What changed in April 2026
On 1 April 2026, Amendment 4 of BS 7671 (the IET Wiring Regulations) came into force, formally recognising plug-in microgeneration as a category of installation. For systems up to 800W AC output, this means:
- A standard BS 1363 plug-and-socket connection to the home circuit is permitted.
- The inverter must comply with BS EN 50549-1, including anti-islanding protection.
- The DNO must be notified via the ENA G98 form before commissioning.
- No MCS-certified installer is required.
This brings the UK into line with Germany, Spain, the Netherlands, and most of the EU — countries where plug-in "Balkonkraftwerk" systems have been mainstream for over five years.
The 800W rule
The 800W limit applies to AC output at the inverter — not panel capacity. You can wire panels totalling up to 1,080W of nameplate DC capacity into an 800W inverter; the inverter caps the export at 800W. This "over-paneling" makes more sense than it sounds because panels rarely hit nameplate output in UK conditions.
Anything above 800W AC moves you into the territory of standard rooftop solar, which requires an MCS installer, structural assessment, and a G99 notification rather than G98.
The G98 notification
G98 is the Energy Networks Association's notification standard for "type-tested" small-scale generators. It tells your local Distribution Network Operator that there's now a generator connected at your address so they can keep accurate records of grid loading.
The G98 form is free to file. It must be submitted within 28 days of commissioning the system. You can file it yourself — or you can pay us £49 to handle it. We file it for every kit we sell at no extra cost.
Six DNOs cover the UK: UK Power Networks (London, East and South East), SSEN (Scotland and Southern), Northern Powergrid, Electricity North West, SP Energy Networks, and National Grid Electricity Distribution (formerly WPD). The form is the same; we handle whichever DNO covers your address.
Renters' Rights Act 2025
For the first time, tenants in England and Wales have a statutory right to make non-permanent energy efficiency improvements to their homes without requiring landlord consent. Plug-in solar — non-permanent, no drilling, clamp-mounted, fully portable — falls squarely within scope.
Landlords can still object on specific reasonable grounds (structural risk, lease covenants on listed buildings, etc.) but blanket "no solar" policies are no longer enforceable. We recommend telling your landlord as a courtesy, not because consent is legally required.
Planning permission
For the vast majority of properties, plug-in solar is treated as a moveable appliance and falls outside the planning system entirely. Exceptions:
- Listed buildings: any external modification needs listed building consent, even if the kit is non-permanent.
- Conservation areas: Article 4 directions in some areas restrict externally visible installations.
- Leasehold flats: your lease may have terms covering "external appearance" — check before installing on a visible balcony.
The Smart Export Guarantee (SEG)
The SEG pays you for electricity you export to the grid. It's open to anyone with a generator under 5MW, but the practical requirement of an MCS-certified install rules out almost all plug-in systems. This is the one regulatory gap that hasn't been closed.
In practice this doesn't matter much. Plug-in solar economics rely on offsetting electricity you would otherwise buy, not on selling exports. At a typical 60% self-consumption rate and a 28p tariff, the unpaid exports are worth maybe £15-£25 a year — not enough to chase MCS certification for.
Product safety standards
The British Standards Institution is expected to publish a dedicated plug-in solar product standard in July 2026 (provisional designation BS 9999-PIM). This page will be updated when it's published. In the meantime, the relevant standards are:
- BS 7671:2018+A4:2026 — wiring regulations covering the installation.
- BS EN 50549-1:2019 — generator interface to the LV distribution network (anti-islanding, etc.).
- BS EN IEC 62109-1/-2 — inverter electrical safety.
- BS EN IEC 61730-1/-2 — solar panel safety qualification.
All inverters and panels we ship are certified to the above. Our Hoymiles HMS-800W-2T includes UK type-test approval covered by the G98 type-tested register.
What we recommend
Don't let regulatory uncertainty be the reason you don't buy. The framework is settled, the standards are clear, and there's a healthy market — Germany passed 4 million Balkonkraftwerk installations in 2025. The UK is starting from zero in 2026; we'd rather you started with us, but the most important thing is that you start.
Run the savings calculator to see what an 800W kit would do at your tariff, or browse the kits.