Install an Electrical Box in an Existing Wall for an Outlet or Switch

Placing outlet box into wall

Lee Wallender

Adding an electrical box to your existing wall for a switch or outlet is easy when you have the right materials and know a few tricks. And you don't have to remove any drywall (except for the box's cutout itself).

The key is to purchase what is termed a remodel box or an old-work box. The type of box that you do not want is called a new-work or new-construction box.

  • New-Work Box: It has nails on it or another fastening method that allows the box to be attached to the side of a stud. Drywall cannot have been installed already to use a new-work box. Drywall is hung after the box is fastened.
  • Old-Work Box: Often called a remodel box, this item allows you to cut a hole in your wall's drywall and slip the box in. Drywall removal is not required. This box attaches to the drywall itself via "wings" that pull inward. You will be using this type of inexpensive plastic box. Single-gang boxes are about $1, and double-gang boxes are a little over $2.

Tape Old-Work Box to Wall Backwards

Many of these old-work boxes you get at Home Depot, Lowe's, and other big home improvement stores do not come with paper templates. Either you make your template, transfer measurements to the wall with a ruler, or use the box itself as a template.

Because these boxes taper, from smaller to larger, you cannot use the back sides as templates. Fortunately, you can use the face as a template, since the face is flat.

  • Tape the box to the wall with painter's tape, face-first. Apply tape to the top and bottom. It's not necessary to tape the sides.
Taping a box to a wall backwards
Lee Wallender

Mark the Box's Horizontal LInes First

The previous step was the fortunate part. The unfortunate part is that you cannot just draw a single outline around the box for your cut.

  • First, mark horizontal lines where the tabs meet the box. The tabs are the flat pieces that press against the wall from the front, creating tension in conjunction with those back "wings."
  • The pen is pointed at this spot.
  • Use a mechanical pencil or well sharpened regular (not carpenter's) pencil, because you need a sharp, precise line.
  • You need to get these lines right, or the box will not stay in place; it will fall back into the wall.
Marking the box's horizontal position
Lee Wallender

Mark Outlet Box's Vertical Lines

  • With the horizontal lines marked, draw two straight vertical lines down the sides of the old-work box. While you should try to be precise, these are less critical because there are no tabs on the sides.
Marking an outlet box's vertical lines
Lee Wallender

Connect Lines for Box Cutout

  • Remove the box from the wall. With your straight edge, connect horizontal and vertical lines to make a complete outline. 
Connecting the lines for box cutout
Lee Wallender

Make Precise Box Cutout With Jab Saw

  • Before you make your cut-out, drill a hole in the center of the outline with a 1/2" auger bit. Now, use your manual jab saw to cut the outline. Be extremely precise about this, preserving your line as you cut with the saw rather than cutting right on the line. 
Making a box cutout with a jabsaw
Lee Wallender

Grab Cutout Before It Falls Into Wall

  • Before you finish your last cut, poke a finger into that 1/2" hole and hold onto the cut-out so that it does not drop into the wall. It makes for a cleaner, neater job if you can retrieve it.
Grabbing the cutout before it falls into the wall
Lee Wallender

File Sides of Cutout to Make Hole Wider If Needed

  • While a perfect cut-out is ideal, it's always better to have a hole that is too small than too large. If the hole is too small, use your jab saw to file down edges until the box fits carefully.
File the sides of the cutout to finish the hole
Lee Wallender