Dimmer & Fan Control in same box?

[cdwirenut]

I want to install a light dimmer switch & a fan controller right next to one another in the same box. Can I do this? Do I need an oversize box or can I squeeze them in?

 

[al hildenbrand]

Apply the calculation in 314.16 and compare to the location you are thinking about.

Read the manufacturers installation instructions for the dimmer and speed control for any additional non-Code requirements such as (but not limited to) fin breaking or VA derating.

 

[milwaukeesteve]

Most dimmers and Speed controls have the fins as Al mentioned to dissapate heat. These fins generally do not allow for the 'ganging' of other Dimmers or Speed control without breaking the fins off. Read the Manufacturers instructions on Watt/VA derating, and procedures for removal of fins.

I always loved seeing the guys that just break off all of the fins right away because it makes the device easier to install, not even giving a thought to load and derating of that particular device.

By the way, they do make combination devices for installing in a single gang space. These are great for bedroom installations. Here the dimmer and the speed control are mounted on the same yoke/device. Follow the manufacturer's instructions, of course.




The only thing I can think of that would limit you from ganging the 2 together would be IF you were dealing with 277V/480V systems. See 404.8 (B) this is for snap switches, but you may not install switches ganged with similar devices if a voltage potential exists of more than 300 V between devices. I don't know if your dimmer or speed control would fit with an installed divider between them. Again, this is ONLY if you have 277V lighting that you would have to start considering this.

 

[infinity]

The only thing I can think of that would limit you from ganging the 2 together would be IF you were dealing with 277V/480V systems. See 404.8 (B) this is for snap switches, but you may not install switches ganged with similar devices if a voltage potential exists of more than 300 V between devices. I don't know if your dimmer or speed control would fit with an installed divider between them. Again, this is ONLY if you have 277V lighting that you would have to start considering this.

I wouldn't call a dimmer or speed control with leads attached to it a snap switch, therefore 404.8 would not apply to two of these devices adjacent to each other with a voltage greater than 300 volts between them.

 

[milwaukeesteve]

It does state 'similar devices'. What is a dimmer but a similar device to a snap switch, in reference to lighting?

 

[iwire]

It does state 'similar devices'. What is a dimmer but a similar device to a snap switch, in reference to lighting?

Dimers and fan seed controls typically have leads instead of exposed terminals.

IMO that would make a difference in the application of 404.( 8 ) ( B )

 

[milwaukeesteve]

I like that answer.

 

[iwire]

I like that answer.

Cool.

It may surprise you to know I was ready to agree with you that an inspector could say that a dimmer is a similar device to a snap switch, I can't see anyway I could fight them on that.

However I figure as a divider allows two opposite phase snap switches to be installed side by side that a devices with a 'built-in dividers' would be OK.

 

[milwaukeesteve]

Not all dimmers though are pigtailed, but I am not going to bother researching whether those with exposed terminals are rated for more than 150V. I don't need to know that bad.