grounded or grounding wire to service

[farmantenna]

a friend installed a 600amp 480vac 3ph service from a 277/480 Y xfmr using the engineered plan provided. This building has no 277 vac equipment but just 480 motors. He installed a #1 GREEN wire in each parallel pipe with 3 350kcmil CU per. I commented that I think it should be a grounded wire(white) minimum size wire of 1/0 or 2/0 CU. That's how Im interpreting 250.

he also said he got a transformer specfied by plan that changes the 480 3phase to 120/208 single phase for a small panel. I commented ,"really, how does that work?" "How can that work?"

 

[augie47]

I would agree with you, a 1/0 Cu White is required due to parallel conductors,

There is no problem with him connecting a single phase transformer to a 3 phase system but a 120/208 single phase transformer would be a rare bird. My money would be on it being 3 phase 208 or single phase 240/120
"220, 221 whatever it takes"

 

[farmantenna]

no, no. he said a 3 ph transformer that converts to 120/208 single phase. His words. I was confused. How does a 3 phase primary magnetic field induce voltages into a single phase 120/208 winding? Well, it doesnt. It's a 480v 2 wire primary to 120/208v 3 wire secondary.

 

[texie]

a friend installed a 600amp 480vac 3ph service from a 277/480 Y xfmr using the engineered plan provided. This building has no 277 vac equipment but just 480 motors. He installed a #1 GREEN wire in each parallel pipe with 3 350kcmil CU per. I commented that I think it should be a grounded wire(white) minimum size wire of 1/0 or 2/0 CU. That's how Im interpreting 250.

he also said he got a transformer specfied by plan that changes the 480 3phase to 120/208 single phase for a small panel. I commented ,"really, how does that work?" "How can that work?"

As you said, the conductor in question is a grounded service conductor, not an EGC and as such should be white or gray sized according to 250.24 and 250.102. As augie47 stated, in this case 1/0 CU would be the minimum in each raceway.
As for the xformer, there is obviously some misunderstanding.