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Thread: 250.30(C) - Outdoor SDS Grounding

  1. #1
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    250.30(C) - Outdoor SDS Grounding

    Is 250.30(C) requiring us to connect to the structure served, or establish a GES at the detached structure (at the detached SDS) by, say, driving a ground rod or two?

  2. #2
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    Quote Originally Posted by George Stolz View Post
    Is 250.30(C) requiring us to connect to the structure served, or establish a GES at the detached structure (at the detached SDS) by, say, driving a ground rod or two?
    250.30(C) is for ungrounded systems and it says to connect the GEC to the disconnecting means. To do that, you would have to run from the SDS or make one there.

    Stop it George!
    If you aim at nothing, you will hit it every time!

  3. #3
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    Quote Originally Posted by Little Bill View Post
    250.30(C) is for ungrounded systems...
    Slow down - you're reading 250.32(C), not 250.30(C).

  4. #4
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    I think this new rule is confusing. It requires that you establish a grounding electrode system at the SDS that is located outside, but it does not permit a second connection between the grounded conductor and the earth at the structure served. When I first saw this change I though it would make it just like a utility owned transformer where the grounded conductor is connected to earth both at the transformer and at the structure, I don't any wording that says you can do this with the SDS. This just requires the grounding electrode to be at the outside SDS.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  5. #5
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    Quote Originally Posted by George Stolz View Post
    Slow down - you're reading 250.32(C), not 250.30(C).
    You're right, I'm using a PDF file and when Adobe got updated it messed my search function up.
    Also, this must be in the 2011 as I don't have 250.32(C) in the 2008.
    If you aim at nothing, you will hit it every time!

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