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250.53A and new to correcting faulty building ground systems-Thx!

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    250.53A and new to correcting faulty building ground systems-Thx!

    Hey thx for reading!

    My understanding of 250 53 A is that

    If it’s only one electrode then it needs to be 25ohms or less.

    SO if your chosen primary electrode is greater then 25ohms and u cant easily measure then 2nd, what do you do?

    I'd like to by an 800 dollar GEP rig but would prefer not to yet.

    This article I read in ECM web mag
    http://www.ecmweb.com/content/who-cares-about-25-ohms-or-less
    and the last hr I just spent reading article 250 up to 250.80 seem to suggest that multiple grounding electrodes that meet code are how it's done if you cant measure the resistance of one Grounding Electrode.


    If there’s one ground electrode w resistance > 25 ohms how many supplementals do you need and I believe the answer is one.

    Thx so much

    #2
    The code only requires a single electrode in most cases however you are required to have a second electrode if one of the electrodes is a water pipe. If one of your electrodes is a ground rod and you do not have less than 25 ohms you're required to put in a second rod. There is no requirement to actually meet 25 ohms if you have two rods. So your best bet if you are using ground rods is just put a second rod and be done with it.
    Bob

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      #3
      As Bob said, simply add a rod and go to your next job.

      Roger
      Moderator

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        #4
        Originally posted by docj67 View Post
        Hey thx for reading!

        My understanding of 250 53 A is that

        If it’s only one electrode then it needs to be 25ohms or less.

        SO if your chosen primary electrode is greater then 25ohms and u cant easily measure then 2nd, what do you do?

        I'd like to by an 800 dollar GEP rig but would prefer not to yet.

        This article I read in ECM web mag
        http://www.ecmweb.com/content/who-cares-about-25-ohms-or-less
        and the last hr I just spent reading article 250 up to 250.80 seem to suggest that multiple grounding electrodes that meet code are how it's done if you cant measure the resistance of one Grounding Electrode.


        If there’s one ground electrode w resistance > 25 ohms how many supplementals do you need and I believe the answer is one.

        Thx so much
        The 25 ohms or less applies only to the electrodes in the section you've stated 250.53(A) which are rod, pipe and plate electrodes. So as Bob and Roger have said just install two electrodes and forget about testing. If you had a CEE then that would be the only electrode required if it's the only one present.
        Rob

        Moderator

        All responses based on the 2014 NEC unless otherwise noted

        Comment


          #5
          Thx so much guys! Grateful for this forum

          Thx so much guys! Grateful for this forum.

          Originally posted by infinity View Post
          The 25 ohms or less applies only to the electrodes in the section you've stated 250.53(A) which are rod, pipe and plate electrodes. So as Bob and Roger have said just install two electrodes and forget about testing. If you had a CEE then that would be the only electrode required if it's the only one present.

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