Part S EV Charging Infrastructure: New Dwellings, 7kW Socket Requirements and Cable Routing

Q: Does Part S apply to an existing house where I am adding a garage?

If you are building a new garage attached to an existing dwelling, Part S may apply as a new associated parking space is being created. Specifically, if the new garage is for a vehicle and serves the dwelling, you should check with your local Building Control Officer whether Part S is triggered. The safest approach is to include a 7kW charge point in the new garage as part of the works — the cost is modest relative to the garage construction.

Q: Can I install a 3-pin socket for EV charging instead of a dedicated charge point?

No, where Part S requires a charge point. A 3-pin socket (Mode 2 charging, via a domestic extension lead or ICCB) is not compliant with the 7kW smart charge point requirement. Mode 2 charging from a domestic socket is also slower (max 3kW at 13A) and creates risk from sustained high current through a non-dedicated circuit. A dedicated 7kW Mode 3 charge point is the correct installation.

Q: Our consumer unit is full — can we still comply with Part S?

Yes, but the consumer unit must be upgraded or a sub-board installed to accommodate the 32A RCBO for the charge point circuit. This is common on older properties. The consumer unit upgrade is notifiable work under Part P. Budget for this as part of the charge point installation quote.

Q: Does Part S apply in Scotland?

Scotland has its own building standards under the Building (Scotland) Act 2003. Section 3.18 of the Scottish Building Standards covers electric vehicle charging provision, with requirements phased in from 2022. Check with the local authority building standards department for current requirements — the framework is similar to Part S but has some differences.

Quick Answer

Approved Document S (Electric Vehicle Charging Points) applies to new residential buildings and buildings undergoing renovation. New dwellings with associated parking must have a 7kW EV charge point as standard. The charge point must comply with the Electric Vehicles (Smart Charge Points) Regulations 2021, meaning it must be smart-enabled. Cable routing (cable containment to the parking space) is required even where a charge point is not yet installed.

Summary

Approved Document S came into force in England on 15 June 2022. It implements requirements for EV charging infrastructure across new and renovated buildings, responding to the government's target to phase out new petrol and diesel car sales. For developers and builders, Part S adds a mandatory element to new residential projects and creates cable routing obligations for some renovation projects.

The requirement is not simply to install a socket — it mandates a specific type of smart charge point that can communicate with the grid, respond to time-of-use tariffs, and potentially support vehicle-to-grid (V2G) in future. This is the Electric Vehicles (Smart Charge Points) Regulations 2021 (EVCSR) requirement, which runs alongside Part S.

For electricians, Part S generates new work: charge point installation is notifiable work under Part P, and the specific requirements for EVSE (Electric Vehicle Supply Equipment) create technical considerations around earthing, circuit protection, cable sizing, and smart connectivity. Understanding both the building regulations trigger and the technical installation requirements is essential.

Key Facts

Approved Document S — Electric vehicle charging infrastructure; in force 15 June 2022 (England)
Wales — Similar requirements under Technical Guidance Document Q (Building Regulations Advisory Committee)
New dwelling with parking — Must have a 7kW EV charge point
Mixed-use with residential — Residential element must comply
Renovation trigger — Renovations costing more than 10% of property value AND creating or modifying ≥10 parking spaces must install EV infrastructure
7kW requirement — Mode 3 Type 2 socket at minimum 7kW; single phase; must be smart
Smart charge point regulations — EVCSR 2021 (SI 2021/1467): all EV charge points in scope must be smart, with randomised delay and ability to respond to signals
Cable only (cable containment) — Where parking is remote from the building, cable routing from consumer unit to the parking space is required even if no charge point is immediately installed
Part P notification — EV charger installation is notifiable electrical work under Part P in England
DNO notification — For 7kW and above, distributor notification under BS 7671 and G98 (if smart metering involved) may be required
Maximum load — 7kW = 32A at 230V; must be assessed against existing consumer unit capacity and supply fuse
Earthing — EVSE requires protective earthing; TN-C-S supplies require additional PME protective measures or TT earthing at charge point
RCD protection — All EVSE must be protected by 30mA RCD; RCBO or separate RCD; vehicle-specific EV RCBO (type B or B+) recommended

Quick Reference Table

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Building Type	Part S Applies?	Requirement	Cable Containment
New dwelling with ≥1 parking space	Yes	1× 7kW smart charge point	Required if parking remote
New dwelling with no parking	No	None	None
New non-residential building (≥10 spaces)	Yes (at least 1 space)	1× charge point per 5 spaces; 1 per 5 EV-ready spaces	Required for remaining spaces
Residential renovation (10% rule)	Conditionally	Per above if parking created/modified	As above
Change of use to dwelling	Possibly	Check with BCO; AD S guidance	As appropriate
Existing single dwelling (no works)	No	Not triggered by existing state	N/A

Detailed Guidance

Part S Trigger Conditions

New residential buildings: Any new residential building that has associated parking must be fitted with a 7kW EV charge point per dwelling. "Associated parking" means:

Integral garage
Attached garage
Allocated parking space
Parking space within the residential development served by the building

If there are multiple dwellings each with allocated parking, each parking space needs a charge point.

Renovation trigger: The renovation trigger is more nuanced:

Works must cost more than 10% of the value of the building
AND the works must include construction or modification of ≥10 parking spaces

This means a standard domestic extension rarely triggers Part S (it does not create 10 parking spaces). Large residential developments undergoing refurbishment where the car park is being modified are more likely to be caught.

Standalone car parks: Car parks with ≥10 spaces being newly constructed: 1 charge point per 5 spaces minimum; remaining spaces must have cable containment ready for future installation.

Technical Requirements: 7kW Smart Charge Point

Charge point specification:

Mode 3 EVSE (IEC 61851-1 Mode 3): dedicated circuit with pilot function and control
Type 2 socket outlet (IEC 62196-2 Type 2, the European standard); or tethered cable with Type 2 plug
Minimum rated current: 32A (7.2kW at 230V); in practice most units are rated 32A = 7.36kW
Smart functionality as required by EVCSR 2021 (see below)

EVCSR 2021 requirements for smart charge points:

Must be capable of receiving and responding to signals from a communication network
Must support randomised delay (to prevent synchronised peak loads)
Must support smart charging (charging based on time-of-use or signal from network)
Must meet minimum cyber security requirements
Must display charging status

Approved products: MCS does not certify EV charge points. The Office for Product Safety and Standards (OPSS) enforces EVCSR. Suppliers sell into this market with self-declared compliance.

Earthing and Electrical Safety

EV charge point installation has specific electrical safety considerations, particularly related to the earthing arrangement of the premises.

TN-C-S (PME) supplies: Most UK domestic properties are supplied via TN-C-S (Protective Multiple Earthing). In a PME arrangement, the supply neutral and earth are combined at the DNO's earth point. If the PME earth becomes broken (open-circuit PEN conductor), the consumer's earthing conductors can become live at a dangerous voltage.

For EV charge points outdoors:

A fault in an EV charger on a PME earth in a broken PEN scenario can place the vehicle body at dangerous voltage
BS 7671:2018+A2:2022 Regulation 722.411.4 requires additional protective measures for PME outdoor EV charging

Compliant options for PME outdoor charge points:

TT earthing at the charge point: Separate earth electrode at the charge point; disconnect from PME; this is the most robust solution
RCD with PEN failure detection: Some EV chargers include a PEN fault detector that trips the EVSE if the PEN conductor becomes broken
Separation from PME using an isolating transformer: Provides safety isolation; expensive

Standard domestic installation: In practice, most domestic 7kW installations use a TT earth electrode at the charge point with a 30mA RCD, and PEN fault protection is provided by the charge point's internal electronics. Always consult the charge point manufacturer's installation instructions and verify the earthing arrangement with the installer.

Circuit Design: Cable Sizing and Protection

Cable sizing for a 7kW charge point:

Load: 32A at 230V
Typical cable: 6mm² or 10mm² twin and earth (or SY multicore for outdoor)
Run length affects voltage drop: check BS 7671 voltage drop limits (<5% from intake to charge point for dedicated circuits)
Consult BS 7671 Table 4D1A or 4E1A for actual current-carrying capacity at the installation conditions

Consumer unit capacity:

Check the existing consumer unit: is there a free way for a 32A RCBO?
Check the main fuse rating: adding 32A continuous load from a 60A main fuse on a property with 45A average demand may overload supply
If DNO main fuse is 60A or 80A: typically adequate for most domestic installations
If main fuse is 40A: check existing loads carefully; DNO fuse upgrade may be required

DNO notification:

G98 registration: single-phase generation ≤16A (3.68kW) has simplified registration — post-connection notification only
7kW charge points (32A) are not generators; G98/G99 does not directly apply
However, some DNOs require notification for load additions above 3.68kW; check local DNO guidance

Cable Containment (Pre-wiring)

Where a charge point is not immediately installed but is required by Part S, cable containment must be provided. This means:

Install suitable conduit or trunking from the consumer unit position to the parking space
Conduit must be suitable for the cable size that will be required (typically 32mm minimum)
Label both ends of the conduit clearly
Terminate at a suitable enclosure at the parking space end

This provision allows the homeowner to install a charge point in future without significant building work.

Part P Notification for EV Charge Point Installation

Under Part P (Building Regulations, England and Wales), EV charge point installation is notifiable work:

Single-phase 7kW charge point: notifiable work
Must be notified to Building Control before starting (or self-certify via a competent person scheme)
Electricians registered with NICEIC, NAPIT, ELECSA, BRE Certifications can self-certify

Certificate: On completion, provide an Electrical Installation Certificate (EIC) and notify Building Control (via competent person scheme or direct).

Frequently Asked Questions

Does Part S apply to an existing house where I am adding a garage?