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Thread: M.H. Illusrated Guide to Electrical Exam Prep...2011

  1. #1
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    M.H. Illusrated Guide to Electrical Exam Prep...2011

    On page 79, for illustrative purposes, Mike's image and calculation of energy used and a monthly cost in a ground fault condition raises a question for me; Why hasn't the fault cleared?

    The example shows a 120V source, 25 ohms to earth ground fault.

    The first thought that comes to my mind is a faulty circuit breaker. The other is an open EGC or an open neutral. Would like to query other possible causes for this condition.
    Charley

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    Quote Originally Posted by ZCBee View Post
    On page 79, for illustrative purposes, Mike's image and calculation of energy used and a monthly cost in a ground fault condition raises a question for me; Why hasn't the fault cleared?

    The example shows a 120V source, 25 ohms to earth ground fault.

    The first thought that comes to my mind is a faulty circuit breaker. The other is an open EGC or an open neutral. Would like to query other possible causes for this condition.
    Can't see the picture, but according to your numbers, the current is only 4.8 amps. a breaker will hold that for a very long time.

  3. #3
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    Yes, I was thinking of a GFCI protected circuit. I agree, it would pass the 4.8A.
    Charley

  4. #4
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    Even at 6 ohms a 20 amp circuit @ 120V will only have 20 amps on it. It would stay like that for some time.

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