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Joined: Jan 2004
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I have not seen anything that said you can't "stack" AFCI or any other breakers. Did I miss that point? Why would there be any more heat with AFCI's than any other breaker? Maybe the manufacturers see that there is not a problem with heat so they are willing to add more breakers to panels? This would be especially true in non-continuous loads.
George Little
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George, Why would there be any more heat with AFCI's than any other breaker? The extra heat is from the electronic circuits that other breakers do not have. This may become a problem if the whole house rule stands. Don
Don(resqcapt19)
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Don- The extra heat is from the electronic circuits that other breakers do not have. This may become a problem if the whole house rule stands. I have not seen anything official on that and was hoping someone else had. Seems that the manufacturers would have provided for that and had the breakers evaluated accordingly.
George Little
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I have a comment in on 2-142 addressing this specifically. I can certainly see a problem if your garage is cruising in the high 90s and you are generating additional heat inside the panel. Breakers seem to be rated at 40c. (104f)
Greg Fretwell
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George, Seems that the manufacturers would have provided for that and had the breakers evaluated accordingly. Why would you expect that when they have not even made the AFCIs do what they promised they could do in the original proposals some 13 years ago? Don edited to add left out word (not) [This message has been edited by resqcapt19 (edited 09-12-2006).]
Don(resqcapt19)
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Okay Don– Now I get your point. I agree they are struggling to producer a product that meets code. I think most people thought these devices were going to detect series arcs and would also protect hazzards from appliances plugged in the outlets but this was never explained. Currently the devices are only capable of detecting parallel arcs but maybe ultimately series arcs. And I still have not seen anything on any stacking or heat problems.
George Little
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George, I think most people thought these devices were going to detect series arcs and would also protect hazzards from appliances plugged in the outlets but this was never explained. We only thought that because of the misinformation that was provided by the AFCI supporters. As far as the heat, I'd bet that they have never even looked at the heat when you fill the panel with AFCI breakers. They operate at a higher temperature than standard breakers as a result of the electronics. Whether this will be a problem of not, when you fill a panel with AFCI breakers remains to be seen. Don
Don(resqcapt19)
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The boys over on the NACHI group (home inspectors) seem to be saying AFCIs run 5-10 degrees hotter than the regular breakers read with an IR thermometer. I think that may just be anecdotal but it is worth a look by a NRTL when you have a panel full. I doubt the electronics are good for much more than 70c (the typical non-milspec rating) and that is junction temp, not the outside of the CB case.
Greg Fretwell
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Won't it be interesting if the code change in 2008 leads to an increase in house fires, if that causes heat/meltdown problems in electrical panels. Not that I want such a thing to happen, do not get me wrong. But it will probably lead to a review of code making procedures and "ethics" of having manufacturers get so much decision weight, if such an unfortunate result does in fact occur.
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I doubt there is any real fire danger. This is more likely to result in more nuisance trips on regular breakers and early end of life of the AFCIs
Greg Fretwell
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