Temperature rating of breaker

[JohnJ0906]

I had to check a residential loadcenter panel that had "warm breakers". I found 4 CH GFCI breakers in a row. I measured the temp at 34 deg. C. However, there was no temp rating on the breaker. I can't find anything in the Cutler Hammer info on the Eaton website. Does anyone know what the temp rating is?

I spread out the breakers to give some space for the heat to dissipate space-breaker-space, etc.

 

[brian john]

What was the load on the CB's?

 

[JohnJ0906]

Zip. House is unoccupied, and lights were off, no loads plugged in.

 

[petersonra]

Zip. House is unoccupied, and lights were off, no loads plugged in.

I beleive the breakers had to have some load on them for any heat to be generated.

IIRC, most breakers are rated for an ambient temperature of 40 deg c.

 

[mdshunk]

34c is only 94 f. Considering that GFCI and AFCI breakers do have a bit of a temperature rise on their own, that doesn't seem too earth-shattering to me. What was the ambient when they were checked?

 

[JohnJ0906]

I beleive the breakers had to have some load on them for any heat to be generated.

The GFCI breakers were noticably warmer to the touch than the standard breakers

"Cicuit breakers, the performance of which may be affected by a 40 deg. C. ambient temperature within the enclosure, and have been investigated for this application, are marked "40 deg. C." "
This is from the UL white book. I really wasn't sure what it meant roll: ), but these breakers had no marking, which prompted this question.

 

[JohnJ0906]

34c is only 94 f. Considering that GFCI and AFCI breakers do have a bit of a temperature rise on their own, that doesn't seem too earth-shattering to me. What was the ambient when they were checked?

About 80 (It was MUCH warmer in the attic, but thats another issue :roll: )

 

[mdshunk]

I wonder if that information is on one of the white papers in a CH GFCI box? I don't have any trucks handy here at home to just go check, but I might have a GFCI white paper in a binder someplace...

 

[mdshunk]

About 80 (It was MUCH warmer in the attic, but thats another issue :roll: )

Well... all this fussin' for a 14 degree F temperature rise? :grin: You did the right thing... spread them out and move on, never to think about it again.

 

[JohnJ0906]

I couldn't find anything on the web site, and I checked several documents. Of course the instructions on the site and the ones in the box could be different.

 

[JohnJ0906]

Well... all this fussin' for a 14 degree F temperature rise? :grin: You did the right thing... spread them out and move on, never to think about it again.

It was the lack of any temp rating that concerned me. I'm used to seeing a temp rating on everything. They were labeled "60/75 deg wire"

Also, as I said, this was with no load. I thought it would be a good idea to run it past all y'all.

 

[davidr43229]

Per UL489 standard Molded Case CB have a temp rating of 40 degrees C.
I would check the wire connections and make sure they are tight.
Also understand that with MCCB they have a trip rating of 1 time in a fault.
Multiple trips introduce carbon and pitting on the contacts.
It maybe time to replace that breaker.
Just my $.02

 

[Pierre C Belarge]

Some of the circuit breakers will have the temp rating stamped on the side of the circuit breaker. You will only see it if you remove the breaker from the panel, or maybe if there are no breakers next to it in the panel.

 

[JohnJ0906]

All connections tight. (1st thing I checked)
I removed all 4 breakers (to relocate) and none had the temp rating stamped on it, I even checked the bottom.

 

[don_resqcapt19]

The UL standard for breakers permits a 50?C rise over the 40?C ambient for the internal parts. This would create a surface temperature that would burn you if you touched it for more than a few seconds. In this case with no load the temperature rise is from the electronics in the GFCI breakers.
Don

 

[brian john]

Totally of the subject, but for those use to USA standard of Fahrenheit a quick conversion in the lower temperatures (courtesy of my English relatives).

Take the Celsius temp times 2 and add 32, gets you in the ball park.

30C X 2 = 60 + 32 + 92F

30C X 1.8 = 54+ 32 = 86F

Would not use for any tight calculations but for quick reference it is usable.

This works best for quick conversions of daily temperatures, it gets way off at higher temperatures.

 

[JohnJ0906]

Thank you all for your replies! :smile:

 

[don_resqcapt19]

For those who need a free program to convert temperatures as well as many other measurements you can go here and download one.
Don

 

[Psychojohn]

You said that there was no current flow through any of the breakers, standard breakers having bimetal trip mechanisms only get warm when a current flows. The gfci has an internal power supply and an IC to measure current differance, these will produce heat, especiany when several GFCI's are placed together.