ENA Type Test Register, G98, G99 and MCS Explained
- ENA Type Test Register and UK Solar Equipment Compliance Explained
- MCS Certification for Solar Installers, Products and Installations
- DNO, G98 and G99 Requirements for Plug-In Solar Grid Connection
- Home Energy Products Within a Compliant Solar and Storage Setup
- Homeowner Compliance Checks Before Solar or Storage Installation
- Conclusion
- FAQs
When installing solar panels, plug-in solar, or battery storage, you need to look at more than capacity and cost. Equipment must also be suitable for the technical and quality standards of the UK electricity system. This is where the words ENA Type Test Register, G98, G99 and MCS come in.
Not all of these requirements are for the same purpose. ENA type-test information can be used to prove that generating equipment has met relevant network engineering requirements, MCS concentrates on recognised standards for low-carbon products, installers and installations. Meanwhile, G98 and G99 relate to generation and its connection to the distribution network.
Knowing the difference helps homeowners avoid assuming one certificate or register entry means full compliance. This guide explains how the systems are interdependent and what to consider when designing solar generation, battery storage, or a plug-in solar connection.
ENA Type Test Register and UK Solar Equipment Compliance Explained
The ENA Type Test Register is a technical resource, first and foremost. It enables manufacturers to sign-up evidence of assessment of generating equipment against relevant engineering recommendations like G98, G99 or G100. It is a practical tool for installers and network operators to verify equipment information.
ENA Type Test Listings for Solar Inverters and Battery Equipment
When the manufacturer has provided compliance evidence, solar inverters and some battery related generating equipment may be listed on the ENA Type Test Register.
This matters because the inverter regulates how locally produced electricity interacts with the public network. Homeowners unfamiliar with this component may first find it useful to understand what a solar inverter does before looking at its network-compliance documentation.
An ENA listing verifies the equipment's technical identity and the engineering recommendation it is evaluated against. It does not, by itself, indicate that the DNO has approved the complete installation.
Verification Reports and ENA Register Listings Serve Different Roles
A verification report includes the technical evidence of the equipment's compliance, and the register is a searchable record of the information submitted by the manufacturer.
The two should NOT be confused. The register can be used by an installer to find an approved make and model and more detailed supporting documentation can be used for a specific connection process.
ENA guidance also sets out different levels of type testing. Compliance with G98 is based on type testing of the relevant generating equipment, and compliance of larger G99 installations may involve further site-specific assessment by the DNO.
Technical Standards Confirmed Through ENA Type Test Registration
The register can be used to help prove that equipment has been evaluated for its compliance with specific G98 or G99 technical criteria, including those concerned with the behaviour of generating equipment when connected to the electricity network.
While helpful for homeowners, it's just one step toward compliance. Equipment can have appropriate type-test evidence, but the installation may require appropriate DNO connection process, competent installation and associated MCS documentation.
The next step should be to separate ENA's technical compliance from MCS certification, which focuses on products, installers, and completed low-carbon installations.
MCS Certification for Solar Installers, Products and Installations
The MCS certification scheme is not the same as ENA type testing. The ENA register is based on technical evidence for network connection, and MCS is a UK quality stamp for small scale renewable technologies. Its standards relate to the design and installation of the certified systems; certification bodies check if installers and products comply with the appropriate scheme.
MCS Certification Across Installers, Products and Quality Standards
Installers of renewable-energy products and the renewable-energy products themselves can be MCS certified. For solar PV, the scheme sets out recognised standards for system design, installation quality, documentation, and customer protection.
MCS certification of an installer does not necessarily indicate solar experience. It means the business has been evaluated against the scheme requirements for the technologies it is certified for. MCS now includes technologies such as solar PV and battery storage.
For homeowners, it adds another layer of confidence when selecting equipment and installation services, especially for larger rooftop solar and storage setups.
MCS Installation Certificates Issued After Compliant Solar Work
Once an installation is MCS-eligible, MCS captures installation details in the MCS Installations Database. An MCS installation certificate is a document which demonstrates that the installation has been verified to meet the applicable MCS requirements.
This document may be important later. Can be requested for some export-tariff applications, for property records and other schemes where evidence of a compliant renewable-energy installation is required.
The certificate should therefore not be considered documentation valuable only on the installation day, but should be kept with the other solar documentation.
Eligible Solar Products and Installer Status Within the MCS Framework
The level of MCS certification should be verified at the level relevant to the project. A homeowner might require confirmation of both the installer's MCS installer certification and that the equipment they are using meets the product requirements (as part of the scheme).
But an MCS certified product or installer will not be a substitute for the network-connection process. Additional ENA type-test evidence may be required for the solar inverter and G98 notification or G99 approval may be required for the entire installation.
That is the key to the UK solar compliance: MCS, ENA and DNO requirements are not interchangeable certificates, but rather complement each other. The next section combines these strands for plug-in solar and grid connection.
DNO, G98 and G99 Requirements for Plug-In Solar Grid Connection
ENA registration and MCS certification pertain to specific aspects of compliance, and neither supersede the process of connecting generation to the local electricity grid. The Distribution Network Operator (DNO) handles that. The principal connection standards that homeowners need to know are G98 and G99 which govern the ability of generating equipment to run in parallel with the public distribution network
Plug-In Solar Systems Bringing DNO Connection Rules Into Focus
A plug-in solar installation can in fact be small, but still be connected with the public electrical grid. Therefore, the DNO must have sufficient information about the generation connected at the property.
Engineering Recommendation G98 covers the fully type tested microgenerators with a total registered capacity of not more than 16A per phase. Ofgem agreed an amendment in 2026 specifically to enable compliant plug-in solar PV, without losing any requirements for network safety, power quality and operability.
However, this should not be interpreted as a lack of responsibility for homeowners with a small system that is easier to implement than traditional rooftop solar. Understanding the relationship between solar and domestic electricity helps explain why the DNO still has a role, even at moderate solar levels.
G98 and G99 Documentation for Generation and Storage Equipment
The route largely depends on the installation's electrical parameters and power rating. Typically, G98 documentation applies to microgeneration up to 16A per phase. If the capacity of an aggregate exceeds that threshold, then the DNO should be consulted before installation, and the G99 process should normally apply.
Part of this assessment is also battery storage, which can be AC coupled and therefore export to the network using an AC-coupled battery inverter. This can mean that existing solar and other generating systems along with additional storage equipment should therefore be evaluated as a whole rather than individually. ENA guidance indicates that extra storage may impact if combined system is G98 or G99 compliant.
Compliance Responsibilities Shared Across Installers and Homeowners
A competent installer will know the requirements for connecting to a DNO, choose the appropriate equipment, and complete the necessary technical documents. Homeowners should keep copies of notifications, approvals, and information about type tests and inverters.
This is particularly critical when a system is expanded. Any change in capacity (addition of another inverter, battery or generation source) may alter the applicable route of connection.
The take-home message is that compliance be considered from a system level. One inverter could be listed on the ENA register, but the entire solar array/storage system would need to go through the applicable G98 or G99 process. With these technical tasks in mind, homeowners can evaluate and choose solar and storage products that will work for them in a properly planned installation.
Home Energy Products Within a Compliant Solar and Storage Setup
However, when the specific ENA, MCS and DNO criteria are known, it becomes easier to put product selection into perspective. The main criteria are selecting equipment to match the domestic enterprise's actual consumption needs and ensuring the entire installation complies with technical and network requirements. While product choice does not replace compliance, appropriate equipment can be part of a well-planned solar and battery storage system.
EcoFlow Plug-In Solar Kit for Simple Home Solar Generation Needs
The EcoFlow Plug-In Solar Kit is an easier way for households to get into small-scale generation than a traditional rooftop solar power system. It is designed for homeowners who want to produce a small amount of electricity for their own use but don't want to make the initial investment in a larger PV array.
The advantage is that it is much more convenient to access, especially where roof space is limited or budget or installation complexity would restrict traditional solar. However, plug-in solar still needs to be considered within the applicable UK electrical and DNO framework.
Therefore, homeowners should review the inverter specification, system output and connection method and not simply assume that a plug-in format meets all the G98 compliance criteria.
EcoFlow STREAM 5000 for New Solar and Battery Storage Systems
If you're a household considering solar generation and storage at the same time, the EcoFlow STREAM 5000 is a more seamless path. It offers 5.24kWh of storage and can take up to 4000W of PV input, making it ideal for building a new solar battery storage system from the ground up.
Planning generation and storage together can help align panel output with battery capacity and household electricity use. It also gives the installer the chance to consider the appropriate inverter and DNO requirements as one system. The STREAM 5000 may then be a viable solution for those transitioning from small-scale generation to a home energy system.
EcoFlow STREAM AC 5000 for Existing Solar Homes Adding Storage
Existing solar households face a different challenge. Their PV system may already be registered and functioning properly, but adding storage requires another inverter or export-capable device, which you must account for when planning the property network arrangement.
The EcoFlow STREAM AC 5000 has a battery capacity of 5.24kWh, and is designed for homes that not only have solar panels but also wish to expand battery storage without replacing the PV system. This may help move excess generation from day to night.
Homeowners should determine if the extra equipment will affect the overall generation and/or export capacity of their property prior to installation. For this reason it is essential that ENA Type Test Register, G98 or G99 checks continue to be a part of the planning process even if the solar system in question is already compliant.
Homeowner Compliance Checks Before Solar or Storage Installation
At this stage, the main compliance frameworks are easier to distinguish: the ENA Type Test Register verifies information on the technical equipment, MCS applies to certified products and installation quality, and G98 and G99 apply to the interaction between generation and storage and the local distribution network. Homeowners can perform practical checks to ensure these requirements are addressed together before installation.
Check relevant equipment on the ENA Type Test Register. Verify the technical listing (if required) of the proposed inverter or other generation equipment. Don't rely on the manufacturer or product family name alone; check the model number, since compliance information may vary by model.
Confirm applicable G98 or G99 connection requirements. Ask the installer about the DNO connection route for the entire system. When considering aggregate capacity and whether G98 or G99 is suitable, consider existing solar alongside new battery storage and additional generation.
Verify installer and relevant MCS certification details. If the project is under the MCS framework, ensure the installer is certified in the technology. It is also helpful to check that any selected products comply with applicable MCS requirements before work begins.
Keep DNO, MCS and installation documentation together. Keep DNO correspondence, inverter specification, commissioning documents and MCS certificates and equipment records in one place. These documents may be of significance for the application for export tariffs, for later sale of the property or for changes in the energy system.
Review compliance again before expanding the energy system. The electrical characteristics of the installation can change when an additional inverter, additional solar system or home storage battery is installed. If a certain system was originally running with G98, it should not be assumed that it will automatically be a part of the same connection route when it is expanded.
Conclusion
Each covers a different aspect of solar compliance in the UK: the ENA Type Test Register, MCS certification, and G98/G99 requirements. ENA listings confirm the technical attributes of generating equipment, MCS endorses established product and installation standards, and the DNO connection process sets the rules for how generation and storage are connected to the public electricity grid.
For homeowners, it is best to think of these requirements together rather than focusing on one certificate alone. This is especially important for additional battery storage units or expanding an existing PV system. Records of equipment and applicable network requirements will help future system changes go more smoothly regardless of whether planning new solar with EcoFlow STREAM 5000 or retrofitting storage with STREAM AC 5000.
FAQs
Can Homeowners Check Equipment on the ENA Type Test Register?
Yes, homeowners can go to the ENA Type Test Register and see if a specific inverter or generating unit is a registered type-test. A product family name is not sufficient and the manufacturer and model number should be compared.
The register can be used to verify if equipment has information to support standards like G98 or G99. An ENA listing does not, however, assure that the full installation has met its DNO connection requirements.
Does MCS Certification Replace G98 or G99 DNO Documentation?
No, MCS certification and G98 / G99 documentation are not the same thing.
MCS focuses on recognised standards for renewable-energy products, installers and installations.
G98 and G99 relate to connecting generation to the electricity distribution network.
ENA type-test information helps demonstrate equipment compliance with relevant engineering requirements.
More than one way of documenting a project may be used. Homeowners should keep the MCS certificate, DNO correspondence, and equipment records together.
Can Plug-In Solar Require Both ENA Listing and DNO Notification?
Yes, plug-in solar may require equipment-level compliance and network notification. The supporting ENA type-test information may be required to connect with suitable inverter equipment and the connected generation may need to be recorded with the local DNO as part of the relevant connection process.
These checks should not be included in a single one, and they cannot be assumed to cover each other.
Does Replacing an Inverter Affect Existing Compliance Records?
Potentially, When replacing a solar inverter, the equipment information of an existing solar installation may be changed, for example, by replacing the solar inverter with another manufacturer model.
Homeowners should have the new inverter specification and determine if any additional DNO documentation is required, as this may differ from the original equipment or rated output/export. It also makes sense to keep the old records in place so the changes to the system are clearly visible.
Can Battery Storage Need Separate Registration From Solar Panels?
The existing network configuration may be impacted by battery storage, especially if the battery is AC connected and has an inverter that can export electricity.
This could mean the installer will need to re-evaluate the overall generation and require the DNO to be notified or approve it again. This is a good reason to check solar battery storage planning before expanding an existing PV installation.