Single Phase Transformer Grounding

[KB8020]

I have - 7000kva transformers 208v single phase step down to 42v single phase for a heater. no neutral.
on the secondary side is 167 amps with #2 high temp srml wire and #4 for the ground.
WHAT DO I NEED TO DO FOR PROPER GROUNDING if the primary is feed from a 2pole 50amp breaker indoors then ran thru a SCR.
DO i need to upsize the primary ground to handle the secondary.

 

[don_resqcapt19]

250.20(A) requires the secondary of this system to be grounded. 250.30 requires a connection to a grounding electrode and a system bonding jumper. 250.121 (2011 code) says you can't use an equipment grounding conductor as a grounding electrode conductor so you can't use the ground run with the primary.

 

[Besoeker]

I have - 7000kva transformers 208v single phase step down to 42v single phase for a heater. no neutral.
on the secondary side is 167 amps with #2 high temp srml wire and #4 for the ground.

I think it might be 7000VA or 7kVA.

WHAT DO I NEED TO DO FOR PROPER GROUNDING if the primary is feed from a 2pole 50amp breaker indoors then ran thru a SCR.
DO i need to upsize the primary ground to handle the secondary.

SCRs on the primary would give me cause for concern.