Step 3 · Install Support Framing
For a secure installation, you must add horizontal blocking. Measure the distance between the two vertical studs inside the wall cavity. Cut two pieces of 2x4 lumber to this length. Position one piece just above where the top of the box will be and the second piece just below the bottom. Secure these blocks by driving 3-inch wood screws at an angle through the ends of the blocks and into the studs (a technique called toe-nailing). These blocks will provide a solid surface to mount the outlet box.