Domakihub How to Install a Time Switch for Lights (and When to Call a Pro)
Understand the job, prep the circuit, and get automated lighting working safely.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
A time switch lets you automate any fixed lighting circuit — outdoor security lights, entrance hallways, pool-area lighting, or the common areas of a rental villa — so they turn on and off without anyone touching a switch. The video above shows a real installation from start to finish; the steps below explain the logic, the safety checks, and exactly where you need a licensed electrician rather than a screwdriver. In Greece, any work that involves opening a mains distribution board or extending circuits must be done by a licensed electrical contractor (ηλεκτρολόγος) and a new or amended Υπεύθυνη Δήλωση Εγκαταστάτη (YDE) issued.
What Is a Time Switch and Which Type Do You Need?
A time switch (χρονοδιακόπτης) replaces or supplements a standard wall switch and opens or closes the circuit on a preset schedule. The two main types you will encounter in Greek homes and rental properties are: the analogue DIN-rail timer (mounted inside the distribution board, uses rotating pins on a 24-hour dial) and the digital in-wall timer (fits in a standard junction box, controlled via a small display and buttons). DIN-rail models are more robust, support weekly programmes, and suit garden lighting, pool pumps, or any circuit that the same electrician who installs it will also wire. In-wall digital timers suit a single light circuit — say, a stairwell or an entrance — and may be owner-replaceable in the same way a light switch is, provided the wiring was done correctly and safely by an electrician first.
For holiday rentals and hotels, a DIN-rail timer inside the consumer unit is almost always the right choice: it is tamper-resistant, survives high-turnover guests, and can handle the full load of multiple fittings on one circuit. For a single outdoor lamp or a bedside reading circuit, an in-wall digital switch is simpler and cheaper.
Safety and Legal Requirements in Greece
Greek electrical installations are governed by ELOT HD 384 (the national adaptation of IEC 60364). Any modification to fixed wiring — adding a new timer inside the distribution board, re-routing cables, or replacing a switch box where the wiring condition is unknown — legally requires a licensed ηλεκτρολόγος-εγκαταστάτης and a new or amended YDE declaration. This is not a formality: old Greek wiring (particularly in buildings from the 1960s–1990s) is often aluminium, undersized, or missing an earth conductor, and opening a live board without proper training is genuinely dangerous.
What a property owner or manager can legally and safely do: turn off the relevant circuit breaker, confirm the circuit is dead with a non-contact voltage tester, and swap a like-for-like in-wall timer switch for an existing one — only if the wiring is already earthed and in good condition. Everything else — new wiring, DIN-rail timers, any uncertainty about the earth — should go to a professional. The steps below describe the full process so you can brief an electrician confidently and check the work.
Tools and Parts to Have Ready
Before your electrician arrives (or before you attempt a simple switch swap yourself), gather: the replacement timer switch or DIN-rail unit rated for the circuit's load (check the amperage), a flat-head and Phillips screwdriver, a non-contact voltage tester (essential — never skip this), electrical tape, wire labels or masking tape and a pen, and optionally a small torch. In Greece, 230 V / 50 Hz is standard; make sure any timer is rated for this. For DIN-rail units, also check the rail width (35 mm is universal) and count the module slots free in your consumer unit.
Installing a Time Switch for Lights: Step by Step
- 1
Switch off the circuit and verify it is dead
Go to the distribution board and switch off the circuit breaker for the lighting circuit you are working on. Then use a non-contact voltage tester at the switch position or light fitting before touching any wire. Do not rely on the breaker label alone — boards in older Greek properties are often mislabelled. If you are unsure which breaker controls the circuit, turn off the main incoming isolator while you work.
- 2
Remove the existing switch and photograph the wiring
Unscrew the switch cover plate and carefully pull the switch out of the wall box. Before disconnecting anything, take a clear photo of all wires and how they are connected. In a standard Greek single-pole lighting circuit you will typically find a live (phase) wire and a switched-live returning to the fitting, plus an earth if the installation is earthed. Some older installations have only two conductors with no earth — a licensed electrician must assess whether this is safe to use with a timer switch, as many digital timers require an earth to function safely.
- 3
Connect the timer switch following its wiring diagram
Timer switches have labelled terminals — commonly L (incoming live/phase), L1 or LOAD (switched output to the light), N (neutral, if the switch requires it), and Earth. Connect each wire to its matching terminal, tighten the screws firmly, and tug each wire gently to confirm it is held. Never leave bare copper exposed beyond the terminal. If the timer needs a neutral wire but your switch box only has a live and a switched-live (a two-wire installation), the switch is not compatible with that box — this is one of the most common fitting problems, and it requires an electrician to run the correct wiring.
- 4
Set the programme before closing up
With the switch wired but the circuit still off, set the on/off times on the timer according to its manual. For an analogue pin-dial model, press the ON pins down for the periods you want the light on (each pin usually represents 15 or 30 minutes). For a digital model, use the programming buttons to enter the day, current time, and the ON/OFF events you want. Test the manual override button to confirm the display responds. This is easier to do now than after the switch is screwed into the wall.
- 5
Restore power and test the schedule
Refit the timer into the wall box, attach the cover plate, and restore the circuit breaker. Observe the light: use the manual override on the timer to confirm the circuit switches on and off correctly. Then let the timer run through at least one automatic ON event (or advance the clock temporarily) to confirm the programme fires as set. If the light does not come on, recheck terminal connections with the circuit off again. If the timer display is blank or the device feels warm, switch off immediately and call an electrician — there is likely a wiring or load mismatch.
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FAQ
- Can I install a time switch myself in Greece, or do I legally need an electrician?
- A simple like-for-like swap of an in-wall timer switch — where the wiring is already correct, earthed, and in good condition — sits in a legal grey area similar to replacing a light switch. However, any work inside the distribution board, any new wiring, or any situation where you are not certain of the wiring condition must be done by a licensed ηλεκτρολόγος-εγκαταστάτης who can issue or amend the YDE declaration. When in doubt, hire a professional: the liability risk and safety risk of amateur mains electrical work are both significant.
- My timer switch needs a neutral wire but my switch box does not have one. What do I do?
- Many modern digital timer switches require a neutral (N) conductor to power their electronics, but older Greek switch boxes were wired with only a live and a switched-live. You cannot safely improvise a neutral connection from the earth wire. The solution is to have an electrician run a new cable with the correct conductors, or choose a timer switch specifically designed for two-wire (no-neutral) installations — some exist but have limitations such as minimum-load requirements.
- How do I calculate the right timer switch rating for my lights?
- Add up the total wattage of all fittings on the circuit, then divide by 230 V to get the amperage. For example, four 60 W halogen spotlights = 240 W / 230 V ≈ 1.04 A. Choose a timer rated safely above that — a 10 A timer covers almost any residential lighting circuit. For circuits with LED fittings, also check that the timer is marked 'LED compatible', as some analogue timers cause LED flicker or ghost-lighting at very low loads.