Amendment 4 to the wiring regulations landed on 15 April 2026, published jointly by the IET and BSI. It's the largest of the four amendments to the 18th Edition so far, with new requirements covering battery storage, network cabling, and medical locations, and a firm compliance deadline attached: the previous edition is withdrawn on 15 October 2026.

BS 7671 is the UK's national standard for how electrical installations are designed, installed, inspected, and tested. Amendment 4, formally BS 7671:2018+A4:2026, is the fourth update to the current 18th Edition, published as a single consolidated document known as the Orange Book.

Key changes in 18th Edition Amendment 4

Amendment 4 adds four entirely new chapters and sections, and significantly revises a fifth, across these areas:

• Chapter 57 (new): Stationary secondary batteries and battery energy storage systems (BESS)
• Section 716 (new): Power over Ethernet (PoE) installations
• Section 545 (new): Functional earthing for information and communication technology (ICT) systems
• Section 710 (revised): Electrical installations in medical locations
• Chapter 81 (new): Energy efficiency, elevated from advisory guidance to a regulatory requirement

Battery energy storage systems

Chapter 57 is likely to be the change with the widest reach, given how many engineers now do battery storage work alongside their core trade.

If your engineers do battery work, Chapter 57 needs careful reading. Location restrictions will affect how and where you install storage systems. High-risk areas such as lofts and escape routes in domestic properties now have explicit restrictions, which changes how installations must be designed and signed off.

Power over Ethernet and ICT earthing

Section 716 brings PoE explicitly within the scope of BS 7671 for the first time, setting requirements for cable derating, load calculations, and protection for data networks.

Section 545 introduces detailed requirements for functional earthing and functional bonding for ICT equipment and systems, distinct from the protective earthing most engineers already know. For anyone working in commercial buildings with structured cabling or smart building infrastructure, both sections apply directly.

Medical locations

Section 710 receives a major revision, including a new schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors. The updates also clarify the classification of medical location groups and update requirements for insulation monitoring devices.

For facilities management contractors responsible for healthcare estates, these changes affect what your engineers must record and verify during each planned preventative maintenance (PPM) visit. If your PPM schedules were built around the previous version of Section 710, the task lists and evidence requirements will need reviewing before October 2026.

Energy efficiency

Energy efficiency guidance entered BS 7671 as Appendix 17 in the original 18th Edition and was developed through Amendment 2.

Moving energy efficiency from an advisory appendix to a normative chapter means it now carries the same regulatory weight as every other requirement in BS 7671. For contracts that include sustainability obligations, this removes any ambiguity about whether energy efficiency must be considered at design and installation stage.

Who needs to prepare for Amendment 4?

The changes above affect a wider group than engineers sitting updated exams. Knowing who in your organisation carries responsibility is the next step.

• Electrical engineers and installers: must work to the updated standard after the transition deadline
• Inspection and testing engineers: all Electrical Installation Certificates (EICs), Minor Electrical Installation Works Certificates (MEIWCs), and Electrical Installation Condition Reports (EICRs) issued after 15 October 2026 must reference BS 7671:2018+A4:2026
• Facilities and estate managers: must ensure maintenance contracts and specifications reflect the updated standard
• Contract managers and procurement teams: tender documents and SLAs should reference BS 7671:2018+A4:2026
• Training and compliance leads: contractors are encouraged to undertake continuing professional development (CPD) to stay up to date and support continued competence in their role

If your contracts involve battery storage, ICT systems, or healthcare estates, those three areas carry the most immediate action.

Amendment 4 release date and compliance timeline

With the scope of the changes clear, the question becomes when your business needs to be ready.

There is a six-month transition period. Until 14 October 2026, new work can use either Amendment 4 or the previous standard. From 15 October 2026, the previous version is withdrawn and Amendment 4 becomes the edition to use for all work designed to BS 7671, as confirmed in NICEIC's Amendment 4 guidance.

During the transition period, you can work to either the old or new standard, but you should be consistent within each project. For any contract scheduled to complete after October 2026, it is worth specifying to BS 7671:2018+A4:2026 from the start.

What happens if you are not prepared

Missing the October deadline creates risk in several parts of your operation. The consequences are not alarming, but they are worth planning around.

• Certification: all EICs, MEIWCs, and EICRs issued after 15 October 2026 must reference BS 7671:2018+A4:2026. Certificates referencing the withdrawn standard may be rejected by building control or scheme providers
• Scheme standing: from 15 October 2026, your business will need to demonstrate access to Amendment 4 to continue to comply with NICEIC scheme requirements
• Scheme suspension: failure to demonstrate Amendment 4 training could result in scope restrictions or suspension from schemes
• Contract risk: clients and managing agents may require evidence of compliance with the updated standard as a condition of tender award or renewal

BS 7671, commonly known as the IET Wiring Regulations, is not statute law in itself, but it is the recognised benchmark for demonstrating compliance with the Electricity at Work Regulations 1989, and competent person schemes require you to work to its current edition.

How to prepare your business operationally

Knowing the rules is one part of the job. Making sure your workflows, documentation, and records reflect them is another.

Here are the five steps to take before the October deadline:

1. Obtain a copy of BS 7671:2018+A4:2026 and share it with relevant engineers and managers
2. Update compliance forms and certificates to reference the correct edition
3. Review asset registers to include equipment covered by new chapters, particularly BESS installations
4. Update PPM schedules where inspection criteria or task lists have changed under the revised sections
5. Brief contract managers so that new tenders and renewals reference BS 7671:2018+A4:2026 from the outset

Update compliance records and audit trails

Once Amendment 4 takes effect, every new certificate, inspection report, and compliance record must reference the updated standard. For businesses running engineers across multiple contracts and sites, keeping form versions consistent is where gaps tend to appear, task lists fall out of step with the current standard, and the audit trail becomes harder to defend.

In Joblogic, mobile compliance forms can be updated once and rolled out to every engineer, so changes like the new BESS location restrictions or Section 710's revised requirements only need entering in one place. Certificates are stored against the relevant asset automatically, so evidence is there the moment a client or auditor asks for it.

Frequently asked questions

Is BS 7671 Amendment 4 the same as a new 19th edition?

Amendment 4 is not the 19th Edition, it's an update to the existing 18th Edition. A 19th Edition has not been announced. As the IET explains, new editions are only issued when changes are extensive enough that an amendment isn't a suitable vehicle for them.

Do engineers need to resit their full 18th edition exam to comply with Amendment 4?

If you currently hold a valid 18th Edition qualification, you do not need to resit the full exam. A dedicated Amendment 4 update course is the most efficient route for engineers who already hold an 18th Edition qualification.

Do Electrical Installation Condition Reports completed before October 2026 need to be reissued?

An EICR records the condition and safety of the installation at the time of inspection. Observations and codes should reflect the risk found, not just the age of the regulations named on an old certificate. EICRs completed before the transition deadline do not automatically need to be reissued.

Does Amendment 4 apply to existing installations that were already signed off?

Amendment 4 applies to new installations and to any alterations or additions made to existing ones. An installation that was compliant when originally signed off does not need to be retrospectively upgraded unless new work is carried out on it.

What is the difference between Chapter 57 and existing requirements for battery installations?

Before Amendment 4, BS 7671 had no dedicated chapter for stationary secondary batteries, so engineers designing battery storage systems worked from guidance written for other equipment types rather than rules built for batteries specifically. Chapter 57 closes that gap with dedicated requirements, including the location restrictions covered above. This matters for commercial sites adopting energy storage as part of resilience, peak shaving, and renewables planning.