For decades, BS 7671, known as the IET Wiring Regulations, has been the definitive reference for electrical professionals across the United Kingdom.

Now, with the arrival of Amendment 4:2026, the standard is not just keeping pace with change, but setting the agenda for the future of safe, modern and sustainable electrical infrastructure.

As the UK accelerates towards ambitious clean energy goals and the electrification of everything from homes to hospitals, BS 7671:2018+A4:2026 is more relevant than ever. Let’s explore what’s new, why it matters to anyone involved in electrical design, installation, or inspection.

What is BS 7671:2018+A4:2026?

BS 7671, or the IET Wiring Regulations, is the UK’s national standard for the design, erection and verification of electrical installations. It brings together European Harmonized Documents (HDs) and international standards (IEC), providing a single, authoritative source for all new and amended electrical installations in the UK.

The Regulations apply to a vast range of environments, from domestic and commercial buildings to specialized locations like swimming pools, highway equipment and solar photovoltaic power systems.

The standard is not static. It evolves to reflect new technologies, emerging risks, and the collective expertise of the industry. Amendment 4:2026 is the latest milestone in this journey, introducing essential updates that address the realities of today’s electrical landscape.

Why does Amendment 4 to the IET Wiring Regulations matter?

The pace of technological change in the electrical sector is relentless.

Energy storage, smart systems, Power over Ethernet (PoE) and advanced medical installations have moved from niche applications to everyday reality. With almost 50% of electrical installers planning to expand into solar PV, EV charging and heat pump installations, future-ready standards are no longer optional, but essential.

BS 7671:2018+A4:2026 keeps the UK’s IET Wiring Regulations fit for purpose, delivering clear, practical guidance for both established practices and emerging technologies.

As Sebastiaan van Dort, Director of Energy & Sustainability at BSI, puts it:

“BSI is proud to jointly publish this vital standard with the IET at a time when the UK is accelerating towards its 2030 clean energy goals. BS 7671 underpins safe, modern electrical infrastructure, essential for delivering the electrification needed to meet net zero ambitions.”

Consider this: there are currently only around 4,000 heat pump installers in the UK - a number that must grow dramatically to meet government targets by 2028. Staying ahead with the latest requirements isn’t just about compliance; it’s about seizing opportunities, driving innovation and safeguarding lives and property in a rapidly changing world.

Who needs BS 7671:2018+A4:2026?

The standard is directly relevant to:

• Designers of electrical installations.

• Electrical contractors.

• Electrical installers.

• Inspectors and testers of electrical installations.

• Specifiers of equipment for electrical installations.

• Lecturers, those delivering courses, students and learners in the field of low voltage electrical installations.

It is also highly relevant to manufacturers and suppliers of electrical equipment - cables, luminaires, sockets, consumer units and safety equipment - as well as anyone responsible for the safety and compliance of electrical systems in buildings and infrastructure.

For these professionals, BS 7671 is a daily working tool, a recognised mark of competence and, in many cases, a legal requirement. Electrical installers use the IET Wiring Regulations to demonstrate that their installations are safe for use and are often required to comply with them, ensuring they have the knowledge and competence to carry out electrical work safely.

What’s new in BS 7671:2018+A4:2026?

Amendment 4 is not a minor update. It introduces several significant changes that reflect the latest industry needs and technological advancements. The key updates include:

• A new chapter on stationary secondary batteries: This addresses the requirements for electrical storage systems used to supply installations, supporting the integration of renewable energy and grid resilience.

• A new section on functional earthing and equipotential bonding for ICT equipment and systems: As information and communication technology becomes ever more integral to buildings, clear rules for earthing and bonding are essential for safety and performance.

• A new section on Power over Ethernet (PoE): With the rise of smart buildings and IoT, PoE is increasingly used to power devices via data cables. The new requirements ensure these systems are installed safely and reliably.

• A major revision of Section 710 (Medical Locations): This includes enhanced requirements and the introduction of a schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors—critical for patient safety in healthcare environments.

• Incorporation of Amendment 3:2024: The latest amendment integrates previous updates, ensuring consistency and clarity across the standard.

• Further adoption of CENELEC Harmonized Documents and IEC standards: This aligns the IET Wiring Regulations with European and international standards, supporting trade and innovation.

Mark Coles, Head of Technical Regulations at the IET, highlights the significance of these changes:

“The Amendment continues the thread of embracing new technologies and the inclusion of a new section on Stationary Secondary Batteries is an exciting step into the future of renewable sources of energy and their integration into our lives. Amendment 4 is an essential update to provide for the safety of electrical installations in the UK and it is now imperative that the industry is ready to work to this amendment before BS 7671:2018+A2:2022+A3:2024 is withdrawn.”

With the publication of Amendment 4, the previous version - BS 7671:2018+A2:2022+A3:2024 - will be officially withdrawn on 15 October 2026 but remains valid for six months after Amendment 4’s release. This transition period gives professionals time to review the changes, update their processes, and ensure compliance. After this window, only the new standard will be recognized as the UK national standard for electrical installations.

Why you should get BS 7671:2018+A4:2026

BS 7671 is the most widely accepted way to demonstrate compliance with UK electrical safety legislation. Working to the latest standard is not just best practice, but often a contractual or regulatory requirement. Using the new amendment signals professionalism and a commitment to safety.

Other benefits include:

• Future-proofing and innovation

By addressing emerging technologies, Amendment 4 supports the move towards smart, sustainable infrastructure and provides clear guidance on how electrical professionals can comply as technologies continue to evolve.

• Risk management and safety

Electrical hazards can have serious consequences, making robust safety requirements essential. Amendment 4 reinforces the role of BS 7671 in setting out clear, technical requirements designed to reduce the risk of electric shock, fire and other electrical dangers, while supporting the safe integration of new and emerging technologies. Updated provisions for medical locations and other critical installations further strengthen the standard’s focus on reliability and protection in environments where safety is paramount, helping to safeguard both installers and end users.

• Sustainability and net zero goals

BS 7671 underpins the electrification needed to meet the UK’s net zero ambitions. By supporting the safe integration of renewable energy and efficient systems, the standard contributes to a more resilient and sustainable built environment.

Ready to secure your copy? Get BS 7671:2018+A4:2026 today and ensure you’re prepared for the future of electrical safety and compliance.