I have a dual gang junction box installed in a space between 2 studs in the wall. I want to add swap the box for a 3-gang box to add another switch for a ceiling fan, however when I took the cover plate off I found that it is nailed directly to studs on both sides. Is there anything I can do to replace it with a bigger box? The wall is exterior and possibly load bearing.

I looked into replacing the 2 current switches with duplex switches, however, one of the lights is an LED (Cree BA21) and its wired on a 3-way dimmer, the Lutron Maestro C+L dimmer along with the corresponding companion dimmer. There doesn't seem to be a dual dimmer for this light in the 3-way configuration (although I could give up the companion 3-way switch).

The only one I could find is the Lutron Skylark dual S2-L, however, it looks funny and I would lose the 3-way. Are there any other options?

Edit: The switch I want to add is for a fan/light so basically another duplex switch.

  • 1
    What is the other switch for? Possible to swap that one for a duplex switch?
    – diceless
    Commented Oct 23, 2014 at 17:03
  • You could add a separate 1-gang box on the other side of the stud.
    – Hank
    Commented Oct 23, 2014 at 17:17
  • 1
    I upvoted @wallyk's hilarious answer, but I was thinking more in the "not do over" line of just add another dual-gang above/below the one you have (leave a blank on half of it if not using it all now.)
    – Ecnerwal
    Commented Oct 23, 2014 at 19:33
  • @Ecnerwal: While the photo I chose is potentially humorous, a three gang version wouldn't look silly, yet be easier to wire since it wouldn't require chaining the power feed into both boxes.
    – wallyk
    Commented Oct 23, 2014 at 19:45
  • IMPE sideways switches can be annoying due to the non-obvious relationship of a direction to "on" (of course, 3-way switches all have that problem as well.)
    – Ecnerwal
    Commented Oct 23, 2014 at 19:51

1 Answer 1


If there are studs at either end of a two gang switch box, that means they are approximately 4 inches apart. A three gang requires 6 inches.

A switch box is usually about 3.5 inches high; with thickness that means turned sideways, it will fit in a dual ganged space. So you have room for 20 switches if you want:

enter image description here

(from here)

  • 1
    Haha. I'd love to see this in a house. It would be especially interesting when the wife got home.
    – Tester101
    Commented Oct 23, 2014 at 18:34

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