Lost a Neutral..

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MattShek

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I have an outlet with 120V from hot to ground, but shows only 14V from hot to neutral...I assume it is either a bad joint or a bad spot in the neutral somewhere....however the building is very old and the wiring is a nightmare, it was a two story home, that is now two seperate businesses...does anyone have any good ideas or tips for tracing the neutral back?? All the raceways are obviously concealed, so I was going to try to open all the boxes nearby and pull the neutral to see which way it runs, and hopefully find where it is good and repull the neutral if necessary......thanks for any help or advice
 
Make sure and check for a GFI recpt. upstream before you go to a lot of trouble shooting removing recpts.

I worked a half a day once and come to find it was a GFI in a closet which used to be a kitchette.

The GFI will open the hot and the neutral when it trips. :)
 
MattShek said:
I have an outlet with 120V from hot to ground, but shows only 14V from hot to neutral...I assume it is either a bad joint or a bad spot in the neutral somewhere....however the building is very old and the wiring is a nightmare, it was a two story home, that is now two seperate businesses...does anyone have any good ideas or tips for tracing the neutral back?? All the raceways are obviously concealed, so I was going to try to open all the boxes nearby and pull the neutral to see which way it runs, and hopefully find where it is good and repull the neutral if necessary......thanks for any help or advice
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I would first turn off the breaker of the affected circuit and see what goes off. That should isolate the area to some degree. Then you need to just open boxes.
 
080802-0846 EST

MattShek:

Put a tracer signal on the hot line. Find other outlets on that circuit. Measure for continuity from neutral of those other outlets to ground. This should allow you to localize the area where the break is located.

Lets assume that there is also the possibility of some miswiring so that some neutral slots might be actually wired to a hot line. You do not want to connect your ohmmeter directly to a hot line. One possible solution is to first check the voltage on the neutral slot to ground before switching to ohms.

Another thought on tracing. If we assume that you have floating neutrals, and apparently you do from the 14 V reading, then just go from outlet to outlet looking for those that show more than near zero volts on neutral. This will localize the fault location.

With a high impedance voltmeter, Fluke digital, there should be at most millivolts between neutral and the EGC if no current is flowing in the neutral. On my bench fed from 50 ft or more of #12 with a printer and computer as load the difference between neutral and EGC is 190 MV, On a different circuit with more computer load it is 250 MV. On another different circuit from a subpanel with no load on the circuit, but other loads on different other circuits from that subpanel 55 MV.

.
 
Sorry didn't mean to mislead you.You said you had 114 volts to Eq. ground.I was assuming you are checking this with a LCD multitester.If so use a low impedence wiggy tester to rule the GFI out. That 114 volts might have been microamps. A wiggy tester will not give you a voltage reading if its a GFI. :)
 
080802-0946 EST

MattShek:

I misread your post as 14 V neutral to ground, but it really doesn't matter the same cause, capacitive coupling to a floating neutral, will produce non-normal readings.

So readings from neutral to ground as I described should be a good tracing technique. But also you can just measure between hot and neutral at othe outlets to look for those on one side or the other of the neutral break.

.
 
Matt, a time-saver can be to plug a working lamp into one of the non-working receptacles and wiggling other receptacles until you find one that makes the lamp flicker.
 
LarryFine said:
Matt, a time-saver can be to plug a working lamp into one of the non-working receptacles and wiggling other receptacles until you find one that makes the lamp flicker.
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OR save yourself some future headaches and just replace all the receptacles... and not backstab the new ones...
 
Thanks for all the help, I'm going to work on the problem the beginning of next week........ I'll keep you posted
 
I found the problem, I traced the wire back through a few boxes and found where someone had taken down a lighting fixture that was on the circuit and disconnected the neutral.....Very easy fix....thanks again for all the help
 
MattShek said:
I traced the wire back through a few boxes and found where someone had taken down a lighting fixture that was on the circuit and disconnected the neutral.....
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Figures. I had a similar thing happen on a renovation/addition job once. It was a kitchen redo and bedroom/den/bath addition. The family was still living in the house. That always makes things interesting.

The panel was in the back wall in the kitchen, inside a pantry closet. About two days after we finished roughing the addition, I got an angry panicked call from the GC's site guy afound 6pm. There was no power in the master bedroom or bath. :-?

I went over right away (15 min) and found the site guy still flipping breakers as if he expected something else to happen. I looked up at the ceiling, where the pantry pull-chain lampholder, as well as the pantry walls themselves, used to be. :roll:

Yup. There were two white wires and two black wires spread apart hanging out of the box. The site guy was still angry, as if we had something to do with it. We joined the wires and sent him a bill for an emergency call. He was still angry. :mad:
 
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