Low voltage reading/resistance in hot conductor

[jefferywebb69]

I am troubleshooting a circuit which part of isn't working properly. It originates from a 100 Amp subpanel that I have already redone because it was bonded and just poorly done. I have isolated down to the specific wire which I believe is causing the problem. Prior to this I am getting 120 V on all devices. I am getting a voltage reading of 72 V hot to ground, 72 V hot (black) to Neutral (white), and 0 V Neutral to ground with my Fluke multimeter. I used a "Wiggie" to verify the problem (no reading), and that I wasn't getting phantom voltage. Also I get a resistance reading end-of-conductor to end-of-conductor of 4+ Ohms for the hot. The Neutral is correct at near 0. I cannot access the area where the wires travel but the only thing I can figure is a loose or damaged conductor, splice, or junction box. It has to be where I can't access it. Please help, I don't want to rip out the ceiling!:happysad:

 

[GoldDigger]

I am troubleshooting a circuit which part of isn't working properly. It originates from a 100 Amp subpanel that I have already redone because it was bonded and just poorly done. I have isolated down to the specific wire which I believe is causing the problem. Prior to this I am getting 120 V on all devices. I am getting a voltage reading of 72 V hot to ground, 72 V hot (black) to Neutral (white), and 0 V Neutral to ground with my Fluke multimeter. I used a "Wiggie" to verify the problem (no reading), and that I wasn't getting phantom voltage. Also I get a resistance reading end-of-conductor to end-of-conductor of 4+ Ohms for the hot. The Neutral is correct at near 0. I cannot access the area where the wires travel but the only thing I can figure is a loose or damaged conductor, splice, or junction box. It has to be where I can't access it. Please help, I don't want to rip out the ceiling!:happysad:

Actually, what the Wiggie is telling you is probably that the 72 volts itself IS a phantom voltage and that the hot wire is completely open somewhere. The 4+ ohms that you are reading is probably from a downstream load that is still plugged in or connected. You can verify this by measuring with your Fluke while the Wiggie is attached.
If it is not a phantom voltage, then you would probably see the full 120 volts if you find and disconnect all downstream loads.

You can attach a wire tracer to the panel end of the wire (disconnected from CB!) and try to follow it to the point where the signal stops. If the run is in conduit, you may well have trouble following it, but at least you will be able to see where it pops up even in boxes where it does not connect to an outlet.

With the panel side open, you can also attach a signal injector at the problem outlet and follow the signal back from there.

Good luck!

 

[jefferywebb69]

Thank you...

Thank you...

It is not in conduit...it is 12/3 with ground NMB. I will try your suggestions and let you know. Jeff

 

[jefferywebb69]

I figured it out and you were right

I figured it out and you were right

I had to eventually cut into the unexposed area and found a poorly connected hot. Installed a new junction box with proper splicing and now am in business, Thanks!