Bonding connections are often overlooked in maintenance programs. Many maintenance electricians are confused as to what a bonding connection is, and that is partly due to language issues in the trade.
We see, for example, a “grounding” bus, lug, bar, or terminal in an equipment enclosure. However, it is actually a bonding connection. A grounding connection is a connection to earth (NEC Art. 100 definition). When you bond, you create a low-impedance path back to the source; it’s completely metallic, no dirt involved. The equipment grounding conductor is really a bonding conductor network, even though it ultimately connects to ground at the power source.
Simply put, you ground on the supply side of the service or separately derived source. You bond on the load side.
Those bonding connections are critical for protecting people and equipment from dangerous differences of potential and for overload protection and ground fault protection devices to work properly.
Over time, those connections loosen and/or corrode. A good maintenance program includes testing and inspection of all “grounding” (bonding) connections.
About the Author
Mark Lamendola
Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.
Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.
Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.