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How to install outdoor lighting and security lights

Difficulty rating: Medium

These tasks may be tricky so will suit you if you're experienced in DIY, or simply love a challenge. Before you get started on any of our 'how to' guides, please take a moment to read through our DIY safety tips.

Be aware...

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.

1. Switching 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 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.
Helpful hint...

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.

2. How to fit an outdoor light on your house wall

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.

How to drill through an 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 1mm2 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. 
How to 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 1mm2 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).
 How to 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 1mm2 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 2.5mm2 cable. Fit a 5 amp fuse in the FCU. 
How to 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 light's baseplate and connect it according to the manufacturer's instructions.
  • Reconnect the power supply and test your new outdoor light.
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
How to connect an outdoor light using a ring main spur
Figure 3

3. 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.

How to fit PIR security lights
  • Place your lights at least 2.5m off the ground. Point PIR lights so passers-by don't trigger them. Don't put a light near your boiler's flue as this can also set them off.
  • PIR lights come with an integral or separate PIR sensor unit. You'll find the integral one easier to fit.
  • When you've decided on your position, drill a hole through the wall to the inside. Line any holes with a plastic conduit. If you don't want to drill, you may be able to feed the cable through your window frame or fascia board.
  • Turn off your power supply when fitting your light. Then connect the light according to the maker's instructions (see Section 2). Once connected, the light can be fixed to the wall (see Section 2). 
How to set your PIR 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.

You can feed the PIR lighting cable inside your home via a small hole drilled through the wall or window frame.
Figure 4
Creating a new circuit for garden lighting - running from the consumer unit.
Figure 5

4. Garden lighting

Planning your lighting design
  • 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.
How to create a safe outdoor electric circuit
  • Remote garden lights need their own electric circuit run from an existing or new fuse box (consumer unit) (fig. 4).
  • The circuit must be protected by a high-sensitivity residual current device (RCD) and controlled with a double pole isolating switch (fig. 4).
  • Running the cables underground
  • Decide where to put your garden lights and mark the route for the cable to link them.
  • Prepare a trench for the cables. This must 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.
  • Here's the kit you'll need: 1.5mm2 2-core SWA (steel wire armoured) cable and weatherproof junction boxes. Route the cable to where each light is to be connected.
How to fit outdoor lights

Turn off the power supply when fitting your garden lights. Connect them to the weatherproof junction boxes with rubber-sheathed, 1.5mm2 3-core flexible cable. Follow the manufacturer's instructions.

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