G99 Fast Track: the quicker DNO connection route

A full G99 application carries a published assessment target of 45 working days from a complete submission, and on some networks the reality runs longer. For a lot of the jobs install businesses actually do, that wait is unnecessary. The G99 Fast Track process exists for exactly those installations: small generation and storage on existing premises that qualify as a Small Generation Installation, assessed in around 10 working days rather than 45, because the equipment is type tested and the network impact is predictable.

Many install businesses first meet the idea as a surprise. You cross the 16A per phase line that separates G98 from G99, assume the job is now into a full assessment with a fee and a three month wait, and quote the customer accordingly. For installations up to 60A per phase of total registered capacity, there's a quicker route, and the DNOs run it as a separate queue.

The three SGI categories

Eligibility is built on three Small Generation Installation categories. Every generating unit, storage included, must run through an inverter that is type tested to EREC G98 or G99, and the installation must sit on an existing premise as a single generator installation. Kit installed before 27 April 2019 can be G59 or G83 type tested instead.

	Design capacity, per unit	Registered capacity, per unit	Total registered capacity	G100 export limit	Form
SGI-1	32A (7.36kW) or less	16A (3.68kW) or less	16A (3.68kW) or less	Not required, the inverter's limit is factory set	A3-3, notification only
SGI-2	32A (7.36kW) or less	16A (3.68kW) or less	32A (7.36kW) or less	May be required, limiting export to 16A (3.68kW)	A1-2 to apply, then A3-2 to notify
SGI-3	32A (7.36kW) or less	32A (7.36kW) or less	60A per phase or less	May be required, limiting export to 32A (7.36kW)	A1-2 to apply, then A3-2 to notify

The distinction between design capacity and registered capacity is what catches most teams out, and it decides the category before any form is filled in. A 7.36kW inverter with a factory-set 3.68kW export limit has a registered capacity of 3.68kW, which can be the difference between SGI-1 notification and a full application. The DNO application checker tells you whether a job is G98 or G99 from the postcode, the capacity and what is already installed at the property, which matters because existing generation counts towards the totals.

DNOs publish their own Fast Track guidance, and it's worth reading the page for your network before you apply: National Grid Electricity Distribution, SSEN and Electricity North West all describe the same three categories.

How the application actually works

SGI-1 is a notification only, on Form A3-3. It behaves like a G98 notification: you tell the DNO about the installation rather than asking permission. SGI-2 and SGI-3 are applications, on Form A1-2, and the difference from SGI-1 matters: you can't connect until the DNO confirms its assessment is complete.

For an SGI-2 or SGI-3 application you'll need:

• The device reference numbers of any new or existing generation devices at the property
• The MPAN, or the property postcode if the DNO's portal generates the MPAN for you
• Inverter and generator details, with the name and power rating in kW exactly as they appear on the schematic
• Type test certificates for the inverter, from the ENA Type Test Register
• Details of any G100 export limitation scheme, where the category requires one
• For SGI-3 applications, the phase to neutral loop impedance measurement on the DNO's own form

How you submit depends on the network. National Grid Electricity Distribution has an online form that gives instant acknowledgement, while SSEN takes Fast Track applications by email. Either way, the DNO's response window starts when it has everything, not when you sent it.

The 10 working days, and what comes after

SSEN states it aims to respond to Fast Track applications within 10 working days, and National Grid Electricity Distribution says you will hear back within 10 working days with the next steps. That's the working pattern across the networks, and it's the number to plan installation dates around rather than the 45 working day target that applies to a full G99 application.

What follows approval has its own clock. Once the DNO confirms the assessment, there's a window to install and commission the generation. SSEN, for example, gives the installer up to three months. The commissioning confirmation, Form A3-2, then goes back to the DNO within 28 days of commissioning, the same notification deadline the G98 route carries. EREC G99 expects the planned commissioning date on the application to fall between 10 working days and three months from submission, so apply when the install date is real.

Where Fast Track applications stall

The route is quicker, but the failure modes are the same ones that stall full applications, just on a shorter clock:

Inverter rating mismatches. The power rating on the type test certificate has to match the power rating on the schematic. When they differ, the application stops while the DNO asks which inverter is actually being installed, and nothing moves until the answer lands. The ENA Type Test Register is the reference to check against, not the manufacturer datasheet.

G100 details that are not really details. An SGI-2 or SGI-3 application that needs an export limitation scheme has to specify the scheme, not state that one exists. The category tables name the export limit the DNO expects, and where the network can't accept full export the application has to describe a compliant G100 export limitation scheme with its agreed limit.

Existing generation that was never mentioned. The totals in the category table cover everything at the property. A previous solar install that isn't on the application changes the total registered capacity, which can change the category, which can change the route from a 10 working day assessment to something much slower.

A request for further information is the usual shape a stalled Fast Track application takes rather than an outright rejection, and a complete answer is what gets it moving again. How to handle a "further information required" response covers what to send back.

Running Fast Track at volume

One Fast Track application is a form. Twenty live at once, across three or four DNO territories, each with its own portal, its own response window and its own install window, is a tracking problem. Because each application is only worth 10 working days when it's watched, the cost of losing track is that the quick route silently becomes the slow one. A works required response can still land on a Fast Track job where the local network needs work, which adds a quote and a decision that someone has to see.

The MCS commissioning requirements run alongside the DNO notification, on their own clock.

Where Payaca fits

Payaca sends DNO applications from the project to the networks through ENA Connect, for solar, batteries, heat pumps and EV chargers. Here's what that takes care of:

• Devices come from the register. You pick each inverter and battery from a searchable copy of the ENA Type Test Register, by manufacturer, model or reference, so the reference on the application is the registered one and nobody types it by hand.
• Existing generation has its own list. The application asks for the devices already at the property as well as the ones you're installing, picked from the same register.
• Export limitation is part of the form. You record the scheme, with a G100 device from the register or the export capacity in kW, and attach the single-line diagram from the project's files.
• The job fills in the rest. Customer, site and installer details come from the project, and the cut-out photo and other attachments are picked from the files already on it.
• Statuses come back to the job. Payaca checks ENA for updates, within minutes of submitting and then hourly, and shows the DNO's status on the project, including further information required, works required and approved. The DNO's comments appear on the application, and the project's owner is notified when the status changes.
• A status change can start the next step. An automation can create a task, send a message or move the job to another stage when an application is approved or comes back with a question.
• Commissioning goes from the same record. For solar and battery applications, the commissioning confirmation is completed and submitted from Payaca once the DNO has approved.

DNO applications are switched on per account for UK install businesses. Book a demo and we'll show you one on a job like yours.