On 2008-12-23, Steve Barker wrote:

being in the same building brings up another question i had the
other day. I've got a sub right next to the main panel ( to add
spots) . Does it still have to have the ground and neutral seperate
and fed with 4 wires in this situation?

Yes. In any building, there is to be only one point in an electrical
system in which the ground and neutral (grounding system and grounded
conductor) are interconnected**. That point is at the main
disconnect; anywhere downstream of it the grounds and neutrals are to
be kept separate.

Cheers, Wayne

** If you have, for example, a generator in which the transfer switch
switches the neutral conductor, then that is called a separately
derived system (SDS), and as a separate electrical system it has
its own ground-neutral bond.