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Thread: How To Test Pool/Marina Grounding and Bonding Grid

  1. #1

    How To Test Pool/Marina Grounding and Bonding Grid

    After discussing pool electrical hazards with my neighbors I often hear questions relating to the proper testing of the pool grounding and bonding grids. What test(s) can be conducted to confirm proper grounding/bonding of the pool and is the electrical technician required to provide a document confirming safe conditions other than the testing of the GFCI?
    This subject would also make a good illustration for the "graphic of the day" section of your web site.
    Info very much appreciated.

  2. #2
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    The more they overthink the plumbing, the easier it is to stop up the drain

  3. #3
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    Quote Originally Posted by dkidd View Post

    Must have had an issue with what they recorded because it is no longer available
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



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    It says that it is private. Maybe there is a password.
    The more they overthink the plumbing, the easier it is to stop up the drain

  5. #5
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    Quote Originally Posted by TVH View Post
    After discussing pool electrical hazards with my neighbors I often hear questions relating to the proper testing of the pool grounding and bonding grids. What test(s) can be conducted to confirm proper grounding/bonding of the pool and is the electrical technician required to provide a document confirming safe conditions other than the testing of the GFCI?
    This subject would also make a good illustration for the "graphic of the day" section of your web site.
    Info very much appreciated.
    I don't see how you can "test" it or provide a document confirming it is 'safe".

    I think you can inspect it and make a determination if it meets current NEC requirements and state that the GFCI was tested and found to be functioning.
    Bob

  6. #6
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    With swimming pools the equipotential bonding is fairly simple concept - you bond everything that is conductive so it is all at the same potential. How do you test it to see if bonding jumpers are still intact - I don't know, but generally they will be unless someone did some work that disturbed something.

    Marinas and other similar applications is pretty much impossible to install equipotential bonding. Even if you tried to, where do you stop? There is always a possibility of a voltage gradient at the boundary of where you installed it.

  7. #7
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    One of the methods that Mike used was to measure the voltage between the service grounding electrode and "remote earth" (that is earth outside the influence of any grounding electrode or grounded object, often defined as being at least 50' from any such object). Then, leaving the remote earth connection in place, he would look for the same voltage on all of the bonded pool items. If that voltage is all the same, then the bonding is complete as everything has been energized to the voltage of the electrical grounding system. One issue with this is that part of the voltage you measure between the grounding electrode and the remote earth connection is the voltage drop on the service neutral between the utility transformer and the main bonding jumper. Also, where the primary of the utility transformer is connected line to neutral, you will have voltage from the voltage drop on the primary neutral. Load changes while you are testing will change the neutral to earth voltage. One way to compensate for that would be to use two meters and two people, always looking for the meters to read the same voltage.
    Don, Illinois
    Ego is the anesthesia that deadens the pain of stupidity. Dr. Rick Rigsby
    (All code citations are 2017 unless otherwise noted)

  8. #8
    Is there a video on this important subject? I did a google search on the subject and found this article: http://aquamagazine.com/builder/how-...ding-grid.html
    Would appreciate subject matter experts comments on the article and correctness of the test method.
    Last edited by TVH; 06-28-17 at 10:11 AM.

  9. #9
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    Mike Holt had a video but it sounds like the link didn't work or the video was taken down.

    Don described part of how Mike checked the bonding. The other part was just a simple continuity check of all the bonded items including the concrete around the pool. He also checked continuity at/in the water to assure it was bonded.
    If you aim at nothing, you will hit it every time!

  10. #10
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    Little Bill contacted Mike and here is his response about the video that was taken down

    It was removed because it was not totally complete… I need to add additional video on checking ‘resistance.’ I should have this done by next week.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



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