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Old 06-14-2014, 09:35 AM   #1
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hot to ground continuity


I had a breaker that tripped and would not reset (after turning off). The circuit contains some garage lights, outdoor lights, canister lights inside, and two plugin receptacles. I've done a lot of hunting, and isolated the problem.

The canister lights are controlled by two 3-way switches and a 4-way in between. With those switches disconnected, the breaker will reset and everything (except the canisters) works fine.

So I replaced the first 3-way with a simple switch, and the breaker will reset. Everything including the canisters works fine. So I have isolated my problem to the runs beyond that first 3 way switch.

The run from the first 3-way to the 4-way is very short. The switches are only 7 feet apart in my house. The Romex (3wire plus ground) runs up into the attic and back down to the 4-way.

I disconnected all four wires on both ends of this run of wire, and here's where I'm stumped: I can use a continuity tester on both ends of the wire easily, since they are so close together. I obviously get continuity when i connect Red-Red, White-White and Black-Black. But I don't get continuity connecting Ground-Ground. I DO, However get continuity between the a black end and the opposite ground end.

Somewhere in between, the ground has to be in contact with the black wire, and completely broken from itself because of the lack of continuity with the other ground end.

No new pictures in the walls, or other disturbance. The house is 10 years old. We were gone from the house during the day when the breaker first tripped, it was raining very heavily (which led me to suspect the outdoor fixtures first ----lots of time wasted there).

I spent a significant amount of time in the attic and located where this run comes up from the 3-way, and back down to the 4-way. No damage to the wire in the attic. It has to be one length of wire. (The run from the 4-way to the Other 3-way tests normal for continuity....it's fine)

A couple questions:
1. If my diagnosis is correct (black wire contacting ground wire - and ground wire not continuous for the 25-30 foot run), how in the heck could that have happened?

2. If I can get past the scientific curiosity of "how did this happen" and actually try to fix it - can I just run another length of Romex and leave the old wire in the wall? I assume it's stapled to the studs so I won't be able to pull it out. I can get a fish tape and should be able to put a new run in, no problem. But obviously I won't be able to affix the new wire to the studs without cutting and patching drywall....I'd rather not do that. Can I leave the loose wire in between the studs? I've got 10 foot ceilings in this room, so there is about 6-7 feet of wire between the switches and the attic.

Thanks for reading all the way through this. I've been testing, thinking, and reading posts online for 5 days now. Any advice is appreciated.

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Old 06-14-2014, 10:45 AM   #2
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hot to ground continuity


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Originally Posted by mrerickson View Post
I had a breaker that tripped and would not reset (after turning off). The circuit contains some garage lights, outdoor lights, canister lights inside, and two plugin receptacles. I've done a lot of hunting, and isolated the problem.

The canister lights are controlled by two 3-way switches and a 4-way in between. With those switches disconnected, the breaker will reset and everything (except the canisters) works fine.

So I replaced the first 3-way with a simple switch, and the breaker will reset. Everything including the canisters works fine. So I have isolated my problem to the runs beyond that first 3 way switch.

The run from the first 3-way to the 4-way is very short. The switches are only 7 feet apart in my house. The Romex (3wire plus ground) runs up into the attic and back down to the 4-way.

I disconnected all four wires on both ends of this run of wire, and here's where I'm stumped: I can use a continuity tester on both ends of the wire easily, since they are so close together. I obviously get continuity when i connect Red-Red, White-White and Black-Black. But I don't get continuity connecting Ground-Ground. I DO, However get continuity between the a black end and the opposite ground end.

Somewhere in between, the ground has to be in contact with the black wire, and completely broken from itself because of the lack of continuity with the other ground end.

No new pictures in the walls, or other disturbance. The house is 10 years old. We were gone from the house during the day when the breaker first tripped, it was raining very heavily (which led me to suspect the outdoor fixtures first ----lots of time wasted there).

I spent a significant amount of time in the attic and located where this run comes up from the 3-way, and back down to the 4-way. No damage to the wire in the attic. It has to be one length of wire. (The run from the 4-way to the Other 3-way tests normal for continuity....it's fine)

A couple questions:
1. If my diagnosis is correct (black wire contacting ground wire - and ground wire not continuous for the 25-30 foot run), how in the heck could that have happened?

2. If I can get past the scientific curiosity of "how did this happen" and actually try to fix it - can I just run another length of Romex and leave the old wire in the wall? I assume it's stapled to the studs so I won't be able to pull it out. I can get a fish tape and should be able to put a new run in, no problem. But obviously I won't be able to affix the new wire to the studs without cutting and patching drywall....I'd rather not do that. Can I leave the loose wire in between the studs? I've got 10 foot ceilings in this room, so there is about 6-7 feet of wire between the switches and the attic.

Thanks for reading all the way through this. I've been testing, thinking, and reading posts online for 5 days now. Any advice is appreciated.
Sounds like the ground wire is broken and is touching the black. I don't see why replacing the black and ground wire wouldn't work. Is there a way you can bypass those wires with new wires to check if it will work? Not sure if I understand correctly so I might be totally off base.

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Old 06-14-2014, 10:49 AM   #3
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I DO, However get continuity between the a black end and the opposite ground end.
great troubleshooting.

not sure, but you could be reading through the bulb to neutral/ground.

but you mentioned not getting ground to ground continuity, so might be that ground is used as neutral.

will read again
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Old 06-14-2014, 10:53 AM   #4
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I had a breaker that tripped and would not reset (after turning off).
?

circuit breaker won't reset
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Old 06-14-2014, 10:56 AM   #5
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hot to ground continuity


Thank you for the replies.

The ends wires I'm testing aren't running through any bulbs. I'm testing either end of the same wire.

I've attached a crude diagram.

I suspect Robpro is right - I've got a black to ground short somewhere. Some screw, nail or staple has connected them and broken the ground I guess. With no new nails or screws in the house, I'm stumped as to where this happened.

One of my main questions is about code/safety if I have to run new wires. Can I just run a new black and ground outside the sheathing of the old 3wire? And will it be okay if I drill a hole from the attic, and pull it up from the J-box? Or do I need to fasten it to a stud inside the wall?

Thanks again.
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hot to ground continuity-wires.jpg  
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Old 06-14-2014, 10:59 AM   #6
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If I can get past the scientific curiosity of "how did this happen" and actually try to fix it - can I just run another length of Romex and leave the old wire in the wall?
still scratching my head why the trip in the first place.
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Old 06-14-2014, 11:03 AM   #7
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[QUOTE=ritelec;1363564]?



Thank you for the reply. I actually found this thread several days ago. I have pulled the breaker-switched it with a known good one, and have the same problem.

In fact, I can get the breaker to reset, as long as I disconnect the wires from my 3-way to the 4way, the ones in the diagram. I'm getting some unusual continuity results that suggest a ground-to-hot connection in that span. I've attached the diagram in an earlier reply.

I'm confident I have narrowed the problem, and will temporarily wire up a two way switch for these lights. My wife is beginning to complain about the lack of lighting in the kitchen. So all elements of this circuit will work (lights and outlets) and the breaker will stay on, but I will only be able to access the kitchen lights from one switch instead of three. that will be temporary until I can run the new wires to the other switch.
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Old 06-14-2014, 11:04 AM   #8
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Can I just run a new black and ground outside the sheathing of the old 3wire? And will it be okay if I drill a hole from the attic, and pull it up from the J-box? Or do I need to fasten it to a stud inside the wall?

Thanks again.
no need to fasten. thats snaking.

run a new cable assembly, not single conductors.

If you can identify it is a wire (cable). disconnect it, safe it off, and add another.

Strange.
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Old 06-14-2014, 11:06 AM   #9
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still scratching my head why the trip in the first place.
Wow, me too. On day 1 of this adventure I was convinced that the hard rain had caused some problems with the outdoor fixtures.

Now I'm driving myself crazy re-testing the continuity of this single run of 3-wire. I can't believe it spontaneously broke.

That's why I'm here. I was hoping somebody would have some similar story.

I wish I was a drywall expert - I'd just rip it all out so I could investigate completely. Kidding.....sortof....
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Old 06-14-2014, 11:13 AM   #10
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no need to fasten. thats snaking.

run a new cable assembly, not single conductors.

If you can identify it is a wire (cable). disconnect it, safe it off, and add another.

Strange.
Thank you. By "safe it off" do you mean wire nut the ends and push it out of the J-box?

Running the new assembly shouldn't be a problem. My neighbor owns a home audio business and I can borrow a fish tape or the drill bits. Maybe I can con him into coming and helping.

I appreciate everyone's advice - running a new assembly seems like the way to go - as I suspected.
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Old 06-14-2014, 11:48 AM   #11
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By "safe it off" do you mean wire nut the ends and push it out of the J-box?
or tape it so as not to eat up a bunch of room in the box with the wire nuts

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