Inverters & components
Grid-tie inverters: how they work and the UK position
A grid-tie (or grid-tied) inverter converts solar DC into mains-compatible AC and synchronises it with the electricity network, so your home draws from the panels first and the grid second. Every plug-in solar system is built around one, in microinverter form.This guide explains how grid-tie works, the types you'll see, and the UK legal position — which is where most confusion lives. It sits under the solar inverters hub.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
How a grid-tie inverter works
The inverter continuously measures the grid's voltage and frequency and shapes its output to match, feeding power into your home's wiring in parallel with the mains. Appliances simply draw from whichever source is available — solar first, grid for the rest. If the grid disappears, the inverter must disconnect within a fraction of a second (anti-islanding), which is why grid-tie systems go dark in a power cut unless paired with a battery that has a backup mode.
String, micro and hybrid
Plug-in solar uses microinverters because they output socket-ready AC at the panel. Hybrid units matter if storage is part of the plan — see solar battery storage. The comparison detail is in microinverter vs string inverter.
| Type | Where it sits | Typical use |
|---|---|---|
| String inverter | One central unit for a chain of panels | Rooftop arrays |
| Microinverter | One small unit per panel (or pair) | Plug-in systems and panel-level rooftop |
| Hybrid inverter | Central unit that also manages a battery | Solar-plus-storage installations |
Are grid-tie inverters legal in the UK?
The hardware itself is widely sold and legal to own — the legal question is about connection and use. Fixed installations must use equipment meeting the network requirements (Engineering Recommendations G98/G99, with type-tested equipment registered through the ENA) and be notified to your DNO. Connecting a grid-tie inverter through a plug and socket is the specific thing that is not yet legal in the UK — the Government consultation on permitting it closed on 30 June 2026 and the response is awaited. Wiring an inverter into a home's fixed installation is work for a qualified, registered electrician.
Safety and compliance
Frequently asked questions
- What does a grid-tie inverter do?
- It converts solar DC into AC that is synchronised with the mains — matching grid voltage and frequency — so your home uses solar power first and grid power for the remainder. It also disconnects automatically if the grid fails.
- Are grid-tie inverters legal in the UK?
- The equipment is legal to buy and own. Fixed, professionally installed and DNO-notified connections are the established route. What is not yet legal is plug-and-socket connection — the plug-in solar question the Government consulted on in June 2026, with a response awaited.
- Does grid-tie solar work in a power cut?
- No — anti-islanding protection shuts the inverter down when the grid fails, to protect engineers working on the network. Backup during outages needs a battery system with a dedicated backup function.
Sources
- 1. Engineering Recommendations G98/G99 (connecting generation) — Energy Networks Association
- 2. BS 7671 Requirements for Electrical Installations (IET Wiring Regulations) — Institution of Engineering and Technology
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