I certainly would not switch the EGC. I'm just wondering if there might be issues with having 2 or more parallel EGCs. For example, existing conduit is filled with power from house to garage. If adding the generator at garage to feed to the house (whether generator to garage power takes it directly at the garage, or lets it loop first through the house), does one need to abandon/replace the existing conduit, so that the new conductors, as well as the old (though possibly replaced to physically new), can both be run immediately adjacent to a single common EGC. Or can they be separate with duplicate EGC which might be interconnected on both ends forming its own loop (but in any case, any fault currents would certainly run parallel in both conduits if set up like that ... plus over the cable TV coax, wtx, so that's not really a solved issue)?

It seems to me (I didn't try to look this up) the correct way is one conduit big enough for all this, 3 conductors for house to garage, 3 conductors for garage/generator to house, and 1 EGC (change 3 to 4 for 3ph where that might happen to be).

Also, it seems to me that if multiple EGC connected together at each end is not a good thing, then letting TV coax shield be wired the same way is also not a good thing.

Last edited by pdh; 02/04/12 12:56 PM. Reason: Also, ...