Every solar install that exports energy needs to be properly connected to the grid — and that means dealing with the DNO. Here's what installers need to know to get it right and avoid delays.
What Does "Grid Connected" Actually Mean?
When we talk about a solar system being grid connected, we mean it's linked to the local distribution network and able to export surplus energy back to the grid. From the DNO's perspective, any new generation asset connecting to their network needs to be notified or approved — even for a small domestic install.
As the installer, you're responsible for making sure the correct DNO application is submitted before the system goes live. Getting this wrong can mean delays, enforcement action, or your customer being unable to register for the Smart Export Guarantee.
G98 vs G99 — Which Applies to Your Job?
The two main routes for connecting solar panels to the grid are governed by Engineering Recommendations G98 and G99.
Notification rather than application. Submit before commissioning — the DNO has 28 days to object, but in practice this rarely happens.
Formal application required. The DNO must approve it before you commission the system. Takes longer and requires more technical documentation.
What Information Does the DNO Need?
G98 Typical requirements
Site address and MPAN Inverter make, model, and rated output Total system capacity (kW) Single line diagram (some DNOs) Commissioning date
G99 Additional requirements
All G98 requirements above Protection relay settings Full technical specification Feasibility study (larger systems)
How Long Does Grid Connection Approval Take?
G98 notifications are typically processed within 24–48 hours. The DNO has 28 days to object, but most are confirmed much faster.
G99 applications are more variable. Simple residential G99 jobs might be approved within 10 working days. Larger commercial systems can take 30–60 working days, especially if they require a connection offer from the DNO's engineering team.
Delays are common when applications are submitted incorrectly or with missing documentation — which is why getting it right first time matters.
Common Reasons DNO Solar Applications Get Rejected
- Incorrect or missing technical specifications
- Wrong application type submitted (G98 when G99 was required)
- System capacity calculated incorrectly
- Missing single line diagram
- Application submitted to the wrong DNO for the area
- Commissioning date already passed at point of submission
How to Speed Up the Process
The fastest way to get grid connection approved is to submit a complete, accurate application first time. That means knowing your DNO's requirements, having all the technical data ready, and submitting through the correct portal.
If that sounds like more admin than you want to deal with, that's exactly the problem we solve. We handle DNO applications on behalf of solar installers — checking every submission before it goes in, chasing the DNO on your behalf, and getting you the export number as soon as it's issued.
Find out how our DNO application service works
We handle submissions for solar installers across the UK — from simple G98 notifications to full G99 applications.
View Our Services