BS 7671 Amendment 4 (2026) Summary: Key Changes for Battery Storage and PoE Installations

BS 7671 Amendment 4 will be published in April 2026 and becomes mandatory in October 2026. This update introduces important changes affecting battery energy storage systems (BESS) and Power over Ethernet (PoE) installations in commercial buildings.

• When Amendment 4 comes into force

• Key changes impacting commercial electrical systems

• New safety considerations for battery storage

• How PoE installations are now treated under regulations

• What this means for EICR inspections and remedial works

• What facilities managers should do now to stay compliant

BS 7671 Amendment 4 represents one of the most relevant updates in recent years for commercial buildings.

Unlike previous updates, this amendment focuses heavily on emerging technologies already widely installed, particularly battery storage and PoE systems.

For facilities managers and contractors, this creates both a challenge and an opportunity to get ahead before enforcement begins.

When Does BS 7671 Amendment 4 Come Into Force?

The timeline is clear:

• Publication expected: April 2026

• Mandatory compliance: October 2026

This short transition period means businesses should begin reviewing systems now rather than waiting for enforcement.

Early preparation reduces the risk of costly upgrades later.

Why Amendment 4 Matters More Than Previous Updates

Amendment 4 is not just a technical revision. It reflects how buildings are evolving.

Modern commercial sites now include:

• EV charging infrastructure

• Battery storage systems

• Smart building controls

• Low voltage distributed power such as PoE

These systems introduce new risks that older regulations did not fully address.

This is why Amendment 4 focuses on practical safety considerations, not just design standards.

Battery Energy Storage Systems: A Major Regulatory Focus

Battery energy storage systems are now common across UK commercial sites.

They are often installed to:

• Store renewable energy

• Reduce peak demand costs

• Support EV charging networks

• Improve energy resilience

However, these systems introduce unique electrical and fire risks.

Key Risks Associated With Battery Storage

Battery systems can present:

• Thermal runaway risk

• High fault current potential

• Fire propagation challenges

• Complex isolation requirements

Amendment 4 is expected to strengthen guidance around:

• System protection and isolation

• Installation location and segregation

• Integration with other electrical systems

• Ongoing inspection and maintenance

For facilities managers, this means battery systems must be treated as high-risk electrical assets, not just energy solutions.

Fire Safety and Battery Systems

Battery installations must also align with the building’s wider passive fire protection strategy.

This includes:

• Maintaining compartmentation

• Ensuring correct fire stopping around penetrations

• Protecting escape routes

• Managing fire load within plant areas

Electrical compliance and fire safety must work together.

Power over Ethernet (PoE): Small Systems, Big Impact

PoE is expanding rapidly across commercial buildings.

It is used to power:

• CCTV systems

• Access control

• LED lighting

• Sensors and smart building devices

While each individual circuit is low voltage, the cumulative effect of multiple PoE cables can create risk.

Why PoE Is Being Addressed in Amendment 4

Key concerns include:

• Cable heating in bundled installations

• Load distribution across multiple circuits

• Long-term thermal effects on infrastructure

• Installation practices that were previously unregulated

Amendment 4 is expected to clarify how PoE systems should be:

• Designed

• Installed

• Protected

• Inspected

For many buildings, this will be the first time PoE is formally treated as part of electrical compliance.

What This Means for EICR Inspections

Amendment 4 will directly influence how electrical systems are assessed.

Future Electrical Installation Condition Reports (EICR) are likely to:

• Identify risks linked to battery storage systems

• Assess PoE installations more thoroughly

• Reference updated compliance expectations

• Highlight previously unregulated risks

This means some installations may receive observations that were not previously identified.

Will You Need Remedial Works?

Not all buildings will require upgrades immediately.

However, where risks are identified, corrective action may be required through EICR remedial works.

This could include:

• Improving isolation for battery systems

• Upgrading protection devices

• Reconfiguring PoE installations

• Addressing thermal risks in cable runs

Proactive review now can prevent reactive costs later.

Practical Steps to Prepare Before October 2026

Facilities managers should use the transition window to prepare.

Key actions include:

• Identifying any battery storage systems on site

• Reviewing where PoE is used across the building

• Assessing electrical load and system capacity

• Scheduling an updated EICR inspection

• Ensuring all future installations align with latest guidance

Preparation now ensures smoother compliance later.

How Protest ES Ltd Supports Compliance With BS 7671 Updates

 

Protest ES Ltd helps businesses stay ahead of regulatory changes through:

• Professional EICR inspections

• Identification of emerging compliance risks

• Delivery of EICR remedial works

• Integration with wider electrical and fire safety strategies

Our approach ensures your systems remain safe, compliant, and future-ready.

Frequently Asked Questions About BS 7671 Amendment 4

When does BS 7671 Amendment 4 become mandatory?

It is expected to become mandatory in October 2026 following publication in April 2026.

What are the main changes in Amendment 4?

The key focus areas include battery energy storage systems and Power over Ethernet installations, along with updated safety guidance for modern electrical systems.

Will existing installations fail under Amendment 4?

Not automatically. However, new risks may be identified during inspections and may require action.

Do battery storage systems need to be upgraded?

Only if they present safety risks or do not meet updated guidance identified during inspection.

Is PoE now regulated under BS 7671?

Yes. Amendment 4 is expected to provide clearer guidance on how PoE systems should be installed and assessed.

Should I get an EICR before October 2026?

Yes. A current EICR helps identify any issues early and allows time to plan remedial works if needed.