Trace circuit for hard-wired smoke detector


Old 12-25-13, 02:23 PM
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Trace circuit for hard-wired smoke detector


I need to replace 3 hard-wired smoke detectors in my house. They are 20+ years old and need updated. Unfortunately, I have no idea which circuit they are powered from. I'd like to avoid shutting down all the breakers in the house.

I have a circuit tracer that you plug into an outlet but I'm not sure how I would trace a wire w/out an outlet. Do they make a tracer for this arrangement?

Is there an easy way to find which circuit is powering these detectors?

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Old 12-25-13, 02:43 PM
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This are typically powered from a lighting circuit. I would start with those.
Old 12-25-13, 02:51 PM
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Have someone stand under the smoke detector and watch the green light. When it goes out the AC is off. Allow five seconds between breaker selection. Skip the two pole and 20 amp breakers.

Also....with the age of the devices..... change them all. Don't intermix old and new.
Old 12-25-13, 02:58 PM
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If you have lights in the attic, that would be a good circuit to start with. I am always reluctant to suggest these because they are not conclusive, and, in my opinion, should never be considered definitive, meaning that you should verify with an actual volt meter before touching anything, but you can get a non-contact voltage detector at your local hardware store or big box, and that might help. Meanwhile, pick up an inexpensive analog volt meter as well, so that you can be sure that the power is off once you start opening them up.
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