how to fit a dimmer switch

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Before working on any electrical circuit isolate the supply by switching off the main switch and remove the fuse to the circuit that you are working on, If it is a circuit breaker switch off the main fuse and circuit breaker and remove the wires from the top of the circuit breaker. Place a sign saying that you are working on the circuits on the consumer unit, then nobody will restore the power whilst you are working on it.

If you are not 100% certain what you are doing call a qualified electrician. Building regulations are changing all the time and modifying your home electrics could be against new rules and could invalidate your home insurance, if in doubt check first!

If you find the lights in your home are too bright you can dim them by fitting a dimmer switch. These switches are popular in living rooms as the lights can be dimmed for watching TV etc. then Un-dimmed for reading etc.

You must check that the bulbs in your light fitting are compatible with dimmer switches, Fluorescent lights and energy saving light bulbs are not compatible and should not be used with dimmers.

Dimmers can be used on a two way lighting circuit or a single one way lighting circuit. The wiring is very simple as you simply follow the wiring of the switch that you are replacing.

The diagram above shows how a two way dimmer would be wired up on a one way circuit- simply leave the L2 terminal empty. For a two way system you should wire up the dimmer the exact same way as the switch that you remove!

A common problem with fitting a dimmer switch is that the back box is often not deep enough to accommodate a dimmer switch and so will need replacing with a deeper back box. This is simply a case of chiselling away the Masonry behind the back box and then refitting a deeper one. Be sure to connect the Earth wire to the back box, then run a earth wire to the dimmer itself!