IET Wiring Regulations 18th Edition and On-Site Guide Bundle (A4:2026)

IET Wiring Regulations 18th Edition and On-Site Guide Bundle (A4:2026)

IET Wiring Regulation 18th Edition and On-Site Guide Bundle (A4:2026) pairs the core UK standard for electrical installation with the practical on-the-job companion many electricians rely on. It’s built for anyone involved in the design, installation, inspection, certification and maintenance of electrical installations across domestic, commercial and industrial environments.

The bundle includes BS 7671:2018+A4:2026 (the 18th Edition Wiring Regulations, commonly known as the ‘orange book’) plus the On-Site Guide (BS 7671:2019+A4:2026), 9th Edition. BS 7671:2018+A4:2026 is the consolidated publication incorporating all previous amendments, with new and revised requirements covering areas such as stationary secondary batteries, functional earthing and functional equipotential bonding for ICT systems, a new Power over Ethernet (PoE) section, and a major revision of Section 710 Medical Locations.

Amendment 4 is due to be published on 15 April 2026 and can be implemented from that date, with the previous edition remaining in use until it is withdrawn six months later (15 October 2026).

For day-to-day site work, the On-Site Guide summarises key requirements in a convenient, easy-to-use format and supports installations up to 100 A, three-phase, updated to include all four amendments and aligned with BS 7671:2018+A4:2026. It also covers practical topics including bidirectional and unidirectional protective devices, stationary secondary batteries, updated rationale for maximum Zs values, guidance on RCD selection, and prospective fault current considerations for protective devices.

Key Features

• Bundle includes BS 7671:2018+A4:2026 and the On-Site Guide (BS 7671:2018+A4:2026), 9th Edition
• BS 7671 is the UK standard for electrical installations in domestic, commercial and industrial settings
• Consolidated BS 7671:2018+A4:2026 incorporates all previous amendments in one publication
• Updates include stationary secondary batteries for electrical storage and supply within installations
• Includes functional earthing and functional equipotential bonding guidance for ICT equipment and systems
• Includes a dedicated section on Power over Ethernet (PoE)
• Major revision of Section 710 Medical Locations and updated test recording guidance
• Amendment 4 published 15 April 2026, with the previous edition withdrawn six months later
• On-Site Guide supports installations up to 100 A, three-phase in a quick-reference format
• On-Site Guide includes guidance on bidirectional and unidirectional devices, Zs values, RCD selection and prospective fault current