EMERGENCY!!? Do I have an electrical problem?

[Dale Thompson]

Hi Folks,
I'm down at the daughter and SILs - leaving tomorrow. I had finished four rooms in their basement and, for expedience, they had a "professional" finish the last one. At the entrance, he ganged four light switches. Three of them are Levitron slide dimmers and the other is simply on or off. The biggest load on any of them is less than 600 watts but when them are turned wide open they get HOT! I'm guessing that the temp is over 120 F because it is hard to keep your finger on the mounting plate after the lights are on for just a few minutes.

Maybe I'm crazy but I can't believe that this is normal. Please tell me I'm wrong. Thanks!!

Dale T.

[David Wilson]

Dale
I'm not sure but it sounds like they installed the old style reostat dimmers which do get hot. The newwer dimmers use a SCR to control the current to the light and run cool.

[Paul Berendsohn]

I'm not sure I've ever seen as much heat as your describing Dale, but dimmers can get quite hot, especially if there are several in the same box. As to rheostat dimmers, forget it, they haven't existed for residential applications in many years, all are SCR type. The better dimmers that use "zero crossing" technology run cooler. If in doubt, I bet Levitron has a tech line you can call for an opinion. If I can give you any assistance, drop me an email...

PaulB

[John Miliunas]

Dale, sounds "normal", but here's some more reading on it: http://www.askthebuilder.com/414_Dimmer_Switch.shtmlBTW, was kinda' wondering if you fell off the face of the planet or something! Nice "hearing" from you!:) :cool:

[Dave Richards]

Another possible issue is having three of them in the same box and having them all on together. That would be three times the heat of a single dimmer. I hope you get it straightened out before there's a fire.

[Dale Thompson]

Thanks guys,
I just talked to the factory rep and he says that 140 F doesn't bother him but if the heat sinks had been cut off for the ganging process, the dimmer should have been derated from 600W to 400W. In this case they weren't. They were just lapped over each other. While not as bad as cutting them off, it still requires some derating. The biggest load on any of the three circuits is 480W so I don't think that we have a problem. I'm not concerned about the daughter and SIL and the two grandkids but I sleep here once in a while and I want to make sure it's safe. ;)

Spring, the link was great and it had my exact question except for the temperature level. Anyway, as you know, I never WAS of this earth. I just stopped back for a short visit to make sure you Creekers were behaving yourselves. :)

Thanks again everyone. I know whom I can depend on. It's a comfortable feeling.

Dale T.

[Michael Gabbay]

Dale - I have the same switches in my basement. They run a little hot but not too hot to hold your hand on the plate. I also used extra large boxes which should help with the heat.

Mike

[Rob Russell]

Dale,

IMO, you do have an electrical problem if you have 480 watts of lighting flowing through a switch that's been derated to 400 watts. You're 20% over the derated capacity of the switch and I'd be concerned about the heat dissipation you're asking the switch to do. Furthermore, if you overlapped the dissipation tabs, you're effectively blocking the dissipating ability of the rear tab.

When we did our addition, I installed a LOT of recessed lighting, all on dimmers. I used the Leviton Decora style dimmers which are the 600W ones, derated to 400W if you break off both tabs.

One thing that I did was to take the outermost dimmers and only break off one tab (the "inside" tab). Taking off one tab was required so I could get all of the switches to sit flat. If you only remove the tabs on 1 side of those dimmers, the switch is derated to 500W, not 400W. So - if you can simply make the 480W circuit controlled by a switch located on either end of the box, you can have that switch derated to only 500W.

Rob

[Dale Thompson]

Dale,
If you only remove the tabs on 1 side of those dimmers, the switch is derated to 500W, not 400W. So - if you can simply make the 480W circuit controlled by a switch located on either end of the box, you can have that switch derated to only 500W.

Rob

Rob,
All of the heat sinks on the switches remain intact. Theoretically, that should double the capacity of the heat sinks even if they are in contact with each other. However, in this application I'm sure that it doesn't. In any case, it is understandable that the derating would not be fully from 600 to 400W. I guess that I will have to live with the factory guy when he said that a 140 F temp didn't bother him. As Michael said, I wish that they had used oversized boxes for greater heat dissipation - but they didn't. I also wish that they had gotten dimmers rated at 1000W but those are $30 apiece versus $15. I know. A small price to pay but who has control over their 30 plus year old kids?? :confused: :rolleyes:

Whatever, I'm going back to Peshtigo tomorrow so, if I can survive the night, I'll let the kids and grandkids take their own chances! ;)

The only caution that I got from the factory rep was that, over the years, the heat buildup could cause some deteriorization of the wire insulation. That, however, would produce a dead short protected by the circuit breaker.

I was never a fan of dimmers for this reason and now I am WAY to old to be infatuated by dimmed light, candles illuminating a sensuous health food dinner and the fruit of the vine.

Just gimme a manhattan, a big black Cuban cigar, some time to float in THE CREEK with a bunch of GREAT folks and a 52-3 Packer win. After that, you can shoot me ANYTIME! :) ;)

Dale T.