BS 7671 Amendment 4:2026 – What Electrical Professionals Need to Know

Introduction

The IET and the British Standards Institution have officially published Amendment 4:2026 to BS 7671:2018, the IET Wiring Regulations, 18th Edition. Released on 15 April 2026 and widely referred to as the Orange Book, it is one of the most significant updates to the UK's national standard for electrical installation safety in recent years, reflecting how quickly the electrical sector has moved on battery storage, Power over Ethernet, and connected building systems.

Key Dates and the Transition Period

The industry has a defined window to move over to the new regulations:

• 15 April 2026 – Amendment 4 published and can be implemented immediately
• 15 October 2026 – the previous edition (BS 7671:2018+A2:2022+A3:2024, the Brown Book) is withdrawn

Between those two dates, installers may work to either edition, though the IET recommends buying the Orange Book now so practices are ready well before the October changeover. From 15 October 2026 onward, Amendment 4 is the only standard in use for all new low voltage installations, additions and alterations to existing ones, and periodic inspection and testing.

What's Changing

A new chapter on stationary secondary batteries. This responds directly to the growth of energy storage, with or without solar PV. It covers system design, power conversion equipment, and bidirectional or hybrid inverters, with particular attention to protective devices suited to two-way energy flow — essential for vehicle-to-home and vehicle-to-grid setups. Batteries are now classified as generating sets rather than loads, and the chapter sets out safety-critical requirements around location, ventilation, and fire-risk mitigation.

A new section on Power over Ethernet. Section 716 sets out requirements for PoE as Ethernet cabling is used more and more to power devices like LED lighting and small appliances over extra-low voltage DC. Key points include the use of SELV/PELV systems, voltage limits of 60V ripple-free DC in dry locations (15V elsewhere), and a requirement that connections comply with BS ISO/IEC 11801-1 and support 750mA per contact. PoE infrastructure must now be assessed as part of EICRs, which narrows the gap between IT and electrical compliance.

A new section on functional earthing and bonding for ICT. Section 545 draws a clear line between functional and protective earthing for ICT equipment, so that a fault in functional earthing can never compromise protective earthing. It covers minimum conductor cross-sections, identification, continuity, and the main functional earthing terminal.

A major revision to medical locations (Section 710). This aligns the UK with IEC 60364-7-710:2021 and introduces clear classification into Groups 0, 1, and 2. For Group 2 locations such as operating theatres and ICUs, medical IT systems with insulation monitoring are now required to maintain supply through a first fault, two independent supplies plus a UPS are mandatory, and AFDDs and Type AC RCDs are explicitly prohibited. Supplementary bonding must be tested annually for Group 2 and every three years for Group 1.

Changes to EICR reporting. An FI (Further Investigation) code can no longer, on its own, push an EICR to an unsatisfactory outcome — only C1 and C2 codes can now do that. This should reduce the number of reports failed unnecessarily, though it puts more responsibility on inspectors to classify observations correctly. Reports can now also carry photographic and thermal imaging evidence, a change reflected in the updated Regulation 653.1 and Appendix 6.

A new chapter on energy efficiency. Chapter 81 points installers to the Building Regulations for England and Wales, Scotland, and Northern Ireland, marking the first time energy performance has been built directly into the wiring regulations.

Supporting Publications

The full suite of supporting guidance has been updated alongside Amendment 4, including the On-Site Guide (9th Edition), Guidance Notes 1 through 8 (covering selection and erection, isolation and switching, inspection and testing, fire protection, shock protection, overcurrent protection, special locations, and earthing and bonding), and the Electrician's Guide to the Building Regulations (7th Edition). Guidance Note 3 is now available within digital subscription packages.

Conclusion

Amendment 4:2026 is a substantial step forward for UK electrical safety regulation, directly addressing energy storage, Power over Ethernet, and ICT infrastructure — areas the previous edition barely touched. The practical takeaway for electrical professionals is the deadline: the industry has until 15 October 2026 to complete the transition. Getting familiar with the sections that affect your work now, rather than later, is the difference between a smooth changeover and a scramble.

This article summarises key information about Amendment 4:2026 to BS 7671:2018. The full document, BS 7671:2018+A4:2026 (Orange Book), is available for purchase via the IET's Amendment 4 publications page.