smoke alarms on arc fault circuit

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jetlag

Senior Member
I think I was using the 2008 nec when I was running the circuit for the smoke alarms . The info I had said the smoke alarms had to fed off of a lighting circuit so you would be sure to know if the circuit went out . Now I have seen where the smoke alarms can't be on an arc fault circuit. So how do I correct that , the lighting circuits are all arc fault in that house now . The house interior is still in rough in stage and I can change the wiring
 
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jetlag

Senior Member
thanks jumper

thanks jumper

I think I saw that info when I had just put a random search in yahoo web search . The weird thing is it also said commercial circuits were exempt from arc fault requirements , so what alarms were they talking about that could not be on arc fault ?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Per the 2013 edition of NFPA 72, you can put smoke alarms or combo smoke/CO alarms on an AFCI or GFCI circuit if they have battery backup.

29.6.3
(5) Operation of a switch (other than a circuit breaker) shall
not cause loss of primary (main) power. Operation of a ground-fault circuit-interrupter (GFCI)
receptacle shall not cause loss of primary (main) power. Smoke alarms powered by branch circuits
protected by arc-fault circuit- interrupters (AFCI) or GFCI circuit breakers shall have a
secondary power source.

It's pretty much the same for the 2007 and 2010 editions as well. So, if you put in hard-wire only smoke alarms, replace them with ones that include a battery backup and you're good to go.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
Per the 2013 edition of NFPA 72, you can put smoke alarms or combo smoke/CO alarms on an AFCI or GFCI circuit if they have battery backup.

29.6.3
(5) Operation of a switch (other than a circuit breaker) shall
not cause loss of primary (main) power. Operation of a ground-fault circuit-interrupter (GFCI)
receptacle shall not cause loss of primary (main) power. Smoke alarms powered by branch circuits
protected by arc-fault circuit- interrupters (AFCI) or GFCI circuit breakers shall have a
secondary power source.

It's pretty much the same for the 2007 and 2010 editions as well. So, if you put in hard-wire only smoke alarms, replace them with ones that include a battery backup and you're good to go.


I guess the NEC is in conflict with NFPA 72.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I guess the NEC is in conflict with NFPA 72.

Yeah, this is the first I've heard of such a thing. (Battery backup when used on arc fault circuits) not saying it's a bad idea.

I think OP might be confusing Fire Alarm systems usually found in commercial applications from Smoke Detectors found usually in residential situations.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I guess the NEC is in conflict with NFPA 72.

No, there's no conflict. Remember, we're talking smoke alarms (line voltage) versus smoke detectors (12 or 24vDC). The first has a little nine volt battery at each unit, the second is backed up by the battery at the fire alarm control panel. You just can't tap power for a panel or a smoke alarm downstream of an AFCI or GFCI receptacle or on the load side of any switch.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
No, there's no conflict. Remember, we're talking smoke alarms (line voltage) versus smoke detectors (12 or 24vDC). The first has a little nine volt battery at each unit, the second is backed up by the battery at the fire alarm control panel. You just can't tap power for a panel or a smoke alarm downstream of an AFCI or GFCI receptacle or on the load side of any switch.

Yup you are correct. I missed the "alarm" part.
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I get it AFCI on smoke detector dewelling unit and they are smoke alarms. I am not arguing about that. Question what if its 120V, 20A or 15A single phase combination of carbon monoxide and smoke detector all in one residential?

Sent from my SM-G935U using Tapatalk
 

480sparky

Senior Member
Location
Iowegia
I get it AFCI on smoke detector dewelling unit and they are smoke alarms. I am not arguing about that. Question what if its 120V, 20A or 15A single phase combination of carbon monoxide and smoke detector all in one residential?

Sent from my SM-G935U using Tapatalk

Amperage is not relevant. Nor does # of phases supplying the building (remember, condos and apartments can have 3ph services). 210.12 requires AFCI protection.

210.12 Arc-Fault Circuit-Interrupter Protection. Arc-fault
circuit-interrupter protection shall be provided as required in
210.12(A), (B), and (C). The arc-fault circuit interrupter shall
be installed in a readily accessible location.
(A) Dwelling Units. All 120-volt, single-phase, 15- and 20-
ampere branch circuits supplying outlets or devices installed in
dwelling unit kitchens, family rooms, dining rooms, living
rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation
rooms, closets, hallways, laundry areas, or similar rooms or
areas shall be protected by any of the means described in
210.12(A)(1) through (6):
 
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