BS 7671 Amendment 4 (2026): What Changed

BS 7671 Amendment 4 (2026): What Changed and What It Means on Site

Amendment 4 to BS 7671:2018 was published by the IET and BSI on 15 April 2026, and the previous version — BS 7671:2018+A2:2022+A3:2024 — is withdrawn six months from that date. In practice that means work you certify from October 2026 should be designed, installed and tested to BS 7671:2018+A4:2026. The headline additions are a new chapter on stationary secondary batteries, a new Section 716 for Power over Ethernet, a major rewrite of Section 710 for medical locations, and new material on functional earthing and bonding for ICT systems.

The dates that matter

Two dates run this transition:

15 April 2026 — Amendment 4 published and available to buy. You can work to it from that day.

Six months later — the previous version is withdrawn, so certification against A3:2024 stops being appropriate for new work.

If you have jobs designed under the old amendment but not yet installed, the sensible approach is the one the industry took at every previous amendment: check whether the design still complies, and if there is any doubt, get it re-checked before you energise and certify. Your scheme provider — NICEIC, NAPIT or whoever assesses you — will be looking for A4 competence at your next assessment, so it is worth having the new book on the van rather than the old one.

New chapter: stationary secondary batteries

This is the change most domestic and light commercial sparkies will feel first. Battery storage has gone from a niche add-on bolted to a solar install to something homeowners ask about on its own, and BS 7671 previously had no dedicated chapter for it.

The new chapter sets out requirements covering:

System design for installations whose purpose is electrical storage and supply.

Power conversion equipment, including bidirectional and hybrid inverters.

Suitability of protective devices for two-way energy flow — a real design issue, because a lot of protection was specified on the assumption that power only ever travels one way.

Safety-critical siting: where the battery goes, how it is ventilated, and how fire risk is mitigated.

The reason this matters beyond storage jobs is vehicle-to-home and vehicle-to-grid. As bidirectional charging becomes ordinary, the installation stops being a load and starts being a source some of the time. If you install EV charge points, expect the questions about export, protection and earthing arrangements to get harder, not easier.

What to change in how you work

If you fit batteries or hybrid systems, the practical shift is at design stage rather than on the tools. Check the manufacturer’s instructions against the new chapter rather than assuming the two agree, confirm your protective devices are rated and suitable for current in both directions, and record your reasoning. On a job where power can flow either way, “it worked on the last one” is not a design.

New section 716: Power over Ethernet

Ethernet cabling is now routinely used to supply extra-low voltage DC to LED lighting, cameras, access control and small appliances. Section 716 brings that into the Wiring Regulations properly.

The section is built around SELV and PELV as the protective measure, and it focuses on correct selection of power supplies and cables. The important detail is that Section 716 sits in Part 7 — Special Locations — so it modifies the general rules rather than repeating them. Conventional SELV and PELV limits are 50 V AC and 120 V DC; Section 716 limits them to 60 V ripple-free DC in dry locations and 15 V ripple-free DC everywhere else.

There is also a connection requirement: electrical connections for PoE must comply with BS ISO/IEC 11801-1 and be capable of supporting a continuous operating current of 750 mA per contact.

Why this catches people out

PoE lighting is often installed by data or AV contractors rather than electricians, and the cabling looks like data cabling because it is. But once it is carrying power to a luminaire, it falls inside BS 7671. If you are the one certifying the installation, you need to know what has been run, what supplies it, and whether the connectors are up to the current they are carrying. Heat in a bundled cable tray full of PoE runs is a genuine design consideration, not a theoretical one.

Section 710: medical locations, substantially revised

Section 710 has been significantly revised and aligned with IEC 60364-7-710:2021 and its CENELEC adoption. Medical locations are now classified into Groups 0, 1 and 2.

Group 2 areas — operating theatres and similar — require medical IT systems using a transformer and an insulation monitoring device, so that supply is maintained during a first fault and staff are alerted before a second fault would cause disconnection. Two independent supplies and a UPS must also be provided, positioned as close as possible to the equipment they serve.

Amendment 4 also introduces a schedule of test results for recording the resistance of supplementary protective equipotential bonding conductors.

Most domestic sparkies will never touch a Group 2 location. But dental surgeries, private clinics, cosmetic and aesthetic treatment rooms and vets’ practices are the sort of work that lands with small local firms, and the classification question — which group is this room? — is now the first thing to settle before you quote.

Functional earthing and bonding for ICT equipment

Amendment 4 adds new material on functional earthing and functional equipotential bonding for information and communication technology equipment and systems. This is aimed at installations where earthing is needed for the equipment to work correctly and reliably, not only for shock protection. If you do comms rooms, server cabinets or building management systems, this is the part to read properly.

Everything else

Two more things worth knowing:

Amendment 3:2024 is now incorporated into the main document. You are not cross-referencing two amendments any more.

Further CENELEC Harmonized Documents and IEC standards have been adopted, continuing the pattern of BS 7671 tracking European and international standards as new technologies arrive.

Changes appear throughout all parts of BS 7671:2018+A4:2026, so the four headline items above are the shape of the amendment rather than the whole of it. Read the book.

What a small firm should actually do

Buy the new copy. BS 7671:2018+A4:2026 is available through the IET. One book per van is cheaper than one dispute.

Book the update training. NICEIC, NAPIT, ECA and the training providers all run Amendment 4 update courses. Your scheme assessment will expect it.

Update your certificate templates and software. Whatever you use for EICs, EICRs and minor works, make sure it references the current version of the standard before October.

Review live designs. Anything designed under A3 but not yet installed should be checked.

Tell your customers early. Especially on battery and EV work, where the design implications are real and may change the price.

Where the work comes from while you are getting up to speed

Compliance work has a habit of arriving in bursts, and the quiet weeks in between are when a lot of small firms wish they had a steadier flow of local jobs. Trade Pilot is free to join and charges per lead — you buy credits and only spend one when a real job in your area lands in your inbox. Each lead goes to a maximum of three trades locally, so you are quoting against two others rather than nine. No monthly plan, no listing fee, nothing to pay in a slow month.

FAQ

When does Amendment 4 become compulsory?

Amendment 4 was published on 15 April 2026 and could be used immediately. The previous version, BS 7671:2018+A2:2022+A3:2024, is withdrawn six months from publication, so new work certified after that point should be to BS 7671:2018+A4:2026.

Do I need to redo work that complied with Amendment 3?

No. Installations are certified against the standard in force at the time. Amendment 4 is not retrospective. What matters is that new installations, additions and alterations, and periodic inspection and testing, are carried out to the current version.

Does Amendment 4 mean I need new training?

There is no legal requirement to hold a specific qualification, but registration schemes assess competence against the current standard, and update courses exist precisely for this. If you are NICEIC or NAPIT registered, expect Amendment 4 to come up at assessment.

Does Amendment 4 affect EV charge point installs?

Indirectly and increasingly, yes. The new stationary secondary battery chapter deals with bidirectional and hybrid inverters and with protective devices suitable for two-way energy flow, which is exactly the territory vehicle-to-home and vehicle-to-grid charging moves into. Design carefully and follow the manufacturer’s instructions alongside the standard.

I only do domestic work. Which bits actually apply to me?

The battery chapter, if you touch storage or hybrid systems, and the general changes spread through the other parts. Medical locations and most PoE work will not come up, but the classification questions can appear on small commercial jobs like clinics and surgeries.

Where can I buy BS 7671:2018+A4:2026?

Through the IET, which publishes it jointly with BSI, along with its guidance and training packages.

Related reading: NICEIC vs NAPIT · Level 3 electrical qualification · do I need Part P · EIC vs MEIWC vs EICR