DIY GUIDE · ELECTRICAL · CHECKED OCTOBER 2026
How to fit solar and low-voltage garden lighting yourself
An afternoon. €9–€93 for a pack of solar lights or a low-voltage plug-in kit.
Solar where there is sun; 12-volt plug-in where there is not. Keep the transformer dry, the cable safe and the mains indoors — new outdoor supplies are for a registered contractor.
- 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 fitting solar lights, or a low-voltage kit whose transformer plugs into an existing socket
- There is an indoor socket near an outside wall, or an existing weatherproof outdoor socket fitted by an electrician
- The lights are going in beds, along paths or on a deck, not wired to the house
- You can lay the low-voltage cable along the surface or just under the mulch
Get a pro if…
- You want a new outdoor socket, or lights wired into the house's mains circuit
- The lighting needs armoured cable buried in a trench to a shed or the end of the garden
- You want to replace an outside wall light that is on the house circuit
- The garden has a pond pump or water feature that needs a mains supply
Safety first
- Keep mains power indoors. Only the 12-volt cable should go outside, through a small sealed hole; the transformer stays in a dry place or at an existing weatherproof socket.
- Use a socket with RCD protection. The HSA's electricity guidance describes RCDs designed to trip at 30 mA and asks that they be tested regularly with their test button.
- The transformer maker we read says it may be used outdoors only on a moisture-protected outlet, and must not be mounted near a sprinkler or water spray.
- Check walls for hidden pipes and cables before drilling the cable hole.
- Lay cables so nobody trips on them, and lift them before you dig, mow edges or rotavate.
Stop here: Stop here: anything on the mains outdoors
Under the Restricted Electrical Works Regulations, S.I. No. 264 of 2013, the installation of a new fixed electrical installation that connects to the network, and a new circuit, are restricted electrical work in Irish law, and that covers a new outdoor socket, a supply to a shed and lights wired to the house. Only a Registered Electrical Contractor may carry them out, and they test and certify the work; the CRU prosecutes unregistered restricted work. Water and mains electricity outdoors are a danger without proper protection, which is why the low-voltage cable is the only part of this guide that leaves the house. How to hire a garden lighting electrician →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Solar stake or deck lights | Panel facing open sky | As many as the path needs |
| Low-voltage plug-and-play kit | Transformer, main cable and lights from one system | One kit, extended with the same maker's parts |
| Extension cable and connectors | Same system as the kit | As needed to reach the far lights |
| Mulch or fine gravel | To cover cable in beds | A bag or two |
Is the transformer big enough
Load = number of lights × watts per light. Six lights at 1.8 W each draw 10.8 W, which fits a 12 W transformer with a little to spare; a seventh would take it to 12.6 W, over the limit.
Leave headroom of at least a tenth of the transformer's rating. Add a second transformer for a separate run rather than overloading one.
Solar lights charge their own battery by day and switch on at dusk. They need several hours of direct light on the panel to last the evening; in an Irish winter, or under trees, they fade early. Use them for markers along a sunny path, not for light you rely on.
A 12-volt system runs from a transformer that turns mains power into a safe low voltage. The lights plug onto a main cable with connectors. The maker of one plug-and-play set we read rates its transformer for use outdoors only if it is connected to a moisture-protected power outlet, and says the total wattage of the lights must not exceed the transformer's rating.
Add up the wattage of every light on the cable and keep it under the transformer's output, with a margin. One kit we read pairs a 12W transformer with lights of 1.8W each. More lights than the transformer can feed overheat it or dim the far end.
Every outdoor light and connector carries an IP rating. The second figure is protection against water: higher numbers cope with rain and spray, the highest with being buried or submerged. Use lights rated for ground level in beds, where water collects, and keep the transformer where its own rating suits.
The safest place is indoors, in a garage or shed, plugged into an ordinary socket, with only the low-voltage cable going outside through a small hole or under a door. If it must go outside, it needs a weatherproof socket already installed by a Registered Electrical Contractor, and a mounting off the ground.
THE PART THAT DECIDES THE FINISH
Before you start — the garden and the power
Walk the garden at dusk with a torch, then look at where the power will come from. Match your plan to one of these.
Path or border with sun
Lights mainly as markers along an edge that gets direct sun.
- Check each spot gets several hours of direct sun on the panel
- Keep the lights out of shadow from hedges and fences
- Mark positions with canes before pushing stakes in
- Avoid edges a mower or strimmer runs along
Patio, deck or shaded beds
Light you want every evening, in places solar cannot charge.
- Choose a low-voltage system and plan the cable route from the power point
- Measure each run so you buy enough cable
- Keep the cable away from where you dig and plant
- Check deck boards can take the lights' fixings
Power from an indoor socket
A socket in the house, garage or shed near an outside wall.
- Check the socket is near enough for the transformer's lead
- Plan a small hole through the wall or frame for the low-voltage cable only
- Check behind the wall for pipes and cables before drilling
- Keep the transformer off the floor where water could reach it
An existing outdoor socket
A weatherproof socket already fitted on the outside wall by an electrician.
- Check its cover closes properly with the plug in
- Press its RCD test button if it has one, or the house RCD, and check it trips
- Mount the transformer on the wall off the ground, as its sheet allows
- If there is no outdoor socket, do not run an extension lead out a window; use an indoor socket instead
THE JOB
How to fit the lights
Plan the layout at dusk
30 minWalk the garden as it gets dark and decide what you want to light: steps, a path edge, a tree, a seat. Mark each light's position with a cane. For a low-voltage system, mark the cable route from the power point to every light, keeping it along edges and away from where you dig.
- Fewer, well-placed lights look better than many
- Light steps and changes of level first
- Photograph the plan with the canes in
Mistake to avoid: Placing lights by day. Positions that look right in daylight often light the wrong things at night.
Do the prep for your power and route
20 minThis is the prep from the cards above. Check the socket, plan where the transformer sits, check for pipes and cables before drilling any hole for the low-voltage cable, and test the RCD on any outdoor socket you will use.
- Keep the drilled hole small and seal it after
- Run the low-voltage cable only through the hole, never the mains lead
- Note the distance of each run
Mistake to avoid: Running a mains extension lead out through a window to a transformer in the garden. That is mains power outdoors with no proper protection.
Set out solar lights
20 minAssemble the solar lights, switch them on if they have a switch, and push each stake firmly into the soil at its cane, panel facing open sky. Use a trowel to start the hole in hard ground rather than forcing the stake.
- Charge them in sun for a full day before judging them
- Clean the panels so dust does not cut the charge
- Turn panels south where you can
Mistake to avoid: Hammering stakes into hard ground. The plastic splits and the light leans.
Lay the low-voltage main cable
40 minStarting at the power point, lay the main cable along the route. Along lawns, tuck it into a shallow slit at the edge with an edger; in beds, lay it on the soil and cover with mulch; along fences and decks, clip it at intervals. Leave a little slack at each light position.
- Keep the cable off paths where people walk
- Leave a loop at each connector point
- Keep it well away from where a mower or strimmer runs
Mistake to avoid: Burying the cable deep in a bed. You forget where it is and put a spade through it next spring.
Fit the lights and connectors
30 minPlace each low-voltage light at its cane and connect it to the main cable with the system's connector, as its maker shows. The maker we read asks for any drain hole in a light to point downwards. Push spikes in firmly or screw deck lights down.
- Use only the same maker's connectors and extensions
- Check each connector clicks fully home
- Keep connectors off the ground where water pools
Mistake to avoid: Mixing makers' connectors. They may fit loosely and let water in, and the far lights fail.
Fit the transformer
20 minMount the transformer indoors, off the floor, or on the wall beside an existing weatherproof outdoor socket if its rating allows. Connect the main cable to its output. Do not plug it in yet.
- Mount it with the cables pointing down
- Keep it away from sprinklers and hoses
- Check its rating label against the total wattage of your lights
Mistake to avoid: Laying the transformer on the ground outside. It sits in water after rain and fails, or trips the house RCD.
Switch on and test
15 minPlug the transformer in and switch on. Every light should come on. If one does not, check its connector first. If none do, check the transformer is switched on and its output cable is connected. Set any timer or dusk sensor as its sheet shows.
- Test at dusk to see the real effect
- Adjust aim on spotlights while they are on
- Note which lights look dim, a sign of overload or a long run
Mistake to avoid: Leaving dim lights at the end of a long run. The transformer may be overloaded; move lights to a second transformer.
Aim, adjust and live with it for a week
20 minGo out on the next few evenings and look at the result from the house, the path and the gate. Turn spotlights so they light the plant or wall, not the neighbours' windows or the eyes of anyone walking up the path. Move a stake light a little if it leaves a dark gap on a step. On a timer or dusk sensor, adjust the switch-off time so the lights are off when you are asleep, which saves power and avoids lighting the sky all night.
- Look from where visitors approach, not just from the patio
- Angle lights down rather than up where you can
- Note any light that flickers; it usually has a loose connector
Mistake to avoid: Pointing spotlights across the boundary. Glare into a neighbour's bedroom is the commonest complaint about garden lights, and it is easily avoided.
Tidy and protect the cable
20 minGo back along the route and tuck in any loose cable, clip it on fences and decks, and cover it with mulch in beds. Seal the small hole through the wall with exterior sealant around the cable.
- Mark cable routes on a sketch of the garden
- Lift cable before you dig a bed
- Check the wall seal keeps out draughts and water
Mistake to avoid: Leaving loops of cable across the lawn. Someone trips, or the mower cuts it.
The mistakes that show
- Running a mains extension lead out into the garden for a transformer
- Overloading the transformer with too many lights
- Burying low-voltage cable where you will dig later
- Mixing connectors from different makers
- Fitting solar lights where the panels get no sun
- Setting the transformer on the ground outdoors
Stop here and get a Registered Electrical Contractor
- You want a new outdoor socket or a supply to a shed or the garden
- Lights wired into the house circuit, including replacing an outside wall light on it
- Armoured cable in a trench to the end of the garden
- A pond pump or water feature on mains power
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| Solar lights fade early in the evening | Not enough sun on the panels, dirty panels, or tired batteries. Move them to sunnier spots, clean the panels, or replace the rechargeable cells. |
| One low-voltage light does not work | A loose connector or a failed lamp. Reseat the connector; if it still does not light, change the lamp. |
| All lights off | The transformer is unplugged, off, or tripped, or its timer is set wrong. Check the plug, switch and timer. |
| Lights at the far end are dim | Too many lights on the run, or a very long cable. Reduce the load or add a second transformer. |
| The house RCD trips when the lights come on | Water has reached the transformer or a mains connection. Unplug it, dry it and move it to a dry place; if it still trips, have it checked. |
| Water inside a light | The light's drain hole is not pointing down, or its rating is too low for its spot. Refit it correctly or swap for a higher-rated light. |
| Cable cut by a spade or mower | Disconnect the transformer, and replace the damaged section with the maker's own extension and connectors. |
| Lights stay on in daylight | The dusk sensor is shaded or the timer is set to always on. Move the sensor into the open or reset the timer. |
WHAT YOU SAVE
What it costs to do it yourself
| Solar decking or stake lights, pack | €9–€45 |
|---|---|
| Low-voltage stake light set | €38.95 |
| Low-voltage festoon set with transformer | €92.95 |
| Total | €9–€93 |
| DIY total | €9–€93 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
Solar is the cheapest start; a low-voltage kit costs more but lights reliably every evening and can be extended with the same maker's parts.
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 light lenses, check connectors are tight and dry, and look along the cable for damage from the winter.
If short days leave them barely working, bring solar lights in over winter to save their batteries.
Solar and low-voltage lights are electrical waste, and the batteries inside solar lights must not go in the household bin. Mywaste.ie says household batteries go to a civic amenity site or a shop's collection box, and the lights themselves to a WEEE drop-off point.
Mark where the low-voltage cable runs on a plan of the garden, and keep it with your house papers. It saves a cut cable next time you dig.
Fitting solar and low-voltage plug-in garden lighting: questions people ask
Solar and low-voltage plug-in lighting, yes. A new outdoor socket, lights wired into the mains or a supply to a shed is restricted electrical work for a Registered Electrical Contractor.
The cable in the garden carries only 12 volts, which is far safer than mains. The transformer must stay dry, ideally indoors, and be plugged into a socket with RCD protection.
Add up the watts of all the lights and keep the total under the transformer's rating, with a margin. The maker we read warns that exceeding it can damage the transformer.
They charge less on short, dull days and may run for only a short while. Low-voltage lights are more reliable from October to March.
You can tuck it just under the mulch or in a shallow slit along a lawn edge. Keep it where you will not dig, and mark the route.
Locufy's Irish price guide puts outdoor and garden lighting at €150–€600 per job, typically €300. Mains lighting with buried cable costs more.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- Techmar — Plug & Play 12 volt garden light set and transformer manual: installation, safety, ratings
- Techmar — timer and transformer installation manual for 12 volt garden lighting
- HSA — guide to Part 3 of the General Application Regulations 2007: electricity
- S.I. No. 264 of 2013 — Electricity Regulation Act 1999 (Restricted Electrical Works) Regulations
- CRU — RGI and Safe Electric schemes
- MyWaste.ie — batteries
- MyWaste.ie — lamps and lighting
- DIY.ie — decking lights (price check)
- Ganly's — exterior lighting (price check)