BS 7671 Amendment 4:2026: What's Changing
Amendment 4:2026 is the next update to the 18th Edition. Here is what is changing at a headline level and how to get ahead of it.
BS 7671 evolves through amendments, and Amendment 4:2026 is the next significant one after Amendment 2:2022. It refines several areas rather than rewriting the standard, but a few changes affect everyday domestic and commercial work.
This guide summarises the headline areas — arc fault detection, model forms, earthing arrangements and surge protection — so you know what to look at before the amendment takes effect and your certification needs to reference it.
Key takeaways
- Amendment 4:2026 updates the 18th Edition; certify to whichever edition and amendment is in force when the work is done.
- AFDD requirements and their scope are revisited.
- The model certificate and report forms are revised, so your certification templates need updating.
- Earthing arrangement guidance, including PME considerations, is refined.
- Surge protection and specific special-location sections receive updates.
Arc fault detection (AFDDs)
AFDDs were introduced as a requirement for certain premises in Amendment 2. Amendment 4:2026 revisits where they are required and recommended, so it is worth checking whether the scope for socket-outlet final circuits changes for the premises types you work in.
If you fit consumer units in HMOs, care homes or similar higher-risk premises, this is the change most likely to affect your standard board build.
Revised model forms
Each amendment tends to update the model forms in Appendix 6 — the EIC, the Minor Works Certificate and the EICR. Amendment 4:2026 brings revised forms, which means the certificate you issue after it lands must match the new layout and declarations.
This is the change that affects everyone: whatever you use to produce certificates has to move to the updated forms.
Forms handled for you
TradePlanr keeps its certificate templates aligned with the current BS 7671 model forms, so you are always issuing the right version without tracking the changes yourself.
Earthing and surge protection
The amendment refines guidance around earthing arrangements — including PME/TN-C-S considerations for certain installations such as EV charging — and updates surge protection requirements.
None of this changes the fundamentals, but it can affect design decisions on specific jobs, so read the relevant sections rather than assuming continuity.
How to get ahead of it
Practically: update your certificate forms, review your standard consumer unit specification against any AFDD scope change, and refresh your knowledge of the earthing and special-location sections you use most.
Because certification declares compliance with a specific version, make sure your team knows the changeover date and issues to the correct edition either side of it.
Frequently asked questions
When does Amendment 4:2026 come into force?
It is the 2026 amendment to the 18th Edition. Certify work to the edition and amendment in force on the date the work is carried out, and follow any transition period announced by the IET/BSI.
Do I need to re-issue existing certificates?
No. Certificates issued under the previous amendment remain valid records of the work at the time. New work after the changeover should be certified to the new amendment and its model forms.
What is the biggest practical change?
For most electricians it is the revised model forms — your certification has to move to the updated EIC, Minor Works and EICR layouts — alongside any change to AFDD scope.
From guidance to action
Related guides
BS 7671 18th Edition: A Working Guide
How BS 7671 is structured, what the parts and appendices cover, and how to actually use it on site.
AFDDs: Arc Fault Detection Devices
What AFDDs detect, where BS 7671 now requires them, and how they differ from RCDs and MCBs.
Consumer Unit Regulations (BS 7671)
The regulations behind consumer units — non-combustible enclosures, RCD/SPD/AFDD provision and RCBO boards.
