I Installed a dimmer switch for an outside light, (the modern type with the little slide beside the switch. over xmas I pluged my LED xmas lites into the socked that the dimmer controls. I noticed when it got dark I could faintly see the xmas lites barely lite, I first thought I had the switch on and the dimmer set low, but the switch was actually off. My question is if the switch is off on a dimmer is it possible that a small amount of current is still getting by?

 

I saw this in a house I was working on this summer. That's the only thing it would be that I can think of. I imagine you could take apart the switch and fix it. but I figure you could just return it and get a new one that works right for free. Somebody who knows more about this than me will prolly be along soon with a better answer.
-matt

 

i have one like that. the switch is off and on and the slide never goes to a complete off. thats what the switch is used for.

 

If I'm guessing right, the dimmer works by chopping the AC cycles by detecting the line voltage as it swings above and below '0V' and switching on or off the rest of the cycle some time afterwards (measured in milliseconds). When in fully on bright mode, it lets all of the AC through. When dimming, it only allows a portion of the power through. Since nothing is perfect, I assume there's some leakage current or it doesn't really turn completely off in the fully dimmed setting.

If you run a normal incandescent light, there's probably not enough current to light it much less warm the filament. LED's don't take more than a few milliamps at a couple of volts to light up, so any leakage would be enough to turn them on.

But the fact that there's some current leaking even when 'switched off' raises my eyebrows... is it UL listed? I don't know what the leakage limits would be assuming that was a tested spec.

 

yes it UL listed. I just wasn't sure if the switch is faulty or it is not unusual that theses dimmer switches leak some current when the switch is actually off, regardless of the dimmer part of the switch I would think that when a switch is off it should be off

 

well yes there should be zero volts. i did not understand that part of your problem.

 

Dimmer switches always allow a small amount of current to flow which can be read by a meter. They need a small amount of current to operate the circuit inside them. Your LED Xmas lights may glow under those conditions. A regular incandescent lamp would not operate. Some dimmer switches have a small on-off switch built into them.

 

I had a situation similiar to this. I installed a flourecent light in my shed (12'X16'), running thru 2 breaker boxes. What it ended up being was GROUND. I had an electrician friend of mine stop by to tell me why when my switch was in the OFF position I was getting a faint charge thru the tubes. He used his meter and there was a major ground difference between my garage and the shed. I installed grounding rods at both locations, installed a grounding terminal block in both breaker boxes and lo and behold, the light does not glow when the switch is in the off position.

 

This really sounds like a backfeed on the Neutral wire somewhere, and it doesn't necessarily have to be at that switch. The switch is either off or on, No voltage should pass through that switch at all, when that switch is off. Underwriters Laboratories would never allow an AC voltage to stray, because there is nothing in the switch to control the voltage from faulting.

Now when the switch is on, and the dimmer is all the way slid down, there will be a minor voltage, It works like variable resistor, The higher the resistance the less light. vice versa. Does the dimmer have leads? I will assume so. And I believe you said it could be used as a 3-way switch. Are you positive you have the proper leads to the prospective locations? The reason I say this if you have it hooked up on the 3-way lead with the switch in the down position it still would be on.

 

no its not a 3way switch the patio light is switched by this one switch only. should I change the switch or do you think the switch isn't the problem here? is it dangerous to leave it this way? thanks for the input guys

 

what brand of dimmer is it? did you buy one of those sockets that you put in a light fixture that you can plug a cord into? The coach light could not be grounded correctly causing this.

neutrals just recirculate the ground for the most part. It can be difficult to explain.

with some dimmers, you just push the **** and it will turn it off completely. If you have it on the lowest dimming setting then there will be very very small amount of voltage which like said before is not enough to show on an incandsent but could on LED.

i think what witdog is talking about is that you can use the dimmer for either a single pole or 3 way. There should be a green lead (ground), white(neutral), and a black coming off the dimmer. If there is a black with white stripe or a red wire also (could even be another black, just depends on brand), then that dimmer can be used for a 3 way.

try pushing on the **** unless it is a slider. look at the schematics that came with the switch. If you want, take it back and say it is a bad dimmer. Tell them you need a single pole dimmer. There isnt a major problem but it may be slightly annoying that your lights dont turn off completely. I havent worked with LED so I dont know much about them.

 

Dimmer switches are not ON-OFF switches. If you don't want the LEDs to glow then replace the dimmer switch with a standard ON-OFF lever switch. It is normal for dimmer switches to let thru a small current, it is required for operation. They are also not a variable resistor although the switch lever or **** is connected to a potentiometer. The potentiometer controls an electronic chopper circuit. Most standard dimmer switches are for use with incandescent lights only. There are some special dimmer circuits for and lamps for use with fluorescent lights.

 

powerstroke I did use one of those sockets you put in the light socket then plugged an extension cord into it. I'm pretty sure its a single pole dimmer. It sounds like what Torque1st said is a small amount of current does run through theses dimmers even when the switch is off.

 

well they do make dimmers that are rotary (round ****) that you push in on the **** and it acts as a switch and then turn clockwise, resistance decreases (light gets brighter) and counter clockwise, resistance increases.

 

I have seen toggle switches with a small slider next to the toggle for dimmer, when the dimmer is set use the toggle for on/off. Home Depot had 'em.
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