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Trying out the OT forum

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Trying out the OT forum

#1

Ellis Walentine

Trying out the OT forum

This is an OT electrical question. Our kitchen has about 15 puck lights mounted under the top cabinets. They are in three groups, each controlled by a Lutron 600w one-way dimmer switch. I just changed all the little G8-20w halogen bulbs out for LEDs, and now, for some reason, they all stay on low, even when the dimmers are switched off. I can't figure out where this residual current is coming from. There's also a recessed ceiling light that stays on when it has a LED bulb in it, but not when a tungsten bulb is in there. Is this a known issue with LED bulbs?

Ellis


Re: Trying out the OT forum

#2

LEDs on OT Forum

There are various issues with changing to LEDs when on a dimmer. Not all dimmers are stated to work with LEDs and some that are aren't happy with any old LED. Often the dimming action is very non-linear or outright sporadic. I have had a bit of luck by installing the LEDs but putting one of the, in your case, G8 halogen bulbs in the string. This seems to put a load on the dimmer that makes it happier. Easy to try.

Bill


Re: Trying out the OT forum

#3

I have the same phenomena

I turn off the switch and the LED dims but does not extinguish.  It takes a piddly amount of voltage and current to run LED's, but where it is coming from I do not know. 


Re: Trying out the OT forum

#4

Peter Martin

Re: Trying out the OT forum

Many electronic dimmers used with halogen or incandescent bulbs don’t suit LED lights. Old electronic dimmers need a minimum load to function correctly, which the economical design of LED light doesn’t offer. If the minimum load is not achieved, the dimmer cannot completely turn off the output voltage even after powering down.

Other things could cause this, such as the neutral not being properly grounded to earth or electromagnetic induction due to parallel cables. 

Occam's razor sez it's the dimmer, tho.

These use Pulse Width Modulation (PWM) and are easy to find:

Maestro LED+ Dimmer Switch for Dimmable LED, Halogen and Incandescent Bulbs, Single-Pole or Multi-Location, White


Re: Trying out the OT forum

#5

Re: I have the same phenomena

The dimmer circuit has some electronics in parallel with the main switching device (triac or whatever) and there is enough current, even though tiny, through this circuit to make a LED show a bit of illumination. 

Bill


Re: Trying out the OT forum

#6

Ellis Walentine

That works

Thanks, Bill. This is encouraging. I did notice that they didn't stay on until I changed out the final one in each group. I just know so little about dimming technology that I didn't realize there was residual current.

Ellis


Re: Trying out the OT forum

#7

Ellis Walentine

Re: Trying out the OT forum

Actually, I kinda like the little bit of ambient light these things put out. They only draw 2 or 3 watts, so I can't imagine a fire danger if they remain dimly lit when the switch is off. And they are supposed to last 25,000 hours, so if I only have to replace them every three years, I can live with that. All good.

Thanks to everyone for the good info.

Ellis


Re: Trying out the OT forum

#8

Why did you change?

I have the same G8-20w puck lights that I installed with a new kitchen remodel just two years ago.  I initially thought about using LED but we personally preferred the warm look of the halogen bulbs.  We did LED can lights and pendants, but stayed with halogen for the pucks.  I'm curious why you chose to change.


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