HV Bushing grounding conductor Sizing (Potential Transformer)

[adityalagudu3291]

We have 3 phase potential transformer, HV H1 terminal: 34.5kV, conductor 1C, 4/0 AAC. What should be the grounding conductor size on the H2 terminal? Any code reference? PT size 1000VA, Secondary voltage 115/67.08 V

 

[LarryFine]

First, it's a grounded conductor. Second, same size as used on the H1s?

 

[adityalagudu3291]

First, it's a grounded conductor. Second, same size as used on the H1s?

Yes, same size has been used on all the H1s, which is 4/0 AAC

 

[LarryFine]

Yes, same size has been used on all the H1s, which is 4/0 AAC

Each H1 and H2 pair will carry the same current, but 4/0 seems large for a voltage tap.

 

[adityalagudu3291]

Each H1 and H2 pair will carry the same current, but 4/0 seems large for a voltage tap.

I assume based NEC 250.102(C)(1), for 4/0 AAC H1 terminal, 1/0 grounded conductor for H2 terminal will be sufficient.