I recently did a survey in a plant and I came across something I'm not sure is or isn't an issue. The survey was of subpanels, some of which powered High Bay HID lighting. The breakers and the wire all appear hotter than (30 - 70 degreesF)  the coolest spot around the panel. The backround temp is from 80 to 100 degrees F, it is a Foundry. I checked the amps, and they were always about half of what the breaker is rated for. I don't know if it might be the type of breaker, they are old, the ballast in the lighting, or the wiring. Any insight or experience would be helpful.

Jon

The breakers that are running the lighting for the plant will run warm and is a normal condition. This is caused by the amp draw on the circuit. As long as the breaker and the wire are rated for the branch circuit you will be fine. There are two situations that could cause alarm. 1. If the breaker is hot and there is no load on it. 2. If the breaker is hot and it is over loaded. But in your case I don't see any thing to be concerned about. As far as the branch circuits that are all tied to gather and appear warm I would not be concerned about. This is a normal condition when you tie everything together like they have here. I would monitor the temp on the wires to make sure that the heat does not increase and become a problem.

Regards

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Jeremy Kays Reliability Technician
Level II IR, MCA Level I, In Compliance with the ASNT guidelines
The Snell Group
jkays@thesnellgroup.com
http://www.thesnellgroup.com

Jon

I also wanted to mention that Ballast and the bulbs also play a roll in the heat you see on the breakers.

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Jeremy Kays Reliability Technician
Level II IR, MCA Level I, In Compliance with the ASNT guidelines
The Snell Group
jkays@thesnellgroup.com
http://www.thesnellgroup.com