If you are installing a GEC at a second building on a service do you still size to 250.66 on the service conductors or do you base it on the feeder?

The size of the feeder to the building in question.

Check out 250.32(E) 2005

OK I was just concerned about what a "supply conductor" really meant. I assumed it was the feeder but I wanted to hear it ... as a sanity check. Thanks

I agree it could be clearer.......