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    #16
    Originally posted by cuba_pete View Post
    This is geared towards linemen....
    Yep, that seems to be the one place where that tool would shine: Doing ground checks on rural pole lines. Lots of tests to perform, and you also know there's very unlikely to be any electrode interference.

    Unfortunately, they are marketed as a general purpose electrode tester, when in all likelihood they will be inaccurate on 99% of structure electrodes.

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      #17
      Originally posted by big john View Post
      Yep, that seems to be the one place where that tool would shine: Doing ground checks on rural pole lines. Lots of tests to perform, and you also know there's very unlikely to be any electrode interference.

      Unfortunately, they are marketed as a general purpose electrode tester, when in all likelihood they will be inaccurate on 99% of structure electrodes.
      For situations where they are inaccurate (such as overlapping electrode SOIs) is a standard basic Fall Of Potential test going to be much better?

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        #18
        Originally posted by GoldDigger View Post
        For situations where they are inaccurate (such as overlapping electrode SOIs) is a standard basic Fall Of Potential test going to be much better?
        Definitely: The results of a clamp on test are based on blind faith: Unless you compare them to a FOP test you may not even realize you have interference. Whereas the FOP test is self-proving based on the plot of the results.

        And if the FOP fails, there are at least some options that may yield acceptable results: Change direction, increase distance, try Tagg-slope calculations. None of that exists for a clamp meter.

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          #19
          The clamp on resistance tester can not be used for the checking of ground resistance in OP's case due to presence of ground ring. But it may be used for checking the ground continuity resistance, where the issue is IMHO.

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            #20
            Originally posted by big john View Post
            Definitely: The results of a clamp on test are based on blind faith: Unless you compare them to a FOP test you may not even realize you have interference. Whereas the FOP test is self-proving based on the plot of the results....
            Which assumes that the user of an integrated three point FOP tester actually runs a plot using different middle electrode positions instead of setting that probe at the "correct" distance and just reading the meter which pre-calculates the earth impedance based on an ideal voltage versus position plot.
            It has the capability to be self-proving, but what I referred to as the basic test (perhaps a misnomer) does not do this.

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              #21
              I have yet to see a job spec that does not specify a FOP test if they want the GES tested.

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                #22
                Originally posted by GoldDigger View Post
                Which assumes that the user of an integrated three point FOP tester actually runs a plot using different middle electrode positions instead of setting that probe at the "correct" distance and just reading the meter which pre-calculates the earth impedance based on an ideal voltage versus position plot.
                Well, yeah, any test is fallible when it's done incorrectly. I know it's a common mistake, but I've never seen any literature that suggests only picking the 62% mark, and that's definitely not an IEEE test. Whereas you can do a clamp on test exactly like the instruction manual dictates and still get a wrong result.

                One is a failure of methodology, which is fixable. The other is a failure of equipment, which ain't.

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