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Posted by Bud-- on September 28, 2006, 4:02 am
Thomas D. Horne, FF EMT wrote:
> phil-news-nospam@ipal.net wrote:
>
>> | phil-news-nospam@ipal.net wrote:
>> |> |> | Arc Fault Circuit Interrupter. The AFCI breakers look like,
>> and wire |> | like GFCIs. AFCIs trip on arcs. The NEC requires them on
>> new circuits to |> | bedrooms. The proposed 2008 NEC requires them for
>> all residential 15 and |> | 20A circuits IIRC (could still be changed
>> though).
>> |> |> And AFCI-only device could be made to work without accessing the
>> neutral
>> |> of the circuit involved. The issue is the AFCI device needs to use
>> power
>> |> to function. Possibly that is the only purpose of the neutral
>> pigtail if
>> |> the device does not include any GFCI function.
>> |> | | But all AFCIs include a 30mA GFCI as part of the protection.
>> (That is | not the same as a 6mA GFCI for shock protection of people.)
>>
>> I've seen some that don't. Those were from Cutler-Hammer, the company
>> that makes AFCI without GFCI, AFCI with 30maGFCI, and AFCI with 6maGFCI.
>>
Have a reference handy for AFCIs without 30mA ground fault detection?
>> If the NEC ends up requiring the GFCI function, then the ones without
>> GFCI would likely end up being no longer made. But right not it is not
>> clear what the NEC requires NOW (2005 code) or will require (2008 code).
>> All we know is that the scope of where AFCI is required appears to be
>> expanding.
>>
>>
>> |> And regarding the issue of putting smoke detectors on AFCI protected
>> |> circuits. The simple solution is keep receptacle circuits and
>> lighting
>> |> circuits separate, and put the smoke detectors on the lighting
>> circuits.
>> |> Those circuits should have much less instance of nuisance trips, and
>> |> would more readily be noticed if they are opened, in case the smoke
>> |> detector false to alarm.
>> |> | | Just to be clear, lighting circuits that include bedrooms have
>> to be on | an AFCI. (I think that is what you said.)
>>
>> All the circuits supplying outlets in the bedrooms must be AFCI
>> protected.
>>
>> The issue with smoke detectors is more complex. I do believe they must
>> be on AFCI, and I think that is appropriate. I do not expect the smoke
>> detectors to be any source of nuisance trips. Thus it might seem to be
>> a good plan to put them all on their own circuit. But I don't trust that
>> they will alarm when the power is lost. The reason is because that would
>> cause problems in utility outages. Do you want all your smoke detectors
>> beeping when a storm knocks out your power? But what if the branch
>> circuit
>> the smoke detectors are on loses power. You might not even notice that a
>> problem exists. Connecting smoke detectors with receptacles is a bad
>> idea
>> becauseof two reasons. Either the receptacle might not even get used, or
>> the receptacle's usage might be the source of excess nuisance trips.
>> That
>> could compromise the safety of the smoke detectors. My idea is to put
>> them on the same circuit as regularly used overhead lights, such as hall
>> lights or stairway lights. That way, if there is a circuit trip that
>> does
>> affect the smoke detectors, you will be alerted to a problem with that
>> breaker, and motivated to correct it.
>>
(There was a proposal for the 2008 NEC to require that but it was rejected.)
>
> Smoke detectors that are designed to be interconnected will usually have
> a backup battery and will chirp every so often if power is lost.
Do they chirp if the battery is dead? Removed? I havn't played with them.
The way I understand the 2008 NEC-ROP, NFPA 760 requires smoke detectors
that are on AFCI circuits have a secondary power source (battery).
Another hidden requirement.
IMHO requiring smoke detectors to be on an AFCI circuit lowers overall
fire safety and is dumb.
bud--
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