How To Wire A Light Switch [Step-By-Step Guide]

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How To Wire A Light Switch

Changing a light switch is the kind of DIY task that can help transform a room quickly and cheaply. Working with electricity does require extra care but taking sensible precautions will help you get the job done. Here at ToolStore UK, we carry a huge selection of hand tools which, when combined with our range of electrical supplies and lighting equipment will help you swap your switches.

What tools do you need to wire a light switch?

The following items will help you get this job done safely and efficiently:

A new light switch, such as those found in our electrical supplies range
An appropriately sized VDE Screwdriver. The Stanley XTHT0-62692 5 piece Slim VDE Phillips Screwdriver Set also includes a voltage tester, which will help you make sure you’re not working with live circuits
Pliers
Electrical tape

Ensure you work safely

Always install or replace light switches in accordance with local building regulations. If you are in any doubt about what you need to do, or are required to undertake by law, then we advise consulting a competent person who is registered with an electrical certification scheme.

Never take risks with electrical safety. Before you start any type of electrical work, you must follow these following safety precautions:

Switch off the main power at the consumer unit/fuse box
Isolate the circuit you plan to work on by removing the circuit fuse. Put this in your pocket to avoid accidental replacement. You could switch off the breaker and lock it where this is possible
Attach a note to the unit to let others know you are working on the circuit
Check the circuit is dead with a voltage tester/meter

READ MORE: How To Put Up A Curtain Rail

Wiring a One Way Switch

A one way switch is the simplest form of light switch, in that a single switch controls a single light fitting. Simple one way switches, such as the DETA VC1202 10AX 1-Gang 1-Way Light Switch are inexpensive, yet practical. When choosing electrical supplies, the word ‘gang’ equals the number of devices which can be operated by the item. For example, a 2-Gang One Way Switch could be used to operate two different light circuits from the same point in a room.

Step 1

To install a new one way switch, start by unscrewing the switch plate. If you're replacing an existing switch, gently pull it out and carefully identify which wire is connected to COM / C (Common) and which runs into L1 (Line out). 'Common' is the terminal to which the live core wire is attached. This will usually be brown, or red on older circuits. L1 is the terminal connecting the circuit to the line out to the light and should be connected to the blue wire. If you have older circuits, the wire connected to L1 might be black.

Step 2

If you’re replacing an older switch with a new one, loosen the terminal screws holding the wires in place. You may need to use pliers to unwind the tight coils of wire around each terminal.

Step 3

Check each wire for damage and use your pliers to trim off any worn out or damaged wire. Leave roughly half an inch of bare wire exposed and use your pliers to form these exposed lengths into rounded hook shapes that will fit securely around the terminal screws.

Step 4

Use the hooked ends to connect the circuit to the new switch, directing the hooks clockwise. Needle-nosed pliers could be used to hold the wires in place while you tighten the screws. Wrap electrical tape around the terminal screws to protect against fire. Tuck the wires into the casing and screw the switch back into the wall. Attach the new switch plate and restore the power.

Wiring a Two Way Switch

The idea behind a two way switch, such as the Deta VC1203 10AX 1-Gang 2-Way Light Switch, is that a single light fitting can be operated by a pair of switches in different locations, which is why these are sometimes called ‘Staircase Switches’. You might need to fit a new switch or convert a one way switch to two way operation. A two way switch has an additional ‘Line out’ terminal – L2. When wired correctly, if L1 is ‘on’, L2 will be ‘off’ and vice versa.

Step 1

If you're connecting an installed light fitting to a new two way switch, start by connecting the light to the first two way switch. Connect the Line (brown) wire to the L terminal, together with the supply cable Line wire and connect the blue wire with a brown sleeve to the SWL terminal together with the lamp's Line wire. It is important to apply this sleeve to the blue wire, as this will indicate that an otherwise Neutral wire (blue) is now being used as a switched Line wire.

Step 2

Now, focus moves to the switching arrangement, which will usually be wired with a 3 Core & Earth cable with brown, grey, and black cores. Connect the Line (brown) wire coming from the light together with the black wire from the 3 Core & Earth cable in to the L1 terminal of the two-way switch. Connect the blue wire with the brown sleeve coming from the light to the L2 terminal, together with the 3 Core & Earth cable's grey wire. Finally, connect the brown wire from the 3 Core & Earth cable to the C (common) terminal. Don’t forget to connect the Earth conductors to the Earth terminal provided.

Step 3

Now, you can connect your second two way switch. Connect the black wire coming from the first switch to the L1 terminal, connect the grey wire to the L2 terminal and connect the brown wire to the C (common) terminal. Again, don’t forget to connect the Earth conductors to the Earth terminal provided.

Step 4

Test the circuit and reconnect the supply.

It’s also possible to add intermediate switches to circuits to create three way and four-way operation of a particular light, but this is a more complex project, and we’d suggest consulting a competent person before starting work.

Supplies for Professionals and Projects at Home

At ToolStore UK, we carry a range of products supplied by Deta Electrical, a market leading manufacturer and distributor of high-quality wiring, lighting and electrical accessories. From cable and extension leads, through to electrical supplies and plugs, fuses and adaptors, we have everything you might need whether you’re a trade professional or just updating your home.

We also have ranges for on-site working, including lighting and fans.

No job is too big when you shop with with ToolStore UK

ToolStore UK has been supplying hand tools, power tools and accessories for almost 60 years so there aren’t many projects our team hasn’t encountered. Our friendly and knowledgeable staff can be contacted via our website, by calling 03330 043777 or by calling into our shop, which is just a short walk from the Wigan railway stations. We’re here to help, whatever your project or level of expertise.