Many prospective or existing solar panel users in Northern Ireland will have come across the terms G98 or G99, whether from discussions with solar panel companies like First Class Solar or with other solar users. But what do these regulations actually mean and what can you safely install by Northern Ireland Electricity (NIE) Networks standards?
What is G98 for Solar PV in Northern Ireland?
G98 is the UK engineering standard that allows small-scale, grid-connected generators to be installed under a “fit and inform” process. This means that solar panel users do not need approval from their Distribution Network Operator (such as Northern Ireland Electricity Networks) before installation – but they will need to be notified after installation.
The key limit under G98 is 16A (amps) per phase, which determines the maximum inverter size:
- 3.68kW for single-phase installations
- 11.04kW for three-phase installations
This ensures smaller solar system installations can be connected to the grid quickly and without a lengthy approval process.
What G98 Means for Your Home in Northern Ireland
The maximum inverter size permitted without pre-approval for most residential homes in Northern Ireland is 3.68kW. Many inverter models – including the Solis Hybrid inverter, the First Class Solar favourite – come as a 3.6kW standard which is generally sufficient for the electric requirements for an average home. To see how these systems perform in real life, check out our blog on Solar Panel Production in Northern Ireland in 2024/2025, where we share real data from First Class Solar solar installations across NI in the likes of Lisburn, Ballymena and Portadown.
Who Handles the G98 Paperwork?
At First Class Solar, we take care of the G98 process for customers. Once your system is installed, we notify Northern Ireland Electricity (NIE) to ensure your system is registered on the grid.
Following this, NIE may contact you directly and, in some cases, arrange a visit to check that your meter is correctly set up to record your solar generation. If you have an older spinning meter, it may need to be upgraded to a modern digital meter – this is carried out by NIE at no cost to you.
As part of your Handover Pack, you will receive a Job Reference Number which you can quote to NIE should you ever need to contact them about your solar PV system.
G98 Fees
NIE does not charge a fee for a G98 size solar PV system. The completion of this paperwork is included as part of your First Class Solar system installation.
What is G99 for Solar PV in Northern Ireland?
G99 is another UK Engineering Recommendation regulation that applies to medium and large-scale grid-tied power-generating equipment such as solar PV, wind or large scale batteries.
If your system exceeds G98 limits (more than 3.68kW for single-phase or 11.04 kW for three-phase), you will need G99 approval from NIE before installation.
Why is G99 Required?
The G99 approvals process allows NIE to perform detailed technical and safety assessments. This ensures larger systems can connect safely to the grid without causing instability or disruption to the local network.
Who Handles the G99 Application?
If you choose a G99 system with First Class Solar, we submit the application to NIE on your behalf, taking the administrative effort off your hands.
How Long Does G99 Approval Take?
G99 approvals take approximately three months in line with regulatory timelines followed by Northern Ireland Electricity (NIE).
G99 Fees
There is a G99 application fee to pay depending on the system size you’d like to apply for. For systems below 20kW capacity, the NIE fee is currently £702. First Class Solar also charges an administration fee to complete and submit this application for you.
This process ensures that larger installations are properly assessed and approved before being connected to the grid.
What Happens if My G99 Is Not Approved?
In some cases, it is not possible for the G99 to be approved due to network or infrastructure limitations, or if the equipment you want to install hasn’t passed the required testing for safe G99/NI installation in Northern Ireland. In these cases, NIE will offer you a full refund of your application fee and it will still be possible to install a smaller G98 compliant system.
In other situations, NIE may offer an alternative solution such as offering a slightly smaller inverter size than requested – for example, offering an 8kW inverter in place of a 10kW inverter. In some cases, your solar PV system may be approved with a Zero Export (G100) configuration, which limits electricity exported to the grid.
No matter the scenario, First Class Solar will guide you through your options, helping you choose the best solution for your home or business.
Remove The Complexity from Solar PV Installation with First Class Solar
At First Class Solar, we pride ourselves on our honest, professional advice and clear communication given to solar customers in Northern Ireland. If you’ve been considering installing a solar PV system in your home, get in touch with the First Class Solar team and let us help make your energy greener, more efficient and cheaper to run.
Give us a call on 02896 005042 or email info@firstclassolar.co.uk and the team will be happy to discuss and advise on your solar PV needs.