Description
18th Edition Amendment 4 – IET Wiring Regulations (BS 7671:2018+A4:2026)
Requirements for Electrical Installations, IET Wiring Regulations, Eighteenth Edition, BS 7671:2018+A4:2026
The IET Wiring Regulations define the national standard for the design, installation, inspection, testing and certification of electrical installations across domestic, commercial and industrial environments in the UK. This publication is the latest fully consolidated version of BS 7671, combining the Eighteenth Edition with all subsequent amendments into a single, authoritative reference.
Widely known as the orange book, this edition reflects the ongoing development of electrical installation practices, addressing new technologies, emerging risks and increased integration of power, data and storage systems. It provides clear, structured requirements to support electrical safety, regulatory compliance and consistency across the industry.
Amendment 4:2026 introduces important technical updates, including new provisions for stationary secondary batteriesused for electrical energy storage and supply. Coverage of functional earthing and functional equipotential bondinghas been expanded to better support information and communication technology equipment and systems. The standard also introduces a dedicated section on Power over Ethernet (PoE), recognising its growing use in modern installations.
A major revision of Section 710 – Medical Locations strengthens safety requirements for healthcare environments, while the inclusion of a schedule of test results improves documentation of resistance values for supplementary protective equipotential bonding conductors during inspection and testing.
From 15 April 2026, electrical work in the UK must comply with this edition of BS 7671, making it an essential reference for professionals working to the 18th Edition Amendment 4 requirements.
Key changes & features
- Fully consolidated Eighteenth Edition including all amendments
- New requirements for stationary secondary battery systems
- Expanded guidance on functional earthing and equipotential bonding for ICT installations
- New dedicated section covering Power over Ethernet (PoE)
- Major revision of Section 710 relating to medical locations
- New schedule of test results for supplementary bonding conductors
- Suitable for domestic, commercial and industrial electrical installations
Product details – 18th Edition Amendment 4
- Subject: Electrical Regulations
- Publication Year: 2026
- Pages: 630
- ISBN-13: 978-1-83953-972-5
- Format: Paperback (PBK)
