Guide · Reviewed against RECI guidance and installer-published documentation. Last verified: 2026-10-22.

Generator installation and ATS explained: the Irish step-by-step

The installation is where a good generator decision is either protected or ruined. A correctly installed standby set runs unattended for a decade; a badly installed one backfeeds the grid, fails its first real storm, or voids its warranty. This guide walks through the Irish process step by step - survey to certification - and explains the automatic transfer switch (ATS), the component that makes the whole thing effortless.

The golden rule: RECI-registered electrical work only

Every connection between a generator, a transfer switch and your distribution board is electrical work that must be carried out by a RECI-registered electrical contractor (Register of Electrical Contractors of Ireland). This is not red tape for its own sake: safe isolation, correct changeover wiring and certification are what stop your generator from electrifying a dead line that an ESB Networks crew believes is safe. Ask every installer for their RECI registration number before you talk prices, and expect an electrical completion certificate with the handover pack.

What an ATS actually does

An automatic transfer switch (ATS) is a self-acting switch that sits between the grid supply, your house and the generator:

1. Senses the outage. The ATS monitors the grid continuously. When ESB Networks' supply fails or drops out of limits, the ATS reacts within seconds.
2. Isolates the premises from the grid. The ATS disconnects your house from the network first - this is the step that makes backfeeding impossible.
3. Starts the generator. The ATS signals the standby set, which cranks and reaches voltage in typically 10-30 seconds.
4. Transfers the load. The ATS switches your house onto the generator supply. From your kitchen, the interruption is a blink and a hum from the yard.
5. Reverses everything when the grid returns. Supply stabilises, the ATS transfers back, the generator runs a cool-down, then shuts down - often with an exercise schedule keeping it ready for the next event.

A manual changeover switch performs the same grid-isolation job but requires a person to operate it: start the generator outside, then switch the house over. It is a legitimate budget option for occupied homes with someone able to do the switching safely - but it cannot protect an unattended property, and the delay is minutes, not seconds.

The installation, step by step

1. Site survey and sizing

A RECI-registered installer visits, reviews your load list (see the sizing guide), checks the distribution board, meter position and earthing, and confirms fuel options - LPG tank, diesel tank, or gas-network connection where available. Out of this comes a written quote with the kVA rating, fuel, transfer-switch type and all civil works itemised.

2. Siting the unit

The unit goes outside, on a plinth, with clearances for exhaust, cooling airflow and servicing access, and with noise neighbours in mind - acoustic enclosures are standard on modern residential sets, but siting still matters. Coastal sites (Clare, Kerry, Mayo, Donegal especially) justify corrosion-resistant enclosures. The siting decision also drives cable-run length, which drives cost.

3. Plinth and groundworks

A concrete or composite plinth is poured or laid, the cable trench between unit and house is dug and ducted, and earthing is installed. On some sites this is a morning's work; on others - long drives, rock, established gardens - it is the biggest line in the quote.

4. Fuel provision

LPG installations may share an existing heating tank (a common cost-saver) or add a dedicated one; diesel installations get a bunded tank sized for multi-day autonomy; HVO is increasingly an option on modern diesel sets. Fuel lines, filters and shut-offs are fitted and leak-tested. Your installer should size storage against realistic outage length - post-Éowyn, three days is a sensible planning assumption in much of rural Ireland.

5. Transfer switch installation

The ATS (or manual changeover) is mounted beside the distribution board, and the electrician wires it into the circuits agreed in the design - whole-home or essential-circuits. This is RECI electrical work through and through: correct isolation, labelling, and interlocking so the generator and the grid can never be connected simultaneously.

6. Commissioning and load test

The engine gets oil and filters checked, the battery and charger are tested, the fuel system is bled, and the set runs a controlled load test. The ATS is exercised end-to-end: pull the simulated grid, watch the start sequence, transfer, return, cool-down, shutdown. You get a walkthrough of the controller - exercise schedules, fault codes, mute settings.

7. Certification and handover

You receive the RECI electrical completion certificate for the connection work, the manufacturer's warranty documents, the service schedule, and the maintenance handover. File the certificate: it matters for warranty claims and for any future house sale.

What it costs and how long it takes

The installed EUR 5,000 - 15,000+ band (ASSUMPTION - indicative, see our cost guide for the layer-by-layer breakdown) typically covers survey through certification. Physically, most residential installations are one to three days of work on site; the schedule risk sits in unit lead times and electrical booking dates, not the work itself. Post-Éowyn, order ahead of storm season.

Maintenance from day one

An installed standby set is a machine with a battery, oil and filters - it needs an annual service (typical requirement; follow your unit's manual) covering oil, filters, battery test and an exercise-run check. Our storm-season maintenance guide sets out the annual rhythm and the pre-storm checks. Buy the service plan at handover: it is cheaper than the call-out it prevents, and it keeps the warranty clean.

The questions that separate good installers from the rest

1. What is your RECI registration number? Non-negotiable, in writing, before the quote.
2. Show me the load list behind this kVA rating. Sizing must trace to your actual loads - well pump surge, heat pump, the lot.
3. ATS or manual changeover, and why? The answer should reference your household pattern, not just price.
4. What is the fuel autonomy at typical load? Hours matter; days matter more.
5. Who attends if it faults during a storm? Get the storm-season response commitment in writing.

An installation done this way disappears into the background of your house: it starts when needed, and you think about it twice a year at service time. That effortlessness is exactly what the ATS and the RECI-certified connection are buying you.

Timeframes and figures on this page are indicative (ASSUMPTION). Every installation varies by site - your RECI-registered installer's survey and quote are authoritative.