The fourth set of amendments to the Wiring Regulations will be published on 15 April 2026. October 2026 will see withdrawal of the previous versions.
Certified NICEIC businesses like MSE will benefit from support to help implement the new requirements. This will include webinars, events and technical resources.
What do the new Wiring Regulation amendments mean?
The new amendments bring the Wiring Regulations in line with new technologies. This includes integration of renewable energy sources into existing electrical systems. The updates will help to maintain and improve electrical safety. They include:
A new chapter on stationary secondary batteries for electrical storage and supply.
A new section on information and communication technology (ICT) equipment and systems.
A new section on power over ethernet (PoE).
A major revision concerning Medical Locations. This includes a schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors.
An overview of Amendment 4 of the Wiring Regulations
Ferromagnetic enclosures and electromagnetic effects. An alternating current induces an alternating magnetic field, which increases if surrounded by a ferrous metal enclosure. The redrafted regulation clarifies the requirements to reduce risks.
Installation of cables. Support prevents premature collapse of wiring systems. This helps to minimise the risk of obstructions for firefighters. Updates will clarify the purpose of the regulation.
Mechanical stress. Wiring system installations should minimise damage from mechanical stress during installation, use or maintenance. This includes:
impact
abrasion
penetration
tension compression.
The requirements won’t change but reorganising them will improve clarity.
Protection, isolation, switching and control. Coordination is essential between low voltage switchgear and control gear assembly and overload protection. The amended regulation will include load curtailment as one of the conditions.
Isolation and switching. To support a building’s overall fire strategy the fire engineer will specify the location of firefighter's switches. The amendment will include examples such as outdoor lighting operating at high voltage.
Information and communication technology (ICT) equipment and systems. A new section will add additional requirements for functional earthing and functional-equipotential-bonding for ICT systems. This will include broadcast, communication technology and computer network systems. It will provide a clear distinction between functional earthing and protective earthing.
Low voltage generating sets. Amendments add requirements for a suitable protective device where energy flow is bidirectional.
Safety services. Amendments cover the general requirements for safety services, selection and erection of electrical supply systems and electrical safety sources.
Stationary secondary batteries. A new chapter will deal with requirements for stationary secondary battery installations for electrical storage and supply. This won’t apply to batteries included in products such as pluggable uninterruptible power supplies.
Periodic inspection and testing. Users must take account of the notes provided by a qualified professional in a Condition Report. Notes and supporting images must include guidance based on the model Included in the Regulations.
Power over ethernet. A new chapter will deal with distribution of extra-low voltage (ELV) DC power using balanced information technology cables and accessories.
Medical locations. Redrafted regulations for power supplies in group 2 medical locations will help to avoid loss of power due to a single fault.
Energy efficiency. A new chapter concerning energy efficiency will refer to the Building Regulations for England and Wales, Scotland and Northern Ireland. This includes buried cables in ducts and protected escape routes.
More detailed information will become available before release of Amendment 4.
Please get in touch if you have any questions about the Wiring Regulations.
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