Electrical Safety First has produced this pocket book guide to what has changed with Amendment 4 (2026) to BS 7671:2018 for domestic installations, and why it matters.
This guide highlights the changes in Amendment 4 that are most likely to affect domestic installations.
It is intended to provide valuable information for designers, installers, and inspectors by explaining what has changed and why it matters in practice.
It does not replace BS 7671, manufacturer instructions, or engineering judgement.
Amendment 4 reflects the rapid change in how electricity is generated, stored, and used in homes.
Domestic installations now commonly include EV charging, battery storage, PV systems, and ICT infrastructure, all of which introduce new risks and design considerations.
The updates included in Amendment 4 BS 7671 better reflect these.
This pocket guide covers:
- Scope and legal context
- Key changes in BS 7671
- Supply characteristics, earthing, and installation structure
- Fire safety, thermal effects, and escape routes
- Protection, coordination, and wiring systems
- Low-carbon technologies and new chapters
- Isolation, inspection, testing, and reporting