There's no literal G98 or G99 certificate, just the DNO's written confirmation. How to apply online, what it costs and how long each route takes.
Customers ask for "the G98 certificate" or "the G99 certificate" all the time, usually because their electricity supplier wants proof the installation was registered with the network. The precise answer is that there's no certificate. What exists is the Distribution Network Operator's written confirmation: on G98, the acknowledgement of your installation notification; on G99, the connection offer approving the installation, and after commissioning, the DNO response confirming your commissioning documents have been logged on their system. That last document is the one suppliers ask for when a customer applies for an export tariff, and SSEN confirms exactly that in its own guidance.
So the job isn't "get a certificate". It's: work out which route the installation needs, submit the right application to the right network, and close it off with commissioning confirmation. Here's that process end to end, what each step costs, and how long each one takes.
The application goes to the Distribution Network Operator that owns the network at the property, which has nothing to do with who the customer buys their energy from. If you don't already know which network covers the job, how to find your DNO covers the lookup, and it's worth doing before you quote rather than after, because every route and timeline below hangs off that one answer.
The 16A per phase threshold decides everything: at or under it, the job is a G98 notification. Over it, the job needs a G99 application with approval before you install. On a standard single-phase supply, 16A per phase works out to 3.68kW; on three-phase, 11.04kW.
Two details catch install teams out, and both are worth checking before the quote rather than after:
The full threshold rules, including the edge cases that override the capacity number entirely, are worth knowing cold. If you'd rather not hand-calculate per job, the DNO application checker works out the route from the postcode, the technology and what's already installed at the property.
Every network's application needs the same core data, and most rejections are this step done badly rather than the site being unsuitable:
Why G99 applications get rejected is mostly a list of mismatches in this data: the inverter model on the schematic not matching the type test certificate, export limitation described vaguely instead of technically, and battery capacity in kWh quoted where the power rating in kW was asked for. The G100 scheme itself, and when it's required, is covered in export limitation and the G100 route.
If the job is G98: you install and commission first, then notify the DNO within 28 days of commissioning. Nothing about a G98 sits on the job's critical path. SSEN, for example, takes domestic notifications by email once the installation commissioning confirmation form is complete.
If the job is G99 Fast Track: the three Small Generation Installation categories decide what you submit. SGI-1 is notification only, on Form A3-3, and behaves like a G98. SGI-2 and SGI-3 are applications on Form A1-2, and you can't connect until the DNO confirms its assessment is complete. The Fast Track process and the three SGI categories are covered in full elsewhere, including the forms and the details that stall applications.
How you submit depends on the network, and this is the part that has genuinely moved online:
There's no single national fee. Charges are set by each network in its own connections charging schedule, and they vary by route and by the complexity of the assessment:
The practical rule is to pull the current figure from your own DNO's charging schedule before you quote the job, not from a blog post, ours included. Fees move, and a full G99 priced without its fee is a quote you'll have to re-issue.
Each route has a different clock, and only some of them can run in parallel with the install:
| Route | The clock | What it means for the job |
|---|---|---|
| G98 | Notify within 28 days of commissioning | Nothing on the critical path. Install first, notify after |
| G99 Fast Track (SGI-2, SGI-3) | About 10 working days from a complete application | SSEN and National Grid both state 10 working days to respond. The clock starts when the DNO has everything, not when you sent it |
| Full G99 | 45 working days to the connection offer, the target for LV generation connections in the ENA's G99 guide | On the critical path, and a rejection resets it |
After approval there's a second clock. Once the DNO confirms its assessment, you have a window to install and commission, up to three months on SSEN, and the commissioning confirmation (Form A3-2 on the G99 routes) goes back to the DNO within 28 days of commissioning.
If you came here to avoid the 45 day wait, these are the things that send a job there:
Once the application is in, it moves through statuses: awaiting assessment, under assessment, then a decision. Two of them need you to act rather than wait. Further information required means the DNO contacts you directly, outside the portal, for what it needs, and the assessment doesn't move until you reply: what the status means and how to handle it. DNO works required means the network itself has to do work before your application can progress, and that changes the timeline you quoted: how the status works.
Then close the loop. Commissioning confirmation goes back to the DNO within 28 days of commissioning on every route, and the DNO's response confirming your documents are logged is what the customer needs for their export tariff application. It's also the point where the rest of the compliance file has to be finished, because MCS commissioning and DNO notification are due at the same moment.
Submitting and tracking applications in the project
Payaca submits G98 and G99 applications to the DNO through ENA Connect from the job's Property tab. The application type is determined automatically from what you select on the job: heat pump, EV charger, battery, V2G or solar panel. Status updates arrive in the project without anyone logging into a separate portal, and you can trigger automations on a status change, like moving the project to Ready to Install when the DNO approves. See how it works.
If you're running multiple installs at once, the submission is rarely the bottleneck. Tracking statuses across 30 active jobs by hand is: a "further information required" that nobody sees costs you the same assessment window as a first-time rejection. That gap, and what to automate around it, is where most growing install businesses lose time on the DNO process.
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The G99 Fast Track process connects small generation and storage installations in around 10 working days instead of a full G99 assessment. The three SGI categories, the forms, and the details that keep an application moving.
'Further information required' is not a rejection. What the status means, where the DNO actually contacts you, and what it does to the 45-working-day clock.
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