The 5th Edition Code of Practice explained against BS 7671:2018+A4:2026 Section 722 — load curtailment, PME and open-PEN protection, cable sizing, RCD and AFDD selection, smart charging law, and the paperwork you leave behind.
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Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.
The short answer
The IET Code of Practice for Electric Vehicle Charging Equipment Installation, 5th Edition (2023) is the UK industry-standard guidance for installing EV charge points. It sits alongside BS 7671 Section 722 and covers supply arrangements, earthing — especially the PME broken-PEN risk — load and demand management, RCD selection with DC fault detection, and installation, testing and handover.
It is guidance, not law, and there is no free official PDF. The requirements you actually certify against are in BS 7671:2018+A4:2026 Section 722 and Annex A722: Reg 722.312.2.1 (no PEN conductor in an EV circuit), Reg 722.411.4.1 (PME not permitted for outdoor charging unless method (b) to (e) is applied, with 5 s disconnection at 70 V RMS under (c)), and Reg 722.311.201 (load curtailment may be counted in maximum demand).
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01 · EV Charging Guide
| Current edition | 5th Edition, published 2023 |
|---|---|
| Publisher | Institution of Engineering and Technology (IET) |
| Free PDF? | No — it is a copyrighted publication sold by the IET Shop and trade distributors. Copies circulating as free downloads are unauthorised. |
| Legal status | Guidance, not a British Standard. Not mandatory in itself. |
| What is mandatory | BS 7671:2018+A4:2026 Section 722 — the regulations you certify against. |
| Covers | Domestic, workplace, public and fleet depot charging; Mode 3 (AC) and Mode 4 (DC rapid) |
The IET Code of Practice for Electric Vehicle Charging Equipment Installation is a technical guidance document that supplements BS 7671:2018+A4:2026 with specific guidance on the design, installation, verification, and maintenance of EV charging equipment. The current edition is the 5th Edition, published in 2023.
The Code of Practice (CoP) exists because EV charging installations present technical challenges that Section 722 states as requirements but does not explain: outdoor earthing risks on PME supplies, load management on multiple charger installations, DC fault current protection, communication protocols, and the interaction between the vehicle, charger, and electrical installation.
The CoP is not a British Standard and compliance is not a strict legal requirement, but it is the accepted industry standard. Competent person schemes expect EV charger installations to follow it. Building control bodies and OZEV (the Office for Zero Emission Vehicles, formerly OLEV) grant funding applications reference the CoP as the baseline technical standard. An electrician who installs an EV charger without following it is exposed on liability if something goes wrong.
What the CoP cannot do is override BS 7671. Where the two appear to differ, the regulation is what an inspector will hold you to — so every figure on this page is quoted against Section 722 and Annex A722, with the CoP cited only where it adds guidance the standard does not.
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Every key change in the 2026 amendment on one page. AFDDs, TN-C-S protection, new schedule columns, model forms. Pinned on your van dash.
02 · EV Charging Guide
Before installing any EV charger, assess the load on the existing installation. The purpose is to determine whether the existing supply has sufficient capacity to support the additional load without exceeding the main fuse or supply capacity.
A domestic 7 kW charger draws 32 A — a significant addition to a typical domestic supply protected by a 60 A or 80 A main fuse. If the existing maximum demand (cooker, shower, heating, and other large loads) is already close to the main fuse rating, adding a 32 A EV charger could blow the main fuse during periods of high demand.
If the existing supply cannot support the EV charger even with load curtailment, the options are: request a supply upgrade from the DNO (which can take weeks and cost thousands), install a lower-power charger (for example, 3.6 kW at 16 A instead of 7 kW at 32 A), or install a dedicated three-phase supply if one is available.
03 · EV Charging Guide
Earthing is the most technically critical aspect of EV charger installation, and it is governed by two separate regulations that are often run together. They are not the same rule.
| Regulation | What it says |
|---|---|
| 722.312.2.1 | A circuit supplying charging equipment for electric vehicles shall not include a PEN conductor. On a TN-C-S supply the EV circuit must therefore originate downstream of the point at which the PEN is split into separate protective earth and neutral conductors. |
| 722.411.4.1 | 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 that might reasonably be expected to be used to charge a vehicle located outdoors, unless one of methods (b) to (e) below is used. |
The underlying problem: in a PME system the earth and neutral are combined in the supply cable as the PEN conductor. If that conductor breaks between the DNO transformer and the property, all metalwork connected to the PME earth can rise towards mains potential relative to true Earth. A person standing outdoors on damp ground while touching the vehicle or charger is directly in that path.
Method (a) was deleted by BS 7671:2018+A2:2022. Four methods remain, and an open-PEN device is only one of them:
| Method | Requirement |
|---|---|
| (b) 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 must be low enough that the voltage between the main earthing terminal and Earth cannot exceed 70 V RMS during an open-PEN fault. Where buried, that protective conductor must be no smaller than Table 54.1 requires. |
| (c) Open-PEN device | A device that disconnects the vehicle from the live conductors and from protective earth within 5 s of the CPC-to-Earth voltage exceeding 70 V RMS. It need not operate if the voltage exceeds 70 V for less than 4 s. It must provide isolation, be selected per Table 537.4, and only be resettable once the voltage is back below 70 V RMS. |
| (d) Voltage window | A device that disconnects within 5 s if the utilisation voltage at the charging point, line to neutral, goes above 253 V or below 207 V RMS. Resettable only once the voltage is back inside 207–253 V RMS. |
| (e) Equivalent device | An alternative device to (c) or (d) that does not result in a lesser degree of safety. Equivalent functionality may be built into the charging equipment itself. |
Downstream of a device provided for (c), (d) or (e), the protective conductors and exposed-conductive-parts must have no connection to the protective conductors or exposed-conductive-parts of any circuit not protected by the same device, and no connection to any extraneous-conductive-part.
Annex A722 is informative. It describes an optional enhanced safety provision in which the device disconnects faster the higher the detected CPC-to-Earth voltage, based on IEC TR 60479-5. These are not the baseline requirement — 722.411.4.1(c) still sets 5 s at 70 V RMS.
| CPC-to-Earth voltage | 70 V | 100 V | 200 V | 400 V |
|---|---|---|---|---|
| Max disconnection time | 1 s | 0.7 s | 0.2 s | 0.04 s |
NOTE 3 to Regulation 722.411.4.1 warns that creating a TT earthing system for the charging equipment, or for the whole installation, as an alternative to using a PME earthing facility with one of methods (b) to (e) may not be an appropriate solution — because of the difficulty of providing sufficient separation from buried metalwork connected to the supply PEN conductor. Where you do go down this route, the separation distance has to be justified, not assumed.
BS 7671:2018+A4:2026 Regulation 722.413.1.2 limits the protective measure of electrical separation to the supply of one electric vehicle from one unearthed source, supplied through a fixed isolating transformer complying with BS EN 61558-2-4. An example arrangement for supplying a Class I charging point from a separated source is shown in Annex A722, Item A722.5 (Figure A722). Note that isolating transformers can draw high inrush currents, so the primary-side overcurrent device needs selecting accordingly.
For TN-S earthing systems, where the earth and neutral are separate throughout, the open-PEN risk does not arise and the earthing arrangement can be used directly for EV charging without these additional measures. TN-S supplies are far less common in the UK — most domestic supplies are TN-C-S (PME).
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Elec-Mate's EV charger certificate template includes the open-PEN verification checklist from the IET CoP.
04 · EV Charging Guide
Cable sizing for EV charger circuits follows the standard BS 7671 procedure, with particular attention to run length (usually longer than a typical domestic circuit) and to the fact that EV charging is a continuous duty rather than an intermittent load.
| Charger | Design current | Typical cable |
|---|---|---|
| 7 kW single-phase | ≈32 A | 6 mm² 3-core armoured for runs up to roughly 30 m; 10 mm² beyond that, where voltage drop becomes the limit |
| 22 kW three-phase | ≈32 A per phase | 6 mm² 5-core armoured for moderate runs; 10 mm² for longer runs — check with the three-phase voltage drop calculator |
| 3.6 kW single-phase | ≈16 A | 2.5 mm² may be acceptable on short runs where the reduced charging speed is acceptable to the customer |
Indicative starting points only. Every one of these still needs the full calculation against the correct Appendix 4 table for the cable actually installed.
Quoting a current-carrying capacity from the wrong table is the most common cable-sizing error on EV jobs, because armoured cable and flat twin-and-earth sit in completely different places in Appendix 4. Each reference method has its own tabulated column — BS 7671 publishes no installation-method multiplier, so applying one on top of a Method C rating applies the method twice.
| Table | Cable it actually covers |
|---|---|
| 4D1A | Single-core 70 °C thermoplastic, non-armoured, with or without sheath — not flat twin-and-earth |
| 4D2A | Multicore 70 °C thermoplastic insulated and sheathed, non-armoured |
| 4D4A | Multicore armoured 70 °C thermoplastic insulated |
| 4D5 | 70 °C thermoplastic insulated and sheathed flat cable with protective conductor — this is twin-and-earth |
| 4E series | The 90 °C thermosetting (XLPE) equivalents — 4E1A single-core non-armoured, 4E2A multicore non-armoured, 4E4A multicore armoured |
Most UK armoured cable sold for EV work is XLPE insulated, which puts it in the 4E series, not the 4D series. Read the tabulated capacity for your actual cable, reference method and core count straight out of the table, then apply the rating factors from Tables 4B1 (ambient), 4C1 (grouping) and Appendix 4 Section 2.6 (thermal insulation) before comparing against the design current.
The charger is often on the side of a garage or at the end of a driveway, 20 to 40 metres from the consumer unit, so voltage drop tends to force the cable size before current-carrying capacity does. Table 4Ab of BS 7671 gives 3% for lighting and 5% for other uses on a low voltage installation supplied directly from a public LV distribution system — so 5% applies to an EV circuit, which is 11.5 V on a 230 V single-phase supply. Where the wiring system exceeds 100 m, that figure may be increased by 0.005% per metre beyond 100 m, capped at a 0.5% increase.
Use the voltage drop calculator to check the run before you order the drum.
05 · EV Charging Guide
The Electric Vehicles (Smart Charge Points) Regulations 2021 came into force on 30 June 2022 and make smart functionality a legal requirement for private EV chargepoints sold or installed in Great Britain. This is separate legislation from BS 7671 — meeting Section 722 does not discharge it.
| Requirement | What the regulations say |
|---|---|
| Off-peak default | Pre-set default charging hours must fall outside peak hours, defined in regulation 10(4)(b) as 08:00 to 11:00 and 16:00 to 22:00 on weekdays. Both windows — quoting only the morning one is a common mistake. |
| User override | The owner must be able to accept, remove or change the default charging hours on first use and afterwards. |
| Randomised delay | Under regulation 11 the chargepoint must be capable of a random delay of up to 1800 seconds, and by default operates with a random delay of up to 600 seconds, so that units do not all start together on the same tariff boundary. |
| Measuring system | The chargepoint must measure or calculate imported and exported electricity in watt-hours or kilowatt-hours, accurate to within 10%. |
| Security | Schedule 1 sets security requirements covering password configuration, secure boot and software updates, encryption, tamper protection and security logging. |
Regulation 3 excludes three separate things, and they are often run together incorrectly: non-smart cables; public charge points, at any power rating, including those in public car parks; and rapid charge points, meaning those allowing a transfer of not less than 50 kW. A 50 kW unit is therefore outside the regulations, not inside them.
OCPP (Open Charge Point Protocol) is the industry-standard communication protocol for EV chargers. It lets chargers from different manufacturers talk to a central management system for monitoring, billing, load management, and remote diagnostics. OCPP 1.6 is the most widely deployed version; OCPP 2.0.1 adds device management, improved security, and support for ISO 15118 (vehicle-to-charger communication for plug-and-charge).
For commercial installations with multiple chargers, OCPP connectivity is what makes load management and billing possible at all. Confirm the charger has network connectivity (Wi-Fi, Ethernet, or 4G) and that the OCPP back-end is configured and tested during commissioning — not left for the customer to sort out afterwards.
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06 · EV Charging Guide
EV charger circuits need specific protection devices that differ from a standard domestic circuit in two ways: the RCD has to cope with DC fault current, and Section 722 carries an explicit AFDD exemption.
Typically a 32 A Type B or Type C MCB for a 7 kW charger, sized so that Ib ≤ In ≤ Iz per Regulation 433.1.1. Type C may be needed where the charger has significant inrush on start-up. An RCBO gives overcurrent and residual current protection in one device.
Regulation 722.531.3.101 governs RCD selection for EV charging installations. Its indents reference BS IEC 62955, the standard for the residual direct current detecting device (RDC-DD) used for mode 3 charging. BS 7671 Part 2 defines an RDC-DD as a detection device having at least the functionality of detection and evaluation of 6 mA DC residual currents and switching of the monitored circuit. In practice DC fault current is handled either by a Type B RCD or by a Type A RCD combined with an RDC-DD — which most modern chargers provide internally, which is why their instructions call for only a Type A upstream. Confirm it in the manufacturer literature rather than assuming; a Type B device is several times the cost, and fitting the wrong one is not a defect you can test your way out of.
Watch the discrimination note in Chapter 53 too: a Type AC RCD should not be fitted upstream of a Type A, Type F or Type B device, and a Type A should not be fitted upstream of a Type F or B, because the load characteristics the downstream device was chosen for can impair the upstream one — commonly called RCD blinding.
Regulation 722.421.1.7.201 states that AFDDs 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. This matters because A4:2026 redrafted Regulation 421.1.7 to make AFDDs a requirement on socket-outlet final circuits up to 32 A in Higher Risk Residential Buildings, Houses in Multiple Occupation, purpose-built student accommodation and care homes, and a recommendation elsewhere. A dedicated EV circuit feeding compliant equipment does not pull that requirement in.
Regulation 443.4.1 was redrafted at A4:2026. Protection against transient overvoltages must be provided where the consequence could result in (a) serious injury to, or loss of, human life; (b) failure of a safety service as defined in Part 2; or (c) significant financial or data loss. For all other cases, protection must be provided unless the owner of the installation declares it is not required because any loss or damage is tolerable and they accept the risk. A4:2026 also deleted Regulation 443.5 (the risk assessment method) and Annex A443 — you can no longer calculate your way out of an SPD, so an SPD is the default position and the omission is the thing that needs justifying. EV chargers carry electronic control circuitry that is susceptible to surge damage.
A means of isolation must be provided so the EV circuit can be safely isolated for maintenance. This can be the MCB or RCBO in the consumer unit where that is accessible.
07 · EV Charging Guide
Installing an EV charger is notifiable work under Part P of the Building Regulations (Approved Document P) because it involves adding a new circuit. Four things need to exist when you leave site:
On new dwellings and major renovations, Approved Document S (Infrastructure for the Charging of Electric Vehicles) applies alongside Part P. Part S requires EV charging infrastructure — cable containment and, in some cases, charge points themselves — to be installed as part of the building work. It covers new residential buildings with associated parking and existing residential buildings undergoing major renovation where parking is provided. Satisfying Part P does not satisfy Part S; they are notified and assessed independently.
08 · EV Charging Guide
Elec-Mate covers the EV charger workflow from load assessment through to certificate delivery and invoicing.
Enter the charger power, cable type, and run length. Elec-Mate returns the minimum cable size with correction factors applied and verifies voltage drop against the Table 4Ab limit. Works for single-phase (7 kW) and three-phase (22 kW) chargers.
Dedicated EV installation certificate template with the IET CoP checklist built in: earthing verification, open-PEN protection details, load management settings, and full test results. Exports as a professional PDF.
In the app
Cable sizing with Appendix 4 correction factors, voltage drop to Table 4Ab, and an EV charger certificate with the IET CoP checklist built in.
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