How to Connect a 4 Wire Line to 2 Wires
- 1). Take the ends of both the 12-2 Romex wire and the 12-3 Romex wire and strip 1/2 inch of insulation off each wire. Push both ends into an electrical junction box. All electrical splices must be made inside a junction box per the National Electric Code.
- 2). Look at the four wires of the 12-3 cable. There are two ways to connect a 12-2 wire to this cable. The first option is to use the black wire of the 12-3 cable as the hot wire. Connect the black wires of both cables together, and connect the common white wires together. Cap the red wire and leave it untouched in the junction box. Place plastic twist caps on all splices. The ground wire may or may not be connected.
- 3). Alternatively, use the red wire as the hot wire. Connect the red wire of the 12-3 cable to the black wire of the 12-2 cable. Splice together the two white wires. Cap the black wire of the 12-3 cable and leave it untouched in the junction box.