How Big a Solar System Can You Install in Ireland?

You can install a solar system up to 6kVA on a single-phase home (or 11kVA on a three-phase home) and connect it to the grid for free under ESB Networks' "inform and fit" micro-generation route, using the NC6 notification form. Go above that and you cross into mini-generation: you need an NC7 application, you pay a connection fee, and ESB Networks issues a formal connection offer before you can energise. For almost every ordinary Irish house, the 6kVA single-phase figure is the number that matters — and it's the inverter's export rating, not the size of your panel array, that the limit is measured against (verified against esbnetworks.ie, 8 June 2026).

This guide covers what really limits your system size, where the NC6/NC7 line sits, why a 10kW array can still be fine, and what crossing into NC7 territory actually costs you in time and money.

It's the Grid, Not Planning Permission

Most people assume the cap on a domestic solar system is planning permission. For a roof-mounted system on a house, that's rarely the binding constraint — rooftop solar on a dwelling is exempt from planning permission in most circumstances, with a few exceptions near airports and in architectural conservation areas. We cover those exemptions in detail in our solar planning permission guide.

The real ceiling is the grid connection. ESB Networks operates two distinct routes for connecting a generator to the low-voltage network, and which one you fall into is decided purely by your inverter's export capacity. That threshold — not your roof area, not planning — is what determines whether your install is a free same-day notification or a paid, offer-based connection that takes a couple of months.

The Two Grid-Connection Thresholds (NC6 vs NC7)

Here is exactly where the line sits, taken from the live ESB Networks micro-generation and mini-generation pages:

The single-phase 6kVA figure has a hard edge to it: since 31 May 2023, ESB Networks no longer accepts units with a rated output above 25 A single-phase under the NC6 "inform and fit" process. A short transitional allowance up to 28 A has ended. So 6kVA single-phase is a firm boundary, not a soft guideline. Once you've established which route you're on, the NC6 form guide walks through the notification itself.

The Limit Is the Inverter, Not the Panels

This is the part that trips people up. The 6kVA cap is on what your system can export — which is governed by your inverter's rated output, not by the kilowatt-peak (kWp) of panels on your roof. The two numbers are routinely different.

It is common and entirely legitimate to fit a panel array larger than the inverter that serves it. A home might install 7–8 kWp of panels behind a 6kVA inverter, because Irish roofs rarely produce their full nameplate output — cloud, low winter sun and panel orientation mean the array spends most of the year generating well below its peak. Pairing a bigger array with a smaller inverter ("oversizing") captures more of those middle-of-the-day hours and only loses a little at the few summer peaks when output would have been capped anyway. The system still sits inside the NC6 route because its export never exceeds 6kVA.

Installers also use export limitation — a setting that caps how much the inverter pushes to the grid — to keep a slightly larger inverter compliant. The practical takeaway: when an installer quotes you a system, ask what the inverter export rating is, because that single number decides whether you stay on the free NC6 route or tip into NC7.

"Is 10kW Enough?" — and Can You Even Fit It?

A 10kW system is more than enough to cover the annual electricity use of a typical Irish home several times over — the average house uses around 4,200 kWh a year, and a 10kWp array in Ireland generates roughly 8,000–9,000 kWh. The real question isn't whether 10kW is enough; it's whether you can connect it simply.

• On a single-phase home (the vast majority of Irish houses), a 10kW inverter exceeds the 6kVA NC6 limit, so it would need either export limitation down to 6kVA or a full NC7 mini-generation application.
• On a three-phase home (more common on larger rural properties and farms), 10kVA sits comfortably under the 11kVA NC6 ceiling — so a system that size can still connect under the free notification route.

For most households, there's little reason to go past 6kVA of export anyway: you only get paid the Clean Export Guarantee rate for what you send to the grid, and beyond a point the extra exported units earn far less than the panels cost. The sweet spot for a typical home is a system sized to its own consumption plus a sensible export margin — which almost always lands inside NC6.

What Changes If You Do Go NC7

Crossing into mini-generation isn't a wall — plenty of farms, businesses and larger homes connect systems between 6kVA and 50kVA — but it is a different process with real cost and time implications:

• You pay an application fee rather than connecting for free.
• ESB Networks issues a connection offer based on your NC7 details, and you energise only after accepting it — you can't simply fit and notify.
• It takes time: ESB Networks quotes 8 to 10 weeks from payment of the fee, longer for complex sites.

The grant and export economics shift too. The SEAI Solar Electricity Grant is aimed at domestic micro-generation, so a step up to a large mini-generation system changes what support you can claim — worth confirming with your installer before committing to a size that pushes you over the line for no real benefit.

Frequently Asked Questions