Electrical Troubleshooting Quiz — April 5, 2022

Your boss sent you to the ABC firm to resolve its complaint. A month before the spring shutdown, it hired a contract thermographer to conduct scans on panels and switchboards. The images and written report identified 62 potentially bad connections. During the shutdown, it addressed all 62 connections.

The original thermographer was out of state on a big project, so ABC contacted your firm and one of your two Level II thermographers repeated those earlier scans.

The complaint is there are now 97 potentially bad connections, including 59 of the 62 identified in the previous scan. ABC has no confidence in the results and wants its money back.

How should you proceed in resolving this?

Show the customer you care and listen

The first thing you have to do in customer relations is listening — no interruptions, no explanations, no arguments. As you listen, take notes on the major points being made. When the customer is done stating his case, thank him for the information and say you have some questions.

Note that the above process is not part of the technical solution; it’s part of showing the customer that his viewpoint matters to you. Before your visit, you should already have looked at your thermographer’s images and written report. You already know the original thermographer had essentially the same information because the crux of the complaint is the overlap of 58 potentially bad connections.

Ask the customer how those connections were addressed. If you hear the word “tighten” mentioned, you have your explanation for the results. There is no other explanation that is even somewhat likely.

The correct way to address potentially bad connections is to measure the ohmic value across them to identify which ones are bad. Then for the bad ones:

• Disassemble.
• Clean the connection mating surfaces.
• Replace the hardware (bolts and locking devices).
• Assemble using the correct torque value.

The more typical way to address potentially bad connections is to go in and tighten them all. This method has many flaws, such as:

• It does not confine itself to only the bad connections, so even good ones are tightened.
• Tightening only rarely improves a connection and usually makes it worse.
• Blindly tightening a bolted connection will almost certainly stretch the bolt too far and reduce its clamping power dramatically.
• Tightening does not remove corrosion or other contaminants from the mating surfaces, so the same contact resistance stays.
• This method essentially involves re-using fasteners after they have already been stretched to or past their elastic limit. Mechanically, that is a failure.
• A lot of labor is used to destroy perfectly good connections while failing even to identify the ones that need repair.

Don’t waste time going into detail about how the customer messed up. Instead, explain the correct procedure and ask if there could be an opportunity to perform it on a few of the 62 connections they addressed. Preferably, repair one that is next to one they merely tightened, but that looks bad in the latest thermographic image. A new thermographic image will show these side by side; the difference will be clear. Once the customer sees the correctly repaired connection does not look hot next to the connection that still does, the company will change its mind about a refund.