here the arc-fault breaker probably needs a load (usually at least 60-100 watts applied) before it will trip from a fault. So if your arc-fault breaker is ok and then you turn on the lights say in the hallway and apply the minimum load it will trip as it now sees the fault. I am not saying it's in the lights it may be in the other wiring, you just may need to apply a small load to all the wiring to track it down.
Sorry for the long winded replay. But I have known guys who install a circuit in home with nothing but outlets test it out all fine. HO comes home in the evening and goes to use the new circuit plugs in a lamp or two and pop the breaker senses the wiring fault once load is applied.


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## user4818 (Jan 15, 2009)

Just say no to AFCI's.


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## Cletis (Aug 20, 2010)

*not*



Peter D said:


> Just say no to AFCI's.


That would be against the law and socially immoral. Someone could get hurt, like an innocent child.


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## user4818 (Jan 15, 2009)

Cletis said:


> That would be against the law and socially immoral. Someone could get hurt, like an innocent child.


I never said don't install them. I still install them. I just don't like them.


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## rock (Mar 17, 2012)

I'd try hooking the circuit to another afci breaker to make sure the problem is not with the afci breaker.


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## sparky250 (Aug 28, 2012)

Thanks for all the feedback guys. I knew I missed out some info

Switches have been tested and replaced, all contacts work.
I have replaced AFCI with another AFCI and problem persists.

I did not know that the AFCI needs a load to trip. I suspect the issue is then in the line with the bedroom light and plugs because once that wiring is added into the circuit, the load from the hallway lights trips the breaker. If that jumper is out of the circuit, the hallway lights work on a AFCI. Hopefully it is a receptacle with the ground touching the neutral like Stickshaker has mentioned.


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## erics37 (May 7, 2009)

sparky250 said:


> Thanks for all the feedback guys. I knew I missed out some info
> 
> Switches have been tested and replaced, all contacts work.
> I have replaced AFCI with another AFCI and problem persists.
> ...


Geez dude. Use some test equipment and sort that s**t out.

Unplug anything and everything from the bedroom. Disconnect the outdoor sensor light, make sure all the wires are isolated from each other.

Disconnect the 14-2 feeding the bedroom, including neutrals and grounds, make sure they aren't contacting anything else in that box. Test for continuity between all the conductors - hot & ground, neutral & ground, hot & neutral (not likely on the last but what the hell). If you pick up continuity with a regular meter then divide and conquer - isolate the circuit and narrow it down until you find the fault and fix it.

If you don't get continuity with a regular meter, hook up a megger (double-check that nothing is plugged in, and that you have the sensor light disconnected and any light bulbs removed from other light fixtures; you just want to test the wiring for now). Test between hot & ground and neutral & ground. Ideally you would have infinite resistance between everything, if you find significantly less than that (like on the order of a couple megaohms-ish) then start tracking that down. I'm betting it's in the bedroom somewhere because the AFCI only trips when that portion of the circuit is connected.


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## mbednarik (Oct 10, 2011)

When installing a piece of equipment like an AFCI, you should really have something like a siemens arc/detect tool. I got mine about 6 months ago and it takes all of the headache out of the afci problems. With in a half hour you usually have it solved.:thumbup:


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## dronai (Apr 11, 2011)

mbednarik said:


> When installing a piece of equipment like an AFCI, you should really have something like a siemens arc/detect tool. I got mine about 6 months ago and it takes all of the headache out of the afci problems. With in a half hour you usually have it solved.:thumbup:


:thumbsup:


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## sparky250 (Aug 28, 2012)

mbednarik said:


> When installing a piece of equipment like an AFCI, you should really have something like a siemens arc/detect tool. I got mine about 6 months ago and it takes all of the headache out of the afci problems. With in a half hour you usually have it solved.:thumbup:


NICE I did not know that one of these tools exist. I am trying to find a link to purchase online. What does one of these cost around?


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## mtylerb (Apr 18, 2012)

I had a similar situation when wiring a friend's basement. Turned on a light and it would blow the AFCI as soon as I turned on a second light.

I found the clamps at the back of a couple of the single gang boxes he had installed were too tight. Loosening those up solved the problem.


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## mbednarik (Oct 10, 2011)

sparky250 said:


> NICE I did not know that one of these tools exist. I am trying to find a link to purchase online. What does one of these cost around?


http://www.homedepot.com/h_d1/N-5yc...eyword=siemens+arc&storeId=10051#.UFkbm41mQig

I got mine for less from the local supply house, i think right around $300.


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## sparky250 (Aug 28, 2012)

Well guys the issue has been solved. I would like to thank you all for your input and tips. A lot has been learned which is exactly why I joined this forum.

Issue turned out to be the sensor light was mounted on a "pancake" box and the 14/2 was coming through a connector in the centre k.o. Had my apprentice mount the sensor and fixture strap then squashed the crap out of the wires coming out of the centre k.o. When the 14/2 was stripped, the white neutral wire was sliced and with the wire bent so hard it was exposes and touching the ground.

Lesson learned, I am definately buying this arc detect tool. 

Thanks again.


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## don_resqcapt19 (Jul 18, 2010)

mtylerb said:


> I had a similar situation when wiring a friend's basement. Turned on a light and it would blow the AFCI as soon as I turned on a second light.
> 
> I found the clamps at the back of a couple of the single gang boxes he had installed were too tight. Loosening those up solved the problem.


If the tight clamp was causing the problem, then the jacket and insulation of the cable has been damaged. Loosening the clamp may have prevented the AFCI from tripping, but it did not solve the problem...the cable is still damaged.


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## HARRY304E (Sep 15, 2010)

D-Bo said:


> This should be an easy troubleshoot. What a waste of time to replace an afci breaker with a gfci breaker. A fault is a fault and its your responsibility to find it. Wasting a day on this is bad, wasting 2 would be disturbing


The GFCI Breaker Is a trouble shooting tool to find out if it is tripping on ground fault and not arc fault.

Instead of giving the guy a hard time offer up what you know about the subject.


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## HARRY304E (Sep 15, 2010)

mbednarik said:


> When installing a piece of equipment like an AFCI, you should really have something like a siemens arc/detect tool. I got mine about 6 months ago and it takes all of the headache out of the afci problems. With in a half hour you usually have it solved.:thumbup:


Do you have a link to that tool?


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## mtylerb (Apr 18, 2012)

don_resqcapt19 said:


> If the tight clamp was causing the problem, then the jacket and insulation of the cable has been damaged. Loosening the clamp may have prevented the AFCI from tripping, but it did not solve the problem...the cable is still damaged.


Agreed, and I advised him of that. I was only there to terminate and tie in to the distribution panel. He wasn't interested in re-running the 14-2, though.


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## RGH (Sep 12, 2011)

Good post!


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