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  1. #1
    Join Date
    Apr 2010
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    Lightbulb The case of the missing neutral

    In my panel box there is a cable with 3 wires, these 3 wires each go to a breaker, so all 3 are hot. There is no neutral. These wires feed 120 V branch circuits in the second floor bedrooms. Yes, I know that is not possible, but yet somehow it delivers 120 V to the rooms. Yes I know that is not code, but I don't think there was any code in 1840.

    Have anyone seen this before ? Could the neutral go to a ground rod ? (bypassing the panel box)

    The puzzled Saturday electrican.

  2. #2
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
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    691

    Default Re: The case of the missing neutral

    RJ, could it be that you have 3 phase power to your house (illegal)? Since the earth normally completes most of the circuit to the utility (something they hate to admit) if you were being feed 120/208V from a wye transformer it's possible to measure 120V from a ground rod to any of the phase connections, also very dangerous.

    Sounds like a call to the utility is in order and ask if you can trade a phase conductor for a neutral. I'm sure they will comply.

  3. #3
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
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    5,773

    Default Re: The case of the missing neutral

    They also didn't have breaker boxes in 1840. It is possible you have a MWBC (multi wire branch circuit) connected to a AFCI breaker which requires the neutral to also be connected to the breaker.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  4. #4
    Join Date
    Dec 2010
    Location
    Houston Texas
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    2,916

    Default Re: The case of the missing neutral

    I think Jack may be on the right track here. Do any of these wires go to a breaker which has a white or red button in addition to the lever?

  5. #5
    Join Date
    Apr 2010
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    6

    Default Re: The case of the missing neutral

    The breakers have only one wire connection on them, they look "normal" to me. The wire has cloth insulation.
    The panel box was installed in 1980, but the house wiring was carried over to the new panel box. Which perhaps was the wrong call, but that was the decision made at that time.
    The point is that the house wiring is quite old and I don't know how they did things at that time.

    As for the 3 phase suggestion, don't you get normally get 120 V between a hot wire and ground you have when single phase and everything is correct ?

  6. #6
    Join Date
    Apr 2010
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    6

    Default Re: The case of the missing neutral

    no, none of the breakers have any buttons on them. I don't think this is driven by the panel box. The wiring was like that when there was a fuse box there. Sorry, I should have said that at the beginging. The wiring is very old and I have no idea when it was installed. It is cloth insulation.

  7. #7
    Join Date
    Aug 2007
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    The Great White North
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    4,045

    Default Re: The case of the missing neutral

    Quote Originally Posted by rjohnson2 View Post
    In my panel box there is a cable with 3 wires, these 3 wires each go to a breaker, so all 3 are hot. There is no neutral. These wires feed 120 V branch circuits in the second floor bedrooms. Yes, I know that is not possible, but yet somehow it delivers 120 V to the rooms. Yes I know that is not code, but I don't think there was any code in 1840.

    Have anyone seen this before ? Could the neutral go to a ground rod ? (bypassing the panel box)

    The puzzled Saturday electrican.
    Just a guess .... Based on the age of the home , at some time when electricity was introduced it was likely knob and tube with a fuse panel. In which case one main conductor for each the hot and neutral were run with the branches spliced along the run ( trunk & branch ), feeding the lights and receptacles. The splices were simply soldered together , taped and left exposed ( open air splice ). One reason it was done this way was because of cost . The wire was expensive and it was very labour intensive boring holes manually with a brace & bit along with soldering -- so having home runs for each circuit like we do today was out of the question.

    Depending on the size of the home it was not uncommon to find only one or two circuits feeding all the general circuits for lights and plugs throughout the entire home. For the most part it was reasonable and safe mainly because the electrical demand back then was nowhere near what they are today --- and is another reason it was done that way.

    Your description of the cable with 3 conductors indicates some electrical upgrade done some time later ( perhaps in the eary 50's ).

    So -- very likely it's one of two scenerios ........

    The old existing knob & tube neutral was left in place connected in the panel and is being used to provide the neutral for those circuits.

    Or ----

    The neutral has been tapped into from another circuit that maybe home run to the panel.

    Either way it was a misguided and unsafe corner cutting attempt at saving some $$.

    What you end up with is a dangerous multiwire branch circuit setup.

    For example --- let's say you decide to do some work one of those 3 circuits in question --- you shut off the breaker thinking you have de-energized that circuit --- the neurtal is carrying return current from the other circuits it is sharing --- you have a dangerous shock hazard.


    2 cents worth.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  8. #8
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
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    5,773

    Default Re: The case of the missing neutral

    With your update, I agree with Canuk's scenario, you most likely have K&T wiring and some updated though old circuits. Those circuits are most likely using a shared neutral and the breakers should probably be derated.

    As far as the aluminum wiring for the service, that is more common than the use of copper for the service wiring. It is perfectly safe as long as the panel terminals are rated AL/CU, anti oxidation gel is used, and the connections are kept tight.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

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