Plug-in solar legalised in the UK: 800W limit, rules explained

Plug-in solar, the kind you mount on a balcony and plug straight into a 13A socket, is now legal in the UK. The Department for Energy Security and Net Zero announced the change on 24 March 2026, and BS 7671 Amendment 4 came into force on 15 April 2026. Maximum output is capped at 800W per home. For renters and flat owners, this is the first time small-scale solar has been a legitimate option in the UK.

What’s legal now

Until last month, plug-in solar sat in a regulatory grey area. BS 7671, the UK wiring regulations, treated any source of generation behind the consumer unit as a fixed installation, ruling out consumer kits that plug into a standard socket. Amendment 4 carves out a new category for certified plug-in solar up to 800W peak. The kit sits on a balcony rail, a flat roof, or a freestanding ground frame, and the microinverter plugs into a normal 13A outlet.

Two conditions still apply. You have to notify your Distribution Network Operator (DNO) under the G98 process before connection, a quick online form rather than an approval gate. And the British Standards Institution is still finalising a dedicated product safety standard, expected around July 2026. Until then, the safest route is a CPS-registered electrician fitting a kit with CE and UKCA marking. Sunflower Solar has a useful technical breakdown of the 2026 regulations for the full standards detail.

How it works in practice

A typical UK plug-in kit is one or two panels of around 400W each, a microinverter wired between the panels and the cable, and a standard 13A plug. The microinverter converts DC to AC and synchronises with mains, so when sun is on the panels your home draws less from the grid.

Output depends entirely on where the panels sit. A south-facing balcony at the right pitch can deliver 250-400 kWh per panel per year. A north-facing wall or heavily shaded balcony might manage half that. Two panels in a good spot offset roughly 500-800 kWh a year, enough for most of a flat’s base load but nowhere near whole-home consumption.

Who plug-in solar actually suits

This rule change matters most to people who couldn’t install solar at all before:

• Renters in flats or houses, where the landlord owns the roof.
• Leaseholders in blocks where roof access is communal property.
• Owners with shaded, north-facing, or structurally unsuitable roofs.

DESNZ paired the legalisation with a £25m pilot announced on 21 April 2026 to put plug-in kits into low-income households, which signals who the policy is aimed at. Germany, where plug-in has been legal for years, registered over 1.1 million installs by mid-2025.

Plug-in vs rooftop solar

The numbers diverge sharply once you compare a plug-in kit to a full rooftop install. Both are useful. They serve different homes.

For more on sizing a full system, see our guide on how many solar panels you need. If you’re weighing storage on top of generation, is battery storage worth it covers the maths.

What to know before buying

A few things worth checking before you order a kit:

• Tenancy and freeholder consent. Balcony installs can fall foul of lease clauses about external alterations. Ask in writing.
• Socket and wiring. Use a dedicated 13A socket on its own circuit, not an extension lead.
• Product certification. Until the BSI standard lands, look for CE/UKCA marking and G98 type-test compliance on the microinverter.
• Realistic expectations. Roughly £150-£250 of grid electricity offset a year. A real saving, not a whole-home solution.

Plug-in solar is a genuine win for the people it was designed for: households that couldn’t get solar before. For everyone else, it’s a complement, not a replacement. If you own your home and have a viable roof, rooftop generates several times more energy, qualifies for the Smart Export Guarantee, and pays back faster. See the full solar and battery storage hub for what a rooftop install involves, or the UK energy grants 2026 guide for what’s currently available alongside it.

Last updated: 12 May 2026