Need some guidance please. When installing an electrical distribution system, what is the requirement for grounding the sub-panels? Are we required to drive a ground rod for each sub-panel? I think not. I've always been taught/told to bond the sub-panels to the service entrance using a grounding conductor sized for the sub-panel's feeder circuit, and the service entrance is connected to the ground rod, but I can't find the reference in the 2002 NEC. Is there one?

Any help is appreciated.

thanx