Unsafe Conditions When Running Raceway — Part 4
Bonding errors can prove fatal. If your raceway job involves metallic raceway (e.g., EMT, IMC, etc.), then visually inspect and electrically test for bonding violations.
On green construction, bonding errors usually are not a problem. At an existing facility, assume they exist until you can prove otherwise. Adopting this strategy probably saved the lives of two electricians who worked for an industrial electrical services firm. They went to a plant that was new on the client roster. They found dangerous voltage on some existing EMT installations that were directly relevant to their project. Whoever installed the 277V lighting used the raceway as the neutral instead of as the equipment grounding conductor.
If you see ground rods on the load side, then expect dangerous differences of potential to exist between metallic objects. Grounding does not eliminate these, only bonding can. You will have to supply the missing bonding jumpers. Discuss with the project manager whether to install permanent or temporary bonding jumpers. Permanent ones should require customer payment; temporary ones could provide a liability once removed.
About the Author
Mark LamendolaMark 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.