Can a low voltage bracket like this be installed next to an existing single-gang box such that it supports a single, standard 2gang faceplate? Is there anything specific to take care or any product that is specifically made for this application?

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I would like to extend the hole of the existing single gang metal box on the side where there is no stud (it is attached to the stud on the other side) without having to remove and install a new box for the receptacle.

I have installed these in the past but I would really like to avoid having to remove the existing electrical box if it can be avoided.

  • 1
    Don't all wires within a box have to tie to a common neutral and ground? Suppose a hot broke off one receptacle post and whipped round to the body of another other, electrifying it. I thought the code tried to cover these kinds of situations. I can't imagine you would fit them close enough together that they would fit a convention 2 gang face plate without mutilating the boxes, and compromising their modularity.
    – AdamO
    Commented Dec 14, 2023 at 18:28
  • If you want the mounting ring to screw the cover plate into, simply cut some of the plastic ring off to make the spacing correct.
    – FreeMan
    Commented Dec 14, 2023 at 19:17
  • @FreeMan I am just concerned that I can’t cut too much (enough) without hitting the screw for the ear. Seems I can only remove a few mm … is this enough? Otherwise there is only one ear to support the plastic ring and I think this won’t be enough support
    – divB
    Commented Dec 14, 2023 at 21:17
  • They're not expensive, cut one down to size. If the ear to hold it is gone, well, it's not structural, the box attached to the stud will hold the cover plate in place, and you can always run a screw through one of the other holes in the ring...
    – FreeMan
    Commented Dec 14, 2023 at 22:06
  • 1
    Remember, the only reason you're putting this thing on there is to have something to hold the cover plate screws in place, right? Heck, you could just glue the screws into the cover plate and be done with it. Two screws into the line voltage device on the other side of the box should be enough to hold the plate in place.
    – FreeMan
    Commented Dec 14, 2023 at 22:08

3 Answers 3


Sure. You can just add on a add-on low voltage bracket box.

enter image description here

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Says it's for new work, but as long as you cut out enough to access the side of the existing box, you should be able to put it in securely. It uses clips to hold on and double sided tape to secure. The manufacturers support on HD says that it can be used on old work as well, with other reviewers having mixed luck. Depends on the thickness of the box you are clipping onto. Just make sure the existing box is sturdy.

It does state it's for plastic and not metal boxes, as metal boxes are thinner walled. You could try to drill a hole and use plastic nut/bolt.

  • This looks like exactly what I’m looking for but I can’t find anything like it. Not even if I look for “add on box”. Do you have a pointer/link?
    – divB
    Commented Mar 15 at 6:24
  • @divB "add on low voltage box" returned this homedepot.com/p/…
    – cde
    Commented Mar 15 at 14:44
  • @divb the q&a and reviews at hd are helpful.
    – cde
    Commented Mar 15 at 15:03

Update: it wasn't immediately obvious from the way you presented your question that this is something you're already aware of and don't like.
Nevertheless I'm still going to leave this answer up for others who may not be averse to using this solution.

No, a pair of single gang boxes or low-voltage rings (or combination thereof) side by side will not fit a standard 2-gang faceplate.

The thing you're looking for is a Dual Voltage Box

enter image description here

This example is a "New Work" box, but they exist in "Old Work" versions too.
The overall shape & size is identical to a standard 2-gang box (unlike what you'd get if you put a pair of single gangs side by side), and you get complete isolation between the line voltage and low voltage sections.

  • 3
    I did not know something like that existed. I always assumed that line and low voltage had to be in separate boxes.
    – SteveSh
    Commented Dec 14, 2023 at 13:06
  • 7
    @SteveSh - they are in different 'boxes' - the left side is isolated from the right. They just happen to be next to each other (OK), and spaced appropriately for standard double-wide face plates.
    – Jon Custer
    Commented Dec 14, 2023 at 13:16
  • 1
    We're nit-pickin' words here, but I would describe that as having two compartments in the same box/assembly/unit.
    – SteveSh
    Commented Dec 14, 2023 at 13:48
  • This assumes the OP intends the expanded space to be used for a low voltage application, of course!
    – Huesmann
    Commented Dec 14, 2023 at 14:17
  • 2
    @SteveSh your assumption is a little off. Line & low voltage must be separated - yes, but there's no requirement for them to be in separate boxes. I've seen some multi-gang box designs which include an option for an insertable separator - so in those cases it really is the same box, but separated.
    – brhans
    Commented Dec 14, 2023 at 14:30

There's no requirement for low voltage plates to be mounted with any kind of ring. You could install an appropriate 2-gang plate mounted to your 1-gang device and let the second half float. The LimeLite SideLite product illustrates the finished concept, though this happens to be a UL-approved line voltage product. (photo: limelight.com; I have no affiliation)

SideLite by LimeLite

Low voltage rings are really only a convenience. You could use drywall anchors to secure the floating portion of the plate to the drywall and have no ring at all.

There also exist metal low voltage rings - these were on the market years before the plastic versions came along. You could cut away one side of one of these rings and place it adjacent to an existing j-box at the correct spacing so a 2-gang plate fits. There are multiple brands and styles. (photos: showmecables.com and grainger.com)

metal low voltage ring metal low voltage ring

  • Thanks, seems modifications to the bracket are required (ie, they don’t automatically fit for 2gang). Modification (cutting) is no problem because low voltage doesn’t need UL?
    – divB
    Commented Dec 14, 2023 at 17:12
  • @divB Good question. Probably all of these low voltage rings carry a UL mark and it seems reasonable that modification would invalidate that. So is it an electrical code violation to install one of these with modifications? Maybe. But so far as I can tell use of a low voltage ring isn't directly required -- if one can achieve secure support of the low voltage device without one of these rings it seems that's OK. We use incomplete electrical conduit for physical protection of cable without regard for fill rules and that's OK.. I don't know if we can do something analogous with LV rings.
    – Greg Hill
    Commented Dec 14, 2023 at 19:00

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