Hi,

I'm installing a new overhead light in my living room to replace a switched outlet. I've installed the new light and 14/3 Romex going from the light to the existing switch which currently controls a "half-hot" outlet (I went with 3 conductor in case I ever want some other gadget on a separate switch, but for now red will be unused). I will replace the switched outlet with a new one which is fully hot. The existing wire, which now carries the hot to the switch and returns the switched hot, will now carry both hot and neutral to the existing switch box. The neutral I will wire nut to the new neutral which goes up to my new overhead fixture. The hot will come into the switch and send the switched hot up to the new fixture over the new black wire.

So here's my question. In terms of NEC box fill what size box do I need. My existing box for the switch is a metal single gang, I think 3x2 but I will need to measure how deep. I think I need 18 cubic inches minimum (2 for black and white coming in, 3 for black white red going out, 1 for grounds, 1 for clamps, and 2 for dimmer switch, all of this times 2 for 14 AWG). Is this right? I don't need to make any extra allowance for the wire nut on the neutrals or anything else, do I? So if my existing box is 3 inches deep will I be ok in terms of NEC (2x3x3=18)? But I believe a dimmer switch might be bulky and maybe I would need to go with a bigger box anyway. Is there a remodel style box that would have enough space for this without going bigger than 3x2? I'd prefer to not have to open up the drywall more for a wider box if I don't have to. The existing box I believe is a remodel box, since there's no stud and it's just fastened to the drywall using tabs. Thanks for the help!

Jeff

 

Neutrals don't get connected, to the switch. Any time that I replaced a switch with a dimmer, I used wire nuts made my Scotch 3M. The small blue & orange connectors saved me from replacing the gang box.

Product Catalog 3M™ Electrical Spring Connectors : Electrical Commercial and Industrial: 3M US

 

Maybe I wasn't clear enough. Neutral is not connecting to the switch, but wire nutting to the neutral going up to the fixture. This is just happening inside the box where the switch is. I'm just wondering first if the 18 cubic inch calculation is correct, and secondly if anyone knows from experience if it's realistic to get all this to fit in the 18 cubic inch box or if not, how big I would need to go.

 

I got everything wired up over the weekend and the dimmer works great. I couldn't find a 2x3x3 box so I ended up with the next size up which was 2x3x3.5 (21 cubic inches, my wiring calls for 18 minimum) and the wiring fits very well.

My only issue at this point is that the switch plate doesn't mount flush to the wall. I think it may be a combination of the fact that I'm using a rework box which has metal tabs for holding against the front of the drywall above and below and then dimmer also has tabs which mount on top of those which adds even more thickness. The rework box is mounted pretty much as tightly as possible and has no front to back movement (attached using the tabs that slide in along the sides and fold around into the box). Anyone know how I might be able to get this switch plate to mount flush?

 

Please post a picture of the switch box with the switch plate removed. http://www.doityourself.com/forum/li...rt-images.html

 

Ray - thanks for the help. This is what the switch looks like with and without the cover.



This is one of the screwless snap-on switch plates. It has a plastic plate that attaches to the screws holding the switch to the box and the top cover snaps onto this. I had also first tried a wooden more decorative plate that screws on which also did not sit flush with the wall. Any ideas what to do or if there's another switch plate I can try? Thanks!

Jeff

 

An "unbreakable" nylon decorator style switch plate should conform better to the wall.

 

FYI I picked up one of the simple switch plates yesterday and I'll give it a try this weekend. I figure at 79 cents it's worth a shot.

 

Alright the new switch plate is on and fits great. Thanks for the help!