The issue is conceptual.

One can have a number of SDS's 'reground' within a structure, or 250.32 a 3-wire feeder to an outbuilding close to the 'supply' building.

Either/Or ends up with gauss or stray voltage bettween the two methods

Then the PQ guys get the biz..... [Linked Image]

This is due to the NEC's stance that the earth is not a conductor, despite other international methods