3-way dimmer and outlet box size

Reply

  #1  
Old 05-29-07, 12:09 PM
Member
Thread Starter
Join Date: May 2007
Location: US and Canada
Posts: 14
3-way dimmer and outlet box size

To follow up on another post...I recently installed a new Leviton 3-way dimmer, (600w for 6 x 60w bulbs) and am concerned about the outlet box size.

I did: two hot leads (black) to two black leads on the dimmer, the two neutrals (white) to each other, load (red) to load, and the green grounding wire attached directly to the metal outlet box along with the bare ground wire. I used properly rated caps.

It took a few tries, but I bent the wires around the back of the box, going in circles so they aren't simply stuffed in (well, sort of), and so the caps aren't all in the same spot. However, it took a little bit of pressure--not much, no forcing, tightening via the screws or anything like that--to fit in the switch. I know that dimmers are never exactly a loose fit. Still, I'm paranoid (as usual) about whether I have to worry about overheating and fire.

Advice very welcome, and guidelines for being able to judge whether an outlet box is too small for wires, switch, etc. would be useful. Thanks.
 
Sponsored Links
  #2  
Old 05-29-07, 12:15 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Can you tell us how many cubic inches the box is? It should be stamped on the back of the box. If you can't find that, take a ruler and measure the height, width and depth of the box.

Can you tell us if the wires are 14-gauge or 12-gauge?

P.S. I didn't understand all of what you did. It's probably a terminology problem. But that's not your question anyway. I assume that the switch is working fine, so it's likely not important that I understand that part.
 
  #3  
Old 05-29-07, 04:29 PM
Member
Thread Starter
Join Date: May 2007
Location: US and Canada
Posts: 14
Answers

Whoops...TMI! In short, I followed directions carefully.

The box seems to be 3.5H x 2W x 2.25D, or 10.5 cubic inches. Its a 15-amp circuit breaker so I assume 14 gauge wire.
 
  #4  
Old 05-29-07, 06:13 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,680
Box is too small. Each #14 counts for 2 cubic inches. All grounds count as 2 ci. Dimmer counts as 2 wires. Clamps count as another wire
I think from your description you have 14/3 and a 14/2 in the box that is That is 5 wires(10) + grounds(2) + dimmer(4) = 16 cubic inches required. larger if you have any internal cable clamps.
 
  #5  
Old 05-29-07, 09:04 PM
Gen
Gen is offline
Member
Join Date: Jun 2006
Location: US
Posts: 379
I believe your CU in is 15.75. Also joed--don't all grounds count as 1??
 
  #6  
Old 05-30-07, 07:04 AM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,680
Grounds count as 1 wire which is 2 ci.
 
  #7  
Old 05-30-07, 07:40 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Replace the box with the largest box you can find. You should be able to find a 22.5 cubic inch box. Boxes as small as you have aren't good for much of anything.
 
  #8  
Old 05-30-07, 04:31 PM
Member
Thread Starter
Join Date: May 2007
Location: US and Canada
Posts: 14
Sigh...it seems we've gone beyond the dimmer issue and are talking about any switch installed in the box, given that the wiring etc will not change. Yes? So by extension were now talking about quite a few of the boxes in a house that's only about 8 or 9 years old.

BTW, the dimmer has been on full for 5 hours and more. The dimmer's metal front plate is nice and toasty, but I can easily hold my finger on the without discomfort. Regardless, Im replacing it with a standard switch, but not replacing the box.

It's not practical to run around changing boxes, so some practical advice would be appreciated.

Sure wish all those web sites giving dimmer installation instructions brought this up. I'm feeling quite frustrated, although happy I followed my instincts and did the research.

Thanks, all.
 
  #9  
Old 05-30-07, 05:48 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,680
Dimmer and switch count the same for box fill. Switching the dimmer to a switch does not eliminate the over fill problem.
 
  #10  
Old 05-30-07, 09:26 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
It's possible that you just don't have enough practice folding the wires, or that your wires are too short or too long. Somewhat counterintutively, if the wires are too short, it can make folding them neatly a bit of a problem.

Don't go fixing problems that don't exist, so if you don't need to make any changes to the wiring in other boxes in your house, leave them alone. I suspect your boxes are large enough to meet code, but just barely so. An experienced electrician is able to repack the boxes comfortably, but you probably are just a bit less skilled in this.

In the meantime, try practicing repacking the one box you are working with to see if you can get it done more neatly.
 
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
Display Modes