A G98 application ensures you can connect your small-scale renewable or storage installation to the grid while maintaining the local grid’s safety, integrity and supply quality.
Installing rooftop solar panels, EV charge points, heat pumps or home battery systems in the UK comes with technical and safety requirements.
The official UK Government framework requires you to register your energy device with the local Distribution Network Operator (DNO) if it connects to the electricity grid.
The government and energy network bodies have defined clear rules to ensure home and business owners can safely connect small-scale renewables to the grid.
One such rule is Engineering Recommendation (EREC) G98. It helps speed up installations, reduce administrative hurdles, and support wider adoption without compromising grid integrity.
But what is a G98 application, and what does it involve?
Key Takeaways:
- A G98 application is required for small-scale systems up to 16 A per phase, covering most UK domestic solar and battery setups.
- Installers can commission systems and then must notify the DNO within 28 days of commissioning.
- Single homes follow a straightforward post-installation notification, while clustered installs need pre-approval.
- DNOs don’t usually charge for G98, and acknowledgements are typically processed within 10 to 15 working days.
What Is a G98 Application?
A G98 Application is the notification process you or your installer submits to your local Distribution Network Operator (DNO) after installing a small-scale generation system that meets G98 criteria.
These systems must possess type-tested inverters, comply with the 16 amps per phase threshold, and include essential safety components.
Once your newly installed microgeneration system is commissioned, you have up to 28 days to inform the DNO using the appropriate form or via Connect Direct.
Failure to notify means your installation is non-compliant, regardless of performance.
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The DNO then reviews your notification to confirm safe grid connection. The more involved G99 route becomes applicable only if your total installed capacity exceeds the G98 limit.
For home systems under the defined threshold, G98 offers a structured, low-friction pathway that meets legal and safety standards while ensuring efficient integration into the UK network.
What is the G98 Application Process?
The way you apply for a G98 connection depends on whether you’re installing the system at a single property or across multiple premises.
The process is relatively straightforward for individual homes, but the rules change when several systems are clustered together, such as in housing developments or blocks of flats.
Understanding the distinction between single and multiple premises is key to following the right process and avoiding compliance issues.
Single Premises
The process is relatively simple for a single premises installation and can be summarised as a “fit and inform” approach. Key actions include:
1. Finding an Installer
Installation must be carried out by installers who are competent and have sufficient skills and training to install a Micro-generator in compliance with EREC G98.
This includes having recognised and approved qualifications relating to the primary energy source and general electrical installations.
2. Installation and Commissioning
These should be in line with EREC G98, including ensuring that the installation complies with the wiring regulations (BS 7671) and is correctly earthed.
The installer must also ensure there are no modifications to equipment, safety labelling is provided, and the manufacturer’s instructions are followed.
3. Informing the DNO
Once your installation and commissioning are complete, the DNO needs to be made aware of your Microgenerator.
This allows the DNO to take this into account when operating and designing the network.
Your installer must notify the DNO within 28 days of commissioning the generating unit and provide them with information on the installation.
This is a legal requirement. The required information should be captured on an “Installation Document”, which is Form B in EREC G98. These forms are available on the Energy Networks Association website.
Multiple Premises
The process is more complex for installations across multiple premises. Although each unit may be under the 16 A per-phase G98 threshold, the combined effect could stress the local network.
The Energy Networks Association (ENA) specifies that you need to get approval from the DNO before you can connect. Key actions include:
1. Finding an Installer
Ensure your installer is appropriately registered and can fully certify and sign off on installations. They should also have the training, competency and skills to install your device in compliance with EREC G98.
2. Discussions with the DNO
You must discuss your plans with the DNO before starting work. This should be as soon as possible in your planning, as the DNO’s response may have a big impact on how you plan your project. You may discuss the feasibility of your connection and whether there will be any charges.
3. Submitting an Application Form
Once you have planned the project and exchanged information about your plans with the DNO, you should submit an application form.
The format of the application form is given in Form A in EREC G98, which is available on the Energy Network Association’s website. Your installer should submit the application form on your behalf.
4. Application Acceptance
When you submit your application form, you need to include technical details of the equipment.
The DNO needs this information to assess the impact that your Micro-generating Plant may have on the distribution system. Once the DNO has conducted these assessments, it will produce a connection offer.
This will specify the conditions for your connection and inform you of any connection charges.
You should ensure that you fully understand this offer before accepting it. Discuss questions with your DNO if you’re unsure.
5. Installation and Commissioning
Your installer should be aware of the requirements to ensure that installation and commissioning are in line with EREC G98. The installer will also check that your equipment is working as it should.
6. Informing the DNO
Once your installation and commissioning are complete, the DNO needs to be made aware of your energy device.
Your installer must notify the DNO within 28 days of commissioning the Micro-generators on each premises and provide them with information on the installation.
How Does the G98 Application Differ from G99?
The UK electricity network uses the G98 and G99 engineering recommendations to ensure safety and regulate microgeneration and larger-scale generation. However, they differ in capacity thresholds and application procedures.
G98 applies to systems rated at up to 16 A per phase (3.68 kW on a single-phase supply).
This category includes most UK domestic rooftop solar PV and small battery systems. The process involves installing first and then notifying the DNO.
G99 applies to anything larger, whether domestic systems exceeding the limit or commercial installations. Unlike G98, G99 requires pre-approval before installation.
The DNO reviews your plans, may conduct a capacity study, and can impose requirements for local grid reinforcement.
The process is longer, often taking 8 to 12 weeks or more, and sometimes comes with connection charges.
G98 is streamlined for small systems, while G99 handles larger or higher-impact projects. Both are essential for maintaining grid stability, but the administrative burden increases significantly once you cross the 16 A per phase threshold.
G98 Application vs G99 Differences:
| Feature | G98 | G99 |
| Capacity Threshold | Up to 16 A per phase (3.68 kW single-phase, 11 kW three-phase) | Above 16 A per phase(anything larger than the G98 limit) |
| Typical Use | Domestic rooftop solar PV, small battery systems | Larger home systems, commercial PV, community projects |
| Application Timing | Install first, notify later (within 28 days) | Pre-approval is required before installation begins |
| Forms Used | Form B (single premises), Form A (multiple premises) | G99 application forms with detailed technical studies |
| Technical Review | Basic checks by DNO after notification | Full technical assessment, which may include network studies |
| Process Duration | 10 to 15 working days or up to 4 to 8 weeks in busy periods | Typically 8 to 12 weeks or more, depending on DNO workload |
| Costs | Usually free | May involve application fees and reinforcement costs |
| Complexity | Simple, streamlined, minimal paperwork | More complex, requires detailed documentation and design |
Common Pitfalls to Avoid in A G98 Application
Missing the 28-Day Deadline
Installers sometimes forget to notify the Distribution Network Operator (DNO) within the required 28 days of commissioning, leaving the system officially non-compliant.
Exceeding the Capacity Limit
Adding multiple small systems that collectively go over the 16 A per limit without seeking G99 approval is a common mistake.
Incomplete Paperwork
Submitting a G98 notification without a circuit diagram, commissioning form, or type-test certificates often causes delays or rejections.
Assuming All Systems Are Eligible
Some assume every domestic installation qualifies for G98, but certain clustered or three-phase systems may fall under G99 instead.
Poor Communication With the DNO
Not checking local grid constraints in advance can lead to unexpected reinforcement costs or project delays if the local network is already constrained.
Final Thoughts
The G98 application process is central to the safe rollout of domestic solar PV and small-scale battery systems in the UK.
Setting a clear threshold like 16 A per phase, or roughly 3.68 kW, distinguishes between simple, low-impact microgeneration and larger systems that require more scrutiny.
The beauty of G98 lies in its simplicity. Households can install first and notify later, avoiding long delays and costly assessments while still meeting essential safety and compliance standards. For most homeowners installing rooftop solar, G98 provides a fast, low-cost route to grid connection.
Compliance is straightforward as long as you install type-tested equipment and submit the notification paperwork correctly. For developments involving multiple premises, the process shifts to pre-approval, ensuring the local network remains stable under clustered generation.
Understanding and following G98 rules ensures your system contributes to the green transition effectively and compliantly.
FAQs on G98 Application
How Long Does a G98 Application Take?
Most Distribution Network Operators (DNOs) process G98 notifications within 10 to 15 working days, though it can take up to 4 to 8 weeks in busy periods.
Do I Have to Pay for a G98 Application?
No. DNOs don’t usually charge for G98 notifications. Some installers may add a small admin fee to handle the paperwork.
What Happens If I Don’t Submit a G98 Notification?
If you don’t notify your DNO within 28 days of commissioning, your system is technically non-compliant.
This can create problems with warranty, insurance, or even SEG export payments.
References
- Department for Energy Security and Net Zero (DESNZ) – How to register energy devices in homes or small businesses: guidance for device owners and installation contractors
- Energy Networks Association – Distributed Generation Connection Guide: G98 & G99
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