Installing A Three Way Switch. Installing a three-way dimmer switch on an existing three-way switch circuit is not only a simple job, but it will add flexibility to your lighting design and improve the overall atmosphere of your living space. One of the most common problems is improper wiring due to connecting the circuit wires to the wrong screw terminals.
All those switches, terminals and wires can confuse experienced electricians, let alone novice DIYers.
Three-way switches are tricky to install, especially for DIYers who are replacing a bad switch.
If you are replacing a three-way switch, one wire will be connected to a screw that is colored differently or labeled "COMMON." Note that this is different from. Installing Three Way Dimmer Light Switches. We'll look at three different layouts depending on if you want the light fitting to be at the beginning, middle or end of the circuit.