One wire comes in from the power source, and one wire goes out to the light (s). A 3-way switch adds two terminals for travelers, which connect two 3-way switches together.

So the existing switch has 2 terminals on one side, and 1 on the other. The 2 terminals have a black sheathed (B) and red sheathed (R) wire attached. The single terminal has a grey sheathed wire.

Below, Donnelly tells AD how to wire a light switch with this simple step-by-step process for a single-pole light switch without zapping yourself along the way. To make the task easier, Character ...