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 - do not 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 ENA's own Type Test Register directly before buying, rather than a third-party tracker. Under the specification, a product must be type tested (including to G98) and confirmed compliant on the register before it goes on sale - and submitting a device to the register does not, on its own, show that it complies.

What a compliant kit must come with

The Interim Product Specification sets out what the product, its plug and its instructions must include. If a kit is missing any of these, check it against the register before you use it:

  • A QR codeLeading to your network operator's notification process, plus a statement that telling your network operator about connection and disconnection is mandatory
  • A moulded plug, correctly markedNon-rewireable BS 1363 plug with a BS 1362 fuse of no more than 5A, marked "one device per household circuit", with its rated current and a warning against extension leads and adaptors
  • A consumer unit labelA durable label to fix at or near your consumer unit
  • Wiring adviceHow to identify which sockets share a circuit, a prompt to check for modern RCBO protection and test it periodically, and advice to consider a professional check of your wiring if the kit has more than 960W of panels
  • Fitting rulesWhere the kit must not be fitted (certain cladding, timber balconies, buildings under remediation, walls shared with a neighbour) and a ban on fixings that rely only on cable ties, tape or straps - see Mounting
  • A battery warningA prominent warning that the kit is not intended to be used with a battery energy storage system - see Battery power

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 is 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 is no installer (you fit it yourself) and no export payment to protect: type testing against the Interim Product Specification and G98, with the model confirmed compliant on the ENA's Type Test Register before it goes on sale, and then your own notification with your network operator once it is fitted (see Registration). If you later upgrade to a full rooftop system, that is a different, MCS-governed process entirely - the two schemes do not 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 GB law currently continues to recognise alongside or instead of UKCA for most products (see GOV.UK: Using the UKCA marking). This is general product law, not part of the plug-in solar specification. 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". The current version is version 2, published 16 July 2026, and as of 29 October 2026 it has not been updated or replaced - the earlier consultation draft is marked withdrawn on GOV.UK. The law (SI 2026/848) refers to version 2 by name and date, so a future update would normally need the regulations to be amended too. DESNZ says work will begin on longer-term standards to succeed it, with no timeline yet. Always check GOV.UK for the current version rather than assuming this page's summary stays accurate indefinitely.

Sources

Rules last checked: 29 October 2026, against the Interim Product Specification v2 (16 July 2026), SI 2026/848 and Ofgem's G98 decision of 11 August 2026. The specification has not been updated or replaced since July 2026.