Page 1 of 2 12 LastLast
Results 1 to 10 of 15

Thread: Lost a Neutral..

  1. #1
    Join Date
    Apr 2008
    Posts
    6

    Lost a Neutral..

    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

  2. #2
    Join Date
    Oct 2007
    Location
    A little piece of heaven!
    Posts
    2,019

    multi-meter

    Multi-meter! Ohm out your conductors. Welcome to the forum!:smile:

  3. #3
    Join Date
    Feb 2003
    Location
    Tennessee
    Posts
    1,564

    Smile

    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.

  4. #4
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    26,345
    Quote Originally Posted by MattShek
    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
    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.

  5. #5
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
    Posts
    4,650
    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.

    .

  6. #6
    Join Date
    Feb 2003
    Location
    Tennessee
    Posts
    1,564

    Smile

    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.

  7. #7
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
    Posts
    4,650
    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.

    .

  8. #8
    Join Date
    Jan 2005
    Location
    Southeast Texas
    Posts
    1,538
    My first bet is the neutral is lost at a back-stabbed receptacle.
    IBEW LU 716

  9. #9
    Join Date
    Aug 2005
    Location
    VA BCH, VA
    Posts
    1,307
    Quote Originally Posted by crossman
    My first bet is the neutral is lost at a back-stabbed receptacle.
    I'll take that bet too.
    VA Master Electrician

  10. #10
    Join Date
    May 2005
    Location
    Richmond, Virginia
    Posts
    21,838
    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.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •