Metal stud construction is gaining popularity in residential building. In metal stud construction, the walls are framed in lightweight steel members instead of wood. Installing wiring in a metal stud wall is very similar to wiring in wood stud walls, with a few exceptions. One of the most helpful features of metal studs is that the verticals have pre-punched holes especially for wiring. You will need to use metal-clad wire, which requires a special tool to cut. You will also need different box clamps than you need for ROMEX®, but these are readily available at a home improvement center or electrical supply store.
Things You'll Need
- Metal-clad (MC) wire
- MC sheath cutter
- Plastic bushings for MC wire
- Diagonal cutters
- Drill and hole saw
- One 4x4 junction box
- Red wire nuts
- 2x4 outlet boxes for metal framing
- Green grounding screws
- Self-tapping sheet metal screws
Install wiring after your metal studs are in place but before your drywall is up. Using a drill and hole saw, drill a hole up from the basement (where your circuit breakers are), and through the metal base for your metal stud wall. Position this hole at one end of your stud wall.
Run MC wire from your circuit breaker through the hole and to wherever you want to place your first outlet. MC wire is covered by a spiral of steel to protect the conductors. To cut it, use the sheath cutting tool to cut the spiral. Twist the spiral counterclockwise to expose the conductor wires. Pull the sheath off to expose enough wire to work with. Place a plastic bushing in the end of any cut section of MC wire to protect the conductors from sharp edges.
If there is already ROMEX® wire run to the room and you're replacing it with MC, you can cut the ROMEX® off in the basement near your hole and install a 4x4 junction box. Connect the ROMEX® and the MC in the junction box with red wire nuts. Run the MC into the metal stud wall.
Install 2x4 boxes wherever you want outlets in your metal stud wall. Use boxes designed to mount on metal stud wall, which have a flat metal plate that gets screwed to the face of the metal stud. Use self-tapping sheet metal screws.
Run MC wire to your boxes through the pre-punched holes in the metal stud uprights. Attach MC wire into the boxes with MC box clamps.
Add a pigtail of wire into each box with a green grounding screw threaded into the tapped hole in the back of each box. The wire coming off the screw should be long enough to easily work with, but not so long it will be a chore to stuff it back in the box.
Add another pigtail of wire to the green grounding screw on each outlet.
Wire outlets as usual, with the black wire going to the brass screw and the white to the silver screw. The green wire from each MC wire should be connected with a wire nut to the pigtails coming off the outlet and the box.