Chris, In a situation such as this I would put a heat detector in the garage
connected to the smoke alarms. That would eliminate the nuisance alarms
from car exhaust and anything else. You would need to use smoke detectors
that have an auxiliary contact such as the ESL brand by GE. The heat
detector would not have an alarm on it, but if you needed one you could also
connect a remote using a smoke detector with a relay in it.


John Grabowski
http://www.mrelectrician.tv





"Chris Lewis" wrote in message
...
Situation: Found out that the home builder had put in AC smoke detectors
that weren't gang-trip. I installed new gang-trip ones, and decided to
put another in the detached garage.

Gang-trip 3-wire type (hot, neutral and trigger).

Occasionally, work in the garage (soldering something, starting the lawn
tractor etc) will set off the garage alarm which immediately fires up
the others... Annoys the rest of the family no end.

Suboptimal.

Been thinking of putting a switch into the garage alarm's supply feed.

Ideally, it'd be a normally-closed timer that when "enabled", it'd
disable the garage alarm and gang trip feeding the other alarms until
the timer ran out.

Has anybody else done something like this? Suggestions?

I could put a double-pole switch in (to cut the hot and neutral), or
even a single-pole (just cutting the hot should work), but these
are battery backup units, so I suspect that wouldn't work...

So maybe the best I can do is disable the gang-trip with a switch.
Are there any cheap "normally closed" mechanical timers?
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.