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How to install outdoor lighting and security lights

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Difficulty rating: Medium

If you're installing new circuits or electrical equipment outside your house, you have to let your local council know before you start. You'll also need to pay a fee to have the work tested and certified when the installation is finished.

None of these jobs are particularly difficult but you will need some electrical skills. Always follow the manufacturer's instructions when you fit electrical equipment.

If you're unsure, ask a qualified electrician for help.

Step 1: Choose an outdoor light fitting

It may be obvious, but make sure the light you choose is OK for outdoor use - even if you're putting it in a sheltered spot.

Exterior security lighting

You've got two main types of exterior security lighting: dusk-to-dawn lighting and PIR lights.

Dusk-to-dawn lights come on automatically when it gets dark and switch off again when the sky lightens at dawn.

PIR lights are triggered by body heat so only turn on if someone approaches your home. These exterior lights could be your best option as they should surprise and scare off intruders and also use less electricity.

Garden lighting

Use outdoor lighting to create an atmospheric extra 'living room' to enjoy after the sun goes down.

Light your outdoor space in different ways. Use task or functional lighting for entrances, paths, patios, garages and sheds.

To create mood and highlight decorative parts of the garden such as plants, trees, ponds or sculpture, go for accent lighting.

Step 2: Switch off the power supply

When installing your outdoor lights, switch off your power supply at the fuse box (consumer unit) before doing any electrical work.

You can do this in two ways. First, you can switch off the miniature circuit breaker (MCB) for the circuit you'll be working on and put red insulating tape over the MCB so it's not switched on accidentally.

Or you can turn off the main switch, remove the circuit fuse, then turn on the main switch again to restore power to the rest of the house.

Step 3: Decide where to put your lights

Exterior security lights

Place your security lights at least 2.5m off the ground.

With PIR lights, angle them in such a way that passers-by don't trigger them. Don't put a light near the flue of the boiler as this can also trigger the light into action. PIR lights come with an integral or separate PIR sensor unit. You'll find the integral one easier to fit.

Position a dusk-to-dawn light where you most need illumination at night.

Garden lighting

Decide where to put your garden lights and mark the route for the cable to link them. There are two ways to run the cable to your light:

Option 1: Run the cable underground

Prepare a trench for the cables – it needs to be a minimum of 450mm deep if it runs under a patio or path. Make it at least 750mm deep it it's going under lawns and flower beds.

Route the cable to where each light is to be connected.

Option 2: Run the cable above the ground

If the span between the buildings is less than 3 metres simply use ordinary PVC-sheathed cable. Anything over 3 metres in length will need to be raised in the air (3.5 metres high over a path and 5.25 metres high over a drive or other area with vehicular access) and supported by a tensioned support wire and cable buckles; this wire must be grounded by way of the house's main grounding point.

Step 4: Drill the outside wall

Use a heavy-duty drill and masonry bit to drill through your outside wall in the spot where the exterior light is going.

When drilling your hole from the outside, direct the drill slightly upwards to prevent water entering your home.

Feed the electrical cable through the wall from the inside. Use rubber-sheathed 1mm 3-core flexible cable to connect the light to the junction box.

On the inside, route the cable towards your chosen connection point.

Now make sure you isolate the electrical circuit you're going to be working on.

You can connect your outdoor light via a fused spur from a ring main circuit or an indoor lighting circuit. 

Step 5: Connect to an indoor lighting circuit

Once you've switched off the lighting circuit, cut the circuit cable. Strip the end of the cable ready to connect it to a four-terminal junction box (figs. 1 and 2).

Run a new length of 1mm twin and earth cable from the position of the junction box to the new switch position (fig. 2).

Connect the four cables to the junction box - circuit cables, switch cable and spur cable (fig. 1).

Illustration showing the correct wiring for a four-terminal junction box
Figure 1
How to connect an outdoor light using an indoor lighting circuit spur
Figure 2

Step 6: Connect to a ring main spur

Ideally use an upstairs ring main circuit so you can gain access via the loft rather than having to lift carpets or floorboards.

Fit a fused connection unit (FCU) close to a socket on the ring main you've selected (fig. 3).

Fit your junction box in the ceiling void. Connect the spur and switch cables to it.

Run a new length of 1mm twin and earth cable from the junction box to the FCU. Connect the cable to the FCU and the junction box.

Connect the FCU to the socket outlet terminals with a 2.5mm cable. Fit a 5 amp fuse in the FCU. 

How to connect an outdoor light using a ring main spur
Figure 3

Step 7: Mount the light fitting

Hold your exterior light over the protruding cable on your outside wall and mark the screw positions.

Drill the holes, insert rawl plugs and fit the light on the wall.

Feed the cable through the base plate of the light and connect it according to the manufacturer's instructions.

Reconnect the power supply and test your new outdoor light.

Set your security lights

With PIR lighting you can set the sensitivity control and adjust the length of time the light stays on once triggered. A few minutes is usually enough to disturb intruders without annoying neighbours if it goes off accidentally.

Dusk-to-dawn lighting is very simple to use, just switch it on and it will work just as you expect.


Top tips

When you're extending an existing lighting circuit, use the upstairs circuit and access cables via your loft. If you use the downstairs circuit you'll have to lift carpets and floorboards to get access.

Turn off the power supply when fitting your garden lights. Connect them to the weatherproof junction boxes with rubber-sheathed, 1.5mm 3-core flexible cable. Follow the manufacturer's instructions.

How to replace outdoor lights

Once you have installed your outdoor light, you might want to replace this light fitting at a later date. Watch our video to help you complete this task:

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