Installing electrical boxes such as switch, outlet or fixture boxes can add functionality and décor to your home. They can also add new hazards to both your home and the people inside if not installed properly. Whether you're installing electrical boxes in a new area or remodeling an existing room they can be safely installed so that you can enjoy your home to the fullest.
Things You'll Need
- Electrical Box
- Stud finder
- Laser Level
- Jig Saw
- Screw driver (Phillips and/or Flat head)
- Electricians Pliers
Purchase the box or boxes. The type will depend on whether you're installing in a new area or remodeling. New construction boxes will generally be outfitted with nails to attach the box to a wall stud. Remodeling boxes will generally have securing "fins" at two or more corners of the box. If you are using prefabricated construction, there are electrical boxes made specifically for those types of construction. See your material dealer for details.
Define the location for your new electrical box.
Clear the area of furniture or other objects that could hinder safety or access.
Locate the electrical panel feeding the area and find the circuit breaker feeding the circuit to which you are adding the new box. Turn off the circuit breaker feeding the area.
Use a voltmeter to verify zero volts to the circuit.
Select the tools required for the installation and bring them to the location. Start installation.
Wall box installation -- new construction or area
Define the height requirement. Codes among municipalities differ but in general receptacles should be 14 to 16 inches above the floor; switches, kitchen receptacles and garage receptacles should be 46 to 48 inches above the floor; and vanity receptacles should be 42 to 44 inches above the floor.
Attach a laser level to a wall stud upstream of the wall box at the proper height to align all boxes being installed then attach the electrical box to a wall stud by hammering the attaching nails on the box into the wall stud. Align the top of the box with the laser level line and attach the box so that the front edge of the box protrudes beyond the stud by the thickness of the wall to be installed.
Punch the required number of knockout plugs from the electrical box depending on whether the circuit will end at the single box or be daisy-chained and install a rubber grommet around the inside of each knockout (if using a metal box).
Run the correct size wire into the grommeted hole and prepare the wire using electrician's pliers.
If device installation will not take place immediately, do not prepare the wire--coil the wire inside the box and attach a cover to prevent accidental access.
Wall box installation - existing area
Attach a laser level to the wall to align the new electrical box (for remodeling) with the existing boxes.
Use a stud finder to locate a hollow area between wall studs to mount the box.
Use the template provided with the box to trace a cutting pattern on the wall, making sure to align the top of the template to the laser level line, then use a jigsaw to cut a hole in the wall, using the tracing as your guide.
Punch the required number of knockout plugs from the electrical box before inserting the box into the wall. Grommet the holes (if using a metal box) and pull the wire into the box. Insert the electrical box inside the hole until it stops. A small ridge on the front edge of the box will keep the box from going through the hole and will aid in securing the box to the wall.
Use a screwdriver to turn the "fin" screws clockwise on each corner of the box until tight. This will turn the "fins" outward to press against the back side of the wall, securing the box to the wall. Complete the installation as previously outlined.
Installing ceiling boxes for fans or other heavy fixtures
Purchase an electrical box made specifically to hold heavy objects (joist-mounted). The assembly will have rails that fit between the ceiling joists and can be either attached (new construction) or pressed (remodel) between the joists. The electrical box will hang off the rail assembly so that the fixture weight will be supported by the ceiling joists and not the ceiling.
Use the correct size ladder to reach the ceiling height for which your are working.
Secure joist attachment so that the electrical box will be flush with the installed or existing ceiling.
Complete installation as previously outlined for either new construction or remodel.
Tips & Warnings
- A "Wiggy" or other voltage-detection device can be used in place of a voltmeter.
- Use a level or a leveled run of string if you don't have a laser level.
- A utility knife and wire cutters can be used in place of electrician's pliers.
- Use the back of the box as a template to trace the hole pattern if no template exists.
- Use a Dremel Tool in place of a jigsaw.
- Tap lightly on the wall if you don't have a stud finder--a hollow sound indicates a hollow spot.
- Turn off the circuit breaker to avoid shock hazards.
- Check your voltage-detection device on a known live circuit to verify proper operation.
- Never use a step stool or chair for ceiling installations
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