Residential Dimmer Switches...How Hot Should They Get?

[ArcNSpark]

I've asked the supply house guys and my boss, but nobody has a solid answer. I've installed 600W Ariadni style (looks like a toggle switch but has a skinny vertical slide on the right side of the toggle) switches in houses for years, but it seems that when they're running, they heat up to an almost dangerous temperature. I'm talking about almost too hot to hold your hand on the cover plate.

And before I get skewered here, I am religious about keeping under the rated limit of 600V, I don't exceed the derated limits of 500V with one side of tabs removed or 400V with both sides removed, and I even recently used a 1000W dimmer for a switch that controlled 9 recessed cans, each with a 65W BR30 lamp, and that 1000W dimmer with a load of under 600W was still hot as hell.

Homeowners have been asking concerned questions lately; even calling me and saying that they can smell plastic burning.

Is there anyone here who knows what the deal is? Thanks in advance...

 

[mxslick]

From the Lutron website:

"Why do dimmers get warm, and is this safe?"

The technical explanation: During normal operation, solid-state dimmers generate heat. A solid-state dimmer is roughly 98% efficient ? 2% of the power is dissipated as heat, which causes the dimmer to feel warm to the touch. The closer a dimmer is run to full output and the higher the load (watts) on the dimmer, the warmer it will feel.

This is perfectly normal and safe. Lutron dimmers are designed to the strictest UL safety standard, and can handle their full rated load (a 600 W dimmer can handle a full 600 W of power* without overheating.
*Dimmers that are ganged together in a common wallbox may need to be derated.

For electrical equipment, "warm" is a temperature that can be very uncomfortable to a hand. (IIRC 40c is about 104f and that is a usual temperature for "warm" electrical equipment.)

As for the "burning plastic" smell, I take a customer's account of that with a huge grain of salt. Plastic that is being heated by a dimmer will exude a smell, as the volatiles in the plastic vaporize.

But unless there is obvious smoke or discoloration there is not a problem.

 

[LEO2854]

I've asked the supply house guys and my boss, but nobody has a solid answer. I've installed 600W Ariadni style (looks like a toggle switch but has a skinny vertical slide on the right side of the toggle) switches in houses for years, but it seems that when they're running, they heat up to an almost dangerous temperature. I'm talking about almost too hot to hold your hand on the cover plate.

And before I get skewered here, I am religious about keeping under the rated limit of 600V, I don't exceed the derated limits of 500V with one side of tabs removed or 400V with both sides removed, and I even recently used a 1000W dimmer for a switch that controlled 9 recessed cans, each with a 65W BR30 lamp, and that 1000W dimmer with a load of under 600W was still hot as hell.

Homeowners have been asking concerned questions lately; even calling me and saying that they can smell plastic burning.

Is there anyone here who knows what the deal is? Thanks in advance...

yes you must watch the wattage double check the lamp wattage sommtimes the home owner will install high wattage lamps and will not understand what they are doing or be deceptive about the la mp wattage after the fact:roll:

 

[glene77is]

For electrical equipment, "warm" is a temperature that can be very uncomfortable to a hand. (IIRC 40c is about 104f and that is a usual temperature for "warm" electrical equipment.)

Thanks for the URL.

I had read that 140 F will cause first degree red burns on tender skin.

At any rate,
if a customer says it smells like it is burning,
then you can bet that he will not call you back again.

I would think about splitting the load across two dimmers.
That would be twice as many heat fins.

comments welcome

 

[TwinCitySparky]

Deep uncrowded metal boxes may help dissipate the heat in future installations.

 

[Buck Parrish]

Here's a 2000 watt made by lutron. http://www.google.com/products/cata...sult&ct=result&resnum=2&sqi=2&ved=0CDoQ8wIwAQ#

 

[hurk27]

Deep uncrowded metal boxes may help dissipate the heat in future installations.

many forget to de-rate dimmers when ganged with more then one dimmer, the instructions will tell you how much to de-rate.

 

[jetlag]

many forget to de-rate dimmers when ganged with more then one dimmer, the instructions will tell you how much to de-rate.

I followered the derate instructions on a 3 gang and customer complained of heat and smell. I told them to leave it on high untill I got there. My non contact heat senser showed 127 F . I removed the the center dimmer and installed it in a single gang deep metal remodeling box and used a make-a-cover for 3 gang with blank in center. I got the temps down to 101 and 109 but costomer still not happy so I had to eat some 2000 watt dimmers. Moral of story, dont allways believe the instructions, they are done under ideal lab conditions with no home owner to please.

 

[ELA]

Here's a 2000 watt made by lutron. http://www.google.com/products/cata...sult&ct=result&resnum=2&sqi=2&ved=0CDoQ8wIwAQ#

I followered the derate instructions on a 3 gang and customer complained of heat and smell. I told them to leave it on high untill I got there. My non contact heat senser showed 127 F . I removed the the center dimmer and installed it in a single gang deep metal remodeling box and used a make-a-cover for 3 gang with blank in center. I got the temps down to 101 and 109 but costomer still not happy so I had to eat some 2000 watt dimmers. Moral of story, dont allways believe the instructions, they are done under ideal lab conditions with no home owner to please.

I have read that a dimmer dissipates approx. 1 watt per 100 watts of load.
If you stick a 4 watt night light in an enclosed space it will get very warm in there.

I do not understand how a 2000Watt dimmer would be a solution to the temperature issue? If it was only a derating issue yes .. but I would expect the dimmer to get just as hot whether it was 1000 or 2000Watt rated when powering the same load. (unless the design was greatly different and used Triacs with an extra low on voltage, or the heatink is external to the box).

jetlag: did you measure the temperature after installing the 2000W units and it was lower? Or was the customer happy just because you installed 2000W units?

 

[jetlag]

I have read that a dimmer dissipates approx. 1 watt per 100 watts of load.
If you stick a 4 watt night light in an enclosed space it will get very warm in there.

I do not understand how a 2000Watt dimmer would be a solution to the temperature issue? If it was only a derating issue yes .. but I would expect the dimmer to get just as hot whether it was 1000 or 2000Watt rated when powering the same load. (unless the design was greatly different and used Triacs with an extra low on voltage, or the heatink is external to the box).

jetlag: did you measure the temperature after installing the 2000W units and it was lower? Or was the customer happy just because you installed 2000W units?

Yes the 2000 watt have better heat removal , but it only helped 7 deg or so ,, I told them that is all I could do , that the heat was in the mfg normal range . They never called me for more work . Since then I never install dimmers or motion and dust to dawn lights . I only do service calls now anyway , if I wired new houses would have to install dimmers and the motion lights if it was called for.

 

[growler]

or the heatink is external to the box).

Some do have an external heat sink with fins that hold the cover plate off the wall an allow for air flow. Some dimmers have a larger heat sink area and are to be mounted in a double gang box and this allows more room for air flow.

All of the suggestion above work to some extent. Metal boxes help to dissipate the heat. A dimmer with a larger heat sink or one with fins (commercial ) will be cooler or just useing smaller lamps in fixtures.

A lot off people don't want that much light to start with so at times it is possible just to reduce the load and accomplish a lot. I have use smaller lamps on big chandeliers to reduce load.

It's best to let the customer know ahead of time what's going to happen when they want three dimmers in a three gange box and load them up.

If I install the box I get rid of some of the surrounding insulation and this will help some. It's all about air flow and heat dissipation for the size of the heat sink and just what is acceptable to the customer.

 

[jetlag]

Some do have an external heat sink with fins that hold the cover plate off the wall an allow for air flow. Some dimmers have a larger heat sink area and are to be mounted in a double gang box and this allows more room for air flow.

All of the suggestion above work to some extent. Metal boxes help to dissipate the heat. A dimmer with a larger heat sink or one with fins (commercial ) will be cooler or just useing smaller lamps in fixtures.

A lot off people don't want that much light to start with so at times it is possible just to reduce the load and accomplish a lot. I have use smaller lamps on big chandeliers to reduce load.

It's best to let the customer know ahead of time what's going to happen when they want three dimmers in a three gange box and load them up.

If I install the box I get rid of some of the surrounding insulation and this will help some. It's all about air flow and heat dissipation for the size of the heat sink and just what is acceptable to the customer.

Telling the customer to use smaller watt bulbs than the fixture and dimmer rating causes them to look at each other like "is he trying to cover up for something because it is not properly wired ?" I dont need that any more, I tell customers I will run a new circuit if they need it with lights connected that are below the a standard dimmer rating but i will only install a snap switch. They can install their own dimmer easily or get a handy man. Needless to say I dont get many of the calls that ask for dimmers.

 

[growler]

They can install their own dimmer easily or get a handy man.

If I went around telling customers to install their own dimmers or get a handyman to do it they would probably think I don't know what I'm doing and they would be right.

The idea is to have confidence in yourself and then the customer will have confidence in your abilities and any advice you give them.

 

[flatlander]

Yes the 2000 watt have better heat removal , but it only helped 7 deg or so ,, I told them that is all I could do , that the heat was in the mfg normal range . They never called me for more work . Since then I never install dimmers or motion and dust to dawn lights . I only do service calls now anyway , if I wired new houses would have to install dimmers and the motion lights if it was called for.

I would not give up on dimmers Dimmers are a valuable tool in lighting design.
You need to look at proper installation. Don't over crowd your boxes with wires. Use deep boxes.

 

[hurk27]

If I went around telling customers to install their own dimmers or get a handyman to do it they would probably think I don't know what I'm doing and they would be right.

The idea is to have confidence in yourself and then the customer will have confidence in your abilities and any advice you give them.

That is why it is so important to know your work, and all that can be expected, so when you do confront a customer, you will have a confidence in what your telling the customer, if you have a problem explaining a situation to a customer, then they will detect this as a weakness in your understanding of a problem, and it can go against you for future work.

I have dealt with this very problem and the first thing I say is: "It is common for dimmers to heat up as they dim large loads, but I will check further to make sure everything is operating like it should" if they wish more explanation then I can go into how the dimmer works, and how it is normal for them to heat up, and show them other common electronic appliances they might have in the home that will also give off allot of heat like the cable box and satellite receiver, (every feel the top of one?) and also offer them the factory number to call if it will help.

You have to watch how you respond to a customer when dealing with something that they feel might be a problem, remember they are many who fear electricity, and or has experienced a fire/shock or knows someone who has, so keeping that in mind, selling your self as a person in the know, is very important.

Of course being in the know is much better

 

[steve66]

I followered the derate instructions on a 3 gang and customer complained of heat and smell. I told them to leave it on high untill I got there. My non contact heat senser showed 127 F . I removed the the center dimmer and installed it in a single gang deep metal remodeling box and used a make-a-cover for 3 gang with blank in center. I got the temps down to 101 and 109 but costomer still not happy so I had to eat some 2000 watt dimmers. Moral of story, dont allways believe the instructions, they are done under ideal lab conditions with no home owner to please.

Strange, nobody ever seems to complain about how hot the lamps get

I would have suggested 127 F is not that hot at all. And if they were really that worried about 127 F, they should have all the wires in the whole house upsized to #10. Hey, maybe I just thought of a new slogan for the copper industry:

"#10 for all 20 amp circuits - it just doesn't get as warm as #12"

 

[jetlag]

If I went around telling customers to install their own dimmers or get a handyman to do it they would probably think I don't know what I'm doing and they would be right.

The idea is to have confidence in yourself and then the customer will have confidence in your abilities and any advice you give them.

They think you dont know what you are doing when you do a proper install and you get a call that the dimmer is hot an it has a smell . I dont go around telling people, I tell them if they call wanting a dimmer installed. So you are saying If I do that I dont know what Im doing , I can add up watts sir, and follow derate instructions , and I dont have to accept any work I dont want to do .

 

[readydave8]

I've sometimes suggested to the customer that he buy the dimmer, people aren't as likely to complain to me about something they chose, some kind of pride involved. Only works occasionally.

I'm thinking about refreshing my memory on some lutron grx controls I put in a job a few years ago, it seems to me that the switch did'nt do the actual dimming and so didn't get warm, the switch told the "central" what to do.

 

[jetlag]

That is why it is so important to know your work, and all that can be expected, so when you do confront a customer, you will have a confidence in what your telling the customer, if you have a problem explaining a situation to a customer, then they will detect this as a weakness in your understanding of a problem, and it can go against you for future work.

I have dealt with this very problem and the first thing I say is: "It is common for dimmers to heat up as they dim large loads, but I will check further to make sure everything is operating like it should" if they wish more explanation then I can go into how the dimmer works, and how it is normal for them to heat up, and show them other common electronic appliances they might have in the home that will also give off allot of heat like the cable box and satellite receiver, (every feel the top of one?) and also offer them the factory number to call if it will help.

You have to watch how you respond to a customer when dealing with something that they feel might be a problem, remember they are many who fear electricity, and or has experienced a fire/shock or knows someone who has, so keeping that in mind, selling your self as a person in the know, is very important.

Of course being in the know is much better

I spent years trying to educate customers on dimmers before I decided not to install them any more. And I already know all the info in the posts about how to do a proper install. . It is my choice .

 

[LEO2854]

I spent years trying to educate customers on dimmers before I decided not to install them any more. And I already know all the info in the posts about how to do a proper install. . It is my choice .

This info may help youhttp://www.smarthome.com/solution41.html