ECN Forum Forums Code Related Discussion NEC & other Code issues bonding a 37.5 single phase transformer

I'm installing a 480/120/240 single phase transformer to feed a 150 amp panel 120/240 in a remote wood building which is a air compressor room no steel to bond to 200' away from the main service. Do I need to run a 3/0 from the building steel of the plant which the main service is grounded to to bond the transformer or is two ground rods all I need.

I think all you "need" is two 8' ground rods on a 6 gauge GEC. You could make that better with longer rods or a ground ring. I am not sure where a plate ranks because I have never seen one or heard much about them.
I know of no rule that requires running a 250.66 GEC back to the other building. At 200', voltage drop will need to be in your calculations tho

In the past I think a ground testing company made me go back to the grid and I had two rods driven but I'm not sure.