Tools & Materials
In this video, master electrician Allen Gallant provides an outlet for high-powered tools and appliances.
1. Turn off power to the electrical sub-panel, then remove the cover from the panel.
2. Use a drill and ⅝-inch-diameter spade bit to bore a hole through the top wall plate directly above the sub-panel.
3. Feed a length of MC 12-2 metal-sheathed electrical cable up through the hole, and then extend it over the ceiling joists.
4. Mark the location of the new 220-volt receptacle onto the wall, making it at least 30 inches above the floor.
5. Hold a metal old-work electrical box against the wall on the mark, then trace around it with a pencil.
6. Drill out two diagonal corners of the box outline with a 1-inch spade bit.
7. Use a rotary cutout tool to cut along the box outline, creating a rectangular hole for the old-work box.
8. Feed the end of the cable down behind the wall to the box location.
9. Pull the cable through the hole in the wall and into the rear of the old-work box.
10. Remove the side plate from the box, then secure the cable to the box by tightening the cable clamp with a screwdriver.
11. Wrap the green grounding wire from the cable around the green grounding screw inside the old-work box. Tighten the grounding screw, then reattach the side plate to the box.
12. Push the old-work box into the hole and flat against the wall. Secure the box by driving two screws through each of its two mounting flanges.
13. Strip the insulation from the ends of the wires inside the box, then make the wire connections to the new 20-amp, 220-volt receptacle.
14. Connect the green wire to the green screw, the black wire to the brass screw, and the white wire to the silver screw.
15. Gently fold and push the wires into the box. Secure the receptacle to the box with two screws. Then put on the cover plate.
16. Remove the knockout plug from the top of the electrical sub-panel.
17. Attach an MC cable connector to the knockout hole.
18. Slide an anti-short bushing over the metal sheathing on the cable.
19. Feed the MC cable through the connector, then tighten the connector to secure the cable.
20. Connect the wires to the circuit breaker and the grounding bar inside the sub-panel.
21. Snap a new two-pole, 20-amp, 220-volt circuit breaker into the panel.
22. Make the final wire connections to the new 220-volt breaker. Replace the cover on the sub-panel.
23. Staple the cable to the wall framing, then turn the power back on.
24. Plug in a 220-volt tool or appliance and check your work.