The UK's Plug-In Solar Standard Has Arrived: What the New Product Specification Says

What Was Published

On 23 June 2026, the Department for Energy Security and Net Zero (DESNZ) published the Plug-in Solar Device Interim Product Specification, Version 1.0 — the technical and safety requirements that a plug-in solar device must meet to be sold and used legally in the UK. It is published as part of an open consultation, so some details may change before the final version — but it is the clearest picture yet of the rules balcony solar will operate under.

This is the follow-through on the March 2026 government commitment to legalise plug-in solar. Where that announcement was a statement of intent, this document is the technical substance: actual numbers, actual standards, and an actual route to market.

The Power Limits: 800VA, 3.5A, and 2,000W of Panels

The specification sets hard limits on what counts as a “plug-in solar device” you can install yourself:

• Maximum 800VA apparent power output. The inverter may feed no more than 800VA into the home — the same threshold used across the EU. This is measured as the highest 10-minute average.
• Maximum 3.5A current. The current at the point of connection must not exceed 3.5A, even when mains voltage drops.
• Up to 2,000W of solar panels. You can connect panels totalling up to 2,000W of DC capacity (the inverter clips output to 800VA). Above 960W of panels, DESNZ recommends a professional assessment of your wiring first.
• One device per household. Only a single plug-in solar device is permitted per household, to keep currents within safe limits. Note: the consultation is considering changing this to “one per circuit,” which would allow more than one device in larger homes.
• 120V DC ceiling at the inverter. Panels must be configured so the open-circuit voltage at the inverter input never exceeds 120V DC.

The Big One: A Proper UK Plug, At Last

For years, the single most-cited frustration with balcony solar in the UK was that imported kits shipped with a European Schuko plug, forcing buyers to use an adapter — including on premium products like the EcoFlow STREAM. The new specification resolves this directly. It permits a plug designed to BS 1363-1 — the standard UK three-pin plug — provided it:

• uses a non-rewireable moulded plug fitted with a BS 1362 fuse not exceeding 5A;
• has partially insulated pins, so live parts can't be touched; and
• connects to a normal BS 1363-2 socket — no special outlet required.

Crucially, the inverter must make those plug pins safe the instant the plug is pulled. The spec requires the device to disconnect within 100 milliseconds of losing mains, with the voltage on accessible pins dropping below 34V in the same 100ms, and internal capacitors discharging to a safe level within one second. This is the anti-islanding and shock-protection engineering that makes a fused UK plug acceptable.

Why the Safety Argument Is Now Settled

The UK's long-standing hesitation rested on a genuine engineering question — how a small AC generator behaves on a British 32A ring circuit, and whether older residual current devices would always operate correctly. The specification addresses this head-on. DESNZ commissioned a dedicated study, “Plug-in PV Systems in the United Kingdom: Electrical Safety, Compatibility and Implementation Considerations,” which concluded that plug-in solar products already in use in Germany and elsewhere are safe on UK circuits under defined limits and conditions. The specification then sets out exactly what those limits and conditions are.

Technically, the document leans heavily on the German standard DIN VDE V 0126-95 (the 2025 plug-in solar safety standard), adapted for the UK, and requires compliance with BS 7671:2018+A4:2026 (the latest IET Wiring Regulations), BS EN 62109 (inverter safety) and BS EN 62116 (islanding-prevention testing). Devices must also not impair the operation of upstream RCDs.

How a Device Gets Approved: G98 and the ENA Register

On the grid-connection side, the specification ties everything to Engineering Recommendation G98 Issue 2 Amendment 1 (2026). Manufacturers must have their devices fully type-tested to G98 and register them on the ENA Type Test Register (the ENA Connect Direct platform) before putting them on sale. For buyers, that eventually means a simple test: is the product on the ENA register? DNO notification of connection and disconnection remains mandatory, and every compliant device must carry a label and a QR code pointing you to the registration process. Our G98 notification guide explains how that works today.

The Installation Rules You'll Need to Follow

The specification is notably detailed about safe installation — reflecting that these are designed to be fitted by “ordinary persons.” The key practical rules:

• Socket circuits only. A device may only be plugged into a normal socket circuit — never a lighting circuit, nor a spur feeding fixed equipment like a cooker or boiler.
• No extension leads or multi-way adaptors. The device must plug directly into a wall socket. Extension cables, travel adaptors and multi-way adaptors are all prohibited.
• A modern consumer unit. Your installation should have modern residual current protection (RCBO or RCD). Homes still on older wired-fuse boards should have them checked and likely upgraded by an electrician first.
• Reversible, non-permanent mounting.Fixings must be reversible and must not compromise the building's structure, fire performance or weatherproofing. Manufacturers must supply a structural analysis covering UK wind and snow loads.
• Fire and flats. Panels must not be mounted on a wall forming a boundary between dwellings, must not block escape routes, and must not compromise fire compartmentation under Approved Document B — an important constraint for flat balconies.

What Happens Next

This is an interim specification published for consultation. Several points carry explicit notes that they may change — most notably the “one device per household” rule, which could become “one per circuit.” DESNZ is also still testing whether installations protected by MCBs with upstream RCD protection (rather than per-circuit RCBOs) can be accepted. The consultation feeds into a final specification, and the broader British Standards Institution (BSI) work we covered in March continues alongside it. The direction, though, is now unmistakable: the UK has moved from “grey area” to a written technical standard in a matter of months.

Source: Department for Energy Security and Net Zero, Plug-in Solar Device Interim Product Specification, Version 1.0 (June 2026), published via gov.uk/government/consultations/plug-in-solar. © Crown copyright 2026, Open Government Licence v3.0.

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