I've got this old light switch/outlet combo. I installed recessed LED lights and want to install a dimmable LED switch.


The wiring seems fairly straightforward, but I'll run through it quickly just to make sure I haven't missed something.
- One 2 conductor cable (#1) enters box and one 3 conductor cable (#2) leaves box.
- The hot from cable #1 connects to black hot from cable #2 and to hot side of combo switch.
- The red hot from cable #2 connects to other side of switch. The red hot powers a switched outlet that powers the prior room lighting - a plug in lamp. I tapped into this red wire at that outlet to power the LED ceiling lights I installed.
- The neutrals from cables #1 and #2 connect together and to neutral side of outlet.
- Ground not connected, but these cables do have ground wires, so I will connect those to new switch.

So the issue is that I don't think most dimmable LED switches will fit. This is the particular dimmable LED switch I'm considering: https://www.homedepot.com/p/Lutron-S...H-WH/202517700

Don't think it will fit in this box, primarily because of the nails that run thru the box (you can see the upper nail in these pics; lower nail is harder to see, but it runs at the same depth as upper nail).



Seems I'd have to remove the box and install an old work box (the style that secures itself to the drywall by use of ears rather than securing to stud) to avoid cutting and patching drywall. To remove the box, I'd have to cut the nails, so I'm thinking this kind of blade for my multitool (and carefully using after moving cables as far out of way as possible).

Hacksaw blade is another option, but it would take forever with such short strokes. Other options I should consider?

 

Those nails are easy to get out. No cutting involved.
Using a pair of wire cutters..... grab the nail and use the cutters as a fulcrum to move the nail.
After the nail moves a little bit. Reload the cutters and move the nail some more.

Watch the following video. They are removing external nails.
The same exact process applies to internal nails.
Removing nails using wire cutters/dykes video

 

Thanks @PJmax, that looks a lot easier than what I was proposing. I'll give it a shot.

 

Actually, that will be very fast and easy unless you have very dull blade.
Put hacksaw blade between junction box and stud, not inside of the junction box. The nail will cut very easy.
I do this often with plastic junction boxes where nails are outside and hidden from the view.

The hardest part will be undoing all the splices and pulling wires out.

Existing drywall opening might be too big to install a remodel junction box though. Might have to use regular plastic junction box and drive screws from inside. This technically is against the code, but done very often.

https://extremehowto.com/wp-content/...ghtTT18&19.jpg

There are special junction boxes that are made to be screwed from inside, but not easy to get locally.
https://www.galesburgelectric.com/ar...angled-screws/


Also, if you go for a deeper box, your existing wire may be too short. Try to keep same depth if possible.

 

Ah. I was thinking inside the junction box, which I was thinking it would be very short strokes. Good call on going outside, keeps the cables out of harm's way too.

Good point. I suppose I could patch and recut the hole, but it would probably break at the patch joint when cutting. So yeah, I may have to drive screws from inside, and try to keep the box close to flush and square while doing so.

I'll see how much slack I have in the cables after removing the old box. I don't think I need a deeper box - the old box is fairly deep, the problem is the nails are near midway down the box. So a similar depth plastic box without that kind of obstruction would probably work.

 

I found a similar box, the Madison Smart Box. From the 360* view on Lowes site, it looks like built-in 1 x 12g and 1 x 14g NM clamps on each of top and bottom of box. So could be an issue for old work where someone has 2 x 12g cables running to the device w/o enough slack for one cable to enter from opposite side of box.
https://www.lowes.com/pd/Madison-Ele...Box/1000156805

The reviews for this box on Amazon are very positive and very numerous, which indicates lots of people are using these, and they are listed (UL), so maybe it is code compliant?

The Arlington box you linked uses different size KOs, so no problem getting 2 x 12/2 into box.


Easiest to source might be these new/old 1-gang boxes at Home Depot:
https://www.homedepot.com/p/Carlon-1...25AB/305110267

Apparently for old work, you break off the stud face mounting tab, and use screws at interior mounting location and toss the nails.

 

@PJmax's suggestion on pulling out the nails worked. I used a pair of needle nose vise grips and was able to wiggle the nails out of the stud. Replaced the old box with the Carlon blue new/old work box pictured above, secured using 2" drywall screws. This blue box was plenty deep enough for the LED dimmers and the cables. Biggest hassle was pulling cables through the built-in NM clamps. These were much stiffer than the ones on Carlon new work boxes, even after I loosened them up a little with a flat blade screwdriver. Plus I didn't have a lot of room to get in there and really push/pull the cables because of the drywall. Next time I use these new/old boxes, I'll open the clamps up a bit more before pulling cables through.

Thanks for all the advice guys.

 

You can remove clamps completely on those metal boxes. That will give you much better access with less snagging.

 

I used a Carlon blue plastic box with integral NM clamp (hinged pieces of plastic you push the cable past). Next time I have to replace an existing box, I might use a metal box with plaster ears and secure it using Madison straps. As you note, with metal boxes, it's much easier to slide cables in.