Diagrams and Help On UK Electrical Wiring

Lighting

Intermediate Light Switch

One of the most common questions we get asked with lighting and light switches is 'What is an intermediate or inter switch and when is it used?"

To keep it really simple it is used when any light point can be switched from 3 or more places. The most common example of this in the UK is on a landing, you will have a 2 way switch at the bottom of the stairs and perhaps across a landing and then the switch at the top of the stairs or in the middle position will be an intermeadiate or 3 way switch.

These are easily identified as they have 4 terminals rather than 2 or 3 on a light switch. This is not to be confused with a double pole switch, witch will also have 4 terminals but these are usually used to isolate appliances, heaters, cookers, showers etc and in the min will have larger cabling.

Intermediate wiring diagram:

One Way Light Switch

Does exactly what it says on the tin! One light point switched from one place, the most common scenario.

If you have a 2 way switch it can be used 1 or 2 way by using common and L1. If the switch then works upside down you can simply spin it round or move the L1 connection in to L2.

Two Way Light Switch

This is when a light point can be switched from 2 positions and most commonly across a room or up/down stairs. A 2 way switch is required on each end, but if you are using a dimmer you can only put a 2 way dimmer on one end of the circuit.  Otherwise one dimmer would end up dimming the other dimmer, so choose which end you prefer to dim from and then fit a standard 2 way rocker at the other end.