Domakihub Install Low-Voltage Garden Lighting: A Step-by-Step Guide
Transform your outdoor space safely with a 12 V system you can plan and partly install yourself.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Low-voltage garden lighting runs on 12 V stepped down by a transformer, which means the cabling itself is safe to handle and bury without specialist permits — the one exception is the transformer's mains connection, which must be made at a properly earthed outdoor socket by a licensed electrician. The video above walks through a real installation from planning to first switch-on; this guide gives you the ordered steps, the buying decisions, and the prep work so you arrive on site — whether at a home in Athens, a holiday villa in Crete, or a boutique hotel garden — knowing exactly what to expect. Greece's outdoor climate is kind to low-voltage systems but hard on connectors, so waterproofing details matter more here than in northern Europe.
Why Low Voltage and Not Mains Outdoor Lighting?
A standard 230 V mains circuit buried in a garden requires conduit, a qualified electrician, and in most Greek municipalities a permit issued through a licensed installation company. Low-voltage (12 V) cable, by contrast, carries so little energy that a nick from a garden fork is not dangerous, the cable can be laid at shallow depth (6–10 cm is typical), and the system can be extended or modified by any careful owner. Transformer wattages from 60 W to 600 W cover everything from a small terrace to a large hotel pool garden.
The trade-off is that low-voltage cable has resistance, so very long runs (over 30 m from the transformer) lose brightness toward the far end. The standard fix is to use heavier-gauge cable (1.5 mm² or 2.5 mm²) for long runs, or to daisy-chain from a second output port on the transformer — a point the Ask This Old House video illustrates clearly.
What Needs a Licensed Electrician
The transformer plugs into a standard outdoor socket, but that socket must be a GFCI/RCD-protected weatherproof outlet rated for outdoor use. If one does not already exist in the right location, a licensed electrician (ηλεκτρολόγος) must install it — this is mains work and is non-negotiable for safety and insurance compliance in Greece. The cost is usually one to two hours of labour and is well worth scheduling before you buy any fixtures.
Everything downstream of the transformer — cable, connectors, fixtures — is 12 V and can be planned, purchased, and laid by the property owner or a general handyman. If you want timer or smart-home integration wired into the main distribution board rather than a plug-in timer, that work also requires a licensed electrician.
How to Install a Low-Voltage Garden Lighting System
- 1
Plan the layout and calculate wattage
Walk the garden at night with a torch to identify what you want to highlight: paths, trees, water features, pergolas. Sketch a rough map and mark each fixture position. Count up the wattage of every fixture and multiply by 1.25 — that is the minimum transformer size you need. A 150 W transformer comfortably handles eight to ten 10 W LED spotlights with headroom for future additions. Decide where the transformer will mount (on an exterior wall, within 1.5 m of the outdoor socket) and trace the cable route to each fixture, keeping cable runs as short and direct as possible.
- 2
Mount the transformer and verify the outdoor socket
Fix the transformer to the wall using the supplied brackets at a height that keeps it clear of standing water. Before plugging it in, confirm the outdoor socket is RCD-protected and earthed — if you are unsure, have your electrician check it now, not after the cable is buried. Set the transformer's built-in timer or photoelectric sensor to your preferred on/off schedule. Do not plug it in yet; leave it unpowered until all connections are made.
- 3
Lay the low-voltage cable
Unroll the two-core 12 V cable from the transformer and route it along the planned path. In planted beds, use a flat spade to open a shallow slot 6–10 cm deep, lay the cable, and close the slot — no conduit is required at this depth in a garden setting, but adding a cable marker tape above the wire is good practice so future digging does not cut it. On hard surfaces such as gravel or paving, run the cable under the edge of stones or through a small chase. Leave 30–40 cm of slack at each fixture location so the spike can be repositioned if the planting changes.
- 4
Connect the fixtures
Most low-voltage garden lights use one of two connector types: a pierce-through (IDC) clip that bites into the cable without cutting it, or a stripped-wire connector where you cut the cable, strip 8 mm of insulation from each core, and make the join with a waterproof push-in or twist connector. For Greece's combination of summer heat, winter rain, and occasional salt air near the coast, the stripped-wire waterproof connector is more reliable long-term — pierce-through clips can corrode at the contact point within two to three seasons. Push the fixture spike firmly into soil so the head sits at the angle you want, then tuck the connector underground or behind a stone.
- 5
Test, adjust, and finalise
Plug in the transformer and switch it on manually to test every fixture before burying cables. Walk the circuit in daylight to check beam angles, then revisit after dark to fine-tune. Fixtures that graze tree trunks or walls should be positioned 30–50 cm away to avoid hotspots and heat damage to bark. Once satisfied, close any open cable slots, cover connectors with soil, and set the timer. Make a quick sketch of the final cable route and store it with your property documents — it will save hours if you or a future owner ever needs to dig nearby.
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FAQ
- Do I need a permit to install low-voltage garden lights in Greece?
- For the 12 V cable and fixtures themselves, no permit is required. However, if an outdoor RCD-protected socket needs to be installed or a mains circuit extended, that work must be done by a licensed electrician (ηλεκτρολόγος) and will typically be documented on the property's electrical installation certificate (ΥΔΕ). Always check with your local municipality for any site-specific rules, especially for listed buildings or properties in protected areas.
- How long will low-voltage garden lights last in the Greek climate?
- Quality LED fixtures with an IP65 or IP67 rating (fully dust-tight and waterproof) typically last eight to fifteen years in Mediterranean conditions. The weak link is usually the connectors, not the LEDs — use waterproof gel-filled connectors or heat-shrink waterproof joins rather than cheap clip connectors, and check them every two or three years. Coastal properties should look for fixtures with marine-grade stainless steel or solid brass housings, which resist the salt air that corrodes aluminium over time.
- Can I add more lights to the system later?
- Yes, and it is one of the main advantages of low-voltage systems. As long as the total wattage of all fixtures stays below the transformer's rated output (ideally using the 1.25 multiplier rule), you can add fixtures by tapping into existing cable runs or by running a new cable from the transformer's second output port if it has one. Smart-enabled transformers sold by brands such as VOLT or Kichler also allow zone control so new areas can be managed independently.