Finding Opens in conduit.

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Sparky555

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I had a recent troubleshoot with an open. The wiring was in conduit. It involved five lights, three outlets and six switches. I eventually found it by opening outlets, switches and a light. Is there any way to systematically find it? It seems like finding shorts is easier than opens.
 
Sparky555 said:
I had a recent troubleshoot with an open. The wiring was in conduit. It involved five lights, three outlets and six switches. I eventually found it by opening outlets, switches and a light. Is there any way to systematically find it? It seems like finding shorts is easier than opens.
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I've only been taught, ID and uderstand the complete circuit and go to half or at 50% of known circuit then if OK, 50% again toward the source.

If you didn't clear it at the first 50% point go 50% backwards away from the source.
 
Circuit tracer. Signal changes at the open.

TDR might work but I have only had limited exposure.
 
Part of the problem was the circuits weren't labeled. In the end I was able to see how the conduits ran in the attic. The first junction box of the circuit was the one furthest from the panel. It was a 2 hour troubleshoot which made it an hour and a half longer than the typical troubleshoot. The problem was in the first junction box so the whole circuit was dead.
 
cadpoint said:
I've only been taught, ID and uderstand the complete circuit and go to half or at 50% of known circuit then if OK, 50% again toward the source.

If you didn't clear it at the first 50% point go 50% backwards away from the source.
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That works just fine for a short, but not an open.

Sparky555 said:
I had a recent troubleshoot with an open. ........
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An open can be located by identifying what part of the circuit works, and what part doesn't. The open will be in the area where the two overlap.
 
Always look at the simplest solution, switched outlet etc. and don't try to think of it as what should be the most logical way, it most probably isn't.
 
Sparky555 said:
Is there any way to systematically find it?
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Try plugging a lamp in one of the dead receptacles, have someone with fast reflexes watch the lamp and call out when you make the lamp flicker, and you start wiggling stuff.

Otherwise, you just have to do what you did, box by box.
 
That works just fine for a short, but not an open.
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Besides how one might approach the problem's, minus tools, (negating the proof given) 50% than isolation, will still be a directional situation.
 
cadpoint said:
Besides how one might approach the problem's, minus tools, (negating the proof given) 50% than isolation, will still be a directional situation.
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OK, so if you have 10 receps on a circuit, and recepts 3-10 are dead, you're still going to start with the 5th one, even though it's obvious the problem is in 2 or 3?
 
I guess that's where two hours come in for trouble shooting.

I'm just saying what I've heard, I've said before I'm blessed with new construction...

I just want'd to qualify that 50% and isolation, down line one has cured half the circuit...

As hard as I've read of appling work lately, 50% sounds pretty good, if 7 or 8 or 9, no?
 
LarryFine said:
Try plugging a lamp in one of the dead receptacles, have someone with fast reflexes watch the lamp and call out when you make the lamp flicker, and you start wiggling stuff.

Otherwise, you just have to do what you did, box by box.
Click to expand...
Sometimes a cord and light will let me do it without needing someone to watch. I have a buzzer too but always forget where it is.
 
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