How to wire a light switch | Downlights Wiring a One Way Switch. A one way light switch has two terminals which is a common marked as COM or C. The common is for the live wire that supplies the input voltage to the switch. The other terminal is marked as L1 and is the output to the light fixture. Wire a light switch in one way lighting circuits - Diy How To Wire a light switch in one way lighting circuits. A simple lighting circuit is where the light switch is installed between the supply and the light fitting. A common place to find in-line switches can be in an attic, in a garage or a shed. How to Wire a 4-Way Light Switch (With Wiring Diagram The two wiring diagrams above are of a 3-way switch setup and the same basic setup with a 4 way light switch added. While the physical location of the 4 way switch may be anywhere, the electrical location of the switch is always between the two 3 way switches. 3 way switching (UK) | Light wiring US – This would be referred to as 4 way switching because it utilises what they refer to as a 4 way switch (what we in the UK call an intermediate or crossover). If you have 1 light controlled by 3 (or more) light switches this is the circuit/wiring diagram you need Three-Way Lighting Circuit Wiring | SparkyFacts Three-Way Lighting Circuit Wiring The 3-way lighting circuit, which is often referred to as the two-way and intermediate lighting circuit, is a common arrangement usually found in large houses. If you are familiar with wiring a two way lighting circuit, then the addition of 4-Way Switches - Electrical 101 Below is a conventional wiring diagram for a 4-way switch configuration. The diagrams below show the conventional wiring for 3-way switches in a 4-way configuration. Unfortunately, not all 3-way switches are wired the conventional way. See Alternate 3-Way Switch Wiring Configuration for another way 3-way switches may be wired.