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Electrical Control Panels Tip(s): Loose Neutrals and Removing ECP Covers

December 21, 2006
(Infrared Thermal Imaging)

A few articles have recently been published about the need to take off the covers in order to effectively shoot control panels for potential hot spots. At Johns Manville, McPherson we took this advice to heart and began implementing ECP’s into our infrared program. It wasn’t long before we got our first payback and avoided some serious downtime.

It started, innocently enough, when we found a hot spot surrounding a GFCI receptacle that was under no load. We replaced the damaged receptacle and expected the hot spot to go away. When we shot the new receptacle we found our hot spot immediately returned. We investigated further and traced our GFCI circuit back to the Electrical Control Panel that fed it.

What we found surprised us!

We removed the Electrical Control Panel cover and shot the contents with our infrared camera. It was then our camera found the source of our GFCI receptacle problem. The main neutral feeder to the ECP was glowing red! We ended up shutting the panel down, locking it out, and replacing the neutral wire (which we found had only 3 tiny copper strands still under the lug). The entire load of the panel was just over 8 amps.

The point of this story is that although we weren’t out there shooting Electrical Control Panels when we stumbled on this, it made us awfully glad that we had started shooting them.

So, the Infrared tip is (actually there are two tips):

(1) Don’t forget the neutrals.
Loose neutrals can be a source for (serious) hot spots.

(2)Take the advice of articles that tell you to shoot ECP’s and remove their covers when doing so.

Most hot spots will escape you if you don’t take the covers off. It doesn’t take many amps to create a serious problem. In our case, it only took 8 amps on the neutral of a 120 volt circuit.

Reader tip provided by Nick Bohonik, Reliability and Thermographer Level 1, Johns Manville, McPherson, Kansas - Winners of the Uptime Magazine PdM Program of the Year Award for Best Infrared Program

Thanks Nick and congratulations again on the PdM Award! Your Maintenance-Tips hat is on the way.

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