Section 722 of BS 7671:2018+A4:2026 sets out the electrical installation requirements for EV charging equipment. A4:2026 was issued on 15 April 2026 and may be implemented immediately; BS 7671:2018+A2:2022+Corrigendum (May 2023)+A3:2024 remains current but will be withdrawn on 15 October 2026. A4:2026 makes significant changes to Regulation 722.411.4.1 on the use of a PME supply — the exception concerning reasonable practicability has been deleted — and further changes to external influences, RCDs, socket-outlets and connectors. Review the revised regulation text before certifying new work.
Regulation 722.411.4.1 — earthing on a PME (TN-C-S) supply
A PME earthing facility shall not be used as the means of earthing for the protective conductor contact of a charging point located outdoors, or one that might reasonably be expected to be used to charge a vehicle located outdoors, unless one of the methods below is used. Indent (a) was deleted by BS 7671:2018+A2:2022, which leaves four.
| Method | What the regulation requires | On site |
|---|
| (b) Installation earth electrode | The main earthing terminal is connected to an installation earth electrode by a protective conductor complying with Regulation 544.1.1. The electrode resistance to Earth shall be such that the maximum voltage between the main earthing terminal and Earth in the event of an open-circuit fault in the supply PEN conductor does not exceed 70 V RMS. | Earth rod plus the calculation in Annex A722, Item A722.3. Where the conductor is buried, its cross-sectional area shall be not less than Table 54.1. |
| (c) CPC-to-Earth voltage device | Disconnects the vehicle from the live conductors and from protective earth, in accordance with Regulation 543.3.3.101(b), within 5 s if the voltage between the circuit protective conductor and Earth exceeds 70 V RMS due to an open-circuit PEN fault. It need not operate if the voltage exceeds 70 V RMS for less than 4 s. Reset must be possible only below 70 V RMS. | Annex A722, Item A722.4 gives guidance, including why measuring CPC-to-neutral or CPC-to-MET does not give equivalent safety. |
| (d) Voltage-window device | Disconnects the vehicle from the live conductors and protective earth within 5 s if the utilisation voltage at the charging point, between line and neutral, is greater than 253 V RMS or less than 207 V RMS. Reset must be possible only within 207–253 V RMS. | The common built-in "O-PEN device" in domestic charge points — no earth rod needed. |
| (e) Alternative device | An alternative device to those in (c) or (d) that does not result in a lesser degree of safety, again disconnecting the vehicle from the live conductors and from protective earth in accordance with Regulation 543.3.3.101(b). | Equivalent functionality may be built into the charging equipment itself. |
- 200 Ω is not the criterion. The requirement is the 70 V RMS limit. The 200 Ω figure comes from NOTE 1 to Annex A722, Item A722.3: electrodes with a resistance above 200 Ω may be unstable, so where the three-phase formula gives a higher value the maximum should be taken as 200 Ω.
- Devices under (c), (d) and (e) shall provide isolation and be selected in accordance with Table 537.4.
- Keep the downstream earthing separate. Protective conductors and exposed-conductive-parts downstream of a device provided for (c), (d) or (e) shall have no connection to protective conductors or exposed-conductive-parts of any circuit not protected by the same device, or to any extraneous-conductive-part.
- A TT island is not an automatic answer. NOTE 3 warns that creating a TT earthing system for the charging equipment or the whole installation, as an alternative to methods (b) to (e), may not be appropriate because of the difficulty of achieving sufficient separation from buried metalwork connected to the supply PEN conductor.
- TN-S supplies do not require a separate electrode for outdoor charging, although many installers still provide one.
Enhanced safety — shorter disconnection times
Annex A722, Item A722.4 notes that a device offering shorter disconnection times at higher detected voltages gives an enhanced level of protection to someone touching the vehicle during a PEN failure. The example times below are informative, not a requirement, and are based on IEC TR 60479-5 and on comparable requirements already in Chapter 41.
| Voltage, CPC to Earth | 70 V | 100 V | 200 V | 400 V |
|---|
| Maximum disconnection time | 1 s | 0.7 s | 0.2 s | 0.04 s |
Table A722 of BS 7671:2018+A4:2026. The voltage is the total voltage drop across the sensing element of the device and the earth electrode, if any, in series.
The rest of Section 722, regulation by regulation
- 722.312.2.1 — no PEN conductor — a circuit supplying charging equipment for electric vehicles shall not include a PEN conductor. The split from PEN to separate line, neutral and protective conductors happens upstream of the charging circuit, never within it.
- 722.410.3.5 and 722.410.3.6 — protective measures not permitted — obstacles and placing out of reach (Section 417), non-conducting location (Regulation 418.1) and earth-free local equipotential bonding (Regulation 418.2) shall not be used for EV charging installations.
- 722.531.3 and 722.531.3.101 — RCD and DC fault protection — an AC charging point requires RCD protection with a rated residual operating current not exceeding 30mA, together with protection against DC fault current. That is met either by an RCD of Type B, or by a Type A or Type F RCD combined with a residual direct current detecting device (RDC-DD) to BS IEC 62955. BS 7671 defines an RDC-DD as a device having at least the functionality of detection and evaluation of 6 mA DC residual currents and switching of the monitored circuit — which is why most dedicated chargers with built-in DC fault detection can sit behind a Type A RCD rather than a Type B. A4:2026 changed the RCD requirements in Section 722, so check the current regulation text against the charger manufacturer's instructions before specifying.
- 722.533.101 — overcurrent protection — the circuit protective device must be rated for the maximum continuous operating current. A 32A charge point (about 7.4kW at 230 V) is typically protected by a 32A Type B or Type C device; a 40A charge point (about 9.2kW at 230 V, uncommon in UK homes) needs a 40A device.
- 722.421.1.7.201 — no AFDD required — arc fault detection devices are not required for circuits supplying EV charging equipment conforming to the BS EN 61851 series that incorporate socket-outlets or vehicle connectors conforming to BS EN IEC 62196-2. Worth knowing, because A4:2026 redrafted Regulation 421.1.7 and made AFDDs a requirement on 32A socket-outlet final circuits in Higher Risk Residential Buildings, Houses in Multiple Occupation, purpose-built student accommodation and care homes.
- 722.311.201 — load curtailment — load curtailment, including load reduction or disconnection, either automatically or manually, may be taken into account when determining the maximum demand of the installation or part thereof. This is the regulatory basis for dynamic load management on multi-charger commercial and fleet sites: the supply can be sized for managed simultaneous demand rather than worst-case peak. Document the scheme — the demand calculation has to be defensible.
- 722.413.1.2 — electrical separation — where electrical separation is used as the protective measure, it is limited to one electric vehicle supplied from one unearthed source, through a fixed isolating transformer complying with BS EN 61558-2-4.
- 722.511.101 — equipment standard — EV charging equipment shall comply with the appropriate parts of the BS EN 61851 series. Where a charging point is built into a low voltage switchgear or controlgear assembly, the relevant part of the BS EN IEC 61439 series applies.
- Certification — EV charging installations must be inspected, tested and certificated in accordance with Part 6 of BS 7671. Use the Elec-Mate EV charging certificate to complete the required documentation on site.