UK DNO G98 Notification for Solar PV and Heat Pumps Guide

Key Takeaways

• Installations meeting microgeneration criteria follow the connect and notify route, allowing equipment to be installed and commissioned before submitting paperwork.
• Installers must submit the relevant Engineering Recommendation G98 form to the DNO within 28 days of installation.
• Statutory microgeneration exemption under ESQCR Regulation 22 applies only where output does not exceed 16 amperes per phase at low voltage.
• Heat pump applications require recording the customer's make and model together with an ENA Heat Pump Database register number.
• Electric vehicle chargepoints require recording make and model together with an ENA EVCP Database register number.
• If an installation exceeds 16 amperes per phase, it transitions to apply to connect under G99, requiring pre-approval before work begins.

The Connect and Notify Framework Under EREC G98

In Great Britain, domestic microgeneration installations that do not present a capacity hazard to the low voltage distribution network benefit from an accelerated administrative procedure known as connect and notify.

Under guidance from the Department for Energy Security and Net Zero:

• If the connection is connect and notify, installers can proceed to install the device and submit the relevant Engineering Recommendation G98 application form to the DNO within 28 days of installation.
• The DNO will assess the notification and contact the installer if details are submitted incorrectly.
• Energy device owners must ensure that your installation contractor has notified the DNO of your installation.

Statutory Parameters Under ESQCR Regulation 22

The streamlined connect and notify procedure is grounded directly in primary UK law under Regulation 22 of the Electricity Safety, Quality and Continuity Regulations 2002.

16 Amperes Per Phase Threshold

Under Regulation 22(2), installers are exempt from prior technical negotiations with the network distributor provided:

1. The source of energy does not produce an electrical output exceeding 16 amperes per phase at low voltage (corresponding to 3.68kW for standard 230V single-phase connections or 11.04kW for 400V three-phase supplies).
2. The source of energy is configured to disconnect itself electrically from the parallel connection when the distributor's equipment disconnects the supply of electricity to the person's installation (anti-islanding protection).
3. The person installing the source of energy ensures that the distributor is advised of the intention to use the source of energy in parallel with the network before, or at the time of, commissioning.
4. The system has the necessary and appropriate equipment to prevent danger or interference with that network or with the supply to consumers so far as is reasonably practicable.

Heat Pump and EV Chargepoint Database Integration

As households electrify heating and transport, paired installations of solar PV, heat pumps, and EV chargers place cumulative loads on local distribution feeders.

Heat Pump Registration

Registration forms require specific technical traceability:

• Part of the application form includes reference to the customer's make and model of heat pump, together with an ENA Heat Pump Database register number.
• Installers must ensure the heat pump's electrical starting current and operating characteristics match certified models listed in the ENA database.

Electric Vehicle Chargepoint Traceability

• Similarly, part of the application form includes reference to the customer's make and model of Electric Vehicle Charge Point, together with an ENA EVCP Database register number.
• This database registration enables DNOs to model transformer loading accurately and maintain local grid voltage stability.

When an Installation Shifts to Apply to Connect

If an installation exceeds 16 amperes per phase—for instance, when installing a 5kW single-phase solar array or pairing a 3.68kW solar system with an unconstrained AC-coupled battery:

• Installers must submit the relevant Engineering Recommendation G99 application form (or G100 if export is limited) to the DNO before installing the device.
• Where battery storage is integrated with generation under apply to connect, installers can utilise a fast track application process (Form A1-2) which reduces the connection time to 10 days or less.