BS 7671 Amendment 4: What Electrical Contractors Should Be Preparing For

BS 7671:2018+A4:2026 was officially published by the IET and BSI on 15 April 2026. Six months later, on 15 October 2026, the previous BS 7671:2018+A2:2022+A3:2024 version is withdrawn. For contracting businesses, the practical question is not whether Amendment 4 matters — it is which parts of your operation need to change, and how you evidence that to commercial clients.

Scope: where Amendment 4 applies

The IET states that the standard applies to new low-voltage installations, to additions and alterations to existing installations, and to periodic inspection and testing. That scope is worth repeating internally, because it is frequently overstated in the trade press. Amendment 4 does not mean every existing installation suddenly requires replacement, and any contractor selling it that way is storing up a credibility problem with professional clients.

Stationary secondary batteries

Amendment 4 brings dedicated treatment of stationary secondary batteries. This matters because battery installations have moved from a niche renewables add-on to a standard component of commercial energy schemes sitting alongside solar PV, EV charging and metering. Contractors quoting battery work now need to be able to talk credibly about protection, isolation, location and the interaction between the battery system and the wider installation. We cover the commercial angle in our article on battery storage and BS 7671.

Power over Ethernet

Power over Ethernet is one of the clearest signals of where commercial buildings are heading. Lighting, sensors, access control, cameras and building controls increasingly draw power over data cabling, which pulls a set of considerations — cable bundling, current-carrying capacity, heat, segregation, documentation — into territory that electrical contractors are expected to own. Firms with both electrical and structured cabling capability are unusually well placed here.

Medical locations

Changes affecting medical locations are relevant well beyond hospitals. Private clinics, dental practices, occupational health suites, veterinary premises and healthcare tenancies within managed commercial buildings can all fall within scope depending on the nature of the treatment carried out. Contractors working in the healthcare and managed-property space should confirm competence and design responsibility carefully before quoting.

What clients will actually ask you

• Are your certificates and reports issued against the current edition of BS 7671?
• Which of your engineers have completed update training, and when?
• Who takes design responsibility on our projects, and what is their competence evidence?
• Can you carry out periodic inspection and testing across a multi-site portfolio to a consistent standard?
• Do you have capability in battery storage, EV, PoE and controls, or do you subcontract it?
• Are your registrations, accreditations and insurances current and verifiable?

Those questions are procurement questions as much as technical ones. Facilities managers, managing agents and housing providers are not usually assessing your terminations; they are assessing whether appointing you is defensible.

Where the commercial opportunity sits

Regulatory transitions tend to concentrate demand in a few areas: testing and reporting activity rises, remedial work follows reports, and specification updates pull in upgrade, energy-storage and smart-building capability. Contractors who can service more than one of those categories become considerably more useful to a client managing a portfolio.

Electrical requirements are already beginning to come through Regency, and we want competent contractors vetted and ready rather than starting the process after a requirement has already been allocated.

Official sources

• IET and BSI publish Amendment 4:2026 to BS 7671:2018