Hot breaker

This breaker in an auxiliary panel for in floor radiant heating was measured at 48 C / 122 F

This temperature appears excessive to me. Is this a reasonable temperature or should sparky be called out?

You took an IR picture… did you by chance check the amperage draw?

I realize that’s probably not the answer you were looking for…

The temp alone does not give enough information to make a determination one way or another.

Hey Jeff!!

I think that’s what I was saying… only clearer!

Another thing about me mentioning to clamp the line there for amp draw would have been something about our SOP??


Always remember that you are looking for spikes in the temperature as a whole. If all the breakers are at a reasonable temperature and one spikes up more than say 15-25 degree’s higher than the others…do not hesistate to recommend it be looked at.

It may certainly be nothing and the manufacturers have agreed that temps can go higher than that on their case molded breakers…if it appears to be well above the others in the panel take a few things into consideration.

1.) Is the circuit breaker in question under a load at that point, this will always make it run warmer than others that are not under a load at the time.
2.) Does the rise in temperature seem grossly higher based on the ambient and other breakers around it.
3.) Is the breaker itself subject to higher heats due to it’s location. ( ie: in the Sun and so on )

Always evaluate the factors involved and in the end if it is really bothering you and you can’t answer the reason for the increased heat rise do not feel bad about callling it out with other electrical defects…

Any time a molded case beaker measures that high above the others around it, something is wrong and should be investigated. There can be many reasons, but a differential that great is abnormal.


I would not go as far as saying “Anytime”. Based on the load being imposed on the circuit at the time may be the cause and is within the specs of the conductor itself. You need to evaluate every situation based on what information is present.

With that said I need to say this; typically you will see a standard breaker around ambient or within 10-12 degrees above and this normal. So as Frank stated in the example above situation I would say the temperature around at the other breakers were possibly in the 90-95 degree range and normal…however this one is more than 20 degrees higher and so it demands you look for a reason as well…check the legend and see what it may be and so on but do not be afraid to call it out like i said when the range exceeds examples I gave in a previous post.

Personally, I like a Hand IR unit for this type of verification but thats me.

Regardless of the other breaker temps, 122 degrees isn’t even likely to raise an eyebrow for me. I consider this to be well within “normal operating ranges” under most circumstances.

This panel had only the A/C running during these pictures. . .



Similar topic from a few months ago.

This post #7 in the thread was particularly helpful and applicable here.

I agree that the IR termometer is perfectly adequate for HI panel surveys. The exact “concern” level is a function of ambient and lots of experinece. Personally, in residential situations, I seldom see any areas of a panel that are more than about 10 deg. hotter than others in the same panel.

How long has there been a load on the circuit, and what is the current draw? You stated that this is for an in-floor heating circuit. Chances are that the load is fairly high and is typically on for long periods of time. I suspect there is nothing wrong here, but as others stated, can’t tell without more info.

Good examples that clearly point out the likely (and normal) heat rise due to any breaker containing electonic circuitry, such as some GFCIs and AFCIs.