Wiring Diagrams For Three Way Switches Adding New Lights to 3-Way Switches; Wiring Three Way Switches - When adding additional lighting to an existing three way switch configuration, the only place the additional lights may be wired to are at the existing light fixture or to the switch box where the existing light fixture is wired to.. Four-way switches can control a fixture from 3 or more locations. Check here for 4-way switch diagrams and to wire 3-way and 4-way circuits with multiple lights see these. On this page are several wiring diagrams that can be used to map 3 way lighting circuits depending on the location of the source in relation to the switches and lights.
3-Way Toggle Switch WiringThe diagrams below show the conventional wiring for 3-way toggle switches.Unfortunately, not all 3-way switches are wired the conventional way.See 3-Way Switch Variation for another way 3-way switches may be wired.. If you have any problems with these switches, it may be best to call an electrician.. The three-way switch wiring diagram depicted at the top of this post is probably the most common method for wiring three-way switches. The two-wire LINE cable goes into one switch box, and the two-wire LOAD cable goes into the other. A three-conductor cable with a grounding wire is installed between the two 3-way switch boxes.