BS 7671 Amendment 4: What Domestic Installers Need to Know

Amendment 4 introduces formal competence requirements in BS 7671 for the first time. While previous editions assumed competence through qualifications and registration, the new approach defines what competent persons must know and be able to demonstrate for specific types of work. For domestic installers — the largest group of BS 7671 users — this has direct implications for training and CPD.

The competence framework in Amendment 4 is not a new qualification requirement. It does not replace the Level 3 Diploma or NVQ Level 3 that form the basis of competent person scheme membership. Instead, it establishes that competent persons must demonstrate knowledge of the specific sections of BS 7671 relevant to the work they undertake. For domestic installers, the key areas of Amendment 4 knowledge are: Chapter 57 (battery storage), Section 716 (PoE derating where relevant), and the EV charging updates.

Battery storage knowledge is now essential for domestic installers. The rapid growth of solar-plus-battery installations means that domestic electricians regularly encounter battery systems. Chapter 57 location restrictions (no loft installations), thermal runaway mitigation verification, and dual-side isolation are all requirements that domestic installers must understand and implement correctly. The IET, NICEIC, NAPIT, and EAL will offer Amendment 4 update courses covering these requirements.

The transition period (April to October 2026) provides a window for training. Amendment 4 permits installations to either the current standard or the new amendment during this period. Domestic installers should complete their Amendment 4 training during this window to ensure readiness for the October 2026 mandatory compliance date. Competent person schemes are expected to require Amendment 4 awareness as part of their annual CPD requirements.

Part P implications are significant. Building Regulations Part P requires that domestic electrical work is either carried out by a competent person registered with a scheme, or notified to Building Control. Amendment 4 does not change this framework, but it adds new notifiable work categories — battery storage installations will likely become notifiable under Part P, requiring either scheme membership or Building Control notification.

Periodic inspection and testing of domestic installations must now check for Amendment 4 compliance where alterations have been made. Domestic installers carrying out EICRs should familiarise themselves with the new requirements to correctly code observations related to battery storage, EV charging, and energy efficiency provisions.

ECalPro's calculators are updated for Amendment 4, giving domestic installers a reliable tool for cable sizing, protection coordination, and compliance verification for all types of domestic work.