smoke detectors

[gabby]

In A single family dwelling how many smoke detectors are required ? If they are installed does it matter if they are hard wired or battery ? p.s. how many can you put on a circuit or does the 80% branch circuit apply. Since this is considered a outlet in a bedroom does the arch - fault rule apply.

 

[tim]

Re: smoke detectors

Gabby, here in central Illinois, we are required to put a detector in every bedroom, also in hallway within 15 feet of each sleeping area, also one on each level of the dwelling. Must be hard wired and interconnected together. We use battery back-up though not required. Champaign Illinois does not want the smokes on the afci circuit. The NEC requires them to be on the AFCI circuit. Check your local codes or with your local inspector. Also, we put the smokes on thier own circuit for convience, I don't think there is a certain amount you can put on a circuit. They don,t pull hardly anything. Hope this helps some.

 

[goldstar]

Re: smoke detectors

I'm sure every state and, in some cases, municipalities have different requirements. Check with your AHJ. Tim gave the basic requirements for new construction (1 in every bedroom, 1 in the hallway outside the bedroom area and 1 on each level). I've had AHJ's make me install photo smokes in attics, heat detectots in each garage bay and over furnaces.

Also, interconnected smoke detectors seem to be the residential standard but check with the manufacturer as to the maximum interconnected quantity permitted. The power requirements for the 120 volt side are minimal. I believe the restrictions have to do with the signaling (red)line. Some are 13 and some are 18 interconnected detectors. You may need an interface module if you go above that.

 

[tom baker]

Re: smoke detectors

If in a dwelling unit bedroom under the 2002 NEC Arc fault circuit protection is required for any bedroom 15A and 20A 125 outlets, a smoke detector is installed at an outlet.
The NEC only covers the wiring to the outlets, not the placement of the smokes. You'll need to ask your AHJ or look on your approved plans.
Also the AFCI requirement is often modified by local codes, it may not be required where you are.

And the instructions in the box with the smokes tell where and how to install. AC power with battery back up, interconnected has been a requirement in the building code for 20+ years.