# Smoke/heat/co2 detectors



## Salvatoreg02 (Feb 26, 2011)

In a residential dwelling a 3wire interlock fire alarm system at 120volt. Shall the circuit be AFCI If these devices are located within the required areas of AFCI protected circuits???


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## chicken steve (Mar 22, 2011)

yes Sal

The smoke might detect the glowing connection before it becomes an arcing one

~CS~


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## Celtic (Nov 19, 2007)

Salvatoreg02 said:


> In a residential dwelling a 3wire interlock fire alarm system at 120volt. Shall the circuit be AFCI If these devices are located within the required areas of AFCI protected circuits???


Why wouldn't it be?


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## Salvatoreg02 (Feb 26, 2011)

chicken steve said:


> yes Sal
> 
> The smoke might detect the glowing connection before it becomes an arcing one
> 
> ~CS~


Well, today I was told, by an official city electrical inspector, since it is considered a life safety device it shall not be required to be AFCI. Assuming I was using a dedicated circuit.


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## Celtic (Nov 19, 2007)

Did the EI give an article number?


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## chicken steve (Mar 22, 2011)

Salvatoreg02 said:


> Well, today I was told, by an official city electrical inspector, since it is considered a life safety device it shall not be required to be AFCI. Assuming I was using a dedicated circuit.


well you could refer him to 210.12 , or whatever state amendment you have Sal

but one can see he's a practical man, and as this is a rather old debate, maybe his consideration is purely _incendary_

i get that

what is worth pursuing are the specifics of WHY this is a viable concern

~CS~


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## Salvatoreg02 (Feb 26, 2011)

Celtic said:


> Did the EI give an article number?[/
> 
> I will leave it at this. This man is a highly regarded city inspector. He told me I need to tell him which code sections pertain to exempting this particular install for residential dwelling.
> I know what you guys are saying, that this guy is full of it, but, he is one of the strictest inspectors I know.


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## Shockdoc (Mar 4, 2010)

I felt the same way about it as your inspector until another AHJ made it clear they wanted it AFCI protected and "that's why they are battery back up".


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## erics37 (May 7, 2009)

On the few occasions that I've roughed in a house, I tapped the smoke detector circuit off of one of the bedroom circuits for just that reason.



> *210.12 Arc-Fault Circuit-Interrupter Protection.*
> *(A)* Dwelling Units. All 120-volt, single phase, 15- and
> 20-ampere branch circuits supplying outlets installed in
> dwelling unit family rooms, dining rooms, living rooms,
> ...


Since smoke detectors are usually required in bedrooms (and elsewhere of course), and because they're wired from an outlet in bedroom, then they need to be AFCI protected.


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## crazyboy (Nov 8, 2008)

CO, not CO2! Have never seen a CO2 detector/alarm in a dwelling.


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## Salvatoreg02 (Feb 26, 2011)

can someone post NFPA 72 " 11.6.3(5). I don't have it.


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## Salvatoreg02 (Feb 26, 2011)

erics37 said:


> On the few occasions that I've roughed in a house, I tapped the smoke detector circuit off of one of the bedroom circuits for just that reason.
> 
> Since smoke detectors are usually required in bedrooms (and elsewhere of course), and because they're wired from an outlet in bedroom, then they need to be AFCI protected.


Understood. He throw me for a loop today when he said they didn't have to be AFCI protected. Maybe he's under the impression it was a low voltage system or referring to a low voltage system. But, I most certainly hard him correctly. Believe me if theirs anyone who does work in White plains, NY. They know how Richard Mecca rolls.


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## Salvatoreg02 (Feb 26, 2011)

NFPA 72 and various building codes have different specific requirements.

Here is a rough summary of what Chapter 11 of NFPA 72 (specifically 11.5.1) requires:
One in each bedroom (to wake people up).
One on each level, including basement.
A smoke in a basement shall be on the ceiling, near the entry to the stairs.
One outside each sleeping area, within 21 feet of the door to any sleeping area. If the hallway is closed off from the sleeping and living areas by doors, then smokes are required on both the living and hallway sides of the door.
When a door is installed in a stairway, smoke rising up the stairwell cannot be obstructed from a detector by the door.
One in the living area of a guest suite.
When a given level of a living area is 1000 sq.ft. or greater, one is required for every 500sq.ft. of floor area for that space, no greater than 30 ft apart.
If a ceiling on any level has an elevation change of 24", each elevation needs one. Example: Vaulted living room on same floor as 8' ceiling for back hall, den, laundry.
No closer than 3' to any cold air return or supply, or ceiling fan. Nuisance alarms due to dust attraction are common when this is done, and the sensitivity can diminish.
No closer than 4" and no farther than 3' to peak of vaulted ceiling. Smoke rolls in corners, bypassing detector.
No farther than 3' from peak of vaulted ceiling.
No closer than 4" from wall on a flat ceiling.
No closer than 4" from ceiling and no farther than 12", when wall mounted.
Ambient temperature cannot exceed 100 F, or below 40 F, as in attics and garages.
Interconnection of detectors is required.
Per NEC 210.12, AFCI protection required. Per NFPA 72 11.6.3(7), if the smoke is supplied by an AFCI, then battery backup is required. By 11.6.4(1), the smoke must audibly report a low battery condition.
The instruction booklet supplied with the smoke detector is required to be provided to the occupant. (72 11.8.4(1).)
Smokes should be replaced every ten years. (72 11.8.5(b).)
Many smoke detectors come with instructions that mirror NFPA 72's requirements, so they could also be considered a 110.3(B) listing issue, if NFPA 72 has not been adopted in your area.

This is from 08' which I found online. Unless their was an admen dent.


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## chicken steve (Mar 22, 2011)

> Per NEC 210.12, AFCI protection required. Per NFPA 72 11.6.3(7), if the smoke is supplied by an AFCI, then *battery backup* is required


 
amazing, we've marketed a bandaid for another market bandaid.....

~CS~


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## Amish Electrician (Jan 2, 2010)

I think we're confusing smoke detectors with fire alarm systems.

NEC already exempts alarm systems from GFCI requirements; a similar logic might be used to extend the exemption to AFCI requirements. Note that this is for central-station alarms, and does not apply to the usual residential interlinked smoke alarms.


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## sbrn33 (Mar 15, 2007)

Why would you put smokes on a separate circuit?


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## Theriot (Aug 27, 2011)

Local inspectors look for alarms and smoke to be on their own circuit.


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## Salvatoreg02 (Feb 26, 2011)

sbrn33 said:


> Why would you put smokes on a separate circuit?


Well the reasoning behind is, if the SD don't have to be AFCI, then they don't have to be battery backed up.


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## sbrn33 (Mar 15, 2007)

Theriot said:


> Local inspectors look for alarms and smoke to be on their own circuit.


That sounds to me like a total waste of a circuit. Especially an AFCI circuit. Somebody could turn them off and leave them off. I always put them on the bedroom circuit.


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## Corn_Fed (Aug 6, 2012)

Our State Electrical Inspectors don't require smoke alarms to be on an AFCI circuit..... and prefer to see them on their own 120V 15A circuit


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## Corn_Fed (Aug 6, 2012)

sbrn33 said:


> Somebody could turn them off and leave them off. I always put them on the bedroom circuit.


 
Don't you interlink all your smoke alarms? If so then you put them all on 1 bedroom circuit? If so that is interesting...... I've just never seen it done that way


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## Celtic (Nov 19, 2007)

Salvatoreg02 said:


> Celtic said:
> 
> 
> > Did the EI give an article number?
> ...


Initially, I thought the guy was full of it....but when you read the code/s....you might see it a bit differently...



NEC 2011 said:


> *210.12 Arc-Fault Circuit-Interrupter Protection.
> (A) Dwelling Units. *
> All 120-volt, single phase, 15- and
> 20-ampere branch circuits supplying outlets installed in
> ...


It could be argued that a smoke is an outlet such as any other device, light, fixture, etc.

But then we see the note..



NEC 2011 said:


> *Informational Note No. 2:*
> See 11.6.3(5) of NFPA 72-2010, National Fire Alarm and Signaling Code, for information related to secondary power supply requirements for smoke alarms installed in dwelling units.


There is no 11.6.3(5) in the 72-2010...











....maybe the 2007 has it?










ok there it is..11.6.3(5)










"Secondary Power Source"?

11.6.4 explains it...










After reading the material.....what do you think...

Smokes on AFCI or not?


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## Salvatoreg02 (Feb 26, 2011)

Celtic said:


> Initially, I thought the guy was full of it....but when you read the code/s....you might see it a bit differently...
> 
> It could be argued that a smoke is an outlet such as any other device, light, fixture, etc.
> 
> ...


At this point I can only say if it is protected by an AFCI, then the detectors must be of the battery back up type


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## Celtic (Nov 19, 2007)

Salvatoreg02 said:


> At this point I can only say if it is protected by an AFCI, then the detectors must be of the battery back up type


Have you ever installed one that didn't have a battery back-up?

I know I haven't ever even seen one w/o back-up.


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