I have a question about dimmer switches for LED flood lights. My kitchen has six floodlights on a Lutron toggler dimmer switch, model AY-603P.


Up until now I have had fluorescent lights in them. The lights needed replacing so I ordered some new ones, however, I accidentally ordered these LED bulbs instead...


The LED bulbs I ordered are dimmable so I decided to try them out and they seem to work just fine on my dimmer switch, no buzzing or flickering. My question is...

Is this safe? I had read that I should only use LED approved dimmer switches with LED bulbs. My dimmer model does not say that it is LED compatible, the manual for the Lutron AY-603P dimmer switch says that it can be used with halogen and incandescent lights, it doesn't say anything about LED lights. Are there any electrical risks to using LED bulbs on a this type of dimmer switch? Any commentary guidance would be welcome. Thanks!

  • 4
    Do the bulbs say "dimmable"? Feb 18, 2019 at 17:01
  • 1
    it's not a safety problem, it's a performance problem. Non-LED dimmers used with cheap dim-able LEDs might only dim for a portion of the range, most commonly "they won't get very dim". You can also have some issues with dark flicker if it's not completely off. However, high-quality dim-able LEDs have extra smarts inside the bulb to behave correctly with older dimmers, so it's been kind of a confusing back and forth.
    – dandavis
    Feb 18, 2019 at 20:48
  • 1
    @TomCarpenter Yes they are dimmable LEDs. I will update my post.
    – b10hazard
    Feb 19, 2019 at 1:21

3 Answers 3



From this LED compatibility guide on Lutron's site, the following output.

enter image description here

Further, The service manual you link states clear that

  1. CAUTION: Use “AY-” or “TG-” models only with permanently-installed 120 V incandescent or halogen fixtures. To avoid overheating and possible damage to other equipment, do not use to control receptacles, fluorescent lighting fixtures, motor-driven appliances, or transformer-supplied appliances.

That's it. It's not "not saying" about LEDs, it's saying very specifically about LEDs, since it allows only incandescent and halogen (which are incandescent). Open up "See Aridani/Toggler model numbers", and open up "Dimmers" (the only category), i.e. here, it lists several categories and the results in each echo the above.

Welcome to the world of off-label usage. Which means UL has not tested this equipment for this usage. It might work, might not, might get magic smoke, it's all on you.

So the ultimate answer to your question is, shrug...

  • Actually -- the Ariadni/Toggler dimmers are all phase-cut types Feb 21, 2019 at 0:31
  • @ThreePhaseEel Yeah, somehow I took a wrong turn and found myself looking at the wrong data sheet. Feb 21, 2019 at 1:32
  • Oh wow. When I purchased my house they had already installed dimmable fluorescent bulbs on this dimmer switch. To think all these years I was using fluorescent bulbs when I shouldn't have been.
    – b10hazard
    Feb 21, 2019 at 18:22
  • @b10hazard: It's possible for a fluorescent or LED lamp assembly to contain circuitry that will make it behave electrically in a manner similar to a low-wattage incandescent lamp, though there are some trade-offs among cost, energy efficiency, and the extent to which their behavior mimics an incandescent lamp. Unfortunately, there are no standards for measuring how similar an particular lamp assembly's electrical behavior is to an incandescent, nor how closely a switch would require a load's behavior to mimic an incandescent.
    – supercat
    Jan 31, 2022 at 17:28
  • @b10hazard No no, the point of the compatibility guide isn't safety, it's performance i.e. will the light work well. They are saying "We tested these and they work great and we warranty our dimmer to work with them". What you have is like a can of soda that expired 2 months ago (they generally get 9 months)... it's still drinkable but the taste might be off. If it still tastes good, go for it. Jan 31, 2022 at 18:23

If the led lamps are dimmable and are working they will be fine. The normal problems with led's is they draw so little current that many dimmers cause them to glow and or strobe, with 6 your load may be enough that you don't see any problems like you may with only a single lamp on that dimmer.


I don't think anyone can advise you with certainty if this is a good idea, except maybe the manufacturer.

That said, yes, this is safe provided the LED lights are rated at 100 watts or less each. Worst case scenario is the bulbs will fail sooner then they would be expected to. My guess is that this is fine to do if it works, but if there is annoying flickering you should drive the dimmer on full until you can get a replacement.

There are 2 reasons for my answer -

  • (Assuming the total load is less then 600 watts, ie the wattage in actual watts the dimmer consumes, not the "incandescent equivalent brightness - - and as you are using LEDs thats a fairly safe assumption) The load is less then the dimmer is capable of handling. This means it is electrically safe, in as much as you are not going to have heat buildup which the dimmer can't handle.

  • Mains rated LED bulbs have circuitry in them to handle dimming. Depending on the manufacturer this circuitry can be quite different. If the circuits are not compatible with the dimmer, it could cause them to not work correctly or fail early.

  • The LED dimmer I have has a setting inside it to make adjustments depending on load. My guess is that this is true of most LED dimmers, and this is needed because LED loads can be way lower then incandescent loads.

  • LED bulbs that aren't designed to be dimmed may use a capacitive-dropper circuit which relies upon the mains voltage to rise and fall gradually during each cycle. Such circuitry would need to be designed to absorb an occasional current spike caused by turning on a light switch when the line voltage is at its peak, but many dimmers designed for incandescent lamps would subject a capacitive-dropper lamp assembly to such stresses 120 times per second.
    – supercat
    Apr 15, 2021 at 21:23

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