Electrical Troubleshooting Quiz — August 6, 2019
An operator reported a smell “like something electrical is burning” coming from the power cabinet of the equipment she operates.
An electrician investigated, but he could not smell anything. He opened the cabinet and did a temperature survey with a handheld infrared (IR) thermometer. No hot spots. The wiring all looked good. He was at a loss to explain the reported smell. After some time, he asked the operator if she could still smell that odor, and she said no. But a couple of weeks later, she reported it again.
So, another electrician investigated. As with his predecessor, he could not smell anything. How would you handle this issue at this point?
Some people have a keen sense of smell. She may have been smelling vapor that did not originate in that panel but traveled there through the raceway. It built up enough for this operator to smell it leaking from that cabinet.
Effectively, the first electrician ventilated the cabinet, thus diluting the vapor below the woman's detection threshold. The fact she again detected the odor after two weeks supports this idea.
She may be smelling the results of overheated thermoplastic, as conductor insulation degrades from being chronically overheated but not overheated enough to simply melt away.
Finding the source is probably not the needle in the haystack problem it appears to be. Start at the feeder that supplies this circuit and look for discolored conductors. This situation existed at a plant because of running differently sized parallel conductors.
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.