AFCI breakers warm?

Please help…New construction AFCI breakers finding them warm to touch. Temp. tested at 100 degrees. Is this normal?
Called several electricans and got mixed bag of answers…

Yes, that’s completely normal. The manufacturers say that they may have up to a 40 degree temperature rise over ambient. Sorta throws you for a loop, doesn’t it?

For this reason, some installers prefer to leave a blank space or a regular breaker between groups of AFCI breakers. Keeps them from heating each other up so much. Give a little room in between to cool off. This isn’t expressly required by any manufacturer, but some installers consider it good practice.

Agreed. . .

Yep. They actually have computer circuitry in them that run a little hotter than normal. The circuitry looks at the wave form and checks it against the wave form of an arc.


I would note if they are stacked more than three together as I remember at least one AFCB manufacturer recommended this be the max…

No real concerted agreement on this either though…

Even the GFCI runs into the 90’s with nothing on the circuit.

Low voltage transformers are another one (up to 120).

I understood it most AFCI’s are rated 140 degrees F. As do not all breakers need to have the temp ratings on them?

Anything around or over this temp. I state futher evaluation by a licensed electrician.


So how much power does that represent? Maybe 10 watts each AFCI (a total SWAG)? Times maybe 10-15 breakers per panel after the new code edition. Times several hunderd thousand new panels per year… Do you suppose these costs were considered by the code generators at NFPA?

lol…well I spoke with Eaton on this and they have done tests…stacking does not harm anything as they have a good allowance of heat factored in.

IN regards to spacing…the new 2008 NEC will make that moot…since all 125V 15 & 20A circuits will require AFCI so people higher than US have determined it is not a problem…

There are over 32 pages of comments on AFCIs in the ROC. NFPA is still pressing ahead on the universal requirement.