BS 7671:2018+A4:2026 (Amendment 4)
The two dates that matter
Amendment 4 was published by the IET and BSI on 15 April 2026. The previous version, BS 7671:2018+A2:2022+A3:2024, is withdrawn six months later on 15 October 2026.
Between those two dates both versions stand. You may design and certify to either. From 15 October 2026 the earlier version no longer exists as a current standard.
The change most people are asking about: EICR observations
This is the change that affects the largest number of working electricians day to day, and it is the one that has generated the most discussion.
C3 and FI have been decoupled from C1 and C2. The IET states the intent plainly: the codes were separated “to make it clear that a C3 or FI classification code does not result in an unsatisfactory outcome”.
In practice:
- C1 and C2 — these, and only these, produce an unsatisfactory overall assessment.
- C3 and FI — recorded as observations and recommendations. They do not make the report unsatisfactory.
The wording of the FI code itself has also softened. Where it previously indicated that further investigation was required without delay, it now reads that further investigation is advised.
Section K of the model EICR has been restructured to reflect this, separating the two groups rather than listing all four codes together.
The IET frames the reasoning in a single sentence worth keeping in mind: “periodic inspection and testing is carried out to determine if an installation is in satisfactory condition for continued use. It is not a fault-finding exercise.”
On this site: the EICR defect code finder and the guide to how the codes are applied.
New: a chapter on stationary secondary batteries
Amendment 4 introduces a new chapter covering electrical energy storage systems. It addresses design requirements, power conversion equipment and bidirectional inverters, and protective devices suitable for current flowing in two directions rather than one. Battery location, ventilation and fire mitigation are covered explicitly.
The practical significance is that storage is treated as a source as well as a load, which changes how protection and isolation have to be thought about.
On this site: battery storage, EPS and islanding and G98 and G99 notification.
New: Section 716, Power over Ethernet
A new section covers the use of Ethernet cabling to supply extra-low-voltage DC to equipment such as LED luminaires. It sets limits of 60 V ripple-free DC in dry locations and 15 V ripple-free DC elsewhere, and requires compliance with BS ISO/IEC 11801-1.
This mainly affects commercial and smart-building work, where power and data increasingly share the same cable.
On this site: 24 V DC, PELV and SELV distribution and the DC voltage drop sizer.
Revised: Section 710, medical locations
Medical locations are now classified in three groups — Group 0, Group 1 and Group 2. Group 2 areas require medical IT systems with transformers and insulation monitoring, together with two independent supplies and UPS provision. The revision aligns the section with IEC 60364-7-710:2021.
New earthing arrangement: PNB
Protective Neutral Bonding (PNB) is now a recognised earthing arrangement, and can be selected as the earthing type on Amendment 4 certificates and reports.
On this site: panel earthing and bonding, the adiabatic CPC check, and the 3D model of how an RCD toroid detects imbalance.
Also incorporated
Amendment 4 absorbs Amendment 3:2024 and continues the adoption of CENELEC Harmonised Documents and IEC standards covering newer technologies.
Timeline
What this page does not cover
Amendment 4 is a substantial revision and this page reports the changes named in the IET and BSI announcement and in the certification bodies' own summaries. It is not a complete list of every regulation touched. Where a change is not listed here, that means we have not sourced it — not that it does not exist.
Sources
- IET and BSI — official publication announcement, 15 April 2026
- IET Wiring Matters — implications of BS 7671:2018+A4:2026 on EICRs, July 2026
- IET — BS 7671:2018+A4:2026 model forms for certification and reporting (PDF)
- NICEIC — understanding BS 7671:2018 + Amendment 4:2026
This page reports what changed and when, with sources. It does not tell you what to do about it. Always work from the published standard and your own scheme provider's guidance.