When nothing is hooked up there is power in the 2 wire plus ground cable on the upstairs switch. This guide highlights the procedures for replacing a broken 3 way electrical switch.
3 Way Switch Wiring Diagram
2 wire 3 way switch. It is a standard single pole switch with three terminals. Looked at an existing home brother in laws and found that the 3 way switch in the dining room only has 2 wire running from 3 way to 3 way. The three terminals are usually named com l1 and l2 but sometimes com 1 way and 2 way are also used. 3 way switch wiring methods 1 upside down up on the ceiling by the light or 2 on the wall by the switch. In one position the com and l1 are connected while in the second position the com and l2 are connected. A three way wall switch is single pole double throw spdt with three connection wires and is typically wired with 123 or 143 cable between the two switches.
Have not found where the switched leg is being picked up for the receptacles in the room. Wiring a 3 way light switch is certainly more. Description power at one end switch leg at the other end with a 2 wire 142 or 122 used as travelers. Two way switches are single pole single throw spst with two connection wires and are wired with 122 or 142 cable between the switch and fixture. Just a word of caution my neighbor was going to attempt to wire a three way switch using existing 142 wiring but using the ground wire as the third wire. Obviously i stopped him and let him know the dangers of this.
Keep this method in mind if you dont have any 3 wire with you. Its tempting but dont do it. Two 3 way switches are required in any 3 way application. With some good fishing skills youre drywall destruction can be kept to a minimum. Before proceeding make sure you are comfortable working with electrical wires and switches. Once youre done youll be able to control a light from two switches.
S3 method 51 four wire 3way with a light at both ends. There is only the single 3 wire plus ground in the downstairs switch box and only two 2 wire plus ground cables at the fixture. This story features diagrams that show how to wire 3 way switches. The two switches appear to be connected by a 3 wire plus ground cable. The wiring is more complicated than a traditional single pole switch but well explain how to make the connections.
Gallery of 2 Wire 3 Way Switch
