Ok, I saw these two kinds of gang boxes, some labeled “old work” and some labeled “new work”. Using the new work boxes is obvious, you just hammer in the two nails jutting on the side.
But now I’m wondering about these old work boxes. They have a screw, which turns a little lever flap. How is that going to secure a gang box to the stud?
I’ve got an existing 1 gang outlet that I want to expand to two gang. I want to rip up my wall as little as possible. Can I use the two gang old work box, or do I need to find the add-on box like the one linked below? Does it matter that the box is orange and says low-voltage? Do these add-on boxes work well?
They don’t secure to the stud. They fit into a hole cut into a pre-existing wall. Here is a tutorial. However, the “low voltage” thing might be a problem, since those are generally meant for things like telephone wiring, ethernet cabling and other low-voltage applications. I’m not positive of the exact definition of “low voltage”, but I believe it’s less than 20 V.
IANAE but as I understand it, the box you linked to would not be legal for 110V. The boxes you linked to are for cable TV, CAT 5 and phone.
From what I can tell, the difference between new work and old work boxes is how they attach. A new work metal box usually has a long strap attached to one side. That strap has several holes in in for nailing to the stud. To use this type of box in a remodel would require tearing up about 8" of wall and patching around the box. Not fun.
An old work box is designed to be installed in an existing wall with a hole slightly larger than the box itself. Much less destructive to the existing wall. Here is a new work boxhere is another Think about the size hole that you would have to punch in the wall to attach these suckers. :eek:
Here is an old work box or this one that I have used.
See how the hole in the existing wall only has to be very slightly larger than the box? Much easier to repair the wall afterwards.
Article 725 would apply to most residential applications such as burglary/fire alarm systems, thermostats, and doorbells, all of which typically operate at nominal 24 volts or less to ground.
If the OP is getting into low voltage lighting, then Article 411 applies. Other articles cover solar photovoltaic systems (Article 690), and even pipe organs (Article 650).
You can’t use the low voltage stuff for 110 volt power, that’s fairly obvious.
What isn’t obvious is changing a single gang box to a two-gang. Have you looked inside the box yet? If you’re lucky, you’ll have a “4x4” metal box in the wall - a square box. How does a square box wind up with a narrow rectangular opening? There are a variety of “mud rings” that screw onto the 4x4 box. If you have one of these in the wall, all you need to do is carefully chip away the plaster/sheetrock to reveal the whole mud ring, remove two screws, swap in the two-gang mud ring, put in the extra receptacle, and if you were careful with the plaster, the two-gang faceplate for the receptacles will cover the larger hole in the wall.
If you are cursed with a narrow rectangular box, (this type also goes by the name “switch box”) you my friend, are truly cursed and faced with either a big nasty plaster bust-out to remove the old box and replace it with a two-gang switch box or a 4x4 or giving up and leaving the box the way it is.
Another option is to use a “starter” box for raceway. This screws onto the existing box and lives on the wall, rather than in it. You’ll wind up with a roughly 5 inch square by inch and a half thick box on the wall, but at least you’ll have the two receptacles you desire.
Maybe not so obvious. All my walls have blue plastic boxes behind the switchplates. As near as I can tell, the only difference with the “low voltage” box is that it is orange plastic.
As for being “truly cursed”, I have a narrow 1-gang box that I am planning to convert into a 2-gang box without busting up my wall. Thanks to QED’s tutorial link, I’m fairly confident I can do that through the magic of “old work” gang boxes.
The “old work” types are also available for 110 V. electrical work. They are blue just like the “new work” boxes. I got one just the other day to add a duplex outlet in my house.
On the other hand, one could just get lucky. I was recently able to pry a one-gang box off of the stud without damaging the surrounding drywall. I just let it fall inside of the wall, and replaced it with a remodel box (hmmm…. they always used to be called remodel boxes, but now all I see are “old work” on the cartons at Lowes/Home Depot.).
I had to make my own starter box to do my garage wiring. Well, I didn’t know there was anything called a “starter box,” and I couldn’t find anything that filled the need, so I guess I went the note-quite-to-code route and adapted a PVC single gang box to do the trick. The whole garage is done with PVC conduit now, which I hope is to code – they sell enough at the big box stores, so I guess it must be :). The only thing I can’t figure out is why the previous owners didn’t run a logical series of outlets before putting up the drywall.
