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How to wire a 3 way switch

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

wiring 3 way switch

Please read the disclaimer before attempting any electrical work. If you are uncertain then contact a qualified electrician.

Information and diagrams below:

Old Colours - New Colours

Step by step instructions on wiring a one gang three way light switch.

Three way switches can appear difficult at first but if you take your time and study the pictures/diagram below, it should be pretty straight forward.

You will need 2x 2way light switch and also a intermediat light switch , they can be identified by looking at the terminals on the back of the switch.

E.g. com (common) L1 terminal, L2 terminal, L3 Terminal and L4 Terminal.

One Way Switch
Two Way Switch
Intermediate Switch

6 Diagrams - Click on the desired colours and difficulty to show diagram

Basic Diagrams - Earths Not Shown But Must Be Connected Full Diagrams - Earths are shown Existing old colours to new 3 core cable (new colours)
New Colours New Colours Basic Diagram
Old Colours Old Colours Full Diagram

Brown sleeving or tape would of been placed on the wires as shown to show the blue is live.

There are other methods of wiring a one gang three way switch but this is the most common way and is the easiest by far - Jamie Vernon of Online Electrical Services LTD.

For 1 gang 3 way switching you will need 3 core and earth cable to reach from your new intended light switchs to your old existing light switch via the easiest route. Click here for permitted cable routes.

Once you have run the 3core + earth cables from A to B to C you will need to place it in the appropriate system. Click here for different back boxes and containment.

After running your cables and choosing the appropriate wiring system prepare the cables.

Below there is 3 pictures listed per stage. The reason being there is different cable colours and this is to be sure that your colour is listed here! (Only one of the pictures per stage will apply for you).

Step 1

New Colours

If your existing light switch cables look like this follow the top pictures.

 

 

Switch 1

 

Old Colours

And

Existing old colours to new 3 core and earth cable.

If your existing light switch cables look like this follow the bottom pictures.

Switch 1

Step 2

New Colours

Now change the brown from common to the L1 terminal and the blue from L1 to L2. (if your brown is already in L1 just move the blue to L2)

 

 

Switch 1

Old Colours

And

Existing old colours to new 3 core and earth cable

Now change the red from common to the L1 terminal and the black from L1 to L2. (if your red is already in L1 just move the black to L2)

 

Switch 1

Step 3

New Colours

Add the 3 core and earth as shown in this picture.

All the wires should have brown sleeve/tape on them, I have left some off so you can see the colours.

 

 

Switch 1

Switch 1, Common = Gray (3core cable), L1 = Brown (twin) and brown (3core), L2 = Black (3core) and Blue (twin)

Old Colours

 

Add the 3 core and earth as shown in this picture.

All the wires should have red sleeve/tape on them, I have left some off so you can see the colours.

 

 

Switch 1

Existing old colours to new 3 core cable

 

Add the 3 core and earth as shown in this picture.

All the wires should have red sleeve/tape on them, I have left some off so you can see the colours.

 

 

Switch 1

Step 4

New Colours

Connect the 3 core + earth cables as shown in this picture.

The wires on this switch should copy/mirror the other switch.

 

Switch 2

Awaiting Image.

Old colours

and

Existing old colours to new 3 core cable

Connect the 3 core + earth cables as shown in this picture.

The wires on this switch should copy/mirror the other switch.

 

 

 

Switch 2

 

Step 4

New Colours

Shown to the left is the back of the 3rd switch. The wires in this switch should copy/mimic the wires on the first switch.

 

Switch 3

Old colours

and

Existing old colours to new 3 core cable

Shown to the left is the back of the 3rd switch. The wires in this switch should copy/mimic the wires on the first switch.

 

 

Switch 3

You can now switch on a light from 3 different locations.

Tips

If you are using metal/chrome/brass switches always make sure the switch is earthed.

Check if your lights have earths, if there are no earths in your switches or lights get in touch with a qualified electrician.

Always use insulated tools when working with electricity.

Take your time and double over your single cables as good practice.

 

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