The Institution of Engineering and Technology (IET) and BSI have published Amendment 4 (2026) to BS 7671, the UK’s wiring regulations.
This is the latest update to the 18th Edition of the IET Wiring Regulations, and it reflects how modern electrical installations are evolving.
What is BS 7671?
BS 7671 is the UK standard for electrical installations.
It sets the rules for:
- New electrical installations
- Additions and alterations
- Inspection and testing of existing installations
In simple terms, it is the rulebook electricians follow to ensure installations are safe.
What is Amendment 4 (2026)?
Amendment 4 is the latest update to BS 7671. It was published on 15 April 2026 and can be used immediately.
The previous version, BS 7671:2018+A2:2022+A3:2024, will be withdrawn six months later.
Key changes in Amendment 4
This update reflects the increasing demand placed on electrical systems and the rise of new technologies in homes and commercial buildings.
The most significant changes include:
1. Stationary secondary batteries
A new chapter has been introduced covering battery storage systems used for electrical supply.
This supports the growing use of energy storage in homes and businesses, particularly alongside renewable energy systems.
2. Functional earthing for ICT systems
A new section covers functional earthing and equipotential bonding for information and communication technology systems.
This reflects the increasing integration of IT infrastructure within buildings.
3. Power over Ethernet (PoE)
A dedicated section has been added for Power over Ethernet systems.
These systems are now widely used for devices such as:
- IP cameras
- Access control systems
- Smart building technology
4. Medical locations (Section 710)
Section 710 has been significantly revised.
This includes updated requirements and the introduction of a schedule for recording test results, particularly for supplementary bonding conductors.
5. Wider updates across the standard
Amendment 4 also includes:
- Integration of Amendment 3:2024 into the main document
- Further alignment with international standards (CENELEC and IEC)
- Updates across multiple sections to reflect new technologies
What this means in practice
This is not just a technical update. It reflects a shift in how electrical systems are used.
Modern installations now need to account for:
- Higher electrical demand
- Energy storage systems
- Smart technologies and connected devices
For electricians, this means staying up to date with the latest requirements.
For property owners, it reinforces the importance of regular inspection and ensuring installations remain safe as demands increase.
When does it apply?
BS 7671:2018+A4:2026 can be implemented immediately from publication.
The previous version will be withdrawn after six months, at which point this amendment becomes the primary standard for compliance.
Final thought
BS 7671 continues to evolve alongside modern technology.
As homes and buildings become more complex, keeping electrical installations safe depends on staying aligned with the latest standards.
If your installation has not been inspected in recent years, it may not reflect current requirements.
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