I work in a factory maintenance department.
Recently a thermal imaging contractor came in and scanned all of our panels for hot spots.
They came up with several breakers that they say are having problems.
In each of these cases they are 20 ampere 120 volt breakers that have a continuous load of 11 to 15 amperes on them for lighting or some other load.
I have checked the wire and breakers for any discoloration and nothing is apparent.
My thoughts on this are there is going to be some heat generated in the breaker and wire with usage, because everything has resistance to some degree.
What is a normal temperature rise in a breaker under continuous use? The breaker is marked 40 C but I can’t find any data on what that stands for.
The temperature rise the thermal imaging people documented is from 9 C to 27 C above ambient.
Thanks for your help.