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Thread: Question on Grounding of an Antenna System Installation

  1. #1
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    Question on Grounding of an Antenna System Installation

    Please see the attached diagram. I am curious if this diagram is compliant with 810.21(F)(1) assuming there is an IBT. I am also not very confident that this doesn't create a ground loop by creating multiple paths to the ground system.

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  2. #2
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    Answer 1: Don't think it matters any. There should be no current flow into the earth anyway under normal circumstances.

    Answer 2: Not compliant. But does it really matter.
    Bob

  3. #3
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    I thought that as long as your ground rods are bonded to the entry ground rod, the above photo is correct. At least, that is what is being shown to many of us in Amatuer Radio and Satelitte communities... plus we have been told to try to use #6 wire as much as possible... but I could be wrong, as I am still learning wiring regulations even though so many years of ham radio and other stuff...

  4. #4
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    Quote Originally Posted by joshaven
    I am curious if this diagram is compliant with 810.21(F)(1) assuming there is an IBT.
    810.21(F)(1)In Buildings or Structures with an Intersystem Bonding Termination.
    If the building or structure served has an intersystem bonding termination as required by
    250.94, the bonding conductor shall be connected to the intersystem bonding termination.
    So obviously it's not. The IBT would be on the side of the building with the service. To be compliant, all one has to do is connect the #6 from your ground rod to the IBT instead of the service grounding electrode as shown.

    I don't see any reason to be concerned about a ground loop.

    -Hal

  5. #5
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    The installation in the picture is identical to what is permitted for communications systems by the exception to 800.100(A)(4). I know we are not talking about an Article 800 installation here, but the principle is the same for this installation.
    Don, Illinois
    (All code citations are 2017 unless otherwise noted)

  6. #6
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    I agree that it really doesn't matter. But 810.21(F)(1) seems to require connection to the Intersystem Bonding Termination block when one has been provided instead of the service grounding electrode.

    They just haven't gotten around to changing the Art 800 requirements to reflect the same thing. Also could be that 800 encompasses a lot of commercial installations which are engineered and where you won't find an IBT.

    -Hal

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