18th Edition Amendment 4: The Top 10 Changes You Need to Know
Not a rewrite, just a clean-up. But the details could still catch you out.
By Gordon Routledge
Wednesday 15th April 2026
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Amendment 4 of BS 7671 has landed—and while it’s not a complete overhaul, there are some meaningful updates that installers need to get their heads around.
Some are long overdue. Others tidy up areas that have caused confusion. And a few… well, they’ll definitely get people talking.
Here are ten changes worth knowing about—and what they mean in practice.
1. A Small Change with Big Consequences
A change that looks minor, but affects the entire document.
The regs have replaced Roman numerals with letters in indented lists.
Why?
- To align with other British Standards
- To standardise formatting
In reality, it means every reference point shifts, which has a knock-on effect for training materials, documentation, and existing resources.
2. EICRs: A Change That Will Divide Opinion
Electrical Installation Condition Reports have always been a hot topic—and this update won’t calm things down.
The revised model form:
- Moves “Further Investigation” (FI) to an advisory status
- Means an installation could still be marked satisfactory even with FI observations
Expect debate around how this is applied—and what it means for consistency across the industry.
3. Adding Visual Evidence to Reports
A useful addition to reporting:
You can now include:
- Photographic evidence
- Thermal imaging results
This improves clarity, supports your findings, and helps clients better understand the condition of their installation.
4. Battery Storage Gets Its Own Chapter
Battery systems are no longer treated as an add-on.
New Chapter 57 focuses entirely on stationary secondary batteries used as a source of supply. It covers:
- Installation requirements
- Suitable locations (particularly in domestic settings)
- Fire and shock protection
- Design considerations
With battery storage now a standard part of many installs, this brings much-needed structure to an area that’s been evolving quickly.
5. Parallel Generation: Clearer Rules
Section 551 has been updated to better define how systems operate when multiple energy sources run in parallel.
This includes:
- Requirements for dedicated circuits
- Proper selection of switchgear and controlgear
- Managing thermal risks from multiple supplies
Notably, battery storage systems are treated as generators, not loads—something installers need to factor into system design.
6. Fire Support Requirements Clarified
The requirement to support wiring systems in the event of fire isn’t new—but it has caused confusion.
A new note now makes it clear:
- The purpose of support systems is to prevent collapse
- Not to maintain electrical performance during a fire
It’s a subtle distinction—but an important one for compliance.
7 Power over Ethernet Now Covered Properly
Power over Ethernet (PoE) has been around for years—but its use has exploded.
Now covered under new Section 716, the regs address:
- Heat build-up in bundled cables
- Load considerations
- Installation best practice
With PoE increasingly used for lighting, CCTV, and access control, this is a timely addition.
8 Medical Installations: Key Updates in Section 710
Medical locations remain specialist work, but Amendment 4 tightens things up.
Changes include:
- Revised requirements for independent supplies in Group 2 locations
- A new schedule for recording test results
- Greater focus on supplementary bonding measurements
If you’re working in healthcare environments, expect more detailed documentation and testing expectations.
9 Cable Installation Made Simpler
One of the more practical improvements comes in the form of Table 52.1.
Previously, selecting the correct cable installation method involved jumping between multiple regulations.
Now, it’s brought together into a single, clearer reference point—making decisions quicker and more straightforward on site.
10 Functional Earthing for ICT Systems
As buildings become more data-driven, the regs are catching up.
Section 545 now introduces guidance on functional earthing and bonding for ICT equipment, focusing on:
- Signal integrity
- Electromagnetic compatibility (EMC)
- Correct conductor sizing and identification
This is particularly relevant for server rooms, comms cabinets, and data-heavy installations.
The eFIXX bottom line
Amendment 4 feels less like a revolution and more like a tidying-up exercise—but don’t let that fool you. It sharpens the detail in key areas like batteries, data systems, and reporting, where installations are evolving fast.
And as ever, it’s the small changes that can catch you out.
👉 Want to see every detail for yourself? Pick up a copy of Amendment 4 from our friends at Docstore and make sure you’re working from the latest edition.
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