Electrical Troubleshooting Quiz — Dec. 17, 2019
An older area of the plant is now nicknamed “The Twilight Zone” because strange things happen there. Sometimes, lights flicker for several hours and then stop flickering. A fluorescent ballast will fail, and after it's replaced another one will fail. One week, electricians changed out 23 ballasts. Then, the problem mysteriously stopped for several months.
A similar thing happened with motors a few months ago. After a series of failures, motors stopped failing. Some operators complain of feeling their fingers tingle during changeovers, and others don't. Several people have complained of “feeling electricity” while using a water fountain. But even at the same fountain, this problem seems to occur randomly.
How can you determine what's going on? These problems are symptomatic of undesired current taking undesired paths instead of an intended path back to the source. Any load can produce undesired current, but particularly non-linear loads such as those motors and fluorescent ballasts tend to be at fault. Look closely at those non-linear loads for:
- Wiring errors. For example, neutral connected to the equipment grounding conductor (EGC). In one plant, electrical metallic tubing (EMT) was used in place of the neutral for 277V lighting.
- Conductor problems. For example, damaged neutrals. In one plant, neutrals were charred; replacing them with the next size up conductor solved several “mysterious” problems.
- Improper bonding. Ensure all non current-carrying metallic objects of any size are bonded to the EGC. Ground rods won't suffice. How are those water fountains bonded?
Also inspect the entire bonding system, ensuring the EGC isn't broken. Consider jumpering across raceway 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.