If you are arranging an EV charger installation in Surrey this autumn, you may have heard about BS 7671:2018+A4:2026, the latest amendment to the IET Wiring Regulations.
The important point is that Amendment 4 is now available and can be used for new electrical work. As of 3 October 2026, the previous version remains in its transition period until 15 October 2026. After that date, BS 7671:2018+A4:2026 becomes the definitive current version.
For homeowners, this does not mean every existing charger must be replaced. It does mean that new installations should be designed properly around the latest requirements for earthing, open-PEN protection, RCDs, DC fault detection, cable sizing and load management.
What does Amendment 4 mean for a homeowner?
BS 7671 is the UK standard used to design, install and inspect electrical systems. It is not, by itself, a piece of legislation, but it is the essential technical benchmark for competent electrical work and is closely connected with Building Regulations, certification schemes, insurance and grant requirements.
Amendment 4 can be implemented immediately. NICEIC confirms that the previous edition can still be used during the transition period, provided the installation was designed to that version and correctly certified. From 15 October 2026, new work should be designed and certified to A4:2026.
For a homeowner ordering a charger, the practical message is simple:
- Your installer should identify the earthing arrangement at your property.
- The charger should have its own correctly designed circuit.
- The RCD and DC fault protection must match the charger manufacturer’s instructions.
- The installer must consider the capacity and condition of the existing consumer unit.
- The installation should be tested, certified and notified correctly.
The IET’s Amendment 4 publication page confirms that the new Orange Book contains extensive changes across electrical installation work.
The EV requirements that matter most
1. Section 722 still governs EV charging
EV charging installations are covered by Section 722 of BS 7671. This applies to domestic chargers, workplace charging, commercial car parks and larger industrial installations.
Amendment 4 updates the requirements for modern EV equipment, including charging protection, earthing, protective devices and installations capable of bidirectional power flow, such as some vehicle-to-home systems.
2. Open-PEN protection on TN-C-S or PME supplies
Many properties around Redhill and Surrey have a TN-C-S supply, often called a PME supply. With this arrangement, the protective earth and neutral originate from a combined supply conductor before being separated at the property.
A broken or “open” PEN conductor can create dangerous touch voltages. An ordinary RCD does not provide open-PEN protection.
This is one of the biggest practical changes sharpened by Amendment 4. The previous version allowed a “not reasonably practicable” exception to be relied on in some PME situations using a note and risk assessment. Amendment 4 removes that route. For a new outdoor charge point on a TN-C-S (PME) supply, one of the explicit protective arrangements must actually be used.
In plain English, the main routes are:
- A TT arrangement with a suitable earth electrode. This means the charger is connected to its own local earthing arrangement rather than relying on the distributor’s PME earth for fault protection in the same way. It can be a compliant solution, but it has to be designed properly, tested properly and considered alongside the rest of the installation.
- An open-PEN protective device. This is a device that monitors for a dangerous supply condition and disconnects the charger if the voltage rises above roughly 70V in the relevant fault scenario.
- A voltage-limit device operating in the 207–253V band. In simple terms, this is another permitted protective approach that keeps touch voltage within defined limits by controlling the voltage seen under an open-PEN fault condition.
On a typical Redhill domestic installation, the route most commonly chosen is usually an open-PEN protective device, either built into the charger or provided as part of the protective arrangement. The honest reason is that it is often the most straightforward fit for a modern 7kW home charger on an ordinary PME supply, without the extra design and site constraints that can come with creating a separate TT arrangement. A TT solution can still be the right answer on some properties, but it is not normally the default just because the charger is outside.
A separate earth electrode is not automatically required for every charger, and installing an earth rod without considering buried metalwork, bonding and the complete earthing arrangement is not a shortcut to compliance.
3. RCD type and 6mA DC detection
Each charging point needs appropriate residual-current protection, normally rated at no more than 30mA and capable of disconnecting all live conductors as required by the design.
For modern Mode 3 charging, the options typically include:
- A Type B RCD where the charger does not provide suitable DC fault protection.
- A Type A or Type F arrangement where suitable DC residual-current detection is provided.
- A Type A RCD used with compatible 6mA DC detection, often built into the charger or associated protective equipment.
Many modern chargers include certified DC fault detection and an internal switching device. However, the installer must verify the product documentation rather than assume that every “smart” charger provides the same protection.
A Type AC RCD is not an appropriate choice for a modern EV charging point. The IET guidance on RCDs for EVSE explains why charger-generated DC residual current affects RCD selection.
4. Bidirectional charging, V2G and V2H
Amendment 4 also updates EV charging requirements for bidirectional energy flow, such as vehicle-to-home (V2H) and vehicle-to-grid (V2G) systems. Section 722 has been reorganised and aligned with the parts of the Wiring Regulations that deal with generating equipment and low-voltage generating sets.
The practical point is that a bidirectional charger is not treated like a standard one-way 7kW charger. Where power can flow back from the vehicle into the installation or grid, the charger is treated as a generating set. That means:
- Protective devices must be suitable for two-way current flow.
- The protective arrangement has to work properly with electricity flowing in either direction.
- Type B RCD protection is generally required for bidirectional chargers, because Type A is often unsuitable for these systems.
Another important point is that you cannot connect a source to the load side of an RCD if that would stop the RCD detecting residual current properly. For a Surrey homeowner considering V2H or V2G, that means the charger and its protective devices must be designed as a complete system, not simply connected into an existing arrangement that happens to suit a normal charger. A standard one-way 7kW home charger is unaffected by this specific bidirectional requirement.
5. Cable sizing and overload protection
A 7kW home charger is a substantial continuous load. Cable selection is not based simply on choosing a standard cable size. The installer must consider:
- Charger rating and maximum demand.
- Cable length and voltage drop.
- Installation method and thermal conditions.
- Grouping with other cables.
- Protective device rating.
- Whether load management is being used.
Amendment 4 reinforces the need to design EV circuits around their real operating load. A longer cable run to a detached garage in Merstham, Nutfield, Salfords, Bletchingley or Whitebushes may need a different design from a short run through the wall of a Redhill home.
6. Outdoor protection and IP rating
An external charger must be suitable for its environment. The correct IP rating depends on the equipment and location, but the installer should consider rain, splash, condensation, dust, UV exposure, impact and the way cables enter the enclosure.
A charger mounted on an exposed wall, beside a driveway or close to a vehicle needs more than simply a weatherproof-looking case. The manufacturer’s installation instructions and the surrounding conditions must be assessed.
What changes on a typical Redhill installation?
| Area | What the 2026 requirements mean | Likely effect on a standard home |
|---|---|---|
| Cable sizing | Designed for the charger’s continuous load, route and voltage drop | Usually no automatic change, but long runs may need a larger or differently protected cable |
| Consumer unit | Must have suitable capacity, protective devices, earthing and space | Around 40% of Surrey properties may need an upgrade or separate EV consumer unit, according to ADS Electrical’s local experience |
| RCD | Correct type, rating and all-live-conductor disconnection | A Type A or Type B solution may be required; Type AC should not be used |
| DC protection | 6mA DC detection or equivalent protection must be provided | Often built into modern chargers, but it must be confirmed |
| Earthing | PME supplies need a suitable open-PEN protection strategy | May require an approved device, earth electrode or other designed solution |
| Price | Depends on the existing installation and cable route | ADS Electrical pricing is typically £895–£1,250 supplied and fitted; consumer unit upgrades are usually £200–£500 extra |
The regulations do not automatically make every installation more expensive. If the property has a modern consumer unit, suitable earthing and a charger with the required protection built in, the standard design may remain straightforward.
ADS Electrical’s home charging point Surrey service includes a site survey, fixed-price quotation, testing and certification.
Why older Surrey homes need a proper survey
Victorian terraces and 1930s semis around Earlswood, St John’s, Linkfield, Meadvale and Redhill town centre can have older consumer units, limited circuit capacity, altered wiring and complicated cable routes.
A charger may also need to be installed some distance from the main board. This is common where a property has a detached garage, rear parking or an outbuilding.
A survey should establish:
- The main fuse and available supply capacity.
- The type of earthing system.
- The condition of the consumer unit.
- Main bonding and existing RCD protection.
- The safest cable route.
- Whether the charger location is exposed or vulnerable to impact.
- Whether future solar PV, battery storage or a second charger should be allowed for.
For homeowners, home charging is typically much cheaper than public rapid charging. Domestic electricity may cost around 7–9p per kWh on a suitable tariff, compared with approximately 30–85p per kWh at public rapid chargers, although tariffs change.
Commercial, industrial and landlord considerations
For businesses around Holmethorpe, Salfords and the A23/A25 corridor, installing several chargers is not simply a matter of repeating a domestic installation.
A commercial design may need:
- Load management to prevent the site supply being overloaded.
- A maximum-demand assessment.
- Individual protection for each charge point.
- Three-phase distribution and larger containment.
- Network connectivity and an OCPP-compatible back-office system.
- User access control, billing and energy reporting.
- Future capacity for additional chargers.
- Coordination with landlords, facilities managers and other trades.
OCPP is not a replacement for electrical compliance, but it can make a multi-point system easier to monitor and manage.
Landlords should also retain the installation certificate, charger information and maintenance records. Periodic inspection and testing remains important, particularly when tenants change or when an existing installation is altered.
If a grant is being claimed, an OZEV-authorised installer and eligible equipment may be required. GOV.UK provides a directory of approved EV chargepoint installers. OZEV approval is a grant requirement; it is not a substitute for proper electrical design or NICEIC certification.
Do existing chargers need upgrading?
Usually, no blanket replacement is required merely because Amendment 4 has been published.
An existing charger may continue to be acceptable where it was legally and competently installed to the edition applicable at the time, has not been altered, and remains safe.
It should be revisited if:
- The charger or consumer unit is being replaced.
- The circuit is being extended or altered.
- Testing identifies a dangerous or potentially dangerous defect.
- The charger lacks required earthing or DC fault protection.
- The property has undergone major electrical changes.
- A periodic inspection or EICR identifies an issue requiring action.
An EICR is an assessment of the installation’s condition. It is not automatically a demand to bring every part of an older installation up to the latest edition, although genuine safety defects should be addressed.
What to ask your installer
Before accepting a quote, ask:
- Which edition of BS 7671 will the installation be designed to?
- What earthing arrangement does my property have?
- How will open-PEN risk be addressed?
- Does the proposed charger provide certified 6mA DC detection?
- What type and rating of RCD will be installed?
- Will the RCD disconnect all required live conductors?
- Has cable length, routing and voltage drop been included?
- Will the DNO or ENA notification be handled?
- Will I receive an Electrical Installation Certificate?
- Will Part P or Building Regulations notification be completed where applicable?
- Is the installer NICEIC-registered and, if relevant, OZEV-authorised?
- Is the quotation clear about consumer unit upgrades and extra cable runs?
A quote that only lists “charger, cable and installation” without mentioning earthing, RCD protection, testing, certification or DNO notification deserves closer scrutiny.
What the regulations do not require
Amendment 4 does not mean:
- Every home needs a new consumer unit.
- Every charger needs a Type B RCD.
- Every property needs an earth rod.
- Every existing charger must be replaced.
- Every installation needs an AFDD.
- OZEV approval is mandatory for every privately funded charger.
- A charger must be installed in one particular brand or location.
The correct design depends on the property, supply, charger, cable route and intended use.
For reliable EV charging solutions Redhill, ADS Electrical offers free surveys and quotes within 24 hours. We are a NICEIC Approved Contractor, provide a 24-month workmanship warranty, manage DNO notification and coordinate with other trades where required.
To speak to experienced electric car charger installers Surrey, call 07870554498 or email [email protected].
Frequently asked questions
Is BS 7671:2018+A4:2026 compulsory now?
It is available for immediate use. Until 15 October 2026, the previous edition remains within its transition period. From that date, A4:2026 becomes the definitive current version for new work.
Does every EV charger need a Type B RCD?
No. A Type B RCD may be needed where the charger does not provide suitable DC residual-current protection. Many modern chargers use Type A protection with certified 6mA DC detection. The manufacturer’s instructions must be checked.
Do I need an earth rod for an outdoor charger?
Not necessarily. The correct solution depends on the property’s earthing system and charger design. A compliant open-PEN protection device or another permitted arrangement may be used instead.
Will I need a new fuse board?
Not always. An upgrade may be needed where the existing board lacks capacity, suitable RCD protection, space or an acceptable condition. ADS Electrical estimates that around 40% of Surrey properties need some form of consumer unit upgrade before installation.
Do existing EV chargers need to be upgraded for Amendment 4?
Not automatically. Existing installations should be assessed if they are altered, replaced, found defective or inspected with concerns during an EICR.
Is OZEV approval required for every home charger?
No. OZEV authorisation is relevant where a government grant or scheme requires it. It is still important to use a competent, properly registered electrical installer for all installations.
What documents should I receive after installation?
You should expect an Electrical Installation Certificate, test results and confirmation of relevant notification. Your installer should also provide charger information, warranty details and any required DNO or Building Regulations notification.
Can one system charge several vehicles?
Yes, but multiple chargers require proper maximum-demand assessment, individual protection and usually load management. Commercial systems may also benefit from OCPP back-office control and energy monitoring.