BS 7671 Amendment 4 and plug-in solar

What is BS 7671?

BS 7671, the IET Wiring Regulations, is the UK standard for electrical installations. In the IET’s words, it “sets out how electrical installations should be designed, built and verified. These regulations do not determine what consumers may plug in”.

Electricians work to it. Householders mostly meet it through an electrician’s certificate or an electrical installation condition report.

According to BSI, the current edition, BS 7671:2018+A4:2026, was published on 15 April 2026. The previous version, BS 7671:2018+A2:2022+A3:2024, is withdrawn on 15 October 2026.

How was plug-in solar actually legalised?

Before the change there were two obstacles, as the Explanatory Memorandum explains:

ESQCR regulation 22(1) required a generator connected to a home installation to comply with “British Standard requirements”, “which refers to BS 7671”.
BS 1363, the plug standard, prohibits using plugs to connect generators. The IET position paper quotes BS 1363-1: “plugs shall not be used for the connection of electrical power generators to socket-outlets”.

SI 2026/848 dealt with both:

It rewrote ESQCR reg 22(1)(c). A generator in a home installation must comply with British Standard requirements, or, if it’s a plug-in microgenerator, with the Plug-in Solar Device Interim Product Specification.
It amended the Plugs and Sockets etc. (Safety) Regulations 1994. A plug for a plug-in microgenerator can now be approved if it meets BS 1363 apart from the generator prohibition and complies with the specification.

The DESNZ Impact Assessment calls this “a narrow exemption/clarification from aspects of BS 7671 compliance”. So the legal test for the kit is the specification, not BS 7671.

Does BS 7671 still matter for plug-in solar?

Yes, for your home’s wiring:

The specification cites it. The Interim Product Specification lists BS 7671:2018+A4:2026 as a document to be read in conjunction with it.
Your installation still has to conform. Ofgem notes that G98’s plug-in exemptions do “not remove any requirements for Customer’s Installations … to conform with BS 7671”.
Protective devices. The IET position paper says 2024 amendments added requirements for bidirectional protective devices. That’s relevant to the RCD advice in sockets and wiring.

Circuit changes are electrician work

If connecting a kit means changing the final circuit, for example replacing its overcurrent protective device “in accordance with BS 7671 Section 551.7.2”, the specification says that must be flagged as work for a qualified electrician only.

What does the specification say about sockets and circuits?

The practical socket, circuit and RCD rules are in the Interim Product Specification, not BS 7671:

plug straight into a fixed BS 1363-2 socket, with no extension leads or adaptors;
use socket circuits only, not lighting circuits or spurs to fixed equipment;
no separate circuit is needed;
check for modern residual current protection (RCBO), and get an electrician if you have older fuses;
consider a professional assessment if your kit has more than 960W of panels.

Full detail: does plug-in solar need a dedicated circuit?

What can we confirm about Amendment 4?

Claim	Status
A4 published 15 Apr 2026; previous version withdrawn 15 Oct 2026	Confirmed by BSI
Plug-in solar legalised by the ESQCR amendment in SI 2026/848	Confirmed (SI 2026/848)
The specification is read in conjunction with BS 7671+A4	Confirmed (IPS)
A4 contains plug-in-specific clauses	Not confirmed

What we couldn't confirm

BS 7671 is a paid standard. We haven’t found a primary source setting out what, if anything, Amendment 4 says specifically about plug-in solar: socket type, dedicated circuits or RCD type. You may see claims that A4 “opened up” plug-in solar, or that a BS 7671 regulation still bars connecting a generator through a socket. We don’t repeat either, because we can’t verify them.

Will the rules change?

The specification is interim. The Explanatory Memorandum says a “full revision of the underlying British Standards is planned … within around 2-3 years”. Until then, the specification is the rulebook for the kit.

What to do next

Read sockets and wiring for the full socket and circuit rules. To check a panel, inverter and plug combination against the plug-in rules, use the compatibility checker.