---
title: "G99 solar grid connection (UK)"
description: "G99 explained for UK solar owners. When prior DNO approval is required, typical system sizes, and how G99 differs from G98."
---

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# G99 solar grid connection (UK)

**G99** is the UK industry rule set for connecting **larger embedded generation** to the distribution network. It replaced the older **G59** standard. The formal name is **Engineering Recommendation G99**, from the Energy Networks Association (ENA).

If your solar, battery, or combined system is **above [G98](/docs/guides/what-is-g98-solar-connection-uk/) limits**, or the DNO treats it as non-small-scale, the connection goes through **G99**.

## When G99 applies

G99 typically applies when generation:

- Exceeds **16 A per phase** nameplate current (above roughly **3.68 kW** single-phase or **11 kW** three-phase under G98 thresholds), or
- Does not qualify for **notify-only** treatment under G98, or
- Needs specific **DNO consent** before export or energisation.

Commercial rooftops, large domestic arrays, and some **battery export** setups often use G99. Your installer assesses the correct route.

## What happens under G99

G99 is usually an **application and approval** process with your [DNO](/docs/guides/what-is-dno-uk-solar/), not a simple post-install notification.

Typical steps:

1. **Application** with site details, equipment specs, and your [MPAN](/docs/guides/what-is-mpan-uk-solar/).
2. **DNO review**, which may include limits on export or extra protection settings.
3. **Commissioning** and **compliance evidence** before or after energisation, depending on the DNO.
4. **Registration** of the connection on the network.

Timelines vary by DNO and system size. Plan ahead for larger installs.

## G99 vs G98 (short comparison)

| | G98 | G99 |
| --- | --- | --- |
| Typical size | Small (up to 16 A per phase) | Larger or complex |
| DNO process | Notification after install | Application and approval |
| Lead time | Usually short | Can take weeks |

Many **Fox ESS** home systems fall under **G98**, but hybrid inverters with high export capacity or additional generation may need **G99**.

## G99 and monitoring your system

G99 governs **permission to connect and export** on the network. It does not change how **Fox Cloud** reports data once the system is running.

**[Check My Solar](https://checkmy.solar)** shows live and historical **Fox ESS** data (PV, battery, grid) when your plant is linked and reporting. See [grid import and export](/docs/guides/grid-import-and-export-solar/) for what appears in the app.

## FAQ

### Do I need G99 for a 10 kW home solar system?

It depends on **phase**, **inverter rating**, and **DNO rules**. A 10 kW inverter on a three-phase supply may still fit **G98** on each phase. A 10 kW single-phase system often needs **G99**. Your installer confirms.

### Can I export before G99 approval?

No. Energising or exporting without DNO approval where G99 applies can breach connection conditions. Follow your installer's and DNO's process.

### Does G99 affect SEG export payments?

SEG is a **supplier tariff**. You still need a compliant grid connection (G98 or G99) and suitable **export metering** to receive export payments.

## Related pages

- [G98 solar grid connection (UK)](/docs/guides/what-is-g98-solar-connection-uk/)
- [What is a DNO?](/docs/guides/what-is-dno-uk-solar/)
- [What is an MPAN?](/docs/guides/what-is-mpan-uk-solar/)
- [See if solar is exporting to the grid](/docs/guides/see-if-solar-is-exporting-to-grid/)
- [All solar guides](/docs/guides/)

Source: https://checkmy.solar/docs/guides/what-is-g99-solar-connection-uk/index.mdx