DIY GUIDE · ELECTRICAL · CHECKED OCTOBER 2026
How to fit solar and low-voltage garden lighting yourself
An afternoon. £17–£25 for a pack of solar stake lights, £54–£57 for a four-light 12 V kit.
Solar, or 12 V from a plug-in transformer indoors. Nothing outside on mains — that is where it stops.
- Every step, start to finish
- Checked October 2026 — sources at the end
- Honest about when to call a pro
FIRST, THE HONEST ANSWER
Do it yourself, or get a electrician?
Do it yourself if…
- You are using solar lights, or a low-voltage kit whose transformer plugs into an indoor socket
- The transformer's plug can sit indoors — in the house, a garage or a shed with a socket
- The cables can run along borders, under decking or under a thin layer of soil where no one will dig
- You can drill decking or steps for recessed lights without hitting pipes or cables
Get a pro if…
- You want mains-voltage lights outside, wired to a switch indoors
- There is no socket indoors near the garden, or you want a new outdoor socket
- The cable needs burying properly across a lawn or under paving
- You want lighting on a shed, garage or outbuilding that has no power
Safety first
- Unplug the transformer from the mains before connecting, moving or maintaining any part of a low-voltage system. The kit maker's instructions we checked say so, and say never to connect the light fittings to the mains without the transformer.
- Keep the mains plug and socket indoors. The kit maker's instructions require the plug to be inside, for example in the house, a garage or a shed, out of the weather.
- Never run an indoor extension lead into the garden to power lights. If an outdoor lead is used for anything temporary, it must be rated for outdoor use and plugged into a socket protected by an RCD. HSE's electrical guidance describes an RCD as a vital safety device that can save your life.
- Lay cables where they will not trip people or be cut by mowers, strimmers or spades.
- Before drilling decking or steps, check for pipes and cables underneath.
Stop here: Stop here: mains outdoors, new circuits and buried cable
Solar lights and a low-voltage kit plugged into an existing indoor socket are the householder's part. Anything on mains voltage outside is electrical installation work. In England, a new circuit is notifiable under Part P of the Building Regulations unless a registered competent person does and certifies it, and gov.uk lists installing electricity to a shed among the examples that may need notifying. Wales has its own Approved Document P, and there electrical work outdoors is never exempt. Scotland works to building standard 4.5 and the wiring regulations, with a building warrant for some work. Northern Ireland has no Part P-style notification for home wiring, but outdoor mains work still needs a competent electrician, buried armoured cable and RCD protection. How to hire a garden lighting electrician →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Solar stake or wall lights | IP rating to suit the spot | As many as the layout needs |
| Low-voltage plug-and-play kit | Lights, junction box and transformer from one system | One kit per transformer |
| Extension cables from the same system | Only if a light will not reach | As needed |
| Cable clips | Outdoor grade | A pack |
Is the transformer big enough
Total load = number of lights × watts per light; it must be below the transformer's rating. Ten deck lights at 0.21 W each is 2.1 W, well within a 5 W transformer.
Some transformers also have a minimum load; with very few small LED lights they may flicker or not start.
Solar lights are the simplest: stake them in, and the panel charges a battery by day. They are as bright as the day was sunny, so in winter and in shade they fade. Low-voltage lights run from a transformer and give steady light all year, at the cost of running a cable. Use solar where the light is decorative and the spot sunny; use low voltage where you need the light every evening.
Every outdoor light carries an IP rating: the first digit for dust, the second for water. Solar wall lights we checked are rated IP44, splash-proof. The low-voltage kit whose instructions we checked rates its lights, junction box and transformer at IP67, suitable for very wet areas but not for permanent submersion. Match the rating to where the light sits: a deck light in a puddle needs more than a wall light under the eaves.
A low-voltage transformer has a maximum load in watts, and some need a minimum load to work. Add up the watts of every light on it and stay within the range; the kit maker warns not to exceed the transformer load. Buy a system whose lights and transformer are designed to work together; mixing brands rarely plugs together.
Plug-and-play kits come with fixed cable lengths: the one we checked has 15 metres from the transformer to an outdoor junction box and 5 metres from the box to each light. Plan the layout on paper before you buy, measuring the actual routes along borders and under decking, so every light reaches without joints you have to make yourself.
Warm white suits most gardens and is kinder to wildlife and neighbours than cool white. Point spotlights at plants or walls, not across the garden into windows. A few well-placed lights look better and dazzle less than many bright ones.
A plug-in timer or a dusk-to-dawn sensor on the indoor socket switches a low-voltage system without any outdoor wiring. Solar lights have their own dusk sensor built in, so they come on as the light fades and run until the battery is spent. Decide whether you want lights all evening or only for a few hours, and choose the control before you finish the layout.
THE PART THAT DECIDES THE FINISH
Before you start — where the lights will go
The ground decides the fixing and how the cable runs. Match each area to one of these.
Borders and beds
Stake lights and spike lights in soil.
- Water the bed first if it is hard; spikes push into damp soil without bending
- For solar lights, place each where it gets the most direct sun
- For low-voltage spikes, lay the cable along the back of the bed, under a little soil or bark
- Keep cables away from where you dig and away from the lawn edge where the strimmer runs
Decking and steps
Recessed deck lights drilled into boards or risers.
- Check underneath for pipes, cables and joists before choosing the spots
- Drill to the size the kit gives; the kit we checked uses a 22 mm hole for its 30 mm lights and a 32 mm hole for its 45 mm lights, at least 30 mm deep
- Run the cables under the deck, clipped to joists, away from where water pools
- Keep the junction box off the ground under the deck
Walls and fences
Solar wall lights or low-voltage wall fittings.
- Solar panels need to face the sun; north-facing walls give little charge
- Fix into brick or a sound fence post, not into a rotten panel
- Check for cables in the wall near outside lights or a meter box before drilling
- Keep low-voltage cable clipped tidily down the post and along the base of the fence
Where the transformer goes
The link between indoors and out.
- Plug the transformer into an indoor socket in the house, garage or shed
- Bring the low-voltage cable out through a small hole in a window frame or wall, sealed afterwards
- If the transformer is rated to sit outside, keep it off the soil in a protective box, as the maker requires
- Never put the mains plug or an indoor socket outside
THE JOB
How to fit the lights
Set up: plan the layout and measure
45 minRead the cards above for each area. Sketch the garden, mark where each light goes and where the transformer will plug in indoors. Measure the actual cable routes and check them against the kit's cable lengths. Check the transformer's load against the lights you plan.
- Look at the garden at dusk to see where light is wanted
- Plan cable along edges, not across open lawn
- Count the junction box sockets and keep one spare
Mistake to avoid: Buying lights before measuring. A kit whose cables are a metre short means a joint outdoors, and joints are where water gets in.
Prepare the ground and the exit hole
45 minThis is the prep from your cards above. Water hard beds, check decking for pipes and cables, and choose where the cable leaves the building. Drill a small hole through a window frame or wall, sloping slightly down to the outside so water runs away, just big enough for the low-voltage cable and its plug.
- Use a detector before drilling through any wall
- A hole through a timber frame is easier to seal than through brick
- Never bring the mains plug or socket outside to avoid drilling
Mistake to avoid: Running the transformer cable out under a closed door or window. It gets crushed every time it is shut and the insulation fails.
Place the solar lights
30 minPush stake lights into damp soil at their marked spots, holding them by the stake, not the head. Fix wall lights with the screws supplied, into brick or sound timber. Switch each one on, as the instructions show, and turn the panel to face the sun.
- Some solar lights have a pull tab or switch under the head; set it before staking
- Give new lights a full sunny day before judging them
- Clear plants away from the panels
Mistake to avoid: Putting solar lights in shade under shrubs. They charge for an hour and are dark by nine.
Fit the low-voltage lights
1 hrWith the transformer unplugged, fix each light: push spike lights into the bed, or feed deck lights' cables through their holes and press the light into the hole. Run each light's cable to where the junction box will sit, keeping it under a little soil, bark or decking, clear of where anyone digs.
- Feed the plug through the hole before pressing the light in
- Leave a small loop of cable at each light for movement
- Clip cables to joists under decking, not loose on the ground
Mistake to avoid: Burying the cable deep across the lawn. Low-voltage kit cable is not designed to be buried like mains cable, and a spade finds it next spring.
Connect the junction box
20 minPlace the junction box where every light's cable reaches it, off the ground under decking or in a dry spot. Screw each light's plug fully into the box's sockets, as the kit maker describes, and fit blanking plugs in unused sockets. Run the transformer's cable from the exit hole to the box and connect it to the input socket.
- Hand tighten each connector fully; a half-screwed plug lets water in
- Blank every unused socket
- Keep the box out of standing water
Mistake to avoid: Leaving sockets on the junction box open. Rain gets in and the whole system trips or corrodes.
Seal the exit hole
15 minPull the cable gently so it lies without strain through the hole, then seal round it on the outside with exterior sealant. Clip the cable down the wall. Leave a drip loop below the hole so rain runs off the cable before it reaches the wall.
- A drip loop is a small downward curve before the hole
- Seal outside and inside if the hole goes through a cavity
- Clip neatly so the cable cannot be pulled out by a passing dog
Mistake to avoid: Leaving the hole unsealed. Rain runs along the cable into the frame or wall.
Plug in and test
15 minPlug the transformer into the indoor socket and switch on. Walk the garden and check each light works. If one is dark, unplug the transformer and check its connector at the junction box. Fit a plug-in timer or a dusk sensor indoors if you want the lights to switch themselves.
- Test after dark to judge the effect, and adjust spotlight angles
- If all are dark, check the transformer's own connection
- Keep the transformer where it is ventilated, not buried in boxes
Mistake to avoid: Plugging and unplugging connectors outdoors with the system live. Always unplug the transformer first, as the maker requires.
Check after the first rain
15 minAfter the first wet night, check every light still works and the junction box is dry. Tighten any connector that has let water in, after unplugging the transformer. Clean the lights with a soft dry cloth.
- Do not pressure-wash low-voltage lights; the maker warns against it
- Wipe solar panels clean every few weeks
- Move any cable that has surfaced
Mistake to avoid: Pressure-washing the patio with the deck lights in it. High-pressure water forces past seals the lights were never rated for.
The mistakes that show
- Running an indoor extension lead into the garden
- Putting the transformer's mains plug outdoors
- Overloading the transformer with too many lights
- Leaving junction box sockets unblanked
- Burying low-voltage cable where a spade will find it
- Placing solar lights in shade and expecting a full evening of light
Stop here and get an electrician
- Mains-voltage outdoor lights or lights switched from inside the house
- A new outdoor socket, or no indoor socket near the garden
- Cable buried across a lawn or under paving, or armoured cable
- Power to a shed, garage or outbuilding that has none
- Any wiring into a consumer unit, fused spur or outdoor junction box on mains voltage
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| Solar garden lights not working | The panel is shaded, dirty or the battery is tired. Move the light into sun, clean the panel, and replace the rechargeable battery if the light allows it. |
| Solar lights very dim in winter | Short days give little charge. Expect less light from November to February, or use low-voltage lights where you need them every evening. |
| One low-voltage light out | Its connector at the junction box is loose or wet. Unplug the transformer, dry and refit the connector fully, and plug in again. |
| All low-voltage lights out | The transformer is unplugged, overloaded or faulty, or its cable connector has come out. Check the plug, the load and the connection at the box. |
| Lights flicker | The transformer is near its maximum, or below its minimum load. Remove or add lights to bring the total into its range. |
| Water inside a light | The seal has failed or it is sitting in standing water beyond its rating. Replace the light; most kits have non-serviceable parts. |
| Cable surfacing in the border | It was laid too shallow or worked loose. Re-lay it under bark or a little soil, along the back of the bed. |
| Socket indoors tripping the RCD | A fault or water in the system. Unplug the transformer, check connectors and the junction box for water, and if it persists, call an electrician. |
| Solar lights come on in daylight | The light sensor is shaded by a leaf, a wall or the light's own head. Clear it and move the light to open sky. |
| Transformer feels hot | It is near its maximum load or boxed in without air. Reduce the number of lights on it and give it space to ventilate. |
WHAT YOU SAVE
What it costs to do it yourself
| Solar stake lights, pack | £17–£25 |
|---|---|
| Low-voltage spike light kit, four lights | £54–£57 |
| Single low-voltage spike light | £17 |
| Total, solar or a four-light kit | £17–£57 |
| DIY total | £17–£57 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
An electrician's guide price for garden lighting usually means mains-voltage lights and cable. Solar and plug-in low-voltage lights cost the kit and an afternoon.
RATHER NOT?
Garden lighting electricians near you, with prices shown
The ones who cover your area, nearest first, with one score from every review. No account needed to look.
Or post the job free and let them come to you.
Wipe solar panels and lenses with a soft cloth. Do not pressure-wash low-voltage fittings.
Bringing them indoors over the darkest weeks keeps the batteries healthy.
Garden lights, transformers and their batteries are electrical waste and cannot go in the household bin. Take them to the electrical and battery recycling at your council's household waste recycling centre. Find your centre on the council website or the recycling pages for your nation.
Sketch where the low-voltage cable runs so it is not dug up when the border is replanted.
With the transformer unplugged, open the junction box, check for water and corrosion, and screw every connector fully home before the summer evenings.
Fitting solar and low-voltage plug-in garden lighting: questions people ask
Yes, solar lights and low-voltage plug-in kits whose transformer plugs in indoors. Mains-voltage outdoor lights, new outdoor sockets and buried cable are for an electrician.
Not for a plug-and-play kit whose mains plug stays indoors. Wiring a transformer into the mains, or adding an outdoor socket, is electrical installation work.
It depends where they sit. Splash-proof IP44 suits walls under eaves; lights in beds, decking or wet areas need more, such as IP67, which the kit we checked uses throughout.
Too little sun: shade, dirt on the panel, short winter days, or an ageing battery.
Lightly, under bark or a little soil along a border, where no one will dig. Properly buried cable across a lawn is a different, mains-style job.
Locufy's UK price guide puts outdoor and garden lighting at £80–£500 per job, typically £200 — the same three figures as the strip at the top of this page.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- Outdoor LED deck light kit installation instructions — 12 V SELV, indoor plug, IP67, hole sizes, cable lengths
- HSE — electrical safety: frequently asked questions (RCDs, isolation)
- gov.uk — Approved Document P: electrical safety in dwellings (England)
- gov.uk — building work, replacements and repairs to your home (England)
- gov.wales — building regulations: electrics
- gov.scot — Building Standards Technical Handbook 2022 (domestic), standard 4.5 electrical safety
- gov.uk — recycling collections: find your council (England and Wales)
- mygov.scot — find your council's recycling centre (Scotland)
- nidirect — recycling and reusing (Northern Ireland)
- B&Q — price check: solar lights
- B&Q — price check: low-voltage garden lights
- B&Q — price check: outdoor extension leads