Hot spot in panel

This panel has aluminum and copper wiring. No obvious deficiencies noted in the panel. Aside from the fridge and a few lights, nothing was drawing in the house. The breakers in question were listed as “lights and outlets”. Comments?

29.1 deg. C is a nice day.

Did you measure the current through that breaker?

No, I normally don’t go as far as testing current. Typically, I don’t get breakers heating up to 29.1C but it’s the 41.7C that really concerns me.


There is just not enough info to advise you. Sorry.

Could be a loose connection
Could be a loaded circuit.
could be perfectly normal.

In my experience, it is likely an abnormal condition that should be investigated. It appears that the connection to the bus may be loose causing a high(er) temp connection. It is not very common to see that much difference in temps n a panel, even if the circuit is loaded. You can’t be wrong by calling it out - otherwise why bother with measuring the temps in the first p,ace?

You are right to be concerned about the temp spread, that is alot for F nevermind C. The conductors’ temp all appear normal and the heat appears to be highly centralized at the point where the breaker tabs connect to the bus bar. My guess would be that the tabs are bent, defromed, seperated, broken…I think you get my drift here.
Good luck

Thanks to all that responded. I recommended that a qualified electrician should correct the concern, to my clients. Then I told the agent to advise the vendors to have an electrician look at it asap. I called the vendors 2 days later to ask if the listing or buying agent had mentioned anything. Nada!
There was a host of issues noted, which I would not disclose. My clients had walked on the deal. However, I did feel that it was my moral obligation to notify them about the electrical issue. You’d think the agent would feel the same way, even if it was for a possible future deal with the vendors in their new home.

41.7° C is only 107° F. Is that really cause for alarm?

Sounds like the right thing to do,

Looks like it’s about 22C above ambient (put a spot on the background for ambient). Worthy of mention, evaluation, not to get excited over.

Dunno, are you suggesting it’s normal and may not get worse?

I’m not sure. I was just asking for my own knowledge. I’ve touched dimmer switches that were hot during normal operation so I was wondering if a CB at this temperature was actually a potential problem or not.

I recommend you obtain some standards as guidance when performing infrared inspections. Guessing don’t cut it. You need guidelines.

Not necessarily “alarm”, but when that is the only breaker with elevated temp and the others in the panel are more like 65-70 F, it is abnormal. Something like dimmers have an “excuse” for being warm - standard breakers usually do not (exceptions are some GFCI and AFCI breakers).

Thanks Linus, I’m sure that the booklet may come in handy and would be an interesting read. However, I really don’t do quantitative scans at this time and having scanned thousands of panels, this is definately an anomaly which should be addressed. No guessing about it. I think that a hot spot such as this, while there is no apparent draw, is an issue. Never mind putting a demand on the circuit! What stumped me is the fact that the wires and the breakers appeared to be secure. I plan on following up with the vendor and will let you all know what it was.
I want to thank everyone for their input and opinions because I think it helps us all along.

I’m just wondering how you can determine that the temperature is abnormal? If all of the breakers had 2 amp loads and operated at 70° F then yes it could be considered out of the ordinary if one operated at 107° F. But if the CB in question was operating with a near maximum load how can you say for sure that there actually is a problem without knowing the ampacity of the load? Or am I missing the point because 107° F on a CB is always indicative of a problem?

Yes, I agree tht could be true for extreme cases. But in a conventional breaker, what would cause enough heat loss to generate a lot of heat. There’s very little in there to cause heat and in this case the heat appears to be at the bus connection.

Thanks, I don’t do scans so I was trying to gather some information.

Always glad to help. I don’t use a camera either, but I do scan all electrical panels with an IR temperature meter. I recently found a fairly hot service conductor (+5-8 Deg. F.) in the main disconnect next to the meter and received much thanks from the PoCo who were glad to come out and re-terminate it.

I see thermal anomalies in panels all of the time. Without referencing some objective standard (e.g., NETA, which is incorporated into the document Linus references) how do you know when to call out an issue or not? Some are obvious, others perhaps, not so much.

I think you leave yourself kind of exposed if you can’t provide some objective standard for how you determine whether something you observe is an issue or not.