Electronic Rheostat ----HOT!

[54FordPanel]

Does anybody have electronic rheostats like this? I use them to tone down my kitchen lights.
I just notice the rheostats are HOT when the lights are on. The screws thru the cover plate are so hot you can't keep you finger on them.
When they aren't on, they aren't hot.
I thought it might be a problem if one was hot and the other one wasn't, but they are both hot.

Is this normal?

 

[sneezer41]

regular dimmers do get warm, but I would not say hot

 

[nehog]

How much of a load do you have on them. What kind of bulbs are they dimming?

 

[54FordPanel]

How much of a load do you have on them. What kind of bulbs are they dimming?

9 65 watt ceiling lights on one circuit, 12 on the other.

 

[electrican]

did you brake off all the tabs when you installed them?

 

[electrican]

your dimmers are overloaded, you need 1000 watt dimmers, also you need to k
reed the instructions about braking off the tabs when you gang them up. because it derates the wattage that the dimmer can handle.

 

[54FordPanel]

your dimmers are overloaded, you need 1000 watt dimmers, also you need to k
reed the instructions about braking off the tabs when you gang them up. because it derates the wattage that the dimmer can handle.

Ok, I need 1000 watt dimmers. But I don't understand the 2nd part of your post....what tabs?
The rheostat switches don't have tabs, they have wire in/wire out.

 

[electrican]

some dimmers have tabs on the side, that you brake off when you gang them up, they are for the dissipation of heat, when you brake them off it derates the wattage

 

[54FordPanel]

some dimmers have tabs on the side, that you brake off when you gang them up, they are for the dissipation of heat, when you brake them off it derates the wattage

Ok, these don't have those, they just have 2 blacks, in/out. So I need to find a rheostat that's rated at 1000 watts....is that my problem?

Edit: I just recounted my lights. I have 9 65 watts on one circuit, 10 on the other.

 

[nehog]

I'm going to assume incandescent light bulbs not CFLs...

Yes, 9 and 10 basically exceeds the rating of that dimmer. You might be able to get a bigger dimmer, but study it carefully and make sure it doesn't require a larger box. Some wall plate dimmers are rated around 400 watts, and will get hot as can be at the full wattage. Dimmers for higher wattage are frequently two piece units, with a module that mounts remotely that generates the heat being outside the box (attic mounted, for example).

What model are your dimmers?

 

[rsanter]

modern dimmers are no longer reostats. they are stepping or switching circuts
the older type dimmers got warm and some got hot (which was a problem)

call the manufacturer, but I suspect a problem and I think you will want to deal with it asap

bob

 

[cowboyjosh]

With the load on the dimmers its only a matter oftme before they fail on their own, its not the end of the world that they are being taxed to their designed limit, but i would rectify the stuation a soon as you get a chance.

 

[54FordPanel]

Thanks for the info, folks.

I went to the Home Depot website and I don't see the exact dimmer switches I have, but I do see that most of the dimmers are 600w, and some are 1000w.
I'll assume the ones I have now are 600w.

If I switch these out for 1000w dimmers, should that fix my problem?

 

[ddawg16]

Just and FYI.....the dimmers are not doing anything to save energy.....

If you really want different levels of lighting....I would suggest switching in banks of lights....that way you reduce your chances of a fire.



(I will NOT mention CFL's....I will not mention CFL's.....I will not mention CFL's)

 

[cowboyjosh]

I hate CFL's in recessed fixtures, so I can't consciously recommend them.

Go to Lutrons website www.lutronstore.com and look for a pair of 1000 watt dimmers, you still might have to derate the dimmers to fit both into the box.

You might also GOOGLE "Lutron 1000 watt dimmers" and get ahold of them that way.

Home Depot and Lowes are going to be pretty much useless to you as I have never seen them carry a dimmer with a capacity greater then 600 watts. You might check you local electrical supply houses, they might have a 1000 watt dimmers in stock in the color you want, but 1000 watters are usually a specialty item, so online might be your best bet.

 

[54FordPanel]

Great, thanks.

 

[Greatbear]

Most if not all dimmers are rated singly. The metal plate on the front of the device is also its heat sink. When installing them ganged together in a box, the metal fronts are too wide to fit next to one another, but you are able to break off removable tabs on the edges that meet one another. This decreases the surface area of the heat sink, and will make the device run hotter. Most average dimmers are rated for 600 watts. Removing the tabs on one side will reduce the rating to 500 watts, and if you gang three or more devices in the same box (and remove the tabs on both sides of the device) the rating goes down to 400 watts for those devices. Do note that 1000 watt dimmers are made differently, they have a finned external heat sink, and they don't use a normal wall plate, instead they mount on the box and extend from the wall. You can gang these devices together as well, but the same rule applies because you have to remove fins from the heat sink to nestle the devices against one another, and you reduce the ratings as well. You'll lose about 200 watts for each side of "fins" removed.

 

[54FordPanel]

Thanks for the info. Since I've read your responses, I googled 1000w dimmers and found out a whole lot I had no idea about. Mainly, that these dimmers are dissipating heat as a percentage of the load. I had no idea.

http://www.smarthome.com/forum/topic.asp?TOPIC_ID=6969

I know now that my load is near my dimmers limit, and that having 2 dimmers working that hard in the same box is a bad idea. I'll rethink it.

Thanks.

 

[mrb]

Just and FYI.....the dimmers are not doing anything to save energy.....

If you really want different levels of lighting....I would suggest switching in banks of lights....that way you reduce your chances of a fire.



(I will NOT mention CFL's....I will not mention CFL's.....I will not mention CFL's)

what are you talking about? of course dimmers save energy.

also they greatly increase lamp life- dimming an incandescent lamp to 75% increases its life by about a factor of four.

 

[54FordPanel]

Follow up:
I found some 1000w dimmers at Home Depot, though not any that had the cool presets on them. I liked those presets.

I put in a 3wide gang box, and put a dummy plate in the center so the dimmers weren't right against each other. I also drilled a bunch of holes in the gang box for air circulation.

Result is zero warmth from the dimmers. Thanks for the info guys.

 

[comedyman809]

modern dimmers are no longer reostats. they are stepping or switching circuts
the older type dimmers got warm and some got hot (which was a problem)

call the manufacturer, but I suspect a problem and I think you will want to deal with it asap

bob

they are TRIACs