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Thread: explain how neutral works

  1. #1

    explain how neutral works

    i posted a message like the following last nite or so i thot but it doesn't show today. would someone please explain as to how the neutral is really supposed to work. that might explain why i had a problem with a house i am rewiring. 3 ways were used for both ends of kitchen. 14/2 was used as travelers, not 14/3 that i am used to. a neutral from a different ckt was run to kit ceiling lt. this worked fine until i replaced 2 slot receptacles on ckt with grounded receptacles. placed a gfi at first receptacle. when either of 3 ways in kitchen were flipped, gfi would trip. why would gfi trip? ckt worked fine before i placed gfi at first receptacle.

  2. #2
    Join Date
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    Re: explain how neutral works

    Ronson you got replies and the post is still up, but new posts push older ones back in the list.

    Here is your post

    How does a Neutral Work

  3. #3

    Re: explain how neutral works

    tony & bob, thanks for info. how can i test the gfi i installed on this ckt? when i plug my little 3 prong gfi tester in, the readout is "open grd" and i can't trip the gfi when i press the black button on my tester.

  4. #4

    Re: explain how neutral works

    tony & bob, i would still like to know how the neutral wire works. have never had anyone give me an explanation that fully satisfied my curiosity. if the neutral is not supposed to be carrying any current as i think my electrical books said, then how can the gfi read anything? the books said that "theoretically", one should not be shocked by touching a neutral but i know from firsthand experience that this is not true. also, for example, picture current flowing to a receptacle. when the receptacle is unused, would no current would flow through to the neutral? if so, why does this not trip the gfi at the first of the ckt? when the receptacle is used, would the neutral only receive a portion of the 120 volts, since an appliance, etc. will use a portion of the 120 volts?

  5. #5
    Join Date
    Jan 2004
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    137

    Re: explain how neutral works

    check through the posts of the last three weeks the neutral was covered completely. Either this subject or another, do a search.

  6. #6
    Join Date
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    Re: explain how neutral works

    Ranson, you said a neutral is not supposed to be carrying any current. This is not true. The equipment grounding conductor shouldn't carry current, so maybe you have them mixed up. The neutral (grounded conductor) carries all the load in a single phase circuit like you are talking about, and the imbalance current in a three-phase circuit. A balanced three-phase circuit is the one case where a neutral won't carry current, if perfectly balanced. If the neutral is grounded, such as your example, the voltage on it should just be from voltage drop so shouldn't shock you. But something could be wired wrong, or a system doesn't have a solidly grounded neutral, so I wouldn't assume a white wire is safe to touch.

    For the GFI, I think you are using the neutral from the load side of the GFI to the light, but the hot to the light is from another source. This trips the GFI because its hot and neutral current are not the same. That circuit setup wasn't a good idea even without the GFI problem. See this post for a discussion of the 2-wire traveller.

  7. #7
    Join Date
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    Re: explain how neutral works

    Ronson,
    i would still like to know how the neutral wire works. have never had anyone give me an explanation that fully satisfied my curiosity. if the neutral is not supposed to be carrying any current as i think my electrical books said
    here are a few drawings.

    Absolute Neutral:



    Neutral carrying unbalance load current:



    Two wire circuit, Grounded conductor is not a Neutral. Same as in a GFCI.:




    when the receptacle is unused, would no current would flow through to the neutral? if so, why does this not trip the gfi at the first of the ckt?
    There would also be no current flowing out the ungrounded condutor.

    Roger

    [ February 24, 2004, 11:34 AM: Message edited by: roger ]
    Moderator

  8. #8

    Re: explain how neutral works

    thanks for replies everybody. will have to run new 14/2 hot to two 3-way switches by back door that were in middle of receptacle run. whoever originally installed 14/2 ran hot for lighting from one receptacle box in middle of run to switches, cutting white neutral short on both ends and using only black hot. this is part of reason no current was passing back through gfi but it still might have been a problem since 14/2 was used as travelers and neutral would have had to have been picked up from original hot 14/2 run to light fixture to begin ckt. might not be much of a problem to run new hot to switches but there is a 3' duct running from one end of house to the other end right up against where rafters & joists meet. will have to crawl around one end of duct & then crawl another 30 feet to top of switches. ain't looking forward to that.

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