Electrical Troubleshooting Quiz — March 17, 2020
Over the past three years, the plant has had seven unplanned shutdowns due to cable failures. With each incidence, maintenance also tests the adjacent cables and replaces those, if necessary.
The plant engineer noticed that about a dozen of the replaced cables have failed during this period — three of them, four times.
The unplanned shutdowns have been very disruptive to production, mostly due to the time it takes to replace the failed cables. So, there is a lot of pressure from upper management to stop the failures.
The plant engineer recently received approval to install a surge protection system at the service and has asked you if there’s anything else to consider.
Why is maintenance testing the cables?
There is much more to cable testing than simply performing an insulation resistance test. The plant engineer should hire a qualified electrical testing firm to properly assess cable condition during a shutdown scheduled for this purpose. If maintenance is also installing cables, how do you know they are qualified and aren’t damaging the cables?
It’s nice to finally provide surge protection at the entrance, but cable-damaging power anomalies typically originate inside the facility. This plant needs a surge protection system designed for its power distribution system. It’s going to be multi-tier, with different levels of protection at the different voltage levels.
Identify large motors that start across the line and consider soft start or VFD control to prevent the cable-damaging effects these motors have.
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.