Active,
Some local codes do not permit a dedicated circuit for the smokes. They require the smokes to be on a general use lighting circuit. The idea is that if they are on a dedicated circuit, then if that breaker is off for some reason, no one will know it. Yes, you should get a low battery alarm, but many times the batteries are never replaced so you don't get the low battery alarm. If they are connected to a general use lighting circuit, and that circuit is off, they will get it fixed because they need the lights.
don
