It's a little tricky, but doable. If you've got 2x3 gem boxes, the end plate
is held on by a screw at the top of the box. If you cut the sheetrock for
the additional gang, then pop a slim screwdriver through the sheetrock at a
steep angle above the retaining screw, unscrew it and remove the end plate.
Next install the additional gang which will have both top and bottom screws
which you can tighten through the existing top hole and by making another
screwdriver hole at the bottom. This way you only have two small holes to
patch.



wrote in message
oups.com...
Currently have a ganged, steel electrical box with two switches, and
need to add a third. Needless to say it's in old work--finished
drywall. Thought about making stud-to-stud cuts above and below
existing boxes, then adding the third section. Then I thought I'd
better ask here first.

Is there a way to do this without so much drywall cutting?