Photo credit: PJ66431470/iStock/Thinkstock
Ecmweb 17757 Thinkstockphotos 487684402screwterminalswebversion 0
Ecmweb 17757 Thinkstockphotos 487684402screwterminalswebversion 0
Ecmweb 17757 Thinkstockphotos 487684402screwterminalswebversion 0
Ecmweb 17757 Thinkstockphotos 487684402screwterminalswebversion 0
Ecmweb 17757 Thinkstockphotos 487684402screwterminalswebversion 0

Check Those Screw Terminal Terminations

Jan. 17, 2018
In a plant with thousands of terminal connections, you can save significant amounts of energy when you make sure your connections are good.

Most energy savings efforts focus on big items such as lighting and motors. Although that focus may produce spectacular results, you also must keep in mind that little things add up, too. The phrase “death by 1,000 cuts” is a good one to keep in mind when looking for energy savings.

How many screw terminal terminations do you have in your plant? Each of those contains multiple points of potential energy waste:

  • Spade lug improperly crimped.
  • Metal interfaces not clean.
  • Termination incorrectly torqued.

If you have all of these problems to a minor degree on only one termination, it might not be worth making the effort to even find that rogue terminal. But these problems are very common. If you have one or more of them on 1,000 terminals throughout the facility, the problem is now several orders of magnitude larger. You’ve got a real problem; it’s just dispersed across many points.

Having a qualified thermographer conduct a thermographic survey, analyze the results, and prepare a report is the most efficient way to get started on solving this problem. The typical solution, however, does not solve the symptoms or the causes of these tiny energy vampires. The typical solution is to just tighten all of the connections.

Some that were loose will probably pass the subsequent thermographic analysis. But why were they loose? What steps did you take to ensure that they now are clean and properly assembled so they don’t come loose again?

Some that were not loose but still showed up as suspect will show up as suspect again. Tightening them, in fact, is likely to exceed their torque limit so that in addition to having a dirty interface or bad crimp on the lug, they will have a loose terminal connection.

The thermographic analysis doesn’t show you which screws are loose. It shows you where a given connection produces more heat than similar connections.

You can use a low-ohm tester to examine each connection more closely and take “before” condition data before repairing suspect connections. This step is optional, but advisable because it will reveal patterns and also eliminate repairing connections that weren’t faulty to begin with.

To repair a connection, replace any locking hardware (e.g., split ring washer), clean the mating surfaces, and tighten to the recommended torque using a calibrated torque screwdriver or wrench. Then measure the connection with your low-ohm tester. This measurement, like the other one, is optional but advisable. It gives you “as left” condition data and a baseline measurement for the future.

A plant with thousands of terminal connections can save significant energy when you make sure that those are good connections, especially if those connections are in air-conditioned spaces. This effort also increases reliability, regardless of where the connections are situated.

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.

Voice your opinion!

To join the conversation, and become an exclusive member of EC&M, create an account today!

Sponsored Recommendations

Electrical Conduit Comparison Chart

CHAMPION FIBERGLASS electrical conduit is a lightweight, durable option that provides lasting savings when compared to other materials. Compare electrical conduit types including...

Don't Let Burn-Through Threaten Another Data Center or Utility Project

Get the No Burn-Through Elbow eGuide to learn many reasons why Champion Fiberglass elbows will enhance your data center and utility projects today.

Considerations for Direct Burial Conduit

Installation type plays a key role in the type of conduit selected for electrical systems in industrial construction projects. Above ground, below ground, direct buried, encased...

How to Calculate Labor Costs

Most important to accurately estimating labor costs is knowing the approximate hours required for project completion. Learn how to calculate electrical labor cost.