Changing a Light Switch - DIY Guide

Changing a light switch is a job which nearly anycannot be re-energised.
competent do-it-yourselfer can do but there are aRemove the switch plate from the wall by
couple of things to watch out for.removing the two screws and pull it gently
Please bear in mind that in the UK it is illegal totowards you. You will now see the connections in
work on any part of the electrical installation in athe back.
kitchen or bathroom without notifying the localNow is a good time to make a note or sketch of
authority or employing a Part P registeredwhere the cables are connected. If you have a
electrician.similar switch the terminations will be a straight
When you decide to change a light switch youreplacement but if it looks different then make
must consider the circuit that the switch is on.these notes.
Prior to the mid 1960's lighting circuits rarelyThe majority of switches follow the same format
incorporated an earthing conductor, properly calledfor marking. 'C' for common, L1 and L2 for the
a circuit protective conductor (cpc).others. One a one way switch the common will
If you have an electrical installation in which thebe the red/brown wire and L1 will take the black
lighting cables do not incorporate a cpc. then youblue wire with a short identifier of brown or red
must not replace any plastic light switch with asleeving or tape.
metal one such as brass or steel. It would beWith a two way switch it is not uncommon to
extremely dangerous to do so.have five wires connected into the back. Making a
Next you will have to ascertain what type ofnote is strongly recommended. The five wires will
switch you are changing.be split up into two pairs and a common. The two
A switch plate which has only one switch is calledpairs can go into either L1 or L2, it does not
a one gang or single switch. One plate with twomatter but the single wire must go into the
switches is called a two gang and so on.common or the switch will not work correctly.
There are basically three types of light switch, aWhen you first remove the switch you may
one way switch, a two way switch and annotice some blue or black wires connected into a
intermediate switch. All switches are rated atblock, these are the neutrals and must not be
either 6 or 10 amps.connected to the other live wires or you will
A one way switch operates a light or lights fromcause an electrical short and a small bang.
one position, normally by a door. A two wayThe earth or cpc wires can be left alone also
switch will have a partner so that a light can beunless you are fitting a metal switch in which case
turned on and off from two positions, say, by theyou must make a connection to the plate to the
kitchen door and the back door. An intermediateterminal provided. This can be achieved with a
switch is used when the light has to be turned onshort piece of copper wire, preferably sleeved
and off from three positions or more.with green and yellow sleeving.
A one way switch will have two terminals on theWhen you have made all the connections and are
back for the cable connections, a two way willsatisfied that they are correct replace the switch
have three and an intermediate will have four.onto the box, ensuring that all the wires are
To change the switch, first turn on the light andpushed away from the screw positions and screw
then take out or turn off the fuse or mcb, thisit down securely.
will ensure you have the right circuit. Put the fuseFollow these tips and changing a light switch will
in your pocket or tape down the mcb so that itnot seem to be that difficult again.