Dedicated circuit for smoke detectors?

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Atlas Shrugs

Member
Location
New York, NY
Hello everyone,

Current argument over here is if they need to be dedicated or not. I'm in New York, I'm used to tying them into the lighting circuit.

Thoughts?


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G

Gregg Harris

Senior Member
Location
Virginia
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Electrical,HVAC, Technical Trainer
Atlas Shrugs said:
Hello everyone,

Current argument over here is if they need to be dedicated or not. I'm in New York, I'm used to tying them into the lighting circuit.

Thoughts?


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Not required unless it is a local amendment. A shared circuit is more likely to be noticed if the circuit is tripped.
 
Dennis Alwon

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
IMO it is a good idea to tie them into a lighting circuit but as stated it is not required by the NEC but there could be a local amendment.
 
david luchini

david luchini

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Location
Connecticut
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R

RICK NAPIER

Senior Member
Location
New Jersey
From the Fire Alarm Code NFPA 72

For smoke detectors
11.6.3 AC Primary Power Source. The ac power source shall​
comply with the following conditions:
(4) AC primary (main) power shall be supplied either from adedicated branch circuit or the unswitched portion of a​
branch circuit also used for power and lighting.
For fire alarm systems
4.4.1.4.1 Dedicated Branch Circuit.​
​
​
​
​
​
​
​
​
​
​
​
​
​
​
A dedicated branch circuitof one of the following shall supply primary power:(1) Commercial light and power(2) An engine-driven generator or equivalent in accordancewith 4.4.1.9.2, where a person specifically trained in itsoperation is on duty at all times(3) An engine-driven generator or equivalent arranged forcogeneration with commercial light and power in accordancewith 4.4.1.9.2, where a person specifically trained​
in its operation is on duty at all times
 
mwm1752

mwm1752

Senior Member
Location
Aspen, Colo
Atlas Shrugs said:
Hello everyone,

Current argument over here is if they need to be dedicated or not. I'm in New York, I'm used to tying them into the lighting circuit.

Thoughts?


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Residential install? do you have a NFPA13D system -- commercial? Agree local AHJ will determine the answer
 
Sierrasparky

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
Weird rule ,
Can be dedicated or not. Why waste the words on paper. The only pertinant portion is that it is not on a switch.
 
G

Gregg Harris

Senior Member
Location
Virginia
Occupation
Electrical,HVAC, Technical Trainer
Atlas Shrugs said:
It is a residential install. Where do I check for local amendments?


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and here is Section R313.1.2:
[F] R313.1.2 Power source. In new construction, the required smoke alarms shall receive their primary power from the building wiring when such wiring is served from a commercial source, or an on-site electrical power system and when primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection. Smoke alarms shall be permitted to be battery operated when installed in buildings without commercial power or an on-site electrical power system or in buildings that undergo repair, alteration, change of occupancy, addition or relocation in accordance with Appendix J .

basically states the same as other locations, not required to be on dedicated.
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construct

construct

Senior Member
Location
Branson, Missouri
If your jurisdiction has adopted the ICCEC or Appendix 'K' of the 2012 IBC (Administrative Provisions for the NEC) They specifically state that single- and mutiple-station smoke alarms installed within dwelling units shall NOT be the only connected load on a branch circuit. Such alarms shall be supplied by branch circuits having lighting loads consisting of lighting outlets in habitable spaces.

But it does not state any requirement for "other than dwelling units". :ashamed1:
 
mwm1752

mwm1752

Senior Member
Location
Aspen, Colo
construct said:
If your jurisdiction has adopted the ICCEC or Appendix 'K' of the 2012 IBC (Administrative Provisions for the NEC) They specifically state that single- and mutiple-station smoke alarms installed within dwelling units shall NOT be the only connected load on a branch circuit. Such alarms shall be supplied by branch circuits having lighting loads consisting of lighting outlets in habitable spaces.

But it does not state any requirement for "other than dwelling units". :ashamed1:
Click to expand...
K111.6 Smoke alarm circuits. Interesting

Nec commentary
Single and multiple-station smoke alarms, such as those commonly installed in dwelling units, are supplied through 120-volt branch circuits rather than through a non?power-limited or power-limited fire alarm signaling circuit that is powered and controlled by a fire alarm control panel. Branch circuits supplying power to single- and multiple-station smoke alarms are not subject to the requirements of Article 760.
IBC does not cover"
Exception: Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories above grade plane in height with a separate means of egress and their accessory structures shall comply with the International Residential Code.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
RICK NAPIER said:
From the Fire Alarm Code NFPA 72

For smoke detectors
11.6.3 AC Primary Power Source. The ac power source shall
​
comply with the following conditions:
(4) AC primary (main) power shall be supplied either from adedicated branch circuit or the unswitched portion of a​
branch circuit also used for power and lighting.
For fire alarm systems
4.4.1.4.1 Dedicated Branch Circuit.​
A dedicated branch circuitof one of the following shall supply primary power:(1) Commercial light and power(2) An engine-driven generator or equivalent in accordancewith 4.4.1.9.2, where a person specifically trained in itsoperation is on duty at all times(3) An engine-driven generator or equivalent arranged forcogeneration with commercial light and power in accordancewith 4.4.1.9.2, where a person specifically trained​
in its operation is on duty at all times
Click to expand...

Just curious, does the actually wording in NFPA72-11.6.3 say smoke detectors or smoke alarms? I know that we often use the terms interchangeably but in this case I believe the question is really about smoke alarms.
 
PetrosA

PetrosA

Senior Member
Location
Lancaster, Pennsylvania
Just to add to the confusion - when we were still under the 05 code, smoke detector circuits were dedicated so that the smokes wouldn't be on an arc-fault breaker. I haven't seen any houses built since the 08 has been enforced, but I suspect they don't do that anymore though I still think it's a sensible idea.
 
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