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Certification

"Legal to sell" and "actually compliant with the technical specification" are two different things - the market is brand new, and not every product a retailer lists will necessarily be on the official compliant list. This page explains how to check, and how the plug-in scheme's lighter-touch compliance route differs from full rooftop-solar MCS certification.

A plug-in solar kit MUST connect directly into a wall socket. Do not use extension leads, multi-way adaptors, travel adaptors or RCD adaptors - the Interim Product Specification requires a direct plug-to-socket connection. See Extension leads for why.

The ENA Type Test Register

Manufacturers submit their plug-in solar products for testing against the DESNZ Interim Product Specification, and compliant models are listed on the Energy Networks Association's Type Test Register. As of this page's last check, that register listed a mix of compliant and non-compliant devices submitted by manufacturers - don't assume a product is compliant just because a retailer markets it as "plug-in solar" or "balcony solar." Always check the specific model against the Plug-In Solar Register (an independent tracker of the live ENA register) before buying.

How this differs from MCS certification

The Microgeneration Certification Scheme (MCS) is the established UK quality standard for professionally installed renewable energy systems - full rooftop solar PV, heat pumps, and similar. It certifies both the product and the installer, and it's a hard requirement if you want to claim payments under the Smart Export Guarantee (SEG), and often a requirement from mortgage lenders and insurers for larger fixed installations.

Plug-in solar deliberately uses a lighter route instead, because there's no installer (you fit it yourself) and no export payment to protect: manufacturer self-declaration against the Interim Product Specification, a listing on the ENA's Type Test Register, and your own registration via myplugin.solar (see Registration). If you later upgrade to a full rooftop system, that's a different, MCS-governed process entirely - the two schemes don't overlap.

CE and UKCA marking

Separately from the solar-specific compliance route above, the inverter and panels should carry general product safety marking - UKCA (UK Conformity Assessed) for products placed on the market in Great Britain, and/or CE marking, which remains widely accepted in practice. These marks indicate the manufacturer's declaration against general electrical/electromagnetic safety standards, not the plug-in-solar-specific rules - you need both the general marking AND the Type Test Register listing, not one or the other.

What "Interim" means

DESNZ has deliberately badged its technical document the "Interim Product Specification" (currently v2.0, July 2026) while a longer-term, fuller British or European standard for this product category is developed. That means the detail can still change - always check GOV.UK for the current version rather than assuming this page's summary of it stays accurate indefinitely.

Sources