Domakihub How to Install a Garden Power Supply the Right Way
A homeowner's guide to understanding what goes into running mains electricity to your garden — and when to call a licensed electrician.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Running mains electricity to a garden, terrace, pool area, or outbuilding is one of the most common upgrade requests for homes, holiday rentals, and hotels across Greece — and one of the most frequently done badly. The video above shows a professional electrician walking through the full process for a garden building, from cable selection to final connection. This article breaks it down into clear steps and explains what you genuinely need to know before the work starts, including where the law requires a licensed electrical contractor.
Why garden power supply work requires a licensed electrician
In Greece, all new mains electrical circuits — including those that run from your consumer unit (fuse board) to an outdoor socket, garden building, or underground cable route — must be designed, installed, and certified by a licensed electrical engineer or contractor (ηλεκτρολόγος εγκαταστάτης) registered with the Technical Chamber of Greece (ΤΕΕ). This is not optional. The installation must be followed by a Responsible Declaration of Installation (Υπεύθυνη Δήλωση Εγκατάστασης — ΥΔΕ), which is the legal document confirming compliance with the Greek Electrical Installations Standard (ΕΛΟΤ ΕΝ 60364 / HD 60364).
Attempting to connect a new outdoor circuit yourself and omitting this certification is not only dangerous — it can void your property insurance, create liability in the event of fire or electrocution, and prevent you from connecting to the grid or selling the property. The guidance below is designed to help you understand the process, prepare intelligently, and have a productive conversation with your electrician — not to replace professional installation.
What the job actually involves
A garden power supply is not just an extension cable buried in the ground. A proper installation feeds from a dedicated circuit breaker in your consumer unit, runs via an appropriate cable type to the outdoor point of use, and is protected by an RCD (Residual Current Device) — typically 30 mA — to guard against shock. In Greece's climate, outdoor circuits for pools, irrigation pumps, and holiday-rental amenities also need to meet specific IP (Ingress Protection) ratings for weatherproofing, typically IP44 as a minimum for outdoor sockets and IP65 or higher near water.
The cable route is the part that surprises most property owners. Underground cables must be buried at the correct depth (usually a minimum of 600 mm for armoured cable under gardens, 750 mm under driveways), must use Steel Wire Armoured (SWA) cable or be enclosed in rigid conduit, and must be marked with protective tiles or cable marker tape above the route so future excavation does not accidentally cut through them. On older Greek properties with stone walls or tile terraces, routing the cable may require careful surface channels (conduit embedded in the wall) rather than underground runs.
The 5 key stages of a garden power supply installation
- 1
Survey the route and plan the circuit
Before any digging or drilling, your electrician will assess the distance from the consumer unit to the end point, identify the load you need (a couple of outdoor sockets and lights is very different from running a pool pump, EV charger, or guest annexe), and calculate the correct cable cross-section. Sketch out what you actually want to power now and in the next few years — this prevents costly upgrades later. Note any existing underground services (water pipes, irrigation lines, old cables) and get a plan of them if possible.
- 2
Add a dedicated circuit breaker and RCD protection
The new garden circuit must originate from a dedicated MCB (miniature circuit breaker) in your consumer unit, protected by a 30 mA RCD. If your existing board is already full or is an older type, your electrician may need to upgrade the board or add a small sub-board. This is also the moment to confirm the earthing arrangement of your property is adequate — in older Greek buildings this is sometimes not the case and must be corrected before any outdoor work proceeds.
- 3
Select and lay the correct cable
For underground runs, SWA (Steel Wire Armoured) cable is the standard choice: it is mechanically protected against accidental damage and does not require additional conduit. Your electrician will select the correct cross-section based on the circuit's design current and the total cable length (voltage drop increases with distance). The cable trench is excavated to the correct depth, a bed of sand is laid, the cable is placed, covered with more sand, then with cable protection tiles or marker tape, and finally backfilled. Where the cable enters walls or surfaces, it must be protected with a gland and conduit sleeve.
- 4
Install weatherproof outdoor accessories
Outdoor sockets, switches, and light fittings must carry an IP rating appropriate for their location. In a covered porch or loggia, IP44 is usually sufficient; near a pool, fountain, or in fully exposed positions, IP65 or higher is required. Boxes must be correctly sized for outdoor flush or surface mounting, sealed with waterproof glands where cables enter, and all connections made with the appropriate terminals — not simple twist-and-tape joints. In holiday rental or hotel contexts, it is worth specifying stainless steel or UV-stable fittings that cope with Greece's summer heat and salt air without corroding.
- 5
Test, certify, and document the installation
Before the circuit is energised, your electrician must carry out a series of tests specified in the ΕΛΟΤ ΕΝ 60364 standard: insulation resistance, continuity of protective conductors, RCD trip-time, and polarity checks. Once passed, the licensed contractor issues the ΥΔΕ certificate. Keep this document — you will need it for insurance purposes, future property transactions, and any subsequent electrical inspection. Photograph the cable route before backfilling so you have a record of where the underground cable runs.
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FAQ
- Can I dig the trench myself to save money?
- Yes — excavating the cable trench is groundworks, not electrical work, and doing it yourself is perfectly legal and a reasonable way to reduce costs. Just agree the exact depth, width, and route with your electrician before you dig, and leave the cable laying, gland making, and board connections entirely to them.
- What cable do I need for a 20-metre run to a garden shed in Greece?
- For a typical 20-metre run supplying a couple of sockets and lights, a 2.5 mm² three-core SWA cable is usually sufficient — but your licensed electrician must calculate this based on the actual load and verify voltage drop is within the allowed 3% limit for lighting and 5% for power circuits under HD 60364. Never guess the cable size on a long outdoor run.
- Does a garden power supply need planning permission in Greece?
- The electrical installation itself does not require a separate planning permit, but it must be certified with a ΥΔΕ. If the outdoor circuit is part of a new structure — a pool, a garden annexe, or a permanent pergola with electrical services — that structure may require a building permit (οικοδομική άδεια) or a notification under the small-works regulations (μικρής κλίμακας εργασίες). Check with your municipality or a local engineer before building starts.