2

Prior to the ubiquity of LED bulbs, I installed a Lutron dimmable light switch in a bedroom that runs a wall socket.

enter image description here

With incandescent bulbs, everything worked great, but when I switched out all of the bulbs for dimmable LEDs (Cree), the bulbs would not turn off all of the way. They would only go to their (assuming) minimum brightness.

I put one incandescent back into the 2 lamp, 4 bulb configuration circuit. With the load an incandescent bulb has by virtue, all the bulbs turn off all of the way. Proving the theory correct, when that incandescent bulb died, the LEDs turned back on to their minimum brightness. Replacing the incandescent with another I had leftover and was holding onto for this very purpose, the issue was once again resolved.

I would like to know if there is another way for me to achieve this without an incandescent bulb on the circuit? Is there something that provides a minimum load that I can add to the circuit (pass-through) that will provide this minimum load?

For those concerned about the dimmer on an outlet, your concerns are founded and understood. Having said that, it's marked as dimmer, it's behind a nightstand, generally inaccessible, and fully occupied by the lighting. I will swap out the dimmer if I ever move. But, whilst I own the property, it'll be okay. :)

5
  • 4
    IIUC, you have a dimmer switch controlling a receptacle into which you have lights plugged? (Sorry, can't see your image here.) That's not recommended, especially in the age of LED-everywhere lighting, but in general. What happens if you plug your vacuum into the outlet but don't turn it up to full "brightness"? Your vacuum won't enjoy running on reduced power, nor will any other non-incandescent-bulb load. Your better bet would be to put in a regular toggle switch and get a dimmable light fixture instead.
    – FreeMan
    Aug 2, 2023 at 16:09
  • 4
    You can only (legally) have a dimmer controlling a receptacle if the receptacle is a special, weird, barely seen in real life (can't say I've seen one) receptacle for lights only, to prevent other things from being plugged in. Then you have to refit the plugs on the lamps to the mating weird plug.
    – Ecnerwal
    Aug 2, 2023 at 16:22
  • 2
    Violating code is one thing. Violating common sense is another.... No electrician worth their salt ever leaves a situation that would have to be explained to the next guy. "I will swap out the dimmer if I ever move." - that's why there's code, because I also will have a hamburger today that I will pay for tomorrow.
    – Mazura
    Aug 3, 2023 at 0:37
  • @Ecnerwal that was a new one for me. Lutron appears to have discontinued them but there's a PDF with info here: files.lutron.com/hwi/TRG/…
    – KMJ
    Aug 3, 2023 at 14:45
  • I wonder if it would be possible for a company to get regulatory approval for a "dimmer" that would act as a switch with a series-wired transformer that would inject a modulated control signal that would be used by the company's light fixtures or lamp adapters? Designing an LED fixture that can receive continuous voltage but dim itself to 1% brightness on command is much easier than trying to design a fixture that can respond sensibly to the output from an ordinary dimmer switch.
    – supercat
    Aug 3, 2023 at 15:53

6 Answers 6

5

Lutron makes a LUT-MLC bypass capacitor which serves the same purpose as the incandescent bulb. Install it according to instructions and see if that takes care of it.

4
  • It's a jumper wire? Nobody makes a thing with just socket ends?
    – Mazura
    Aug 3, 2023 at 0:30
  • @Mazura you have to install the bypass device inside the dimmer, not inside the socket. Or perhaps you refer to the light socket, rather than the mains socket? Aug 3, 2023 at 9:46
  • 1
    @Mazura it goes behind the lamp socket on the lamp side of the wiring. Aug 3, 2023 at 10:05
  • Now that one is pretty cool.
    – KMJ
    Aug 3, 2023 at 14:42
5

Frame challenge: The solution is to buy a new dimmer switch that uses a mechanical on/off switch and a physical slider, eliminating the need for idle current. This eliminates any kludges and wasted energy.

As you state, the problem is your pre-LED/CFL dimmer is obsolete.

2
  • I know, I'm just being cheap. Aug 2, 2023 at 18:06
  • 1
    @RoyHinkley even if you have to pay an electrician to do the replacement, the cost of the power wasted by the incandescent bulb will end up more expensive than fixing it the right way over the long haul. Aug 3, 2023 at 22:49
5

Some LED-compatible dimmers have a dark-level control knob behind the plate that adjust how much electricity the full-dark switch position puts out. This allows for adjusting to different bulb types (incandescent, CFL, LED). (Citation: I put one in on my old house for the bedroom, where the lights were incandescent but I knew I'd be going to LED one day. I do not remember the manufacturer, but I got the dimmer at Home Depot.)

Incandescent bulbs will be unavailable one day, making the present full-dark solution not future-proof, and they take up too much electricity to run. Time to get a new dimmer.

3

It is not a good idea to use a wall dimmer switch on a switched receptacle that might be used to power electronic devices, e.g, notebook computer power supplies or phone chargers. In my experience a dimmed receptacle will cause these to fail internally.

2

There's another way to get a minimum load: you could put in a heater that doesn't have the side effect of providing light. They are often sold as 'reptile heaters' and screw in to an ordinary light socket.

The better plan is either to keep using one incandescent bulb so you get the benefit of the light being produced, or to replace the dimmer switch with an LED-compatible one. My experience dimming the Cree bulbs with LED-compatible dimmers has been excellent.

It's also possible that this dimmer is connected to a switch loop without a neutral. If that is the case, it's drawing power to run the electronics inside it through the bulbs, and that happens to be enough energy to light the LEDs. To fix that issue without rewiring, you will want to switch to a dimmer that has a physical switch alongside the dimmer setting. Those can work properly on a switch loop even with LEDs.

1

Just use different bulbs.

Many bulbs, for example ecosmart include a small resistor across the internal LED string. This provides a back-connection to your dimmer so it has power to run the small LED brightness indicators and internal logic. It also snubs out that small current that can cause "ghost" lighting on lesser bulbs resulting from triac-based switches like motion, non-ticking timers, dusk-to-dawn, fancy dimmers, etc.

You could argue that such resistors impose a minimum brightness, which they do, but it's hard to have a very dim LED that doesn't flicker with line voltage fluctuations anyway. The bulbs I have play well with the wide variety of dimmers and doo-dad switches I've picked up from Habitat ReStore.

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.