Could a light dimmer be triggering my smoke detectors?

Question

I had LED recessed lights with a wall dimmer installed in one of our bedrooms by an electrician. Everything was working. Later in the day smoke detectors started to go off.

I called the electrician, he came back, wired the detector to the electric box to another breaker. Everything was fine for a few days, then they went off again just once a day with out any other lights on. When we have the lights on and shut the light dimmer off, the detectors stop.

Could the LED dimmer still be the problem?

Answer 1

Some dimmers cause electrical interference (radio frequency interference, RFI).

Check if it's heat or smoke causing the problem.

• If the issue starts immediately after the lamp is switched, perhaps only at a specific brightness setting, then it is likely RFI, not heat or smoke, causing the alarm.
• If the alarm(s) go on only after the lamp has been on for some time, this is a safety issue, due to overheating. Have this fixed for safety, and do not use that lamp until it has been fixed.

If it's RFI, then you have a few ways to try to fix the issue.

• Put ferrite filter chokes, like these, over wires coming from the dimmer. They might also need to go near the lamp, as well.
• Add an inline noise filter, such as this to the dimmer circuit.
• Replace the dimmer with one that has internal RFI suppression, such as this.
• Replace the dimmer switch with a simple on/off toggle switch.

The examples above are just for reference, and might not be suitable in your locale.