Wiring Diagram Light Switch 3 Way. You should only need to change the wiring in each switch box (light box(es). It is much more complex than installing Wifi Light Switches.
The white wire of the cable wiring is marked with black electrical tape, and is going to the switch. A three-way switch is built and wired a little differently than a conventional single-pole light switch. The colors will vary depending on whether NM cable or conduit was used.
Three-way light switches control a light from two locations, such as from both ends of a staircase or hallway.
These are commonly used for lighting in a stairway where you want a switch on each floor entering the stairway.
They are always installed in pairs and use special wiring connections. It is installed between two three-way switches. You should only need to change the wiring in each switch box (light box(es).