The IET Wiring Regulations have been updated again. Amendment 4 to BS 7671:2018 was published in April 2026, and since 15 October 2026 it has been the only version in force. That means any EICR carried out from that date has to be done against Amendment 4.
If you’re responsible for a building, whether that’s an office, a school, a warehouse or a rental property, here’s what has changed and what it means for you, in plain English.
The key dates
- 15 April 2026: Amendment 4 (BS 7671:2018+A4:2026) published.
- 15 October 2026: the previous version (including Amendment 3:2024) withdrawn. Amendment 4 is now the only current standard.
- From 15 October 2026: all new EICRs must be carried out to Amendment 4, and certificates will reference BS 7671 2026.
The big change for building owners: how EICR results are graded
Every observation on an EICR gets a code. C1 means danger present, C2 means potentially dangerous, C3 means improvement recommended, and FI means further investigation is needed because the inspector couldn’t confirm something during the test.
Under Amendment 4, those observations are now split into two groups. C1s and C2s affect the overall outcome, so any one of them makes the report unsatisfactory. C3s and FIs don’t. Previously, an FI could tip a report into unsatisfactory on its own and was flagged as needing attention without delay. That’s no longer the case.
For most clients, that makes reports clearer and fairer. But an FI still means something wasn’t confirmed, so it’s worth getting it investigated rather than leaving it. On our EICR remedial quotes we price C2s and FIs separately, so you can see exactly what you must fix to get a satisfactory report and what we’d strongly recommend on top.
AFDDs in care homes, HMOs, student accommodation and high-rise flats
Arc fault detection devices (AFDDs) are now required on socket-outlet circuits up to 32A in care homes, HMOs, purpose-built student accommodation and high-rise residential buildings, which Amendment 4 defines as over 18 metres or more than six storeys.
BS 7671 isn’t retrospective, so an existing installation without AFDDs doesn’t automatically fail its EICR. But if you’re planning a rewire, a board change or new circuits in one of these buildings, AFDDs need to be part of the design.
Batteries, Power over Ethernet and IT earthing
Amendment 4 adds brand new sections for things that have become common in commercial buildings:
- Stationary batteries: a new chapter covering battery energy storage, such as batteries paired with solar PV.
- Power over Ethernet (PoE): a new section for PoE systems powering lighting, cameras, access control and Wi-Fi.
- Functional earthing for ICT equipment: new rules for IT and comms systems, which is especially relevant in server rooms and data centres.
Healthcare and medical locations
Section 710, which covers medical locations, has been substantially revised, including a new schedule for recording supplementary bonding test results. If you manage a GP surgery, dental practice, clinic or care setting, expect your next inspection to be recorded slightly differently.
What should you do now?
- Check your dates. Find your last EICR and when the next one is due. Most commercial premises and schools are tested every five years, and industrial sites more often.
- Don’t ignore old FIs. If a previous report flagged something for further investigation, it’s still worth getting checked.
- Planning work? Design to A4. Any new installation, rewire or board change should now be designed and certified to Amendment 4.
- Use a contractor who’s up to date. Make sure whoever tests your building is working to the current standard.
Martin Cook Electrical Services carries out EICRs and fixed wire testing to BS 7671:2018+A4:2026 across London, Bedfordshire, Buckinghamshire and Hertfordshire. If you’d like your installation tested, or you want a second opinion on a recent report, request a free quote or call us on 01525 582582.
