Smoke Detectors

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Should they be on their own branch circuit? How do they communicate?

I can't seem to find it in the NEC.
 
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Although the NEC doesn't require that single station type smoke detectors be on a dedicated circuit, from the outlet that you tap an existing circuit, you will need 14/3 or 12/3 to interconnect the smokes. The third insulated wire is the communication path between the detectors. The third communication wire must be in the cable along with the ungrounded, grounded and grounding conductors.
 
sirbph said:
Do smoke detectors have to be on their own dedicated circuit?
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No. In fact, some people advocate they shouldn't be on a separate circuit because it makes to too easy for the HO to disable them if they get annoyed by false alarms.

Sharing a circuit with other outlets or on their own is purely a design decision. However, most smoke detector requirements are driven by the building code, not the electrical code, and local rules often apply.
 
Typically I will install the smoke detector on a bedroom receptacle or lighting circuit. This will make sure that the smoke detector is on an AFCI protected circuit and if the circuit is tripped it will be noticed.

Chris
 
sirbph said:
Do smoke detectors have to be on their own dedicated circuit?
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They DO in Delaware. And, you have to provide and install a lock-on device on the breaker for that circuit.

Personally, I do not agree with this, but when politicians are involved with making knee-jerk reactions to tragic events, stange rules can come forth.
 
I'll double check tomorrow, but I believe that in MA, 120V smoke alarms are required to be on a lighting circuit. As stated previously, to make it more noticeable if circuit is shut off.
 
Most electricans in my area install them on there own seperate afc to avoid triping. In my last own house, I installed them on a seperate circuit with the garage door opener and put it all on a switch in the bedroom. When they got turned off, I remembered it cause the garage door would not open in the morning. Hey It was MY house. The buyer thought it was also a good idea.
 
Cavie said:
In my last own house, I installed them on a seperate circuit with the garage door opener and put it all on a switch in the bedroom. When they got turned off, I remembered it cause the garage door would not open in the morning. Hey It was MY house. The buyer thought it was also a good idea.
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When would putting smoke detectors on a switch ever be a good idea?
 
Hey Guys,

Usually, we install a dedicated circuit for the Smokes and place it on AFCI and end it at the attic light....usually a pull chain.

Just so happens it has been working fine that way but as many have stated nothing says it has to be dedicated and be on one of the bedroom AFCI's if you wish.
 
infinity said:
When would putting smoke detectors on a switch ever be a good idea?
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Never, and Cavie, this was also a violation of NFPA72 11.6.x.x (I'm going from memory here, I do not have my NFPA 72 in front of me) the smoke alarms can not be turned off by a switch or a GFCI activating unless the GFCI is for the whole house. (i don't know when that would come into play)

Roger
 
Yea, I knew this was a violation. It goes back to the late 80's. lots of false alarms. The switch was a much better idea than a 10 foot ladder at 3 o'clock in the morning. Get the picture. like I said, they didn't stay off cause the garage door would not open in the am if they wern't turned back on. I Would not recomend this to anyone today cause just like GFI's, they have improved the smoke alarms and they are much less problems with them now.
 
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