I just replaced the guts of some ceiling cans with retro plug in LED lights. However, I didn't replace the 40 year old dimmer with a dimmer for LEDs. Is that a fire hazard?

  • 3
    From what I read on here, it is more possible that you do not get dimming. For dimming LEDs both the lights and the dimmer must work together. Not all LEDs can be dimmed/placed on a dimmer and newer dimmers work differently than the older types. Probably not a fire hazard but the life span of the LEDs might be shorten a lot.
    – crip659
    Commented Dec 24, 2023 at 16:21

1 Answer 1


It is not a fire hazard. A dimmer or timer or any other device that acts as a switch but is more than just a physical on/off switch has a power limit. (Actually, even a simple switch has a power limit, but in the US switches are normally rated at least 15A, and in any case a simple switch doesn't care what type of load you have.) LED lights are far more efficient than incandescent lights, so even if your LEDs provide twice as much light as before, the total power used will be far less than before. A typical 60 W incandescent bulb produces 800 lumens of light. An equivalent LED uses consumers around 9 W of power (more or less depending on type, brand, etc.).

However, there are methods of dimming which simply do not work well with most LED lights. A 40-year-old dimmer will cause problems with many LED lights, such as:

  • Always 100% brightness
  • Always very dim
  • Blinking/flashing
  • Dim or off at low settings, 100% at higher settings

and it is really hard to predict the results. So if your dimmer works with the lights you installed then you are OK. If it doesn't work then look for a dimmer specifically rated as "LED compatible", and ideally one that is recommended by your light fixture manufacturer or that has your light fixtures listed as specifically compatible with that dimmer - some manufacturers have compatibility lists available online.

Note that there can be fire hazards in other situations. For example, running a motor (e.g., ceiling fan) on a regular (lighting) dimmer can cause serious problems and is not recommended.

  • Thanks. I did see that Lutron renamed "C.L." model dimmers for LED to the new "LED+". So, most of their dimmers in big-box stores have a "LED+" logo on the box.
    – wjktrs
    Commented Dec 25, 2023 at 20:34

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