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Discussion Starter #1
A dimmer quesition for you. I have 12 can lights on a 20amp circuit in my house in the basement. That is all that is on the circuit. The 12 cans are divided on to 2 switches (6 cans per switch).

I wanted to switch the switches over to dimmers. Bought 2 of those $30 Levitron lumitron fancy touch dimmers rated at 600 watts according to the box.

6 x 75 watts = 450 watts on each dimmer according to my calculations.

After they are on for about 8 hours each bank starts to flicker and blink independently of each other. The metal on the dimmers get really hot.

The cans are all IC rated and there is even no insulation in the ceiling.

I switched out one of the dimmers yesterday and replaced it back with just a switch, turned on both banks, about 8 hours later the 6 cans on the dimmer started doing the flicker dance, the 6 on the regular switch burn true.

What the hell is going on? A 600 watt dimmer can't take 450 watts? 12/2 wire throwing off these dimmers? 20 amps throwing off teh dimmers?
 

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You failed to allow for resistance in the wiring and connections and are operating on the edge of destruction, stinkin' good. Even the box stores sell a 900W dimmer, just have to look for them. You know the other options.
 

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Mike Finley said:
What the hell is going on? A 600 watt dimmer can't take 450 watts? 12/2 wire throwing off these dimmers? 20 amps throwing off teh dimmers?
I have (13) 40 watt cans and (6) 75 watt cans each on 600 watt dimmers - been years without a problem. I have the on/off model switch that has a little sliding tab next to the toggle.
 

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Mike, I'm still working on this and can't come up with an answer right now. You are not using CFL's are? What type of bulb is in the fixture?
 

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i had the same problem and it had nothing to do with the load. the switch in my house just wasnt performing to specs. first put your amp probe around one of the sw legs at the switch when they first come on and then when they get hot that might be the problem also check the can rating br 30 par 38 30 watt make sure you are useing the right lamps. but your amp probe should tell all.
 

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Mike Finley said:
Is there a scientific way to figure this out such as measuring the resistance?
yes but it should not be causing that kind of reaction. you didnt put the dimmer on the neutral did you? also there are two ratings on dimmer wattage one for incandesent and one for ballast and or hid tfs.
 

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dimmers use a device called a triac (a type of thyristor)which is a solid state switch to control illumination by turning the light bulb on for only a part of each ac half-cycle (100 or 120 times a second depending on where you live) as determined by the adjustment knob or slider.once on it remains on for the remainder of the half-cycle:
For low intensity, the current is switched on late in the half-cycle.

For medium intensity, the current is switched on around the middle of the
half-cycle.

For high intensity, the current is switched on early in the half-cycle.

For full intensity, the triac may be bypassed entirely. There will probably
be a detectable click position with the control set to full brightness

it is best to select a dimmer with a higher power rating than your maximum load. For example, if you are using four 100 W bulbs, a 600 W dimmer should be the minimum choice and one rated at 1000 W would be better. This is particularly true if halogen bulbs are used since these may be harder on dimmers than normal types. Further derating should be applied where multiple dimmers are installed in the same outlet box resulting in greater combined heating. Higher wattage dimmer switches will have better heat sinking as well which should result in the active components - the
thyristors - running cooler. Dimmers are under the most stress and generate
the most heat when operating at about 50% output.
all that being said check the amps when its hot. :)
 

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Discussion Starter #9 (Edited)
jbfan said:
Mike, I'm still working on this and can't come up with an answer right now. You are not using CFL's are? What type of bulb is in the fixture?
Don't know what a CFL is. There are just 75 watt light bulbs, same as you would put in a lamp or any other fixture.

This is the dimmers I have.



Here are the spec if that helps, I means its supposed to be a dimmer, how complicated can it be?
http://www.ylighting.com/ln-ma-600.html

I see they make a 1000 watt version, but they retail for $97 each!!!!!!!!!!!!!
I'm gonna have second thoughts about spending $200 bucks.
 

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Discussion Starter #10
marxlaws said:
yes but it should not be causing that kind of reaction. you didnt put the dimmer on the neutral did you? also there are two ratings on dimmer wattage one for incandesent and one for ballast and or hid tfs.
Don't know what in the world you are referring to can rating br 30 par 38 30 watt? I know the cans are IC, rated at 75 watts each.

The neutrals are tied together, just the black wire with power in on one wire of the dimmer, the black wire going to the cans connected to the other wire of the dimmer.

Unfortunately, my volt meter is in my sailboat, 3 1/2 hrs away.
 

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Mike, I'm shocked! You always sounded so intelligent. Now I find out that you are a cave dwelling diaper hoister. I'm so disappointed. LOL
 

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Mike Finley said:
Don't know what in the world you are referring to can rating br 30 par 38 30 watt? I know the cans are IC, rated at 75 watts each.

The neutrals are tied together, just the black wire with power in on one wire of the dimmer, the black wire going to the cans connected to the other wire of the dimmer.

Unfortunately, my volt meter is in my sailboat, 3 1/2 hrs away.
the ic can has ratings listed in big print on the inside that refer to wattage and type of bulb you can safely use. br or par or etc .. not all lamps are created equal. and your not dealing with the old rehstat dimmer these are a different animal
 

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I assume you took derating into account? If you removed the fins on the sides of the dimmers each one would be rated at 400 watts. Even with one side broken off you are looking at a max of 450. Lutron dimmers are rated to carry the full wattage but after such a long period that heat will build up and cause problems.
 

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Light switch into an outlet??

Is there a way to turn a light switch that is no longer used into an outlet? How tough is this. The light that the switch controlled before is now controlled by a differant switch. But where the old switch is, i need an outlet. figured it would save time if there was a safe way to convert.
 

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Is there a way to turn a light switch that is no longer used into an outlet? How tough is this. The light that the switch controlled before is now controlled by a differant switch. But where the old switch is, i need an outlet. figured it would save time if there was a safe way to convert.
Yes, magic, call David Copperfield he'll be able to take care of that for you.


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If you are leaving these lights on for hours, you REALLY need to switch to CFL (compact flourescent light) bulbs. They'll use 25% of the electricity to produce the same light. Regular bulbs are really little electric heaters that produce a little light. AC to remove that heat uses still more electricity (and money)! They make dimmable ones and, if they don't fit in your cans, use a socket extension.

I just saved you hundreds of dollars.
From everything I have heard, dimmable CFLs are expensive, and do not work very well.
 

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Discussion Starter #19
If you are leaving these lights on for hours, you REALLY need to switch to CFL (compact flourescent light) bulbs. They'll use 25% of the electricity to produce the same light. Regular bulbs are really little electric heaters that produce a little light. AC to remove that heat uses still more electricity (and money)! They make dimmable ones and, if they don't fit in your cans, use a socket extension.

I just saved you hundreds of dollars.
I have 10,000 freqent flyer carbon offset miles to use up so I'm not worried about that.
 
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