I would hate to try and figure a problem when you have 40 residential smokes connected together. If one was set off how would you know what unit to look in?
There are 2 limits to the number of interconected smokes:
1. Factory directions - Kidde is 24 smokes & accesories
2. NFPA 72 - no more than 18 initiating devices can be interconnected on a multiple station system, of these 18 alarms NO MORE THAN 12 CAN BE SMOKES
To interconect all of them 120v you would need relays. If you have to interconect all I would think your looking more at a supervised system.
Tom
