Thread: Hot temp on ACFI's

The Seimens ACFI's measured 15-20 degrees hotter than standard breakers. I've not seen this much variation on AFCI's before. Is this common?

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Originally Posted by Gregg Austensen

The Seimens ACFI's measured 15-20 degrees hotter than standard breakers. I've not seen this much variation on AFCI's before. Is this common?

Yep, pretty normal. One of the reasons they should not be stacked on top of each other.

I seen'em with a 50 degree difference on a regular basis (summer time).

M-sparky's around here pretty much agree that to be normal when stacked and in the summer-time.

rr

See following PDF:
http://www.eatonelectrical.com/unsec...D00402001E.PDF

Jeff Euriech
Peoria Arizona

Jeff,

Thanks for the pdf! Great stuff.

Gregg,
I see the temperature variances upwards of twenty degrees quite regularly when there are three or more stacked. I have talked to some of the sparkys in the area and they say that "they" always stagger them or alternate left and right side. I have made it a suggestion with a short explanation in the "nice to know" section of my reports.

Jeff,
thanks for the link to the pdf. muchy much awesome and will forward it on to the local chapter here.

Scott:

My understanding is that stacking AFCI's is not recommended due to the heat issue. Not sure that it's something one could make much of an issue on, though best practice would dictate no stacking. Yes?

When the 2008 NEC takes affect, "stacking" will be the norm as all 15 and 20 circuits will be required to be AFCI protected.

Originally Posted by Michael Larson

When the 2008 NEC takes affect, "stacking" will be the norm as all 15 and 20 circuits will be required to be AFCI protected.

Thus, the newer AFCI breakers produce less heat, trying to combat this know .problem'. How well the manufacturer's have done this will only be known for sure when we start seeing AFCI breakers stacked.

That will be "Truth or Consequences" time.

Eaton has a new version of their tech bulletin on AFCI operating temperatures up at http://www.eaton.com/ecm/idcplg?IdcS...me=AD00402001E

Thanks Michael. The old one is gone anyway.

Michael,

They didn't address the cumulative temperature increase by placing more than one, or by stacking more than one above another, other than as a maximum temperature rise.

"On residential circuit breakers, the temperature rise of this terminal must be 50°C or less above ambient when carrying rated current, or 65°C or less above ambient in an enclosure."

That means, say in a 90 degree F (approximately 32 degrees C) garage the maximum temperature rise (at full rated current) allowed is 65 degrees C, or to approximately 98 degrees C (which is approximately 205 degrees F).

Now, if you have that temperature rise at limited current flow, that would (to me) indicate there was a potential problem with the breaker(s) - all based on their information.

However, the handle shall not exceed 60 degrees C (140 degrees F).