Things You'll Need
12 or 14-gauge electrical cable
Insulated wire connectors
Black electrical tape
You may want to control two lights with one switch in certain locations around your home, such as the front entrance or a double-bay garage. With some basic tools you can easily do the wiring yourself, whether you are adding a light to an existing light circuit or adding a completely new circuit. You'll learn two methods in this article: use the first when the power source comes in at the first light and the second when the power source comes in at the switch.
Go to the service panel and turn off power to the circuit you will be working on. If there is already a switch with one light installed, return to the switch and remove the cover. Check all wires for current with your voltage tester. If there is only one black wire connected to the switch, follow the instructions in step two. If there is more than one black wire connected to the switch, follow the instructions in step three.
The power supply connects to the first light: Connect the white wire from the power supply to the white wire from the light. Connect the black wire from the power supply to the white wire of the cable connected to the switch. Wrap a piece of black electrical tape around each end of this white wire to indicate that it is a hot wire rather than a neutral wire. Run your cable from the first light to the second light. Connect the black wire from the switch to the black wire from the first light and the black wire coming from the second light. Attach the white from the second light to the white from the power supply.
The power supply connects to the switch: Connect the black wire from the power supply to the switch and the white wire from the power supply to the white wire of the cable connected to the first light. Connect the black wire from the first light to the switch. Run your cable from the first light to the second light and connect black to black and white to white.
Connect all bare or green wires together and to the boxes if they are metal. Any green screws on the switch or lights should also be connected to the bare wires. Screw insulated connectors over all wire connections.
Etienne Caron teaches English to speakers of other languages and has been writing for Demand Studios since 2009. He graduated from Westfield State College in 1993 with a bachelor's degree in regional planning.