In Episode 28 of “EC&M Tech Talk,” Randy Barnett, a journeyman electrician, inspector, author, trainer, and electrical safety expert, covers the topic of bonding of electrical systems and equipment. Understanding the reasoning behind bonding helps electrical professionals grasp the compliance requirements found in the National Electrical Code.
Beginning with the six definitions relating to “bonded” or “bonding” found in Art. 100 Definitions, Randy discusses the practical side of the terms using electrical components to demonstrate. He presents the need for establishing electrical continuity and conductivity along with explanations to the requirements of Sec. 250.4 to establish an effective ground-fault current path. Without going into the mathematical formula for impedance, he explains the components of impedance and the importance of maintaining low-impedance paths along the equipment grounding conductor back to the source.
Part V of Art. 250, Grounding and Bonding addresses specific requirements for bonding. Bonding of services and of systems over 250V to ground are somewhat similar. Other specifics include use of the table to size the grounded conductor and the various bonding jumpers. Locations for information on the types of equipment grounding conductors and their sizing is also provided.
