Hi Marc,
Not sure if I explained what I was saying well ...
Jerry Peck - Codeman wrote:From some other information I found, the handle on an AFCI breaker, and presumably all circuit breakers, must not exceed 60°C or 140°F.
Marc M wrote:This I found and thought it to be the standard. However, it appears based on your answer that each and every situation is different and as such, much must be taken into consideration in order to determine the Max temp of that individual breaker/ circuit.
There are multiple things being stated here (and on the first post, and which I tried to specify in my response):
One: The temperature of "the breaker".
Two: The temperature of "the terminal connections" in the breaker.
Three: The temperature of "the handle" of the breaker.
To address them in order:
- One above: "the breaker" - That is what you asked about in your first post and re-stated in your second post ... the temperature of "the breaker".
- Two above: That is why I specified ... " 'at the wire terminal connections' " in my first response. I wanted to differentiate between " 'at the wire terminal connections' " and "the handle" and "the breaker" ("the breaker" is what you had asked about).
- Three above: That is why I specified "the handle on an AFCI breaker, and presumably all circuit breakers", to differentiate "the handle" from "the breakers" ("the breakers" is what you had asked about).
The A/C breaker was hotter than the rest so I wanted to find out what exactly is "too hot".
What I am saying is that checking the temperature of a breaker tells you little about it. Yes, the a/c breaker would be hotter than other breakers, it has more current going through it.
However, to make those measurements meaningful, the temperature would need to be taken 'at the wire terminal connections' of the breaker, and, if you can get to it, the bus bar connection, AND, you would need to know the ambient temperature withing the panel with the cover on, AND, to make the number really meaningful, have the current through the breaker at 100% of the rating of the breaker, AND, ... and even then the numbers are not compatible to what was tested for the listing. Those tests were made under conditions which were different, 100% rated load at 40°C in open air (which you are not doing) and/or 100% rated load in the smallest enclosure the breaker is approved for use in (which you are not doing either).
Thus, taking the temperature of a breaker in a panel is ... fun to do and interesting ... but yields limited usable results. That is what I was saying.
Can you have a really hot breaker in a panel? Yep. Does it mean the breaker is bad? Nope. Could the breaker be bad? Yep. Could the breaker be good? Yep.
Is it more likely that the breaker/bus bar contacts are the cause? Very well could be. The main things, though, when checking breaker temperatures is: a) not to put a lot of faith in them; b) take the temperature at the wire terminal; c) not to put a lot of faith in them; d) take the temperature at the bus bar connection; e) not to put a lot of faith in them.
Should you recommend the breakers be checked out by an electrician? Certainly would be logical to do so, as long as you did not say they were "bad" or "too hot", only that they were "hotter than you expected".