3 Way Switch Wiring Diagram - Do It Take a closer look at a 3 way switch wiring diagram. Pick the diagram that is most like the scenario you are in and see if you can wire your switch! This might seem intimidating, but it does not have to be. With these diagrams below it will take the guess work out of wiring. Interested in How To Wire a 3 Way Light Switch | Family Handyman Figure B: Three Way Switch Wire Diagram—Power to Light Switch. This three way switch wiring diagram shows how to wire the switches and the light when the power is coming to the light switch. Family Handyman. In the diagram above, the incoming hot wire attaches to the first switch’s common dark-colored terminal.Author: The Family Handyman Three Way Light Switch Wiring Diagrams - MrElectrician The photo below shows the wiring at the other 3-Way location which was a single pole switch originally. Three-way switch wiring. The black hot wire in the electrical box above is connected at the other end to the black LINE wire and gets connected to the black or red screw on the 3-way switch.