3 way switch wiring diagrams are shown in above Figure for each of the switching connections discussed. The first diagram is a schematic drawing and is valuable when visualizing the current path. The second diagram represents the situation where a raceway will be available for installing the conductors. The third diagram illustrates the connection necessary when using a cable such as armored cable (AC), metal-clad cable (MC), or nonmetallic-sheathed cable (NM). Equipment grounding conductors and connections are not shown in order to keep the diagrams as simple as possible.

3 way switch wiring . A 3-way switch should really be called a 3-terminal switch. Three-way switches provide switch control from two locations.

A 3-way switch, has a common terminal to which the switch blade is always connected. The other two terminals are called the traveler terminals. In one position, the switch blade is connected between the common terminal and one of the traveler terminals. In the other position, the switch blade is connected between the common terminal and the second traveler terminal. A 3-way switch can easily be identified because it has no On or Off position. Note that On and Off positions are not marked on the switch handle i. A 3-way switch is also identified by its three terminals. The common terminal is darker in color than the two traveler terminals, which have a brass color

first figure shows 3-way switch connections, one with the source feeding at the light, the other with the source feeding at one of the 3-way switches., orange has been used for the switch return (switch leg/switch loop) in the raceway (conduit) diagrams. Any color other than white, gray, or green could have been used for the switch return.
For the travelers, purple was selected. Other colors could have been used. Always use a color that is different from the switch return.