Wiring Smoke Detectors

[lsaxton]

I want to replace our old smoke detectors with hard wired ones. My question is do they go onto the same circuit as the room or area they are protecting or feed from a different circuit.

[Speedy Petey]

Well you just named both schools of thought. You can do it both ways. Some areas actually have codes requiring one way or the other.
I would use a local lighting circuit and wire them together interconnected with 3-wire (eg: 14/3 or 12/3 nm).

[lsaxton]

Thanks for the quick reply, I wasn't sure and figured it was better to ask before screwing something up. Thanks Again

[HayZee518]

the hard wired smoke detectors use a three wire for the interconnection. the dc produced uses the white neutral and the red for carrying the power to the other detectors trip circuit. in electronics it is possible to have a dc component riding on an ac line.

[Kidd6488]

Yep, we installed these in our house when we remodelled. There is a combo CO/Smoke Detector in every bedroom, and Smoke detector in every other room. They all just need to be wired together using 14/3, any way or any order you can. Then the power can enter the circuit at any point. We have a dedicated 15A circuit just for these (which use very little power), and our modem/router, and other communications things. They all also have battery backup.

It's really cool when people come over to press the "Test" button on any of them when you're not looking. Then every smoke detector in the house starts going off, and the talking ones will warn "Warning, Fire! Fire!" "Warning Carbon Monoxide!" Ours go one at a time, suprisingly when doing the test."