EV Charging Infrastructure: The Civils, Ducting and Groundworks Guide for Commercial Projects
The Civils, Ducting and Groundworks Guide for Commercial Projects
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Installing electric vehicle charging points is often described as an electrical project. On commercial sites, that is only part of the job.
Before a charger can be connected, the site may need excavation, ducting, cable protection, foundations, reinstatement, drainage considerations, inspection chambers and carefully planned routes between the electrical supply and charging bays.
For contractors, developers and groundworkers, getting the civils infrastructure for EV charging right at the beginning can make the difference between a straightforward installation and an expensive retrofit.
This guide explains the key civils considerations when preparing a site for EV charging, including EV charger ducting, cable routes, chamber access and future-proofing.
What civils work is needed for EV charging?
The amount of civils work required depends on the site, charger specification, electrical connection and location of the charging bays.
The earlier these requirements are considered, the easier it is to coordinate the electrical and civils elements of the project.
A charger location that looks ideal on a site plan may not be the easiest location to install. The route from the power source, existing utilities, finished ground levels, drainage, vehicle movements and future expansion all need to be considered.
EV charger duct routing.
Ducting is one of the most important parts of the civils installation.
An underground duct provides a defined route for electrical cables between the supply point and the charger infrastructure while helping to protect the installation from the surrounding ground conditions and future excavation.
The correct duct specification depends on the cable requirements, installation environment, route, depth, number of cables and project specification.
Twinwall ducting and other underground duct systems are commonly used in civil engineering applications where cables need to be protected below ground.
United Civils Supplies stocks a range of underground ducting and electrical cable ducting products suitable for civils and infrastructure applications.
Underground Ducting Pipe Colours Explained
Choosing the right EV charger ducting
There is no single duct size that is correct for every EV charging installation.
The specification should be established from the cable design rather than selecting ducting based simply on the charger output.
Consider:
Cable size and quantity
Higher-powered charging equipment may require larger cables, while multiple charging points may require several cables within the same route.
The duct needs to accommodate the cable arrangement without creating installation or maintenance problems.
For an individual AC charger where small diameter cable will likely be used, consider our 50/63mm twinwall ducting. This has been used when connecting a distribution point to a charger.
For larger AC or small DC charging points consider the 94/110mm twinwall ducting.
Large DC rapid chargers would need to be sized up again due to the significantly larger diameter cables. We would recommend our 150/178mm ducting sticks. In our experience, when using sticks and long radius bends its easier in a practical capacity to feed cables with as much excess diameter as possible.
150/178mm ducting Is also the ducting of choice when installing the main EV infrastructure and feeder routes. The cables are as large as the ones used for large DC rapid chargers.
DNO incoming supply will depend on the design and spec provided by the network operator; this may be specified as needing to be Class 2 ENATS 12-24 duct. The ENATS 12-24 which stands for ‘Energy Networks Association Technical Specification’ is the standard for network adoption by most DNOs because of its impact resistance, wall thickness and compression ratings. We supply ENATs ducting in a range of diameters, most commonly 150/178mm, but contact our sales team if you require any other Class 1 or Class 2 ducting.
Future capacity
If the site is likely to add more charging points later, it can be worth considering spare ducts or additional capacity during the initial civils work.
Installing an additional duct while a trench is already open can be considerably easier than returning later to excavate an occupied car park.
Inspection chambers and access points
Long underground routes may require suitable access arrangements depending on the project design.
Chambers can provide access to underground duct routes and help with cable installation, maintenance and future works.
Their location should be considered carefully.
A chamber positioned in a vehicle loading area, for example, may have very different loading requirements from one positioned within a landscaped area.
To create access points, we offer a range of diameter access boxes and covers. Our 300mm, 450mm and 600mm ranges are available through our website. These are modular stackable sections to achieve the depth required and different diameter pipe inlet cut outs that can be selected and cut out by the installer. we offer a composite cover range that are designed specifically for the duct boxes, or a ductile/ galvanised steel cover that can be installed to cover over the boxes. Be aware of the load requirements when selecting the cover for your project.
EV charging regulations and standards
The regulatory requirements for an EV installation depend on the type of project and its location.
In England, Approved Document S provides technical guidance relating to EV charging infrastructure for new buildings and certain major renovation projects. It applies to new residential and non-residential buildings, among other specified circumstances.
Electrical installations must also be designed and installed to the applicable electrical requirements, including the current edition of BS 7671 and the relevant provisions for EV charging.
Where grant-funded chargepoints are involved, the equipment may also need to meet the applicable government technical specification.
The government's commercial chargepoint specification states that equipment used for relevant OZEV grant schemes must meet specified technical requirements, including smart functionality and cybersecurity requirements.
The Electric Vehicles (Smart Charge Points) Regulations 2021 also establish requirements for relevant private chargepoints sold for workplace or domestic use in Great Britain, although rapid chargepoints and public chargepoints are treated differently under the regulations.
Because requirements can change, project teams should always check the current legislation, standards, manufacturer's instructions and project specification.