Is BS 7671 a legal requirement?

BS 7671 is a British Standard, not legislation, so it is not law in itself. It is the standard that the Electricity at Work Regulations 1989 and Part P of the Building Regulations point to as the way to demonstrate compliance. In practice, an installation certified to BS 7671 is taken as meeting the legal duty, and one that departs from it needs justification.

What is the current edition of BS 7671?

BS 7671:2018+A4:2026, the 18th Edition with Amendment 4, published 15 April 2026. It runs alongside BS 7671:2018+A2:2022 during a six-month transition; A2 is withdrawn on 15 October 2026, after which new work should be designed and certified to A4.

What changed in Amendment 4?

The headline changes are a new chapter on stationary secondary batteries and battery energy storage systems, functional earthing and bonding requirements for information and communication technology, guidance on Power over Ethernet, and a revised Section 710 for medical locations. Requirements on RCDs, AFDDs and consumer units carried over from Amendment 2 are retained.

Do existing installations have to be upgraded when BS 7671 changes?

No. BS 7671 is not retrospective. An installation that complied with the edition in force when it was built does not become non-compliant when a new edition is published. On an EICR, departures from the current edition that are not dangerous are recorded as C3, improvement recommended, and do not make the report unsatisfactory.

Who publishes BS 7671?

BS 7671 is published jointly by the Institution of Engineering and Technology (IET) and the British Standards Institution (BSI). The IET also publishes the supporting On-Site Guide and Guidance Notes 1 to 8, of which Guidance Note 3 on inspection and testing is the one most relevant to certification.

What is BS 7671? The IET Wiring Regulations explained

BS 7671, the IET Wiring Regulations, is the British Standard that sets the requirements for the design, installation, inspection and testing of electrical installations in the UK, published jointly by the IET and BSI. The current version is BS 7671:2018+A4:2026, the 18th Edition with Amendment 4, published 15 April 2026; the previous version, A2:2022, is withdrawn on 15 October 2026. Every EIC, Minor Works Certificate and EICR certifies compliance with, or reports against, this standard.

Key takeaways

BS 7671 is a standard, not a law, but the Electricity at Work Regulations 1989 and Part P rely on it.
The 18th Edition was published in 2018 and has had four amendments: A1:2020, A2:2022, A3:2024 and A4:2026.
A4 was published 15 April 2026; A2 is withdrawn 15 October 2026.
It is not retrospective; older installations are judged for safety, not for compliance with the latest edition.

What is BS 7671 in practice?

The Wiring Regulations began in 1882 as rules issued by what became the IET, became a British Standard in 1992 as BS 7671, and are now aligned with CENELEC harmonisation documents and the IEC 60364 series. The book has seven parts, from scope and fundamental principles through protection for safety and selection of equipment to inspection and testing and the special locations such as bathrooms (Section 701), solar PV (712) and EV charging (722), followed by appendices with the model certificate forms.

For an electrician, the regulations most often in play are Chapter 41 (maximum Zs), Regulations 411.3.3 and 411.3.4 (RCD protection), Regulation 421.1.201 (non-combustible consumer units), Chapter 54 (earthing and bonding), and Chapters 64 and 65 for testing.

When is BS 7671 used?

Its legal weight comes from other instruments:

Instrument	How it uses BS 7671
Electricity at Work Regulations 1989	Compliance with BS 7671 is accepted as meeting the duty to keep systems safe (HSE Memorandum of Guidance)
Part P of the Building Regulations (England and Wales)	Approved Document P cites BS 7671 as the means of showing electrical safety
Electrical Safety Standards in the PRS (England) Regulations 2020	Requires landlords' installations to meet the 18th Edition, evidenced by an EICR

Edition and amendment history

Version	Published	Notes
BS 7671:2018 (18th Edition)	July 2018, effective 1 January 2019	AFDD recommendation, SPD requirements, Section 722 EV charging
A1:2020	February 2020	Small amendment to Section 722 EV charging, followed by a corrigendum
A2:2022	28 March 2022, effective 28 September 2022	AFDDs mandatory in specified premises (421.1.7), Type AC RCD restrictions, new certificate forms
A3:2024	2024	Small amendment on bidirectional and prosumer protective devices (Regulation 530.3.201)
A4:2026	15 April 2026; A2 withdrawn 15 October 2026	New chapter on stationary secondary batteries (BESS), functional earthing and bonding for ICT, Power over Ethernet, revised Section 710 medical locations

Between 15 April and 15 October 2026, work may be certified to either A2 or A4. After 15 October, certificates should state BS 7671:2018+A4:2026.

What does BS 7671 contain that matters for certification?

Chapter 64, initial verification, requires every new installation, addition or alteration to be inspected and tested before use, with an EIC or Minor Works Certificate issued. Chapter 65, periodic inspection, requires existing installations to be inspected at intervals informed by Regulation 653.2 and Table 653.2, with an EICR issued. Appendix 6 provides the model forms for all three certificates and the schedules; certificates produced by scheme members or software must contain at least the information on those forms.

Because BS 7671 is not retrospective, the EICR judges an installation for safety rather than for compliance with today's edition. IET Guidance Note 3 and Electrical Safety First's Best Practice Guide 4 translate that principle into the C1, C2, C3 and FI codes.

Common mistakes with BS 7671

Citing the wrong edition on a certificate. After 15 October 2026, "BS 7671:2018+A2:2022" is a superseded reference.
Treating a departure from the current edition as a C2 on an EICR. Non-dangerous departures are C3.
Quoting regulation numbers from memory. Numbering shifts between amendments; check the book.
Missing Amendment 3. Small, but its bidirectional device requirements apply to any board feeding PV or battery storage.
Confusing Part P with BS 7671. Part P is the requirement to notify; BS 7671 is the technical standard the work must meet.

Related terms

How Certio helps

Certio records this on the BS 7671 model forms without the typing: photograph the board to draft the circuit schedule, point the camera at a Megger MFT-X1 to capture readings, or dictate them. Starter is free for 7 days.

Written by the Certio team. Last checked 14 September 2026.