Controles

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 asingle 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.

250.2 Bonding Jumper, Supply Side (New)
This new definition applies to bonding jumpers on the supply side of services or separately derived systems. The new term supply-sidebonding jumper has been incorporated within Sections 250.30, 250.102, and others to provide clarification for sizing equipment bonding jumpers installed on the supply side of a service or separately derived system. The revision should promote more accurate application of Tables 250.66 and 250.122 for sizing supply-side bonding jumpers.

Article 100 Grounding Conductor (Deleted)

The definition ofgrounding conductor was deleted, since it is unnecessary to have two defined terms that describe the same component of the grounding system. The term grounding electrode conductor applies more accurately in instances where the term grounding conductor was previously used. Revisions have been made to articles 250, 770, and the Chapter 8 articles accordingly, to replace the term grounding conductorwith the term grounding electrode conductor or the term bonding conductor, depending on which is appropriate for the particular rule.

Article 100 Separately Derived System (Revision)

The definition of separately derived system was revised to clarify what constitutes a separate system, specifically in relation to the direct connection between system circuit conductors. The revised secondsentence now clarifies that, although there can be connections between equipment grounding conductors or bonding conductors, the circuit conductors of other systems are not directly connected together other than through metal enclosures, earth, metallic raceways, or equipment grounding conductors. This is often the case for transformer separately derived systems having a primary and a groundedsecondary.Read More

Michael Johnston is NECA's executive director of standards and safety. Mike is a certified master electrical inspector through IAEI and ICC and has worked as an electrical inspector and electrical inspection field supervisor for the City of Phoenix, AZ. Mike achieved a BS in Business Management from the University of Phoenix. He served on NEC CMP-5 in the 2002, 2005, and chair ofCMP-5 representing NECA for the 2011 NEC cycle. Mike currently chairs the NEC Technical Correlating Committee. Among his responsibilities for managing the codes, standards, and safety functions for NECA, Mike is secretary of the NECA Codes and Standards Committee. Mike is a member of the IBEW and has experience as an electrical journeyman wireman, foreman and project superintendant. Johnston is anactive member of IAEI, NFPA, ASSE, the NFPA Electrical Section, Education Section, the UL Electrical Council, and National Safety Council.

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 connectedto 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.

250.2 Bonding Jumper, Supply Side...