How to Connect Two Sub Panels to One Breaker in the Main Panel
- 1). Turn off the main breaker in the main breaker panel. At some point between the main breaker panel and the first sub-panel, cut the wire connecting the two breaker panels with wire cutters. This cut should be made near a stud. Install a junction box by attaching it to the stud with a screwdriver and screws or a hammer and nails.
- 2). Feed both ends of the cut wire into the junction box. Feed the end of the wire that will feed the second sub-panel into the junction box. Remove 4 inches of the outer insulation from the ends of all three wires with wire strippers and separate the inside wires. Use the wire strippers to remove 1 inch of the coating from the ends of each of the inside wires.
- 3). Hold each of the ends of three of the wires with matching colors next to each other and screw a wire nut onto them with your fingers to hold them together. Repeat this process for each of the other sets of matching wires. Go to the second sub-panel to complete the installation.
- 4). Push the wire into the sub-panel box. Strip 12 inches of the outer insulation away with wire strippers from the end of the wire. Use the wire strippers to remove 1 inch of the coating from each of the inside wires.
- 5). Slide the ends of the black and red wires into the two lugs in the center of the top of the box. These are both power wires, and it does not matter which wire goes into which lug. The end of the white wire should be inserted into the opening under the lug at the top of the neutral bus. Insert the bare wire under the upper screw on the ground strip that is located at the far right or left of the sub-panel box and tighten the screw with a screwdriver.
- 6). Use a wrench or screwdriver, depending on the type of sub-panel box, to tighten all of the lugs to secure the wires. The sub-panel is now powered and ready for its circuits to be installed. If both sub-panels are being installed at the same time, go to the other sub-panel and repeat the procedure for installing the wiring inside the box. When the wiring is complete, turn the main breaker in the main panel back on.
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