The plant has a 400-hp motor that drives a big compressor for the plant air system. A few months ago, it was tripping its feeder overcurrent protection device (OCPD) on a regular basis. The plant engineer suspected a problem with the motor windings, so he brought in a thermographer to check things out.
The thermographer noticed discoloration on the feeder cables. He recommended shutting down the compressor long enough for him to perform some tests on those cables, including leakage