Explanation

Lighting circuits often use a system where each lighting point is fed with a Live, Neutral and Earth (CPC). These are then extended to give the next light its Live, Neutral and Earth (CPC). Each light is then switched on & off using a switch or combination of switches that are appropriate to that lights use.

Often lights need to be switched from two different positions such as a landing light or one lighting a a corridor. There is more than one way of wiring a light to be operated from two different positions. This demo will now look at the way in which a light wired in conduit can be wired so that it can be switched from two light switches so that either can switch it on or off irrespective of the position of the other. This is slightly more complex than you might think as wiring two one way switches in series would be limited in its functionality. For example if switch 1 was on switch 2 could switch the lamp on or off, and similarly if switch 2 were on switch 1 could switch the light on or off, BUT if both switches were off neither could switch it on by themselves. We NEED to wire it so need either switch can turn the light ON or OFF irrespective of the state of the other. Starting with the light to be switched carry out the following.

• Taking a permanent live and connect it to the common terminal of the first two way switch.
• Run two cores between the two switches connect L1 to L1 and L2 to L2 between the 2 two way switches. If wiring in singles 2 brown cores can be used which would mean there is no need to flag these wires with brown sleeving.
• Run a wire between the second two way switches common terminal and the lights switched live terminal.
• Run cpc between light and switches irrespective of whether they are needed by the current light or switches so that one is present should one be needed later on.

NB CPCs are not shown in the interactive tools for clarity (plus drawing green/yellow striped lines is ricky in this software).

The switch wires between two switches are often referred to as strappers.