Latest Discussions : Electrical & Lighting


05:06AM | 07/26/05
Member Since: 07/25/05
2 lifetime posts
In my basement I have 4 zones of recessed lights on 2 separate 20 amp dedicated light circuits. Each zone has (9) Halo (H7T) recessed halogen flood lights with 75 watt bulbs for a total of 675 watts per zone. I installed (4) 1000 watt single pole dimmers to control each of the zones. I placed 2 dimmers in each 2 gang thermoplastic switch box (~4 & 3/4" deep) so the box wouldn't be overcrowed with wires.

I would like to know if it is normal for the metal face plates of the dimmers to get hot enough that you cannot touch them for more than a couple of seconds without having to remove your fingers from the metal facing of the dimmer (Note: The termoplastic boxes are not hot to the touch, just the dimmers). I know dimmers are supposed to get warm but

it makes me a little uncomfortable that they are so hot. I have used lower watt dimmers (600 watt) in other areas of the house in the past but I just don't remember those dimmers getting so hot. I realize that the higher watt dimmers are going to generate more heat but how much

heat is too much?

Does this seam right? Does anyone have any recommendations on how to dissipate some of the heat on the dimmer switch?


04:51PM | 07/26/05
Member Since: 05/03/05
79 lifetime posts
To answer part of your question: Your 1000 Watt dimmers are no longer 1000 Watt. Once you "gang" them together, you needed to break off some of the heat sink. This means the dimmers are probably only good for 700-800 Watts depending on manufacturer. Check your paperwork on the dimmer if you still have it or post the mfg and model #.

Some require metal boxes for added heat disipation.


01:22PM | 08/01/05
Member Since: 07/25/05
2 lifetime posts
Thanks for the response. This weekend I swapped out the thermoplastic boxes for metal ones. That helped to reduce the heat a bit. The dimmer switches are Lutron Skylark 1000 watt dimmers. The maximum wattage is 800 watts when you break off one side of the heat fins (600 when you break off 2 sides). I'm currently running 675 watts through each zone so I'm running at approximately 85% capacity. One thing that I did notice while experimenting with the dimmers is that they seem to get hotter when the lights are fully turned on. I was surprised by this as I thought dimmers were supposed to get hotter when they are dimmer.

I remember someone telling me that they make dimmers that click to the full on position and they act like a regular switch. Supposedly, they don't produce heat like a regular dimmer when they in the full "on" position. Has anyone heard of such a dimmer switch? If so, would you know where I can get my hands on one to test?


02:47PM | 08/01/05
Member Since: 04/25/05
1915 lifetime posts
Dimmers use electronic switches called tracs. When on they have a small, but constant voltage drop across them which produces the heat.

They turn off each 1/2 cycle and delay until they turn on for the next 1/2 cycle. The more that they delay the dimmer the light. When they are not on the don't have a voltage drop and don't generate heat. So the dimmer the less heat that they put out.

The type of dimmer that you are talking about is called a bypass dimmer. Pass and Seymour (sp?) make some.

I don't know how "sensitive" your fingers are, but they do get fairly hot.

Another option would be to go up in side, but they are double size and have heat sink fins on the surface.

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