Maintenance, Repair & Operations

Symptoms vs. Causes

Aug. 5, 2019

As a rule of thumb, use the "Five Whys" method to make the repair process quicker.

Sometimes, it's hard to tell the difference between a symptom and a cause. This is especially true when you're under the time pressure of performing a repair.

Root cause analysis can prevent recurrence. But how much effort should you put into it? Does every repair tech have the training, time, and aptitude to perform a complicated root cause analysis? (That's a rhetorical question).

Are there some easy rules of thumb that can make the process quicker, even if less precise? Do you need or can you afford total precision in all cases? (Another rhetorical question).

Yes, there are some easy rules of thumb. For example:

Look for what has changed.
Ask the operators.
Use the “Five Whys” method.

What is the “Five Whys” method? Here's an example:

The motor vibrates badly. Why? It spun a bearing. Before replacing the motor, you ask the next question.
Why did it spin a bearing? Looks like arcing damaged the bearings.
Why was there arcing? Undesired current flowed through the motor.
Why did current flow through the motor? The motor wasn't properly bonded.
Why wasn't it? The installers didn't connect it to the EGC. You found the root cause. Now when you replace the motor, you will also connect it to the EGC.

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.