6 Tips for Installing Electrical Boxes in Walls

Plastic electrical box

Yenwen / Getty Images

Installing electrical boxes is one of the first stages in electrical rough-in work. It is regarded as very easy work—more like carpentry than electrical wiring. But there still some common errors that do-it-yourselfers frequently make.

Follow these easy tips to make sure your electrical box installations look professional and meet code requirements.

  • 01 of 06

    Mounting Electrical Box Between Studs

    Electrical Box With Light Switch

    Don Nichols / Getty Images

    Electrical boxes typically are mounted to the sides of studs for stability. Whether nailed to the studs or screwed in with adjustable brackets, boxes on studs tend to stay in place for a long time.

    But sometimes, it's not always possible to find a suitable mounting point against the studs. What about between the studs?

    Using old-work electrical boxes is one way to hover the boxes between studs. Old-work boxes attach directly to the drywall, not to the studs.

    After cutting a rectangular hole in the drywall, you insert the electrical box in the hole. Then, with either a manual Phillips screwdriver or a cordless drill/driver, you turn the two screws clockwise.

    Turning the screws also turns the two plastic wings behind the drywall, forcing the box against the drywall. While it's not as strong as a stud-mounted box and sometimes the wings will break off, often it's the only option when you want the box to be between studs.

  • 02 of 06

    Install Wall Boxes at Uniform Heights

    Electrical Box Installation Mark Height
    Lee Wallender

    There are no precise code guidelines for how high wall switches or outlet boxes should be positioned. But professionals follow certain standards for a uniform look. Whatever standard you choose, try to maintain uniformity for all electrical boxes. Irregular box heights will flag a home's electrical work as that of an amateur.

    Wall Switches

    It is standard practice for wall switches to be installed about 48 inches above the floor, but this distance can range from 43 to 53 inches, depending on your preference. For spaces used by people with accessibility issues requiring a wheelchair, for example, lower switch heights might be practical.

    Outlet Boxes Over Flooring

    The common practice for receptacle outlet boxes is to install them so the bottom edge is between 12 and 16 inches above the floor. This distance, too, can be adjusted for special circumstances.

    Outlet Boxes Over Countertops

    For switches and outlets above countertops, install them so the bottoms are about 4 inches above the countertop surface.

  • 03 of 06

    Use a Drywall Reference Strip

    Electrical Boxes Installing
    Lee Wallender

    In new construction, attaching a strip of drywall to the front face of studs can serve as a guide for attaching wall boxes. Without some kind of guide, it can be difficult to install the boxes with the proper offset to ensure the front edges of the electrical boxes will be flush with the finished drywall surface. When you install an electrical box, make sure it is flush with the surface of this drywall strip; this will ensure the boxes are at the proper depth when the walls are finished.

    Most residential drywall is 1/2- or 3/8-inch thick, so keep a handful of drywall strips of this thickness on hand to facilitate electrical box installation. If you are using a different wall thickness (such as 5/8-inch thick, required for some firewalls) make sure the reference strips match that thickness.

  • 04 of 06

    Use the Box's Measuring Tab

    Plastic nail-in electrical boxes may have 3/8-inch measuring tabs along the sides. You can use these to indicate how far to extend the electrical box from the face of the studs.

    Begin by slightly pushing out the nails on the box by hand, so that when you place the box against the stud, the tips of the nails lightly pierce the wood. This helps hold the box in place during those first couple crucial strikes of the hammer as you drive the mounting nails into the stud.

    Continue to 5 of 6 below.
  • 05 of 06

    Hammer Box Nails Carefully

    Nail In Electrical Box
    Lee Wallender

    When nailing the box, use light, careful blows rather than heavy swings of the hammer. Make sure to keep your blows perpendicular to the stud. If you strike too hard, you risk pushing the box backward along the face of the stud.

  • 06 of 06

    Alternate Blows Between Nails

    Install Electrical Box
    Lee Wallender

    Rather than hammering in one nail fully before proceeding to the next one, it's best to alternate back and forth between the nails, hammering each nail in about 1/4 inch each time. This will keep the box from twisting or deflecting as you attach it.

    Some electricians stop just short of driving the mounting nails completely into the studs. This allows the box to be easily removed should the layout need to be changed before the NM cable installation.