Electronic Alarms and Home Security Devices - Add-on Hard Wired Smoke Detector

As part of finishing my basement, code requires that I update my smoke detectors to add a detector to each bedroom. my home was built in 1995 when code only required one per floor.

One option is to add in battery powered detectors in each bedroom, but I'd rather have them wired in if practical so that if one goes off the others go off. Currently I have three wired together, 1 per floor. Issues with running wires etc. aside, can I add 5 more (1 per bedroom + a second in the basement) to the same circuit?

Yes you can, but it's 110v wiring and has to conform to those wiring standards. You use standard 14-3 with ground for this type of wiring.

The other option is to use low voltage device throughout but you need a security system that accepts them, and some locals are very specific about what configurations are acceptable.

Also, NFPA requires these smokes all tie into each other. Normal battery operated units do not do this.

They now have wireless interconnected units, but they cost more.

That's why 14-3 with ground: Hot, Neutral, interconnect, and ground.

Normal romex is 14-2.

What's NFPA? The permit guy specifically mentioned the battery operated units as an option, so I assume that's OK here. I'd rather have them tied in to the existing detectors, though, if I can.

Can you elaborate on complying with 110v standards? Are you simply saying that the wiring has to meet the same codes as regular house wiring would? Would that have an impact on how I'd have to string them together?

I have 4 bedrooms to add to the one that's in the upstairs hall. Can I just tie into that one and go from room to room, or will 8 detectors (3 existing + 4 bedrooms + one additional in the basement) on a circuit be too many?

Yes, your existing smoke alarms are 110v hardwired devices and must be wired as per electric code. NFPA is the organization that writes the fire and electrical codes (and other construction codes) that most state and local governments adopt or model their local codes on.

To do this right, you have to connect your new circuit to the existing circuit.

Smokes are such low power devices that you can have quite a few (12-16) on a single circuit (read the instructions for the device for the number allowed on an interconnect circuit. It varies by brand and model).

Seriously, you need to look up your local code requirements before you try to tackle this. There is no generic answer.

Thanks for the info, I plan on checking further into the local codes.

This was a surprise to me. I figured I'd have to add one in the basement for inside & outside the finished area, but I hadn't planned on doing anything upstairs.

Who would expect that working below ground would impact the second floor? Well, I guess folks that do this every day would ... :D

Even more so. There are specific rules for spaces that are over and under each other because of smoke transmission.