Smoke Alarm Goes off When I Turn Lights on or off

At first I thought I was just walking too hard and setting it off but now I know it’s when I turn either bathroom, hallway or of or two bedrooms (near the alarm)
Lights on or off it sets it off and beeps non stop unless u press stop.

It’s hard wired - would this be something I could fix myself?


  • You should probably get that checked by a professional.

  • is this recent development or been there for a while?

  • Despite being Hard Wired, does it have a Battery back-up… maybe the Battery need a change.

    It could be trying to switch to Battery on a momentary power fluctuation when you switch on/off.

    • I had the same issue, every time I switched on the aircon the smoke alarm started beeping (not going off like OP though). A few months later and the flat battery alarm started going off.

      After swapping the battery out, I can use the aircon now no problems.

  • just walking too hard and setting it of

    Why would walking too hard set off your smoke alarm?

    Also is it a smoke alarm or some other kind of fire alarm? And are you sure it's not a motion alarm.

    • Maybe OP is walking so hard that it's making enough friction with the carpet to start a fire.

  • would this be something I could fix myself?

    Don't see why not. Give it a crack.

  • +1 vote

    It might not even be a smoke alarm - might be a security alarm

  • Smoke Alarm Goes off When I Turn Lights on or off

    Stop playing with the fire alarm switch! :p

  • If the Light Switch is activating anything else but the Lights, then it's definitely time to call the Electrician.

  • most hard wired smoke detectors are wired into a light circuit. I have come across this same issue with brand new property builds.
    So whether its a faulty unit, incorrectly wired, poor old wiring or
    if its a pre-existing and older unit and has replaceable battery backup, that would be worth a shot to see if new batteries fix it..
    These are usually 10 year Lithium batteries, anything else may not allow the unit to function properly. Perhaps someone put in generic batteries..
    If it has replaceable battery backup batteries and that happens to be the issue then great, though a lot are Not replaceable.
    you may need an electrician…

  • This is an easy fix (For an electrician). The alarm needs to be connected to the permanent active not the switched active. It is quite common to see this on smoke alarms.
    Smoke alarms are wired on the lighting circuit but you need to connect to the permanent active so that the alarm has power regardless of the light switch position.
    I hope that helps.