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Thread: Ohms on a branch circuit

  1. #1
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    Ohms on a branch circuit

    If I were to check ohms from neutral to ground on a plug, what should it read ?


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  2. #2
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    Quote Originally Posted by electricalist View Post
    If I were to check ohms from neutral to ground on a plug, what should it read ?


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    A receptacle or male cord end?

    Define plug.
    Tom
    TBLO

  3. #3
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    Sorry a receptacle.


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  4. #4
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    I'll answer your question with a question. Considering that the neutral and ground are connected together at the main panel, what would you expect to read?

    -Hal

  5. #5
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    Unless the receptacle was the only one on the circuit, I would think return current on the neutral from other receptacles would mess up your ohm measurement,
    Ron

  6. #6
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    Quote Originally Posted by electricalist View Post
    If I were to check ohms from neutral to ground on a plug, what should it read ?


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    I would expect not more than a few ohms.
    Si hoc legere scis nimium eruditionis habes.

  7. #7
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    Quote Originally Posted by ron View Post
    Unless the receptacle was the only one on the circuit, I would think return current on the neutral from other receptacles would mess up your ohm measurement,
    The first step before taking an ohm measurement should be to check whether there is a voltage difference between the two points.
    To some extent the existence of an AC voltage difference may not necessarily affect the result of a DC ohm check. It depends on the test circuit design.

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  8. #8
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    I would guess less than 1Ω.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  9. #9
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    We have a customer who bought a " plug" tester made by the people who make green tools. Not greenlee. He says if it detects 10 ohms or more it lights up red.
    I checked at the panel from neutral to ground ( all bonded at the first disconnect) it read 0. I checked at the outlets he checked and it read .01.
    Now he feels like he just got a bad tester and is gonna return it for another one.
    All bs aside I don't know enough info to give him a real answer or how to honestly explain what it should read safely.


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  10. #10
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    Quote Originally Posted by electricalist View Post
    We have a customer who bought a " plug" tester made by the people who make green tools. Not greenlee. He says if it detects 10 ohms or more it lights up red.
    I checked at the panel from neutral to ground ( all bonded at the first disconnect) it read 0. I checked at the outlets he checked and it read .01.
    Now he feels like he just got a bad tester and is gonna return it for another one.
    All bs aside I don't know enough info to give him a real answer or how to honestly explain what it should read safely.


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    I would think it should "red" well before 10 ohms. Pure waste of pennies.
    Tom
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