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Thread: current on a grounding electrode conductor

  1. #1
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    Oct 2003
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    current on a grounding electrode conductor

    Could you please let me know what is acceptable current on the grounded electrode conductor for a new 120/240V Single phase system.
    Thanks B.Y.

  2. #2
    Join Date
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    Re: current on a grounding electrode conductor

    That is a hard question to answer. Typically less than 1-amp. If you have an extremely low ground electrode system (GES) impedance, and a lot of unbalanced load current on the neutral (grounded circuit conductor) it can approach 1-amp. There will always be some current, if not you have probably got a different problem like a poor connection in the GEC, MBJ, or extremely poor GES.

    On the other hand if there is a problem with the neutral conductor (grounded circuit conductor) between the transformer and your service, like poor connections, the GEC current will be high.

    Look at the voltage between each phase to the grounded circuit conductor (neutral). It should be balanced or approx the same voltage from each leg to neutral (grounded circuit conductor)

    Edit made for Charlie B.

    [ October 10, 2003, 01:15 PM: Message edited by: dereckbc ]

  3. #3
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    Seattle, WA
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    Re: current on a grounding electrode conductor

    (I see Dereck has beaten me to the draw. But I'll post my response anyway.)

    I hope you won’t mind my being picky here, but you need to restate your question. You have used words in a not-precise-enough manner. Here’s the problem:

    The “grounded” conductor is also called the neutral.

    The “equipment GROUNDING conductor” is also called the ground.

    Which do you mean? (I think you mean the later, and so, apparently, did Dereck.) Also, can you give us an idea of why you are asking? It might help us understand your needs, and help us provide you with a useful answer.
    Charles E. Beck, P.E., Seattle
    Comments based on 2014 NEC unless otherwise noted.

  4. #4
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    Oct 2003
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    7

    Re: current on a grounding electrode conductor

    Thanks for the help. As for the situation I have driven an 8' ground rod for the 200A 120/240V single phase service and installed a #2 grounding conductor to supplement the coldwater pipe ground. I am seeing anywhere from 2.0A to 5.0A of current on this conductor. Line to neutral voltage for Phases are 123.7V and 122.7V and that varies at different times of the day. I am suspecting that the neutral is giving me the problem but would appreciate any of your info.
    Thanks again,
    B.Y.

  5. #5
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    Re: current on a grounding electrode conductor

    Are you measuring the current on the conductor going to the water pipe or ground rod?

    If you see the current on the water pipe bond, have a metallic water service, and you share a transformer with your neighbors, you are probable seeing a return on the water pipe which is normal

    [ October 10, 2003, 01:29 PM: Message edited by: dereckbc ]

  6. #6
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    Re: current on a grounding electrode conductor

    #2Conductor going to the ground rod.
    B.Y.

  7. #7
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    Re: current on a grounding electrode conductor

    Is your water service PVC?

  8. #8
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    Oct 2003
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    7

    Re: current on a grounding electrode conductor

    No. It is 1" copper line out to the curb.
    B.Y.

  9. #9
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    3,172

    Re: current on a grounding electrode conductor

    Does this No.#2 run to the rod then to the water pipe? or are you feeding each electrode separately?

    Have you made a current measurement with the service turned off?

  10. #10
    Join Date
    Oct 2003
    Posts
    7

    Re: current on a grounding electrode conductor

    #2 to the ground rod only the coldwater pipe is a #4 and the current on it is .7A.

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