Grounding for a 3 phase 4 wire 75kVA transformer

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fandi

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Electrical Engineer
Hello All,
This is a downstream 480/277V Delta -208/120V Wye 75kVA transformer. Water pipe is PVC and not metal. No building steel around. How do we ground the transformer, for example drive a separate rod?
Thank you.
 
Yes, a pair of rods is compliant when there are no other qualifying electrodes.

Are you sure the incoming water supply is non-metallic?
 
The building is required to have some type of GES so you would connect to that whatever that may be.
 
I agree with Infinity (Post #4)
The NEC states: in 250.30: (4) Grounding Electrode. The building or structure grounding electrode system shall be used as the grounding electrode for the separately derived system. If located outdoors, the grounding electrode shall be in accordance with 250.30(C)
so investigate the building electrical for that GES and connect to it.
 
augie47 said:
The NEC states: in 250.30: (4) Grounding Electrode. The building or structure grounding electrode system shall be used as the grounding electrode for the separately derived system. If located outdoors, the grounding electrode shall be in accordance with 250.30(C)
so investigate the building electrical for that GES and connect to it.
Click to expand...
I agree, so even if you decided to pound in two ground rods then those would need to be connected to the existing GES anyway.
 
Before there was an exception to drive ground rods if other electrodes weren't readily available.

What if there is not access to the GES anywhere near the new Transformer location?

Why wouldn't an EGC pulled with the primary feed to the Xfmr, or, driving ground rods at the Transformer location still not serve the purpose?

JAP>
 
jap said:
Before there was an exception to drive ground rods if other electrodes weren't readily available.

What if there is not access to the GES anywhere near the new Transformer location?

Why wouldn't an EGC pulled with the primary feed to the Xfmr, or, driving ground rods at the Transformer location still not serve the purpose?

JAP>
Click to expand...
I’m theory I believe it would be no different. I havnt dug into it my self but there are some stipulations about using the EGC and an GEC. Such as being continuous from the electrode?
 
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