Help finding the right switch box...

Reply

  #1  
Old 02-21-19, 06:26 AM
P
Member
Thread Starter
Join Date: Sep 2009
Location: Pittsburg, PA
Posts: 376
Received 0 Votes on 0 Posts
Help finding the right switch box...

I'm trying to install a 3 gang switch box into a shallow wall. By shallow, I mean the wall was built using the edge of the 2x4 instead of the width, leaving only 1 1/2" of space between the drywall.

Therefore, what I need is a 3 gang 1 1/2" deep switch box. I don't care if it's metal or plastic, but if metal I'd rather use outside-the-box romex connectors to save on space inside the box. I could use three metal gangable boxes if they are 1 1/2" deep.

Ideally, I'll have two single pole switches and one 4 way switch in the box. So that's two 14/2 and two 14/3 for a total of 10 conductors + ground + 2 for each switch (so 2X3)... for a total of 17. The 4 way is part of a three switch setup from other locations. If necessary, I could rewire everything such that this box is at the end of the run. Then, I'd only need one 14/3 wire entering the box going to a 3-way switch. Then my total count would be 14.

(Please let me know if I messed up my counting!)

Problem is I'm having a lot of trouble finding any 3 gang 1 1/2" deep boxes, so I'm not even able to determine the dimensions in order to calculate cubic inches.

Long story short, I need a 3 gang 1 1/2" deep switch box able to hold 17 count, or 15 count. Thanks for your advice!
 
Sponsored Links
  #2  
Old 02-21-19, 06:45 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,943
Received 43 Votes on 41 Posts
With 1/2" drywall you can use a 2" deep box. If you get Raco 445 boxes they are 2" deep and gangable to as wide as you need. You'll have to be a little creative in mounting as these are more of an old-work box, but it can be done.

Another option would be to use 1-1/2" deep 4x4 steel boxes with 3/8" mud covers, but in that case you'd have to group your switches into groups of two.
 
  #3  
Old 02-21-19, 08:33 AM
P
Member
Thread Starter
Join Date: Sep 2009
Location: Pittsburg, PA
Posts: 376
Received 0 Votes on 0 Posts
With 1/2" drywall you can use a 2" deep box.
Of course! Why didn't I realize that. Thank you.

You gave a good recommendation, but I think the Raco #420 model would be better for me because I'd like to avoid having to count the inside clamps:
https://www.homedepot.com/p/RACO-2-i...-420/205471029

As I understand it, this is a 3 x 2 x 2 inch box, or 12 cubic inches. If I gang 3, then that's 36 cubic inches.

To repeat above, I'll have two 14/2 (2x2), two 14/3 (2x3), two single pole switches (2x2), and one 4-way switch (2), plus ground (1). If my count is right, that 17 "wires".

So that's 17 (14 AWG) "wires" in a 36 cubic inch space. Provided I counted everything correctly, I think that means I'm within code limits. Can I get someone to confirm this?

ALSO: I should mention that I'll be using the rectangular dimmer switches. Do these still count as two? These models have wires running off the switch rather than the conductors being screwed on directly.
https://www.homedepot.com/p/Lutron-D...-_-View+Item__
 
  #4  
Old 02-21-19, 09:03 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,943
Received 43 Votes on 41 Posts
Right, you have 17 "wires" @ 2.0 cu/wire required for #14 equals a 34cu box minimum. Large dimmers still only count as 2 fills each, but you will have to be cautious when making up this box as it will be just under the limit.

Don't forget to derate the dimmers too. You have to break the cooling fins on them for multigang use and that decreases the rated wattage.
 
  #5  
Old 02-21-19, 10:31 AM
P
Member
Thread Starter
Join Date: Sep 2009
Location: Pittsburg, PA
Posts: 376
Received 0 Votes on 0 Posts
Don't forget to derate the dimmers too. You have to break the cooling fins on them for multigang use and that decreases the rated wattage.
Thanks, I probably wouldn't have realized that until the point at which I installed them and I wasn't aware about the wattage impact. Each dimmer is good for 150 watts LED which is plenty for my needs so a reduction would likely not have affected me. However, as it turns out it's not even an issue for this particular dimmer.

Quoted from Dimmer Install Sheet:
"NOTE: Maximum wattage ratings are not affected when using only LEDs or CFLs." (I'm guessing this is because the wattage max is effected by the heat generated.)

https://images.homedepot-static.com/...83d08b92d3.pdf

Anyway, thanks a ton ibpooks. It's gonna be tight, but I can now do my project according to code without having to reroute the wiring.

 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: