The following was from a recent NFPA necplus newsbriefs
Grounding and Bonding Revisions in the 2011 NEC®
Michael Johnston
Grounding and bonding requirements in the National Electrical Code® are not as difficult to understand as many tend to think. The term grounding, as used in the NEC, simply means connected to ground (earth). Bonding simply means connected together. Grounding and bonding are functions that happen simultaneously, often through a single conductor or conductive path. Section 250.4 describes what is intended to be accomplished by grounding and bonding. This article reviews a few of the significant NEC revisions related to grounding and bonding.