In short
BS 7671 Amendment 4 now applies to new installations. What it changes for downlights: PoE lighting, RCDs for public lighting, AFDDs and medical locations.
Amendment 4 to the IET Wiring Regulations took full effect on 15 October 2026 (UK Electrical News). The IET and BSI published BS 7671:2018+A4:2026 on 15 April 2026 and said the previous version would be withdrawn six months later (IET).
According to Select's overview, a new installation from 15 October 2026 must comply with the latest version. An installation already under construction and designed to the previous version may continue to be erected and verified to it, subject to the contract (Select). This guide picks out the parts that matter most when you specify recessed lighting and downlights.
Power over Ethernet lighting
Amendment 4 adds Section 716, covering Power over Ethernet (PoE). The IET says Ethernet cabling is increasingly used to supply extra-low voltage DC to low-wattage equipment such as LED lighting (IET). Key points from the IET summary:
- Power supplies and cables use SELV or PELV
- Limits are 60 V ripple-free DC in dry locations and 15 V ripple-free DC elsewhere
- Connections must comply with BS ISO/IEC 11801-1
- Connections must carry a continuous operating current of 750 mA per contact
If a scheme uses PoE downlights, confirm early who designs the PoE network and how it will be inspected and tested. Our guide to controls for recessed lighting covers the wider choice between control systems.
RCDs for lighting accessible to the public
Select highlights a clarification to Regulation 714.411.3.4. Except for lighting supplied from a SELV source, lighting that is accessible to the public must have additional protection by an RCD. An informative note says lighting includes luminaires, control equipment and wiring. Lighting is treated as inaccessible if live parts are out of reach, or inside a locked or secured enclosure with an impact rating of at least IK08 (Select).
Section 714 deals with outdoor lighting installations, so this matters most for recessed fittings outside: soffits, canopies, ground-recessed uplights and step lights. See our guide to IP ratings for recessed downlights when choosing fittings for exposed positions.
Arc fault detection
Select reports that AFDDs remain recommended for single-phase final circuits supplying socket-outlets up to 32 A. They must be provided in high-rise residential buildings, a term that broadly aligns with buildings that have a storey more than 18 m above ground, and in HMOs, purpose-built student accommodation and care homes (Select). Check the circuit design with the electrical engineer on residential and care projects.
Medical locations
Section 710 has been significantly revised. Medical locations are now classified as Group 0, 1 or 2. Group 2 areas, such as operating theatres, need medical IT systems, and the IET summary says two independent supplies and a UPS must also be provided (IET). For luminaire choice in clinical spaces, read recessed lighting for healthcare.
What to check on your next project
| Topic | Question to ask |
|---|---|
| Design version | Was the installation designed to A4, or to the previous version under an existing contract? |
| PoE downlights | Who designs, tests and certifies the PoE network? |
| Public outdoor lighting | Is RCD protection provided, or is the lighting SELV or inaccessible? |
| Residential and care | Are AFDDs required for the building type? |
| Healthcare | Which medical location group applies to each room? |
Fittings themselves still need the usual checks. See fire-rated downlights and emergency lighting with recessed fittings. For trimless details, read controls for trimless lighting, and for linear systems, DALI vs Casambi.
299 Lighting can help coordinate fittings, drivers and controls with your electrical designer through project support. Talk to the team about your scheme.
Further reading at 299 Lighting
Next steps on recessedlighting.co.uk
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Start a project →Frequently asked questions
When did BS 7671 Amendment 4 take full effect?
On 15 October 2026, when the previous version, BS 7671:2018+A2:2022+A3:2024, was withdrawn. It was published on 15 April 2026.
Does Amendment 4 cover PoE lighting?
Yes. New Section 716 covers Power over Ethernet, including LED lighting, using SELV or PELV with limits of 60 V ripple-free DC in dry locations and 15 V elsewhere.
Do outdoor recessed lights need RCD protection?
Under Regulation 714.411.3.4, lighting accessible to the public needs additional RCD protection unless it is supplied from SELV or treated as inaccessible.
Can a project designed to the old version still be installed?
Select says an installation under construction and designed to the previous version may continue and be verified to it, subject to the contract.
