On June 12, 2017 at 23:21, cma said...
I would not use these,
1. they are against code if your jurisdiction follows the NEC since they are UL listed but not for that application.
2. the smoke detectors will not trip the relay if they are on battery.
there is a company that makes a smoke that is UL listed for both life safety and property safety, I can't think of it now of the top my head.