The IET Wiring Regulations (BS 7671:2018, 18th Edition) are set for another major update. After Amendment 2 (2022) and the free Amendment 3 (2024), the industry is now preparing for Amendment 4:2026 Wiring Regulations.
This update is expected to be the most wide-ranging since the 18th Edition launched in 2018. Here’s what it means for electricians — and how you can prepare.
Table of contents – Amendment 4:2026 Wiring Regulations
Why Amendment 4 Matters
The Wiring Regulations evolve to keep pace with:
- European harmonised standards (through CENELEC).
- UK legislation, including the Building Safety Act.
- New technology such as battery storage and PoE systems.
The IET and BSI ran a Draft for Public Consultation (7 August – 3 November 2024), and the final publication is expected in 2026.
Key Draft Changes in Amendment 4
Chapter 52 – Ferromagnetic Enclosures and Eddy Currents
- Regulation 521.5.1 has been redrafted.
- Previously, all AC conductors in a circuit had to pass through the same hole in a ferromagnetic enclosure to avoid excessive heating from induced magnetic fields.
- New note: For switchgear/controlgear assemblies to BS EN IEC 61439, circuits up to 200 A can pass through separate holes in ferromagnetic material.
- Above 200 A, designs must be verified by temperature-rise tests.
Read “Amendment 4 and Consumer Units” to find out more
Section 545 – Functional Earthing for ICT
- New requirements for ICT, broadcast, and network systems.
- Clear distinction between functional earthing and protective earthing.
- Rules for bonding, identification, and continuity of conductors.
Chapter 57 – Stationary Secondary Batteries
- Dedicated chapter on battery storage installations.
- Domestic systems must comply with PAS 63100.
- Fire protection measures linked to the building’s risk assessment.
⚡ Section 716 – Power over Ethernet (PoE)
- Rules for distributing ELV DC power over IT cabling.
- Applies to both new and existing telecoms infrastructure.
- Covers balanced cables and accessories primarily designed for data transmission.
Section 551 – Low-Voltage Generating Sets
- Expanded detail on bidirectional energy flow and protective devices.
- Restrictions on connecting sources downstream of RCDs.
- Clarified requirements for systems operating in parallel with other supplies.
Section 710 – Medical Locations
- Extended provisions for Group 2 medical areas.
- Stronger rules to avoid single-fault power loss.
- Updated requirements for insulation monitoring and supplementary bonding.
Section 537 – Firefighter’s Switches
- Placement now tied to the building’s fire strategy.
- Must be specified by the fire engineer, with practical examples provided.
✅ Chapter 65 – Periodic Inspection & Testing
- Condition Reports must follow the revised Appendix 6 model.
- Reports may now include photographic or thermographic evidence.
♻️ Chapter 81 – Energy Efficiency
- Ensures energy efficiency is considered at design, installation, and verification stages.
- New chapter introducing efficiency requirements for electrical installations.
- References BS HD 60364-8-1:2019 and UK Building Regulations.
What Electricians Must Do Now – Amendment 4:2026 Wiring Regulations
Until Amendment 4 is published, compliance means working to:
- Amendment 2 (2022) – the brown book.
- Amendment 3 (2024) – the free PDF bolt-on.
Future-proof your work by understanding how Amendment 4 will affect:
- Battery storage installations (domestic & commercial).
- ICT and PoE cabling systems.
- Healthcare projects.
- Energy-efficient builds.
Stay Compliant with Electrical4Less
At Electrical4Less, we stock the products and publications you need to stay current:
Plus all the essential hardware for safe installs:
- Consumer Units – including FuseBox Kits and Live Electrical Kits.
- RCBOs – including Three Phase RCBOs.
- SPDs, SWA Armoured Cables
About Electrical4Less – Amendment 4:2026 Wiring Regulations
Based in Fulham, London, Electrical4Less is a trusted trade counter and online supplier. As members of the IBA buying group and the EDA, we supply electricians across the UK with:
- Fast delivery.
- Competitive pricing.
- Friendly trade-counter support.
We’re electricians’ first choice for consumer units, RCBOs, cable, and publications.
FAQs – Amendment 4:2026 Wiring Regulations
Q: When does Amendment 4 come into effect?
A: Publication is expected in 2026, after consultation closes and committee approval.
Q: Do I need to follow Amendment 4 now?
A: No — you must currently comply with Amendment 2 (2022) and Amendment 3 (2024).
Q: Will Amendment 4 affect domestic installs?
A: Yes — especially where battery storage and energy efficiency are concerned.
Q: Where can I buy the official Wiring Regulations?
A: You can buy the IET Wiring Regulations (18th Edition) and guidance notes directly from Electrical4Less.
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Amendment 4:2026 – What Electricians Need to Know About the Next 18th Edition Update