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# Ground fault current on neutral resistor

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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?

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?

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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.

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Originally Posted by SecondGen
4160/12=346.66

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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.

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

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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

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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

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