Wiring Regulations UK 2026 (BS 7671 A4 Explained)

Electricians mention the wiring regulations on every job, on every certificate, and in the reasoning behind why something needs to be done a particular way. This guide walks through what BS 7671 is, how it relates to UK law, what the 18th Edition and its amendments mean, and what changed when A4:2026 came into force on 15 April 2026.

The short version

The wiring regulations are a British Standard, BS 7671, that sets out the requirements for the design, installation, inspection and testing of electrical systems in the UK. The current text is BS 7671:2018+A4:2026, the 18th Edition with its 4th amendment. Think of it as the technical rule book electricians work to. It does not tell you whether to install a circuit, it tells you how that circuit has to be designed and installed to be considered safe ^[1].

The text is produced by the IET in conjunction with the British Standards Institution. The IET has been publishing rules for electrical installation since 1882, when the first edition was called the Rules and Regulations for the Prevention of Fire Risks Arising from Electric Lighting. It has been through 18 major editions since.

Amendment timeline

The current edition was first published in 2018 and has been updated four times. Each amendment adds or changes specific clauses without producing a new edition. Here is how the recent history looks:

1. 200817th Edition published. Introduced mandatory RCD protection for socket outlets and cables concealed in walls.
2. 201818th Edition published. Overhaul of protection against overvoltage and fault currents, tightened earthing requirements, initial text on EV charging.
3. 2020A1 (1st amendment). Minor clarifications.
4. 2022A2 (2nd amendment). Non-combustible consumer units in domestic premises became a firmer expectation, Type 2 surge protection guidance tightened, initial AFDD recommendations introduced.
5. 2024A3 (3rd amendment). Further EV charger clauses, electric and arc protection updates.
6. 15 April 2026A4 (4th amendment) comes into force. Current text: BS 7671:2018+A4:2026.

What changed in A4:2026

A4:2026 is not a rewrite. It is a targeted set of updates to specific clauses in the 18th Edition. The four headline changes most homeowners and landlords should know about:

• AFDD requirements extended. Arc Fault Detection Devices are now required on final circuits supplying socket outlets rated up to 32 A in specific higher-risk premises, including Houses in Multiple Occupation (HMOs), purpose-built student accommodation, and care homes. Recommended, not mandatory, in other domestic premises.
• Type 2 surge protection as the default. Where a SPD would previously have been specified after a risk assessment, A4:2026 expects a Type 2 SPD at the origin of most new domestic installations unless the assessment specifically rules one out.
• EV charger circuits clarified. The residual current protection requirement is confirmed: either a Type B RCD on the dedicated circuit or an EV charger with built-in 6 mA DC protection. Installer credentials and DNO notification requirements have been reinforced.
• International alignment. Several sections have been reworded to bring UK text closer to the IEC 60364 international series, reducing divergence between UK and European practice.

Are the wiring regulations the law?

Not directly. This is the question I get asked most, and the honest answer is: not directly, but in practice they function like law.

BS 7671 itself is a British Standard, a technical specification and not legislation. You cannot be prosecuted for a breach of a specific regulation number in BS 7671 on its own.

However, two pieces of UK law govern electrical work and both point at BS 7671:

• The Building Regulations 2010, Approved Document P covers electrical safety in dwellings. It requires that all electrical installations are designed and installed to protect persons, livestock and property, and it names compliance with BS 7671 as the recognised method ^[3].
• The Electricity at Work Regulations 1989 require that electrical systems at work are constructed, maintained and used to prevent danger. Compliance with BS 7671 is again the recognised method of satisfying this duty ^[4].

The practical effect is that BS 7671 defines what safe means in UK electrical installation. Deviating from it without a demonstrably equivalent alternative means you are in breach of the Building Regulations and the Electricity at Work Regulations at the same time. For most purposes, treat BS 7671 as law.

Who must comply

Every party involved in UK electrical work is expected to work to BS 7671:2018+A4:2026:

• Electricians designing, installing or testing an electrical installation in a domestic, commercial or industrial property.
• Inspectors carrying out an EICR assess the installation against the current edition of BS 7671, with any departures noted on the report.
• Competent Person Schemes (NICEIC, NAPIT, ECA, Stroma) audit their members against BS 7671 during annual assessments.
• Insurers, solicitors and surveyors reference BS 7671 when assessing risk on a property.
• Homeowners do not need to know the text of BS 7671, but should expect their electrician to work to it and to issue the certificates it requires.

Notifiable vs non-notifiable work

Under Part P, some electrical work is notifiable, which means it has to be approved through Building Control or self-certified through a Competent Person Scheme. The distinction matters because notifiable work produces paperwork that follows the property at sale ^[3].

The simple rule: if it is in a bathroom, adds a new circuit, or replaces the consumer unit, it is notifiable. Everything else is a case-by-case call.

The certificates you should receive

If you pay for electrical work, you should leave with one or more of the following. No certificate, no record the work was done to BS 7671:2018+A4:2026.

Penalties for non-compliance

Three consequences, in rough order of frequency:

• Insurance. A fire or electrical incident traced back to unregistered, non-compliant work can void a home insurance claim. This is by far the most common real-world penalty and the one most homeowners only find out about after the fact.
• Property sale friction. Missing Part P or EIC certification at conveyancing is the single most common reason a sale slows down on the electrical side. The buyer's solicitor either demands indemnity insurance or knocks the price down to cover the risk. See the selling your house electrics guide.
• Enforcement. Under the Building Regulations, a local authority can issue an enforcement notice requiring non-compliant work to be removed or made safe, and in rare cases take the owner to court. The power exists, the practice is selective.

How to verify your electrician is BS 7671:2018+A4:2026 compliant

1. Ask which competent person scheme they are registered withThe main UK schemes are NICEIC, NAPIT, ECA and Stroma. Ask for their registration number and check it on the scheme's public register.
2. Ask whether they hold a current 18th Edition qualificationThe qualification is City and Guilds 2382 or equivalent, and confirms they have been tested on the current BS 7671 text including A4:2026.
3. Ask whether the work is notifiable under Part PIf yes, ask whether they will self-certify via their scheme, or whether the work will go through Building Control. Self-certification is faster, simpler, and saves the local authority fee.
4. Ask which certificates you will receiveEIC, MEIWC, Part P compliance, EICR as appropriate. If the electrician is not sure what applies, walk away.
5. Ask for the Ze loop impedance reading at the intakeA reputable electrician takes this reading at the start of any notifiable job. No test, no certification. No certification, no record the work was done to BS 7671.

Why the regulations keep changing

Because the world keeps changing. When the first edition was published in 1882 there were no domestic appliances, no ring circuits, and no RCDs. Each amendment reflects three forces:

• New technologies. Heat pumps, EV chargers, solar PV inverters, battery storage, and smart controls all create electrical conditions earlier editions did not anticipate.
• Incident analysis. When fires or electrocutions happen and investigations identify a contributing factor, the regulations are updated to address it. AFDDs exist because arc faults were identified as a significant cause of domestic fires that RCDs and MCBs do not detect.
• International alignment. The UK broadly follows the IEC 60364 series. As those international standards evolve, BS 7671 follows.