Plug-in solar in the UK: what the rules actually say

What the legislation itself says

The Plugs and Sockets etc. (Safety) Regulations 1994 and Electricity Safety, Quality and Continuity Regulations 2002 (Amendment) Regulations 2026 (SI 2026/848) was made on 16 July 2026, laid before Parliament on 17 July 2026, and came into force on 27 August 2026.

It contains one number that matters to a buyer. A plug-in microgenerator is defined as one that “has a maximum rated alternating current output not exceeding 800 watts” (regulations 2(3) and 3(2)).

Everything else about the product is not in the instrument. It is in the Plug-in Solar Device Interim Product Specification, which the instrument names and therefore incorporates.

What the product specification requires

From version 2.0 of the specification, July 2026 — the government's own page marks an earlier version “[Withdrawn]”, so check you are reading the current one:

• “maximum apparent power not exceeding 800 VA”, at “up to 253 V (AC)” and 50 Hz (Scope, §1)
• “maximum current does not exceed 3.5 A” (§4.1)
• “the maximum permissible sum of PV module DC power output … is 2000 W” (§4.1) — the panel side may be larger than the 800 VA the inverter is allowed to deliver
• “No more than two PV modules shall be connected in series”, with open-circuit voltage at the inverter inputs not exceeding 120 V DC (§4.2.2)
• The inverter “shall automatically disconnect from the mains supply within 100 ms”, and the voltage at accessible plug pins must fall “below 34 V within 100 ms” (§6.2.3.3.3)

Why a European balcony kit is not automatically legal here

This is the part that is easy to get wrong if you have been reading German Balkonkraftwerk pages, and it is a hardware difference, not a paperwork one.

The specification requires the device to be connected “solely by the manufacturer-supplied standard plug” (Scope, §1), and that plug must be “designed to BS 1363-1”, must “incorporate partially insulated pins to prevent access to live conductive parts”, and must be a “non-rewireable moulded plug fitted with a BS 1362 fuse not exceeding 5A” (§6.2.3.2). A German kit ships with a Schuko or Wieland connector and does not meet this.

There is also a registration requirement on the manufacturer, and it gives you a check you can actually perform: manufacturers “shall register devices on the ENA Type Test Register (ENA Direct Connect platform) and obtain confirmation that the device has been assessed and identified as compliant prior to placing them on the market” (§7). If a product is not on that register, its compliance is not something a seller's description can establish for you.

One device per household — and where that rule actually comes from

Several pages currently state that the statutory instrument limits you to one device. It does not. The specification says “Only one plug-in solar product shall be used per household final ring circuit” (Scope, §1), and explains where the limit originates: network requirements, specifically “Engineering Recommendation G98 Issue 2 Amendment 1 2026”, which “restrict this to one device per household”.

The distinction is not pedantry. A rule that lives in an engineering recommendation can be revised by the body that publishes it, on a different timetable from the legislation — so “the law says one” and “the current network rules say one” will not necessarily stay the same statement.

Notifying your distribution network operator is separately mandatory; the specification requires manufacturers to tell you so, and to say how (§8.2.3.1).

Planning permission, and a trap for balconies specifically

The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026 (SI 2026/896) was made on 29 July 2026 and came into force on the same day as the safety regulations. It brings plug-in solar into permitted development — with an exclusion that matters if you are reading this because you have a balcony.

Permitted development does not apply “in the case of plug-in solar, where any part of the plug-in solar would be installed on a wooden wall, balcony or enclosure” (article 3), nor on “a wooden fence, gate, wall or other means of enclosure” (article 4). A timber balcony is a common thing to want to hang panels on, and it is precisely the case the Order carves out.

Note the territory. This Order “extends to England and Wales” and amends the England permitted development order; the safety regulations are the Great Britain instrument. “The UK” is doing a lot of work in most articles on this subject — Scotland and Northern Ireland have their own planning regimes, and this page does not cover them.

Whether anyone pays you for what you export

Almost every page on this subject assumes a plug-in system earns export payments the way a roof installation does. The legislation does not support that assumption. SI 2026/848 does not mention the Smart Export Guarantee, MCS certification, export payments, export metering or feed-in tariffs anywhere in its text. It changed what you may plug in, not what a supplier owes you for it.

The answer sits in the Smart Export Guarantee instead, and it is a discretion rather than a prohibition. Ofgem’s guidance to SEG licensees describes how an applicant shows an installation qualifies — “This may be a Microgeneration Certification Scheme (MCS) certificate, but the SEG recognises other schemes may be equivalent to MCS” — and then states what follows without one: “If a generator is unable to demonstrate that their installation is suitably certified, a SEG licensee is not obliged to offer payments under the SEG, but they can make payments if they wish.”

A second condition does not depend on a supplier’s goodwill at all. The same guidance requires that the meter “must have an associated export MPAN and be registered under the Balancing and Settlement Code, regardless of capacity”. A device you plugged into your own socket has neither an installation certificate nor an export MPAN, and nothing in the August regulations created a route to either.

So the accurate statement is narrower than “you get nothing”, and more useful than it: nothing entitles you to be paid for what you export, and no supplier is obliged to pay you for it. Suppliers set their own position here, so if it matters to your arithmetic, ask yours rather than assuming a figure.

This is also what decides which calculation is the right one. If the surplus you send back is worth nothing to you, the only units worth anything are the ones your household uses in the hour they are generated. For a device capped at 800 W that share is not a detail at the edge of the answer — it is the answer, and it turns on when somebody is at home rather than on which kit was bought.

What this page deliberately does not tell you

It names no product, quotes no price and estimates no saving. stromFit's calculators model a household hour by hour against a verified catalogue of systems, and both the catalogue and the load model are German. Producing a British payback figure from them would mean presenting a German answer in pounds.

If you want to see the method in the meantime, the payback calculator and the methodology are both in English — they are about the German market, and they say so.

The two questions this page hands off

This page is about what the rules say. Two questions follow straight from it, and each has its own page because each moves on its own clock: the rules change when Parliament changes them, the register changes weekly, and prices change whenever a shop decides.

• Which devices are actually registered — the specification requires registration before a device is placed on the market, so the register, not a seller's description, is the thing to check. It also shows how few entries carry the separate Northern Ireland type test.
• What a compliant kit costs — every price we could read on a manufacturer or official seller page, with the panel capacity beside it, and why the number in a kit's name is not its output.

Sources

Every quotation above was read in the primary document, not taken from another article. The instruments and the specification were read on 30 August 2026; where a source was read on a different day, that day is the one shown against it.

• SI 2026/848 — The Plugs and Sockets etc. (Safety) Regulations 1994 and Electricity Safety, Quality and Continuity Regulations 2002 (Amendment) Regulations 2026 — read 10 September 2026. Re-read 2026-09-10 to confirm scope: it amends only SI 1994/1768 and SI 2002/2665, revokes nothing, and contains no mention of the Smart Export Guarantee, MCS, export payments, export metering or feed-in tariffs.
• SI 2026/896 — The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026 — read 30 August 2026. Extends to England and Wales; amends the England permitted development order.
• GOV.UK — Plug-in solar: regulatory amendment and interim product specification — read 30 August 2026. Landing page rather than a direct PDF link on purpose: it names the current Interim Product Specification and marks the superseded one [Withdrawn]. A deep link would go stale silently at the next revision. Version read: 2.0, July 2026.
• Ofgem — Guidance for SEG Licensees (December 2019) — read 10 September 2026. Source of the two quotations about certification and about the export MPAN. Ofgem's consumer-facing SEG pages state the technology list and the capacity ceiling but not the certification condition, which is why this document is cited rather than those.
• Ofgem — Smart Export Guarantee (SEG): Generators — read 10 September 2026. Read to confirm a deliberate absence: the generator-facing eligibility page names the five technologies and the capacity limit and says nothing at all about self-installed systems. The condition is in the licence guidance above, not here.
• Households can save as plug-in solar panels come to market — DESNZ press release — read 11 September 2026. The single figure nearly every downstream article repeats. Recorded as DATA rather than typed into a page because it is somebody else's claim and must stay attached to the document it came from. The release states the saving as an upper bound and gives no household, orientation, kit size or tariff behind it, which is the whole reason /en/guides/uk-plug-in-solar-savings/ exists: an upper bound with no conditions attached cannot be checked, and the model says it is both too high and too low depending on the house.

This is a summary of published rules, not legal advice, and it is accurate as of the date above rather than as of the date you are reading it.