# Dedicated circuit for smoke detector?



## End Grain (Nov 17, 2007)

I am NOT speaking to specific CODE here but it has been explained to me by some tradespeople on occasion that smoke detectors should not be on a dedicated circuit simply because if the breaker ever trips, you would have no way of distinguishing that there was a problem. The breaker could stay off for months without your being aware that it had tripped. Few people pay much attention to an LED that blinks once every 30 or 45 seconds. Obviously, this is an important enough question for you to research the correct CODE answer for your locale.


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## Silk (Feb 8, 2008)

Smoke detectors connected to a 15A or 20A circuit *must be AFCI-protected* if the smoke detector is located in the bedroom of a dwelling unit. The exemption of AFCI protection for the fire alarm circuit (760.41(B) and 760.121(B)) doesn't apply to the smoke detector circuit, because a smoke detector circuit isn't defined as a fire alarm circuit; it's an "alarm circuit" as defined by NFPA 72, National Fire Alarm Code. I don't like the rule, but it's there.


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## Randell Tarin (Jan 19, 2008)

So, does it go on the same AFCI circuit as the bedroom or its own?


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## Silk (Feb 8, 2008)

Smoke detectors are not required by the NEC. They would be covered under your state or municipal codes. Where I live they are not required at all. You can put them under any circuit you want, but if they're in a bedroom they must be AFCI protected.


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## CowboyAndy (Feb 19, 2008)

It's pretty common to see them on a bedroom lighting circuit or some other type of lighting circuit.


Silk, thats an addition in the '08 code, right?


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## Speedy Petey (Feb 1, 2004)

Silk said:


> Smoke detectors connected to a 15A or 20A circuit *must be AFCI-protected* if the smoke detector is located in the bedroom of a dwelling unit.


.........*IF* your area requires AFCI protection at ALL _outlets_ in bedrooms.
Some areas still do not.


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## CowboyAndy (Feb 19, 2008)

Speedy Petey said:


> .........*IF* your area requires AFCI protection at ALL _outlets_ in bedrooms.
> Some areas still do not.


 
Ya, my area specificly does NOT require them. I have them anyways on the bedroom circuits, though.


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## jogr (Jul 24, 2007)

Randell Tarin said:


> So, does it go on the same AFCI circuit as the bedroom or its own?


Do not put it on it's own dedicated circuit for the reasons End Grain stated.


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## Randell Tarin (Jan 19, 2008)

I called the inspector of a nearby municipality, and their requirement is that smoke alarms be on an independant circuit. He also stated that ALL bedroom circuits required AFCI circuit protection. 

I'm a little confused as to why a smoke alarm circuit would require AFCI protection. Aren't arch faults generally caused by appliances plugged into a receptacle?


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## LawnGuyLandSparky (Nov 18, 2007)

Your better interconnected smoke detectors will also have battery backup. Even better, get the ones with built in egress lights that illuminate when the alarm sounds. These detectors will emit an annoying chirp if either the battery is low or missing, or the 120v power fails.


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## Pudge565 (Jan 27, 2008)

i just read in mullins residential wiring book that if they are in the bed room they must be on the same arc fault breaker as the bedroom. even if somthing were to trip it the detector will still work since it must be battery back up. even if the battery dies the alarm must chirp to warn the homeowner that the battery is dead.


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## Silk (Feb 8, 2008)

Pudge565 said:


> i just read in mullins residential wiring book that if they are in the bed room they must be on the same arc fault breaker as the bedroom. even if somthing were to trip it the detector will still work since it must be battery back up. even if the battery dies the alarm must chirp to warn the homeowner that the battery is dead.


 
No they don't. Mullin is just giving suggestions as to what circuit to put it on. Again, Smokes aren't required by the NEC, if they are installed they must be afci protected in bedrooms. If Randall called the municipal inspector, then what he says is what is required, as he is the "authority having juristiction"


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## Pudge565 (Jan 27, 2008)

no the NEC doesn't require them but NFPA 72 does require them the requirements are as follows must be run by 120v ac primary and have a secondary power source of a 9v battery.


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## CowboyAndy (Feb 19, 2008)

Pudge565 said:


> no the NEC doesn't require them but NFPA 72 does require them the requirements are as follows must be run by 120v ac primary and have a secondary power source of a 9v battery.


Right, but they are enforced by building codes, not electrical codes. Therefore, an electrical inspector can't cite you for anything regarding smokes, EXCEPT for HOW they are wired.

My electrical inspector tried to tell me that he couldn't give me the final for one of the bedrooms I did here because the smoke detector was too close to a ceiling fan (by 1 1/2" none the less). When I asked him for a reference where the NEC says how far apart they must be, and he couldn't provide it I told him to send me my final certificate and I would take it up with the building inspector.


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