Adding a heat sensor to an existing, interconnected smoke alarm system

[Promise]

I currently have a home with 7 interconnected, hard-wired smoke detectors. I have a hard-wired heat alarm in the garage that I need to have interconnected to the rest of the system, per local regulations. My solar installer added the heat sensor but does not seem to know how to handle the interconnection, and from what I can tell was just hoping the inspector wouldn't test it.

They are all on the same breaker, but the heat alarm is not directly connected to the closest smoke alarm. My question is, can a single interconnect wire be run from the nearest smoke detector to the heat alarm? That is, leave the wiring on the heat alarm that provides power as is, and just run the interconnect wire. Or is interconnecting them more involved than that? They're all the same brand (Kidde), new or fairly new, and interconnect compatible.

This isn't something I'm planning to do myself, I'm just looking to find out what would be involved if I wind up having to find someone else to do this part of the work. The installer's current solution is to replace every device with wireless combination heat smoke detectors at $130 each.

 

[littlespark]

if you can get a new cable between the unlinked one, and any other detector, then run a 3 core and earth between…. Live, neutral and signal.

I don’t know about kidde, but another manufacturer (aico) can be linked by radio, even between two mains powered ones.

 

[Promise]

The goal is definitely to either directly wire them together, or replace one of the wired units with a wired/wireless bridge model in the entryway and garage, in order to interconnect the heat alarm. Having said that, is running 3 wires rather than a single interconnect more a matter of best practice, or is there some risk to doing so?

The Aico devices don't seem to be readily available here. Kidde does make a wired/wireless bridge model that is compatible with the heat alarm, but the current model seems to be notorious for false alarms.

 

[littlespark]

I didn’t twig straight away that you’re in the US… even the fact you used a $ sign in the OP.

My suggesting a “3 core and earth” may be skewed as I don’t know if that exists over there…

If your detectors are all on the same circuit, then it should just be a case of running a single signal wire between, but how that would be done is either an easy job, or very very difficult.

 

[Megawatt]

I currently have a home with 7 interconnected, hard-wired smoke detectors. I have a hard-wired heat alarm in the garage that I need to have interconnected to the rest of the system, per local regulations. My solar installer added the heat sensor but does not seem to know how to handle the interconnection, and from what I can tell was just hoping the inspector wouldn't test it.

They are all on the same breaker, but the heat alarm is not directly connected to the closest smoke alarm. My question is, can a single interconnect wire be run from the nearest smoke detector to the heat alarm? That is, leave the wiring on the heat alarm that provides power as is, and just run the interconnect wire. Or is interconnecting them more involved than that? They're all the same brand (Kidde), new or fairly new, and interconnect compatible.

This isn't something I'm planning to do myself, I'm just looking to find out what would be involved if I wind up having to find someone else to do this part of the work. The installer's current solution is to replace every device with wireless combination heat smoke detectors at $130 each.

I really don’t see why you can’t do that. So have your electrician to take loose the wiring that the solar person did for you. He can now come off the last smoke detector in that circuit and add the heat sensor.