BS 7671 Amendment 4 (A4:2026): what changed

Amendment 4 to the 18th Edition Wiring Regulations becomes the only current version on 15 October 2026. Here is what changed, the dates that matter, what it means for EICRs and certificates, and which certificate apps we found were already A4-ready when we checked on 12 October 2026.

What is BS 7671 Amendment 4, in short?

BS 7671 is the UK standard for electrical installations, published by the IET and BSI and known as the Wiring Regulations or the 18th Edition. Amendment 4, written BS 7671:2018+A4:2026 and nicknamed the Orange Book, updates it and absorbs Amendment 3 into the main text.

What changed in Amendment 4?

The IET lists four headline technical changes, and NICEIC adds several more that matter on day-to-day jobs.

New and revised sections

• Stationary secondary batteries (new Chapter 57): rules for battery storage used to store and supply electricity in an installation. Relevant to anyone fitting home batteries alongside solar PV.
• Functional earthing and functional equipotential bonding (new Section 545): for ICT equipment and systems.
• Power over Ethernet (new Section 716): for PoE lighting, cameras and devices powered over data cables.
• Medical locations (Section 710): a major revision, with a new schedule of test results for supplementary bonding conductor resistance.

Changes NICEIC highlights

• PNB earthing: Protective Neutral Bonding systems are included for the first time, and PNB can be selected as an earthing arrangement on the forms.
• RDC devices for EV charging: residual direct current protective devices are introduced for EV charging installations.
• AFDD wording: "high rise residential buildings" replaces "higher risk residential buildings". The AFDD requirement itself is unchanged.
• Bidirectional devices: recorded by British Standard only, with a comment box to note whether a device is bidirectional.

Changes to EICRs

This is the change that reaches landlords and homeowners. On A4 forms, observations are split into two parts. C1 and C2 (which make the result unsatisfactory) are separated from C3 and FI (which do not). The IET's Wiring Matters explains that FI now reads "further investigation is advised" rather than "required without delay", and that where FI is used "it does not result in an unsatisfactory outcome". NICEIC asks its contractors to explain this to clients. Our guide to EICR codes walks through an example.

Changes to certificates and forms

• Form references show the amendment: 18.3 for Amendment 3 and 18.4 for Amendment 4.
• The declaration states the standard version: "BS 7671 2026" for A4 work, "BS 7671 2024" for A3 work.
• Minor Works end-to-end resistance tests are recorded as r1-r1, rn-rn and r2-r2, replacing L/L, N/N and cpc/cpc.
• Both electronic and handwritten forms remain available.

For what each form is for, see our guide to EIC, Minor Works and Part P.

Who is affected most?

For most domestic electricians, the day-to-day change is small: new forms, a new earthing option and a softer FI code. The bigger technical changes land on firms doing battery storage, EV charging, data and medical work. If that is you, the new chapters are worth reading in full rather than relying on summaries, because the IET says there are further changes "throughout all parts" beyond the headline items.

What do electricians need to do?

1. Get access to the A4 book. NICEIC requires certified contractors to show access to A4 from 15 October 2026 to keep their certification.
2. Update your certificate software. Check every app you use offers A4 forms, with PNB, the new observation layout and the new Minor Works test fields.
3. Use A4 forms for new work. Anything designed after 15 October 2026 needs A4 certificates. All EICRs from that date should be issued to A4.
4. Finish A3 jobs properly. Work designed to A3 before 15 October can still be certified to A3. Record the right standard in the declaration.
5. Check contracts. NICEIC advises checking contract wording and discussing any design to a withdrawn standard with the client.
6. Do the CPD. NICEIC expects you to be conversant with A4 changes that affect your work. Supervisors need an 18th Edition qualification, but an A4 upgrade course is not required.
7. Brief landlord clients on FI. Explain that a report with FI only is now satisfactory, but they should still investigate within the landlord deadline.

What will A4 cost you, and what is the deadline?

The hard deadline is 15 October 2026. Costs fall into three areas: the book itself, any update course you choose, and your certificate software. Most subscription apps include A4 updates in the subscription. One-off licences may need a support renewal. EasyCert, for example, sells a one-off EasyCert Pro licence at £174.95 with a separate 12-month Customer Care renewal (the renewal price is not shown on its site), and Clik's NICEIC Cert Software at £280 ex VAT includes the first year of updates and support. If your software is out of support, budget for renewal before 15 October.

Worked example: which version applies to which job?

Software maths: if your one-off licence is out of support and you switch to Tradecert from £18 a month, that is £216 a year. Switching to iCertifi's 12-month unlimited plan costs £125.99 including VAT. A NAPIT member renewing FastTest pays £195 ex VAT (£234 inc VAT).

What if a client asks for an A3 design after 15 October?

NICEIC advises checking the contract wording and talking to the client about any design to a withdrawn standard. In practice, a design finished before 15 October 2026 can still be signed off to A3 afterwards, but a new design started after that date should follow A4. If a client's specification still names the 2024 edition, raise it in writing before you start, so there is no argument at handover about which version the certificate should state.

What mistakes are electricians making with A4?

• Assuming software updated itself. Check the form footer shows 18.4 and the declaration reads "BS 7671 2026".
• Telling landlords FI can be ignored. A4 makes FI advisory, but landlord deadlines still apply.
• Thinking it is the 19th Edition. It is still the 18th Edition, amended.
• Booking an unnecessary requalification. NICEIC does not require an A4 upgrade for supervisors, although CPD is expected.
• Using A3 forms for new designs after 15 October. Only work designed to A3 before that date can still be certified to A3.

Which certificate apps are ready for A4?

For full reviews of each option, see our electrical certificate software comparison.