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Ground Fault Exemptions

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  1. Kalbi_Rob's Avatar
    Kalbi_Rob is offline Experienced Member Pro Subscriber
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    Ground Fault Exemptions

    So, a few years ago I got into an argument with Eaton rep about a solar site requiring ground fault on the 4000A breaker downstream a 12kV Delta/480V Wye transformer but 3W breaker. He convinced the customer that it was not required because the breaker was a three wire system. I came behind, and he pulled out the below website with ground fault exemptions, which I had never seen. It does give the general exemptions to NEC 230.95, 215.10, and 240.13, but he failed to realize the transformer was a solidly grounded 480/277V Wye because only 3 phases were landed on the breaker.

    My question is, has anybody ever seen these exemptions used to avoid installing ground fault protection?

    http://www.cooperindustries.com/cont...ements_GFP.pdf

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    Just read through those sections in my handbook. The one exception in 230.95 "continuous industrial process" wouldn't fly, 215.10 exception No.1 is the same wording. 215.10 exception No.2 basically says if there is upstream GFP then it isn't needed on the feeder I think. 240.13 shouldn't apply either.

    Was it Eaton gear? Maybe he said that because they didn't put the correct main breaker in.

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    Kalbi_Rob is offline Experienced Member Pro Subscriber
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    Quote Originally Posted by phasor View Post
    Just read through those sections in my handbook. The one exception in 230.95 "continuous industrial process" wouldn't fly, 215.10 exception No.1 is the same wording. 215.10 exception No.2 basically says if there is upstream GFP then it isn't needed on the feeder I think. 240.13 shouldn't apply either.

    Was it Eaton gear? Maybe he said that because they didn't put the correct main breaker in.
    Yes it was Eaton gear, and it originally had a trip unit with ground fault. They replaced it between my walkthrough and actual testing the next day. He stated that it was a three phase system so it didn't need ground fault, and less than 6 disconnects. What he failed to realize was they had a solidly grounded Wye with no neutral pulled on the upstream transformer and 8 disconnect loads. They re-installed the ground fault trip unit after I pointed out these exemptions did not apply. Of course only after having my PE for the coordination study and the onsite inspector stepping in to back me up.

    Needless to say, I've rarely found ground faults that fall within these exemptions outside of the main NEC requirement. I was just curious if anybody ever came across the 5 main exemptions not stated in the initial requirement established by the NEC.

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