There are two clear giveaways that identify a switch as being a three way type. The whole wiring a light switch project can be completed in a few hours if you dont have to do any drywall removal and repair.
3 Way Switches Electrical 101
3 way switch connection. There are three screw terminals on the body of the switch in addition to the green grounding. With these diagrams below it will take the guess work out of wiring. 3 way switches have three terminals one common usually black color and one pair of travelers usually brass color. When wiring a 3 way switch first screw the terminal screws of the new switch until they are difficult to turn. The black line wire connects to the common terminal of the first 3 way switch. The key to wiring 3 way switches the power feed and the switch leg leading to the fixture s typically one at each switch location are attached to the screw terminal found at one end of the switch by itself.
A 3 wire nm connects the traveler terminals of the first and second 3 way switch together. 3 way switch wiring diagram. This terminal is usually identified by a darker colored screw. There are no onoff markings on the switch toggle. Connect the ground wire to the green screw. This might seem intimidating but it does not have to be.
Connect the wire marked common to the black or dark colored screw. With conventional wiring the common wire from one switch connects to line the common wire from the other switch connects to the load lights. Such markings are not needed with this type of switch as they are. This configuration may be used in open plan homes or in large kitchens or great rooms where a central bank of lighting fixtures might be controlled from more than two entry points. Connect the two remaining traveler wires to the two brass or light colored screws. Pick the diagram that is most like the scenario you are in and see if you can wire your switch.
Take a closer look at a 3 way switch wiring diagram. So what you should see if you have correct 3 wire electrical cable romex is a black power white neutral and now a 3rd red wire. A third type is the four way switch which is used in conjunction with two three way switches to control lighting from more than two locations. With a pair of 3 way switches either can make or break the connection that completes the circuit to the light. The three way switch is a variation of the standard single pole switch which controls a light only from one location. Keep reading and learn how to wire a light switch.
Run new cable romex between the 3 way switches regardless of what 3 way switch wiring diagram youre following youll need to use a 3 wire cable to connect the two 3 way light switches. All of the switches shown below are 3 way. Typical 3 way switch wiring nm cable in the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box.