BS 7671:2018+A4:2026 is officially here. If you manage a commercial property or work as a commercial electrician, this isn’t just another paperwork update. It marks a significant shift in how we handle modern technologies like large-scale battery storage and smart building infrastructure.
The publication landed on 15 April 2026. You have a six-month transition period where you can still use Amendment 3, but from 15 October 2026, Amendment 4 becomes the mandatory standard for all new work.
At Dragon Security & Electrical Ltd, we stay ahead of these changes so our clients don’t have to worry about compliance. Here are the five most critical changes in Amendment 4 that will impact your next project or safety inspection.
1. New Chapter 57: Stationary Secondary Batteries
The rise of Battery Energy Storage Systems (BESS) and PV solar storage has outpaced the previous regulations. Amendment 4 introduces Chapter 57 to fix that. It provides a dedicated set of rules for selecting, installing, and protecting stationary battery systems.
Why it matters:
Batteries are a high-fire-risk asset. The new rules focus heavily on thermal effects, ventilation, and physical location.
- Location Restrictions: There is now strong discouragement against installing batteries in roof spaces or lofts. Access for emergency services and containment of fire are the primary concerns here.
- Ventilation: Proper gas management and heat dissipation are now strictly regulated based on battery chemistry.
- Protection: New requirements for overcurrent protection and specific switching arrangements ensure that systems can be safely isolated during maintenance or emergencies.
For property owners, this means your “cheap” battery install in the attic might no longer meet compliance standards. If you’re looking at renewables, check out our renewables services to ensure your storage is up to code.
2. New Section 716: Power over Ethernet (PoE)
Smart buildings are the future, and PoE is the backbone. For the first time, PoE systems: where data cables also carry extra-low-voltage DC power: are explicitly included in the scope of BS 7671.
Why it matters:
When you bundle hundreds of data cables together in a tray or conduit, and each one is carrying power to a smart light, sensor, or access control unit, they get hot.
- Thermal Limits: Section 716 addresses the temperature rise in these cable bundles.
- Derating: Electricians now need to perform formal cable sizing and derating calculations for PoE, much like they do for traditional power cables.
- Smart Integration: This affects everything from CCTV cameras to smart office lighting. Using the wrong cable or over-stuffing a conduit could lead to thermal failure and signal loss.
3. Section 710: Revised Medical Locations
The rules for medical locations have seen a major rewrite. This doesn’t just apply to large hospitals; it covers care homes, dental clinics, and specialized treatment centres.
Why it matters:
Patient safety relies on uninterrupted power and the total elimination of touch voltages.
- Resilience: There are stricter requirements for continuity of supply in Group 1 and Group 2 locations (where patients are under treatment).
- Bonding Records: A new schedule has been introduced specifically for recording the resistance of supplementary protective equipotential bonding.
- Traceability: You can no longer just “check” it; you must document the measured resistance to ensure long-term verification.
If you manage a healthcare facility, your electrical testing services just got a lot more detailed.
4. Section 545: Functional Earthing for ICT
Modern commercial offices are packed with ICT equipment that is sensitive to electrical noise. Section 545 is a new addition that focuses on functional earthing and functional equipotential bonding.
Why it matters:
Functional earthing isn’t about safety (that’s what protective earthing is for); it’s about system performance and signal integrity.
- EMC Support: It provides clear guidance on how to manage electromagnetic compatibility (EMC) without compromising the safety of the protective earth.
- Data Reliability: By reducing electrical noise, you prevent “ghost” errors in servers and data equipment.
- Coordination: Amendment 4 clarifies how these two earthing systems must be connected and documented, ensuring that “noise control” never comes at the cost of a blown fuse or a shock risk.
5. EICR Overhaul: Photos, Thermals, and Coding
The way we conduct an Electrical Installation Condition Report (EICR) has changed. The goal is to move away from subjective “opinions” and toward objective, evidence-based reporting.
Why it matters:
Transparency is the focus of this overhaul.
- Use of Photography: It is now becoming standard practice (and heavily encouraged in the new appendices) to include photos of defects within the report. Seeing a scorched terminal is much more effective than just reading a code.
- Thermal Imaging: For commercial and industrial sites, thermal imaging is now a key part of the inspection toolkit. It identifies hotspots that aren’t visible to the naked eye.
- Observation Codes: Coding (C1, C2, C3) has been clarified to ensure consistency across the industry. A “C2” from one company should mean the same thing as a “C2” from another.
Staying Compliant
BS 7671 Amendment 4 is a reflection of how fast technology is moving. Whether it’s the batteries in your plant room or the PoE cables in your ceiling, the standards have caught up to the reality of 2026.
If you’re unsure if your property meets the new standards, or if you need a professional EICR that goes beyond the bare minimum, get in touch with the team. We provide expert electrical testing services throughout North Wales and the UK.
Dragon – Secure Living Starts Here.