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Ground fault current on neutral resistor

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  1. MrBolt is offline Junior Member Pro Subscriber
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    Ground fault current on neutral resistor

    A given 4160V 3-phase wye connected system is grounded by a 12 ohm resistor, what would the ground fault current be limited to? the Answer is 200A but I don't understand how?

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    Quote Originally Posted by MrBolt View Post
    A given 4160V 3-phase wye connected system is grounded by a 12 ohm resistor, what would the ground fault current be limited to? the Answer is 200A but I don't understand how?
    What was your answer and why?

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    Quote Originally Posted by MrBolt View Post
    A given 4160V 3-phase wye connected system is grounded by a 12 ohm resistor, what would the ground fault current be limited to? the Answer is 200A but I don't understand how?
    The key takeaway here is that it is a wye connected system.

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    Quote Originally Posted by SecondGen View Post
    What was your answer and why?
    4160/12=346.66

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    Quote Originally Posted by MrBolt View Post
    4160/12=346.66
    That would be correct if it was a delta system. In a wye, you must divide by the square root of three and then your resistor.

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    Quote Originally Posted by MrBolt View Post
    4160/12=346.66
    As others have stated, the key is to use phase to ground voltage.

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    Quote Originally Posted by MrBolt View Post
    A given 4160V 3-phase wye connected system is grounded by a 12 ohm resistor, what would the ground fault current be limited to? the Answer is 200A but I don't understand how?
    4160/1.732=2401
    2401/12=200

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