How to check a plug-in solar kit is actually legal in the UK

From 27 August 2026, plug-in solar became legal to self-install in Great Britain. You can buy a kit, hang it on a balcony railing or stand it in the garden, plug it into an ordinary three-pin socket, and start offsetting your daytime electricity. No electrician, no roof work, no scaffolding.

What did not change is that most of the kits currently on sale to UK buyers still cannot lawfully be connected this way.

The listings look identical. Same panels, same micro-inverters, often the same factory. The difference is a certification most sellers have not obtained and many do not know exists. If you buy the wrong one you are left with a choice between paying an electrician several hundred pounds to hardwire it, or owning an expensive sheet of glass you cannot legally use.

This is how to tell the difference before you spend the money.

The one question that settles it

Ask the seller this, in writing:

Is this exact model certified as a complete kit to the DESNZ Plug-in Solar Device Interim Product Specification, and what is its entry on the ENA register?

A seller with a compliant product will give you a reference. A seller without one will change the subject, send you a CE certificate for the inverter, or tell you it is "fully certified" without saying to what.

That vagueness is the answer. Certification of this kind produces a specific register entry for a specific model. If nobody can name it, it does not exist.

You do not have to take their word for it either. The Energy Networks Association maintains the register of approved equipment, and you can look up the model yourself before you buy.

Four things that sound like certification and are not

A CE mark

CE marking shows a product meets EU requirements. It is genuinely meaningful, and it is not the same as UK plug-in approval. A kit built for the German market carries a CE mark and is completely legal there. That tells you nothing about whether it can be plugged into a British socket.

A UKCA mark on the inverter

This is the one that catches people, because it is so nearly right. The UK specification applies to the complete kit — panels, inverter, cabling, mounting hardware and the fitted plug, assessed together as one product. A UKCA-marked inverter inside an otherwise unassessed kit does not make the kit compliant. Components are not the same as the assembled thing.

A European kit with a UK plug fitted

Swapping a Schuko plug for a British one is a five-minute job and changes nothing about the product's legal status here. If anything it is a warning sign, because it suggests someone has thought about the plug and not about the specification.

"800W" printed on the box

The UK limit is 800VA of inverter output, not panel capacity. Those are different numbers and the difference is deliberate: you are allowed considerably more panel than that, up to around 2,000W, provided the inverter caps what actually reaches your home at 800VA. So a kit advertised as 1,600W might be entirely compliant, or might not be, and the headline figure does not tell you which.

The other rules worth knowing before you buy

Even a properly certified kit comes with conditions. These trip up more people than the certification itself.

One device per household

You cannot buy two 800VA kits and run them both. The limit applies to the property, not the purchase. If you want more generation than that, you are into a conventional installation with an electrician and a full application to your network operator — a different product at a different price.

No batteries

Battery systems are excluded from the plug-in category at the definition level. A product that charges from the socket and discharges later is not a plug-in microgenerator under these rules, whatever the listing says. Some well-known brands are still selling exactly that. Read carefully.

No extension leads

The plug must be factory-fitted and it must go into a socket directly. No extension leads, no adaptors, no multi-way blocks.

Some buildings are excluded outright

The specification rules out buildings with ACM, MCM, HPL or timber cladding, timber balconies, and any building currently undergoing external wall fire remediation. If you live in a block affected by cladding works, the answer is no for now regardless of what you buy. Your building manager will know the status.

Northern Ireland is not covered

Regulation 3 of SI 2026/848 extends to England, Wales and Scotland only. At a Northern Ireland address a solar system still needs a conventional installation by a registered electrician. Any retailer selling you a plug-in kit as socket-ready for a BT postcode is describing it incorrectly.

You still have to tell your network operator

This surprises people who have understood everything else. Not needing an electrician does not mean not needing to notify anyone.

G98 notification goes to your distribution network operator — the company that owns the wires in your street, not the company that bills you. It is free, it is a short online form, and it should be done before you connect.

Which operator is yours depends on your postcode. Great Britain is divided between six operators across fourteen licence areas, and the boundaries do not follow the map in the way you would expect. Liverpool is not on the same operator as Manchester. Aberdeen is not on the same one as Glasgow. Your electricity bill names yours, or you can check your postcode here.

If you already have rooftop solar, note that the threshold is counted across the whole property. Adding a plug-in kit on top of an existing array can push you over and into a formal application that takes weeks rather than minutes.

A checklist you can take to a listing

• Ask for the ENA register entry for the exact model. No reference, no sale.
• Check the inverter output is 800VA or less. Panel wattage can be higher.
• Check there is no battery in the kit.
• Check the plug is factory-fitted and the instructions do not mention extension leads.
• Check your building is not excluded on cladding grounds.
• Check your address is in England, Wales or Scotland.
• Find out which network operator covers your postcode, and notify them before connecting.

Why the cheap listings are cheap

It is worth being fair about this. Most sellers offering uncertified kits are not running a scam. They are importing a product that is entirely legal and widely used across Europe, and either have not registered that Britain has taken a different route, or are hoping nobody asks.

The result is the same for you either way. You end up with hardware you cannot use as advertised, and a return process for a 21kg sheet of glass that you will not enjoy.

Certification costs money and takes time, which is why certified kits are not the cheapest listings on the page. If a price looks notably better than everything else, the certification is usually what is missing.

If you have already bought one

Do not plug it in and hope. Two options.

Return it, if you are inside the seller's returns window. If it was described as suitable for plug-in use in Great Britain and it is not certified, you have a strong case that it was misdescribed, regardless of the stated returns policy.

Or have it hardwired by a registered electrician as a conventional micro-generation installation. This is legitimate and it works. It also costs several hundred pounds and requires a full application to your network operator, which usually erases whatever you saved by buying the cheaper kit.

The short version

One question, asked in writing, before you pay: what is the ENA register entry for this exact model?

Everything else in this article is detail. If a seller can answer that, you are almost certainly fine. If they cannot, nothing else they tell you matters.