BS 7671 Amendments Explained: A2, A3, A4 and What Comes Next

BS 7671, the IET Wiring Regulations, sets the requirements for electrical installations in the UK. The 18th Edition was published in 2018, and since then it has been amended several times — most recently by Amendment 4, published in April 2026. Each amendment changes what new installation work must look like, what inspectors check during periodic inspections and how defects are recorded.

If you own or manage buildings, you do not need to know every regulation number. But you do need to understand the direction of travel, because it affects your EICR results, the specification of refurbishment and fit-out work, and your budgets. This guide explains each amendment in plain English, sets out the key dates and looks at what may come next.

BS 7671 in context: why amendments matter

BS 7671 is published jointly by the IET and BSI and maintained by a national committee, JPEL/64. It is not itself a statutory document, but it is woven into the legal framework. HSE’s guidance on the Electricity at Work Regulations 1989 recognises that installations meeting BS 7671 are likely to satisfy the relevant parts of those Regulations, and the Building Regulations guidance for electrical safety in dwellings (Approved Document P) relies on it. Insurers, landlords, lenders and fire risk assessors all treat it as the benchmark.

Because the underlying international and European standards are revised on their own cycles, BS 7671 is updated regularly. Small or targeted changes are made through amendments; a new edition is published when changes affect a large part of the document. Both matter to building owners, because they change the yardstick against which installations are designed, installed and inspected.

A timeline of the 18th Edition

Version	Published	Main focus
BS 7671:2018 (18th Edition)	July 2018, in force from 1 January 2019	Full new edition, including the first recommendations for arc fault detection devices
Amendment 1:2020	February 2020	Electric vehicle charging installations (Section 722)
Amendment 2:2022	28 March 2022, mandatory from 27 September 2022	Surge protection, AFDDs, RCDs, protected escape routes, prosumer installations (new Part 8), revised model forms
Amendment 3:2024	July 2024, for immediate use	Unidirectional and bidirectional protective devices
Amendment 4:2026	15 April 2026; previous version withdrawn 15 October 2026	Battery storage, PoE, functional earthing, medical locations, escape routes, major EICR form changes

Amendment 2 (2022): the big practical changes

Amendment 2 was the most significant change of the 18th Edition so far, and its effects still show up on EICRs today. The headline changes were:

• Surge protection (Section 443). Protection against transient overvoltages became required where the consequences of an overvoltage could affect human life, safety services, or cause significant financial or data loss — which covers most commercial installations. The old risk-assessment route was removed.
• Arc fault detection devices (Regulation 421.1.7). AFDDs became required for single-phase final circuits supplying socket-outlets up to 32 A in higher-risk residential buildings, houses in multiple occupation, purpose-built student accommodation and care homes, and recommended elsewhere.
• RCD protection (Regulation 411.3.3). The requirements for 30 mA additional protection of socket-outlets were redrafted and tightened, and Type AC RCDs were restricted to circuits where the load has no DC components — making Type A the practical minimum in most situations.
• Protected escape routes (Regulation 422.2). Limits were placed on what wiring and equipment may be installed in protected escape routes, with requirements for cable support that will not collapse in a fire.
• Prosumer installations (Part 8). A new part addressed installations that generate and store energy as well as use it.
• Testing changes, including how RCDs are tested and a 250 V insulation test after equipment is reconnected.

For facilities managers, the most visible consequences have been C3 recommendations on EICRs for surge protection and RCD upgrades, and increased cost and specification changes on refurbishment projects, particularly in residential and care settings.

Amendment 3 (2024): bidirectional protective devices

Amendment 3 was published in July 2024 and was intended for immediate implementation. It was much narrower than A2. Its main purpose was to address protective devices — circuit-breakers, RCDs and RCBOs — in installations where current can flow in either direction, which is increasingly common with solar PV, battery storage and other on-site generation.

A3 introduced definitions of unidirectional and bidirectional protective devices and a requirement (Regulation 530.3.201) for designers to consider which type is appropriate. Some devices are only designed to be fed from one direction; connecting them the wrong way, or using them where power can flow back from a generator or battery, can compromise their performance. If you are adding solar panels, battery storage or similar technologies, make sure your designer has considered this.

Amendment 4 (2026): what is new

Amendment 4 — the “orange book” — was published by the IET and BSI on 15 April 2026. It is still the 18th Edition, but it makes wide-ranging changes. Based on the IET’s announcement and NICEIC’s overview of Amendment 4, the most relevant for building owners are:

New technology brought into scope

• Stationary battery storage (new Chapter 57) — requirements for the selection, earthing, protection and isolation of secondary battery installations.
• Power over Ethernet (new Section 716) — extra-low-voltage DC power delivered over ICT cabling, increasingly used for lighting, access control and building systems.
• Functional earthing and bonding for ICT equipment (new Section 545), with pink introduced as the identification colour for functional earthing conductors.
• Protective neutral bonding (PNB), a variant of TN-C-S earthing, recognised for the first time.

Changes affecting fire and life safety

• AFDDs — the requirement now refers to high-rise residential buildings (over 18 m), alongside HMOs, purpose-built student accommodation and care homes, with AFDDs still recommended elsewhere for socket-outlet circuits up to 32 A.
• Protected escape routes — further restrictions on cables in fire-fighting shafts and protected stairways, and rewritten guidance in Appendix 13.
• Wiring systems in fire — clarification that wiring must not collapse in a way that hinders evacuation or firefighting.

Changes to inspection and reporting

• Revised EICR model form — Appendix 6 contains major changes to the EICR. NICEIC’s summary notes that C1 and C2 observations determine the overall outcome, while C3 and FI items do not on their own make the installation unsatisfactory.
• Photographs and thermographic images may now be attached to reports (Regulation 653.2), giving clearer evidence of defects.
• Section 710 (medical locations) has been substantially revised, which matters for GP surgeries, clinics and other healthcare premises.
• Energy efficiency (Chapter 81) is now informative only, and Appendix 17 has been removed.

Our guide to EICR codes C1, C2, C3 and FI explains how observations are classified in practice.

Key dates and the transition period

Amendment 4 could be used from publication on 15 April 2026. The previous version — BS 7671:2018 incorporating Amendments 2 and 3 — is withdrawn on 15 October 2026. From that date:

• new installation work should be designed, installed and certified to A4;
• periodic inspections and EICRs are carried out against A4, using the revised forms;
• certificates should state the version used, so that anyone reading them can see which requirements applied.

NICEIC advises that work designed before 15 October 2026 may still be completed to the previous version, but recommends that clients are told and that contracts, insurer requirements and licensing conditions are checked, since some may call for the latest standard. If you have a project that straddles the date, agree the basis of design in writing.

What it means for existing buildings

BS 7671 is not retrospective. An installation built to an earlier edition does not become illegal or dangerous overnight because a new amendment is published. However, every change does affect existing buildings in three ways:

1. Periodic inspections. Your next EICR will be carried out against the current version. Departures from it should be coded on the basis of the actual danger they present, not simply because the installation pre-dates a requirement — but you can expect more C3 recommendations as requirements move on.
2. Alterations and additions. Any new work — a new circuit, a fit-out, an EV charger, a battery system — must comply with the current version, and the existing installation must be adequate to support it.
3. Budgets and planning. Upgrades such as surge protection, RCD protection and AFDDs are best planned into capital or refurbishment programmes, rather than discovered piecemeal.

A good contractor will help you distinguish between what is genuinely urgent and what can be planned. Our commercial EICR guide covers how to turn a report into a prioritised action plan.

A practical checklist for building owners

• Check that your electrical contractor is working to BS 7671:2018+A4:2026 and is registered with a recognised scheme.
• Update specifications, tender templates and maintenance contracts to reference the current version.
• Review any project that straddles 15 October 2026 and agree the basis of design in writing.
• If you have, or are planning, battery storage, solar PV or EV charging, ask your designer how A3 and A4 affect the design.
• For residential, care or student accommodation buildings, confirm whether AFDD requirements apply to planned work.
• When you receive your next EICR, ask for the C3 recommendations to be grouped and costed so they can be budgeted.
• Make sure as-built drawings, distribution board schedules and certificates are kept up to date as work is completed.

What comes next: is a 19th Edition on the way?

There is plenty of speculation about a 19th Edition of the Wiring Regulations, often based on the roughly ten-year gap between the 17th Edition (2008) and the 18th (2018). At the time of writing, we are not aware of any official publication date for a 19th Edition. What the IET and the certification bodies have made clear is that BS 7671 will continue to evolve as the international and European standards it is based on are revised, through further amendments or, when changes are extensive enough, a new edition.

For building owners, the practical message is not to wait. Work to the current version, keep your records in order and use a contractor who keeps their knowledge current. When the next change is announced, the IET’s press office and the major certification bodies will publish details, and we will update this guide.

How JKS London can help

JKS London is an NICEIC-approved electrical contractor that has been working with commercial, public-sector, retirement living and airport clients since 2004. “Our business is to understand the regulations, procedures and legislative requirements that you need to address” — and that includes making sense of each change to BS 7671 for your buildings.

We carry out periodic inspection and testing, witness testing and consultancy to BS 7671 through our electrical compliance services, and design and install compliant new work through our installations and refurbishment team. If you would like help reviewing your specifications, prioritising EICR recommendations or planning upgrades, contact us to arrange a free, no-obligation site visit.

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