3 Way Light Switch Diagram. All of the switches shown below are 3 way. The black line wire connects to the common terminal of the first 3 way switch.
In the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. This is the 3 wire cable which you must have to wire a 3 way. All of the switches shown below are 3 way.
In the above 3 way switch wiring diagram at each switch the black wire gets connected to the copper or black screw.
To get started take a look at the first diagram below. Three wire cable runs between the switches and 2 wire cable runs to the light. 3 way switch wiring diagram depicting all wires in the ceiling junction box. All of the switches shown below are 3 way.
