Short answer
Outdoor lighting belongs on its own circuit behind an RCD, with underground cable in the garden and watertight connections. Switching can be done with a dusk sensor, a timer, a motion sensor or a combination. Always lay an empty duct alongside: extending is then an afternoon instead of digging again.
Who this article is for Anyone who wants light in the garden. Installing the supply is work for the installer; you choose the light fittings together with me.
A circuit of its own
Outdoor lighting does not belong on the living room circuit. Two reasons: moisture outdoors is the most common cause of a tripping RCD, and you do not want a fault in the garden to take the rest of the house with it.
So: its own circuit, behind a 30 milliamp RCD.
The cable
In the ground you need underground cable, not ordinary installation cable in a conduit from the DIY store. The rules of thumb are the same as for an EV charger: at least 60 cm deep, a bed of sand, warning tape above it and an empty duct next to it.
That duct is the best advice in this article. A pond pump, a camera by the gate or light at the garden room is then a matter of pulling cable through instead of digging up the garden again.
Switching
| Method | When it suits |
|---|---|
| Dusk sensor | light on when it gets dark, off at sunrise |
| Timer | until a set time, for example until midnight |
| Motion sensor | at the drive, the back door and the gate |
| Dusk sensor plus timer | the most used: on at dark, off at twelve |
| Smart | app and scenes, but dependent on your network |
The middle combination is what most people end up choosing.
A motion sensor by the back door is the cheapest burglary prevention there is, and handy when you come home with your hands full.
What to look for in light fittings
- the protection rating: outdoors at least IP44, higher on the ground or in the grass
- material: aluminium with a good coating or stainless steel; cheap steel rusts within two winters
- colour temperature: warm white looks calmer than cool white, and attracts fewer insects
- direction: shine downwards, not into the neighbours' window
What it costs
The light fittings account for most of it. The work depends on the metres of cable and whether digging is needed or it can run along a fence. I list the cable and the groundwork separately in the quote, so you can see where the money goes.
For spotlights and garden lighting I do a lot of made-to-measure outdoor lighting; that page also shows what is possible in light fittings.
From my own work
In a garden in Ulestraten six spotlights ran off an extension lead under the fence, with a multi-socket in a plastic tub. It had worked for three years. An underground cable was laid with a junction point by the shed, everything on its own circuit, and an empty duct to the back for the pond pump that is still to come. The customer now also has light at the gate, which would never have worked on the extension lead.
When to call an electrician
- A cable needs to go into the garden
- You currently have extension leads or multi-sockets outdoors
- You want automatic switching on dusk or motion
I lay the cable straight away so that you can extend later. See outdoor lighting and request a quote.
Frequently asked questions
Does outdoor lighting need its own circuit?
That is strongly recommended. Moisture outdoors is the most common cause of a tripping RCD, and then you do not want the whole house to go off with it.
Which protection rating do I need outdoors?
At least IP44, and higher if a fitting is on the ground or in the grass.
Can I add more lights later?
If there is an empty duct, that is an afternoon's work. Without that duct the garden has to be dug up again.
Further reading
The light is not working: check it yourself in four steps
Nine times out of ten it is the bulb, the lampholder or the switch. The tenth time it is a connection, and then you call.
Dimming LEDs: why they flicker, buzz or do not switch off
Almost every LED dimming problem comes from a dimmer made for incandescent bulbs. A new dimmer solves it.
Smart lighting without the hassle: what works and what to avoid
Smart bulbs are fun until someone presses the ordinary switch. Smart switches are more boring and work better.
Questions and comments
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