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# Ground fault current on neutral resistor

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1.  Junior Member Pro Subscriber
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Reputation ## 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?  Reply With Quote

2. Originally Posted by MrBolt 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?  Reply With Quote

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Reputation       Originally Posted by MrBolt 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.  Reply With Quote

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Reputation  Originally Posted by SecondGen 4160/12=346.66  Reply With Quote

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Reputation       Originally Posted by MrBolt 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.  Reply With Quote

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

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Reputation   Originally Posted by MrBolt 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  Reply With Quote

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Reputation  Originally Posted by rofo42 The key takeaway here is that it is a wye connected system.

(4160/(root scuare 3))/12=(4160/root scuare 3)/12 = 200.1480 Amp
i used Ohms law V=IR...... I=V/R..... this V is the voltage divided by scuare 3 because is a wye  Reply With Quote

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electrical calculations, electrical theory, neta exam questions, neta level 2, neta level 3, transformers, ttr, turns ratio testing  