G98 and G99 DNO Applications Explained

When you install solar panels or a battery that connects to the grid, the company that runs the local electricity network has to be told about it - or, for bigger systems, asked first. That's the G98 and G99 process, and it's one of the things we handle as part of every solar and battery installation we do across Greater Manchester.

The network operator for this area is Electricity North West. The rules are national, but the application goes to them, and the state of the local network they're looking at can affect what's accepted.

G98 - the small-system route

G98 covers generation up to 16 amps per phase, which on a standard single-phase house supply means an inverter output up to 3.68kW (three-phase supplies get the same 16A allowance per phase). It works on a connect-and-notify basis: the system is installed and commissioned, then the DNO is notified within 28 days. No prior permission, no waiting.

Most domestic installations that stay under the threshold follow this route. Where a system would nudge over it, the inverter can often be export-limited to 3.68kW to stay within G98 - the panels can still outperform the inverter's cap at times, and you're mainly giving up a slice of peak export that you were probably storing in the battery anyway. Whether limiting or applying under G99 is the better call depends on the property, and it's a design decision we make with you rather than a default.

G99 - permission first

Anything capable of exporting more than 16A per phase needs a G99 application, and written acceptance has to be in place before the system is connected. Bigger domestic systems, most commercial solar installations and some battery retrofits fall under it. The application includes the inverter details, protection settings and installation specifics, and Electricity North West assesses what the local network will take.

The timescale is the part to plan around. For low-voltage generation connections the DNO has a statutory period of up to 45 working days to respond, and complex cases can take longer. We submit applications as early in a project as we can, with the technical detail done properly first time, because a bounced application costs more time than a careful one.

Batteries and aggregate capacity

Adding equipment to an existing system can change the answer. The DNO looks at the total generation capacity at the connection point, so retrofitting a battery or expanding an array on a property that's already under G98 can tip the combined system into G99 territory. It's one of the compatibility checks we do when quoting a battery retrofit, so the paperwork doesn't surface as a surprise after the equipment's ordered.

What we handle

All of it. The G98 notification or G99 application, the technical schedules, the commissioning confirmation after installation - it's part of the job, not an extra. The MCS certification for the installation (ours is NAP-66870) ties in with the same process, and your electricity supplier will want the connection details for export payments under the Smart Export Guarantee, which we provide at handover.

If you're planning solar, a battery or a commercial array and want the grid connection side done properly, get in touch.