Family Handyman gives instructions for wiring a three-way switch, which involve connecting both switches to the light that they control. Before working on this DIY electrical project, it's essential to turn off the relevant circuit at the electrical panel to prevent accidentally electrocuting yourself.
The first step in wiring a three-way switch is to add an electrical box for the second switch. The existing switch box might also need to be replaced with one large enough to accommodate the extra wires.
The next step is to connect the two boxes with a 14-3 NM cable. Inside this type of cable are three insulated wires which have white, red and black insulation, as well as a bare ground wire. Each set of three insulated wires needs to be connected to the terminals of the three-way switch. It is also necessary to connect the ground wire to the common terminal of the switch.
Wires with white insulation are usually neutral wires. However, the white wires contained within the cable that runs between the two three-way switch boxes are hot. Therefore, it's a good idea to wrap black insulating tape around these wires as a reminder that they are hot and not neutral.