[Badfish740]

So I finished the recessed lighting in my basement and I have two banks of lights-one with 11 lights and one with 4 each controlled by it's own dimmer. The dimmers are mounted at opposite ends of a triple gang box with a three way toggle switch in the middle that controls the lights on the stairs (separate circuit). I did this deliberately because by placing the toggle in the center of the two dimmers I didn't have to remove any of the cooling fins which would derate the capacity of the switch. After turning the lights on I noticed how warm the dimmer switch with the 11 lights (65W x 11 = 715W) got and held my finger on the switch (no switch plate, just the aluminum cooling fin) and it was beyond warm-I'd say uncomfortably hot as I felt compelled to remove my finger. To me that's more than warm. However, everything checks out-the bulbs are all 65W and the fixtures are 65W max anyway-and there are definitely only 11 of them :laughing:Given that, I really wonder how hot the switch would get with a full 1000W load! Can anyone corroborate this? I mean, as a test I left the lights on literally all day on Saturday at various levels. When the lights are dimmed all the way the switch runs noticeably cooler-likewise if you remove 4 or 5 bulbs. Nevertheless, I let the lights go for about 5 hours at full power (I was home the entire time working in the basement) and checked the switch periodically-nothing so hot as to cause burning or melting, but still, it seemed more than just "warm."

 

[Saturday Cowboy]

they do get pretty warm. However don't throw caution to the wind. I am going to say that nothing is wrong, but I cannot see feel or other wise look at it.

Now some times the manufacturer requires derating even if no fins are removed if more than one is installed in the same box.

The cover plate is used to prevent direct contact with switch, thus reducing the preceved heat of the device.

 

[nap]

I saw one that caught on fire, and it wasn't overloaded based on the specs.

I tend to go by feel. If I cannot keep my hand on it, it's too hot and you need a larger (rated) dimmer or a smaller load.

While they are supposedly tested at the rated current, after seeing the one catch fire that was definitely not overloaded by the rating, I tend to be cautious.

 

[Badfish740]

I saw one that caught on fire, and it wasn't overloaded based on the specs.

I tend to go by feel. If I cannot keep my hand on it, it's too hot and you need a larger (rated) dimmer or a smaller load.

While they are supposedly tested at the rated current, after seeing the one catch fire that was definitely not overloaded by the rating, I tend to be cautious.

Then what the hell good is Undewriters Laboratories or the NEC? It's not as
if I'm applying a 999W load to the switch. I suppose I could find a 1500W dimmer but I'm guessing I'd have to order it. I got the 1000W for an extra margin of safety and that was tough to find at Lowes. Perhaps it's a good idea to go with dimmable CFLs ($$$$$$$$ ) as well? I think 65W incandescent translates to about 14W CFL so 14 x 11 = 154. Then I suppose the 1000W dimmer was a waste of money...

 

[dmxtothemax]

All dimmers will produce some heat,
But it is usually made worse by putting it in a sealed enclosure,
where no air can circulate. The heat has to go somewhere.
Is there any room behind it ?
Can any air circulate around it ?
If not perhaps you should try to allow some air behind it ?
Or use a remote controled type of dimmer,
where the main control unit can be located in a better position.

 

[Saturday Cowboy]

some dimmers will not work with CFLs