I have hard wired smoke detectors. I've noticed that when I plug my tablet into a power strip connected to an outlet in my living room it caused the upstairs detector to emit a quick beep.

I now have an air conditioner in the same outlet. Whenever it kicks on, the detector on the same floor and upstairs would beep.

Tonight while it was running we started hearing a continuous quick beeping; it was the detector in the basement. As soon as we switched the ac off, it stopped.

It seems that whenever there's a quick rise in power usage, these things react.

Any idea what is going on?

  • What is the nominal voltage at your location? Jul 7, 2013 at 1:12

1 Answer 1


The detector beeps because the momentary drop in voltage (or aberration in waveform) at the detector is sufficient for the detector to pick up, perhaps interpreting drop/aberration as a sign that it is about to lose power.

Might be a:

  • hardware/software bug in the device
  • feature for letting the owner know that the detector is functioning properly
  • feature that warns of a low battery (the battery that powers the detector during black outs, etc ...)
  • feature to indicate that the detector's service life or warranty has ended
  • sign that the circuit is excessively overloaded
  • sign that the detectors are wired improperly

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.