EV charging building regulations: what Approved Document S requires for company car parks

In England, EV charging in company car parks is governed by Part S of the Building Regulations and its guidance, Approved Document S, in force since 15 June 2022. A new non-residential building with more than 10 parking spaces must have at least one chargepoint and cable routes for one in five of the remaining spaces. The same applies to a major renovation, unless the charging works would exceed 7 % of the renovation cost.

Existing car parks that are not being built or majorly renovated have no obligation to add chargepoints. Scotland has its own, stricter standard; Wales and Northern Ireland have no equivalent rule in force at the time of writing.

This guide covers who is caught, how many chargepoints and cable routes each site needs, the minimum technical specification, the rules for homes and mixed-use buildings, the other UK nations, grants, and how to size charging for a fleet without overbuilding it.

The essentials in 30 seconds

• Legal basis: Part S of Schedule 1 to the Building Regulations 2010, with Approved Document S (2021 edition) as statutory guidance, England only.
• New non-residential, more than 10 spaces: 1 chargepoint + cable routes in at least 1 in 5 of the remaining spaces.
• Major renovation, more than 10 spaces after works: same rule, if the works touch the car park or its electrics and the charging cost stays within 7 % of the renovation cost.
• Chargepoint spec: at least 7 kW, Mode 3 on a dedicated circuit, universal socket, status indicator.
• No retrofit duty for existing sites in England. EU rules on buildings do not apply in the UK.
• Beyond compliance: a fleet's real need depends on where drivers charge. Most company EVs charge at home.

What Part S and Approved Document S are

The Building Regulations 2010 set legal requirements for building work in England. Part S, "Infrastructure for the charging of electric vehicles", was added by amending regulations and took effect on 15 June 2022. Approved Document S is the statutory guidance that shows one way to comply. Building control (the local authority or a registered approver) checks the work.

Approved Document S covers six types of work:

• new residential buildings (requirement S1);
• buildings undergoing a material change of use to dwellings (S2);
• residential buildings undergoing major renovation (S3);
• new buildings that are not residential or mixed-use (S4);
• non-residential buildings undergoing major renovation (S5);
• mixed-use buildings, new or undergoing major renovation (S6).

Transitional rule: the requirements do not apply to work covered by a building notice, full plans application or initial notice submitted before 15 June 2022, provided the work started on site before 15 June 2023.

Sources: gov.uk, Approved Document S and Planning Portal, Approved Document S.

How many chargepoints does a new office or industrial site need?

Requirement S4 applies to a new building that is neither residential nor mixed-use, with more than 10 parking spaces within its site boundary. It requires:

1. one parking space with access to one chargepoint; and
2. cable routes in at least one fifth of the remaining spaces.

Approved Document S gives its own example: with 11 spaces, one space gets a chargepoint and two further spaces get cable routes.

Examples by car park size

The number of cable routes is one fifth of the spaces left after the chargepoint space, rounded up.

The obligation is light on chargepoints and heavier on preparation. That is deliberate: cable routes are cheap to build into a new car park and expensive to retrofit by breaking up tarmac later.

What counts as a cable route

Approved Document S defines a cable route as a safe, unobstructed route from the power supply to the planned chargepoint location, for electrical cabling to be installed in future. In practice: ducting under the car park surface, cable trays or containment in a building, and a future connection location at each prepared space. Spaces that already have a chargepoint count as having a cable route.

Covered car parks

Where some spaces are in a covered car park (a car park with a roof, such as a multi-storey or under-croft), the chargepoint should go in an open-air space. Cable routes go into the covered car park only if there are not enough open-air spaces to meet the one-in-five rule. If all spaces are covered, no chargepoint is required, but cable routes for at least one in five spaces still are.

Accessible spaces

Where chargepoints or future connection locations are provided and the site has accessible parking spaces, at least one accessible space should have access to a chargepoint or a future connection location. Accessible bays must also meet Approved Document M.

Minimum chargepoint specification

Each chargepoint installed to meet Part S should, according to section 6 of Approved Document S:

Private chargepoints sold for workplace use in Great Britain must also meet the Electric Vehicles (Smart Charge Points) Regulations 2021: smart functionality, default off-peak settings, randomised delay and security requirements. Source: gov.uk, smart charge point regulations.

Other rules sit alongside Part S: fire safety under Part B, the Electricity at Work Regulations 1989 for workplaces, and, for chargers open to the public, the separate legislation on public charge points.

Major renovation: when an existing site is caught

An existing building is caught only when it undergoes a major renovation, defined in the Building Regulations as renovation of more than 25 % of the surface area of the building envelope. For a non-residential building, requirement S5 then applies if all of the following are true:

• after the works, the site will have more than 10 parking spaces;
• the works include the car park (such as resurfacing or new electrical infrastructure), the car park's electrical infrastructure, or the building's electrical infrastructure where the car park is inside the building.

The 7 % cost cap

The cost test works as a cascade:

Costs are materials and labour, excluding VAT, compared with the total cost of the major renovation including the charging works. Land, fees, insurance, tax and financing are left out.

Worked example: refurbishing a 1980s office

A company refurbishes a 1980s office: new façade and roof (well over 25 % of the envelope), and the car park is resurfaced. The site keeps 40 spaces. The renovation costs £3 million.

• Required: 1 chargepoint + cable routes for 8 of the remaining 39 spaces (one fifth, rounded up).
• Cost test: the charging works are a tiny fraction of £3 million, far below the 7 % cap (£210,000), so the full requirement applies.

Had the works been limited to the interior, with no work to the car park or the electrical infrastructure serving it, Part S would not apply at all.

Existing car parks: no retrofit obligation in England

A company that keeps its building and car park as they are has no obligation under Part S to add chargepoints. The requirements bite only on new buildings, material changes of use to dwellings and major renovations.

This is a frequent source of confusion, because European rules are often quoted in UK articles. The EU's recast Energy Performance of Buildings Directive sets retrofit targets for existing non-residential car parks in EU member states. It does not apply in the UK.

Homes and mixed-use buildings

The residential rules are more demanding than the non-residential ones:

• New homes (S1): every new dwelling with associated parking must have access to a chargepoint. The number is limited by a £3,600 cap on the average grid connection cost per chargepoint; above it, cable routes go in instead.
• Larger residential car parks: where a new residential building has more than 10 associated parking spaces, the spaces without a chargepoint must have cable routes.
• Material change of use to dwellings (S2) and major renovation of residential buildings (S3): when the building will have more than 10 associated parking spaces, chargepoints and cable routes apply, with a 7 % cost cap for major renovations.
• Mixed-use buildings (S6): the residential rules apply to the residential parking and the non-residential rules to the rest.

For company car drivers living in flats, the practical question is not the building regulations but consent from the freeholder or managing agent, covered in our guide to installing a chargepoint in a block of flats.

Scotland, Wales and Northern Ireland

Building regulations are devolved, so Approved Document S applies in England only.

Scotland: the Building (Scotland) Amendment (No. 2) Regulations 2022 added standard 7.2 on electric vehicle charging. It does not apply to non-domestic buildings with ten or fewer parking spaces. Chargepoints must deliver at least 7 kW and be at least a Mode 3 system on a dedicated circuit. The required proportions of chargepoints and ducting are set out in the Non-Domestic Technical Handbook and are higher than in England; check the current handbook for your project. Source: legislation.gov.uk, SSI 2022/349.

Wales: the Welsh Government consulted on EV charging requirements for new residential and non-residential buildings and major renovations; the consultation closed on 29 November 2024 and a summary of responses has been published. Source: gov.wales, EV charging consultation.

Who carries the obligation: owner, developer or tenant?

The Building Regulations bind whoever carries out the building work. In practice:

• New build: the developer or owner commissioning the building.
• Major renovation by the landlord: the landlord.
• Fit-out or works by a tenant: the tenant, if the tenant's works amount to a major renovation and touch the car park or its electrics. Most tenant fit-outs do not.

Leases matter more than the regulations for existing sites. A tenant who wants chargepoints usually needs the landlord's consent, an agreement on who owns the equipment at lease end, and a decision on who pays the electricity. Settle these before applying for any grant.

Grants: the Workplace Charging Scheme

The Workplace Charging Scheme contributes up to 75 % of the cost of buying and installing chargepoints, capped at £500 per socket for installations completed from 1 April 2026, up to 40 sockets across all of an organisation's sites. It is open to businesses, charities and public sector organisations with dedicated off-street parking, and has been extended for a final year to 31 March 2027. Source: Find a grant, Workplace Charging Scheme.

Whether the grant can fund the chargepoint required by Part S on a new build depends on the scheme's current conditions; ask your installer, who applies for the voucher. The full list of funding options is in our guide to EV charging grants for businesses.

Tax: workplace charging is not a benefit

Charging at work creates no taxable benefit for company car drivers, because electricity is not "fuel" for the car fuel benefit. For employees' own cars, charging at the workplace has been exempt since 6 April 2018. Source: HMRC, EIM23900.

Four common misconceptions

"Every company must install chargers by a set date." No. In England the duty is triggered by building work, not by a deadline for existing sites.

"We need a chargepoint for every EV in the fleet." No. Part S asks for one chargepoint and cable routes. How many points you actually need depends on where your drivers charge.

"Any socket will do." No. Part S chargepoints must be at least 7 kW, Mode 3, on a dedicated circuit, with a universal socket.

"The rules are the same across the UK." No. England, Scotland, Wales and Northern Ireland each have their own building regulations.

What happens if the rules are not met?

Building control checks Part S as part of the building regulations approval. If the work does not comply, a completion certificate can be refused and the local authority can require the work to be put right. Contravening the Building Regulations is an offence. Beyond enforcement, a missing completion certificate causes problems on sale, refinancing or letting, which is usually what puts pressure on developers.

Complying in four steps

1. Check whether your project is caught: new building, material change of use, or major renovation (over 25 % of the envelope) touching the car park or its electrics, with more than 10 spaces.
2. Count the spaces: 1 chargepoint, then one fifth of the remaining spaces for cable routes; open-air spaces first, accessible bay included.
3. Specify the equipment: 7 kW minimum, Mode 3, universal socket, smart functions, installed to BS 7671 and the IET Code of Practice.
4. Document the cost test if it is a major renovation, and keep the calculation for building control.

Designing cable routes that will actually be used

Part S tells you how many spaces to prepare, not how to prepare them well. A few design choices made at construction stage decide whether adding chargepoints later is a one-day job or a building project.

• Check grid capacity early. Ask the distribution network operator (DNO) what capacity the site connection can take. A connection sized for the building alone may not carry twenty 7 kW chargepoints later without load management.
• Plan for load management. Smart chargepoints can share a fixed power budget between cars. Designing for it from the start means a smaller connection can serve more sockets.
• Group the prepared spaces. Cable routes clustered in one area, near the electrical intake, keep cable lengths and voltage drop down. Scattered spaces multiply trenching.
• Size the ducts generously. Ducting is cheap; replacing undersized ducts under finished tarmac is not. Leave draw cords in every duct.
• Leave space for distribution. A future feeder pillar or distribution board near the prepared bays avoids running every circuit back to the main switchroom.
• Think about the accessible bay. Approved Document S asks for at least one accessible space with a chargepoint or future connection location; place it so the cable does not cross the access zone.
• Record everything. As-built drawings of duct routes, capacities and spare ways will save the next contractor days of surveys.

Checklist for landlords and tenants

Landlords building or majorly renovating:

• Confirm whether Part S applies and document the 7 % cost test if relevant.
• Decide whether chargepoints will be landlord-owned (recharged through the service charge) or tenant-owned.
• Include rights to install, maintain and remove chargepoints in new leases.

Tenants who want charging:

• Ask whether the landlord has already provided cable routes under Part S; the cheapest chargepoint is one installed on an existing route.
• Agree in writing who owns the equipment at lease end and who pays the electricity.
• Check the Workplace Charging Scheme conditions before ordering, since the installer applies for the voucher.

Key dates for UK workplace charging rules

Worked example: a new 60-space office for a company with 20 EVs

A company builds a new office with 60 parking spaces. It runs 20 electric company cars and expects more.

What Part S requires:

• 1 chargepoint (7 kW, Mode 3, universal socket);
• cable routes in at least 12 of the remaining 59 spaces;
• at least one accessible bay with a chargepoint or a future connection location.

What the cost looks like: prices vary with the site, the grid connection and the groundworks, so treat these as orders of magnitude to check against quotes. Ducting laid while the car park is built costs far less per space than trenching through finished tarmac later. A workplace 7 kW chargepoint installed typically costs in the low thousands of pounds per unit, and the Workplace Charging Scheme can contribute up to £500 per socket.

What the fleet actually needs: that depends on where the 20 cars charge. If 16 drivers have off-street parking at home and charge overnight, the office points serve visitors, pool cars and the 4 drivers without home charging. Four to six sockets on the prepared cable routes would usually be enough, not twenty.

Building more than required is not wrong; building it before knowing where drivers charge often is. Our guide to installing chargepoints at work covers load management and sizing, and our explainer on how a charging system is built covers the components.

Compliance at the office, reimbursement at home

For most fleets, the car park is not where the bulk of charging happens. Company car drivers with a driveway charge overnight at home, on cheaper electricity, and the employer can repay that electricity in full, tax and NIC free.

Voltaback measures each car's home charging from the vehicle itself, values it at the driver's own tariff, and produces a monthly reimbursement statement, without installing anything. That lets you size the office installation for the drivers who genuinely need it. On measurement, Voltaback relies on the home's MID-certified meter, not on a standalone cable meter.

To estimate how many workplace points your fleet needs, use our charging installation recommendation simulator, or see how Voltaback helps you get comparable quotes for chargepoint installation.

Size for your fleet, not just for the rulebook

Approved Document S sets a floor: one chargepoint and room to grow. Your fleet's real need depends on how many drivers charge at home, how many cannot, and how often visitors and pool cars need a socket.

Talk to Voltaback to see how much of your fleet's charging already happens at home, and how to repay it automatically, before you decide how many points the office needs.