Vehicle and parking inputs
The design uses the vehicle’s maximum AC charging power, inlet position and normal parking orientation. Where a second car may use the chargepoint, its inlet and AC limit form part of the same assessment.
The energy needed between charging sessions is more useful than the traction battery’s total capacity. A car that returns home most days with a moderate state of charge may need only a few hours of charging. A car used for irregular long journeys may need more flexibility in the schedule. The design should state the intended ready time and what must happen if the normal cheap charging period is not long enough.
The parking position must be legal and consistently available. A cable should not be pulled tight, run through a doorway or lie across a routine pedestrian route. The siting assessment covers credible parking positions rather than the inlet position of one car in one photograph.
Where the parking space is rented, leasehold or separate from the home, obtain the necessary rights and permissions before installation. Work across a pavement or other public land needs the current local-authority route. A cable channel or other approved cross-pavement solution does not reserve the parking space.
7 kW, 22 kW and the vehicle’s AC limit
A familiar domestic chargepoint is described as 7 kW because a 32 A single-phase supply at nominal UK voltage is about 7.4 kW. The actual charging power can be lower because of the vehicle limit, a site limit, load balancing, voltage and conversion losses.
A nominal 22 kW AC chargepoint requires a suitable three-phase supply, circuit and vehicle. The Type 2 connector does not prove that the car can accept three-phase charging. A car may accept less than 22 kW AC even if it can use much higher power at a public DC rapid charger.
Keep the three ratings separate:
- chargepoint rating is the maximum AC power the equipment is designed to make available
- vehicle AC limit is the maximum the onboard charger can accept
- site limit is the maximum the installation or control system permits at the time
The lowest applicable limit determines the delivered power. Compare the energy that normally needs to be added with the average accepted power and available time. Do not use a universal miles-per-hour figure as the design basis.
The 7 kW single-phase AC charging and 22 kW three-phase AC charging entries set out the electrical and vehicle boundaries.
Supply and maximum-demand assessment
The installer should inspect the electricity supply rather than rely on a photograph of the consumer unit. The assessment includes:
- supply phase arrangement
- service head and main fuse information
- earthing arrangement and main bonding
- existing maximum demand
- large loads such as electric heating, an immersion heater, battery inverter or electric shower
- consumer-unit condition and capacity
- cable length, route and installation method
- any planned solar, battery, heat pump or second chargepoint
A spare way in the consumer unit does not prove that the supply or board can accept the proposed circuit. The work may require a separate enclosure, changes to existing protection, DNO work or a lower charging limit.
Dynamic load balancing can reduce EV demand when the home is already drawing heavily. Its meter or CT (current transformer) has to measure the correct conductors and phases. Solar, batteries, branched supplies and multiple consumer units can make that measurement point less obvious.
The configured site limit and the response to a sensor, cable or communications failure are part of commissioning. Load balancing manages demand within a limit. It does not increase the main fuse rating or create additional network capacity.
Tethered or untethered chargepoint
A tethered chargepoint has a permanently attached vehicle cable. An untethered unit has a Type 2 socket and uses a separate cable.
A tethered unit is quicker to connect each day, but the cable length and connector are tied to the product. An untethered cable can be replaced or stored separately, but it has to be taken out and connected for every session. Compare:
- reach to each credible vehicle inlet position
- cable storage when the car is absent
- risk of the lead crossing a path or shared area
- exposure to vehicle impact or deliberate damage
- ability to keep connectors clean and dry
- accessibility of the controls, socket and connector
- likely compatibility with a later vehicle
Do not assume that the longest available lead is best. Its full reach defines where a connected vehicle can stand and which metalwork may be touched at the same time. The charger cable routes and parking entry covers fixed cabling and vehicle-lead placement in more detail.
Fixed circuit and cable route
The chargepoint normally uses a dedicated final circuit. The electrical designer selects the cable and protective devices from the design current, route length, grouping, ambient conditions, voltage drop, fault conditions and mechanical risk.
External and buried routes need suitable environmental and impact protection. There is no universal trench detail that can be copied to every property. Existing buried services must be located and the route designed for the ground, access and future disturbance.
The installation drawing and circuit schedule show:
- chargepoint make, model, connector and cable length
- circuit route and visible building work
- consumer-unit or separate-enclosure work
- isolation and overcurrent protection
- RCD and DC residual-current protection
- earthing and open-PEN protective measure
- load-management sensor and control connection
- making good, sealing and surface finishes
- work outside the installation scope
Where Wi-Fi, mobile data or Ethernet is needed for smart functions, test availability at the proposed location. Safety and load limiting still need a defined state when communications are unavailable.
RCD, DC fault current and open-PEN protection
EV charging has protective requirements that are not established by the presence of a circuit breaker or an “integrated protection” label.
A normal Mode 3 charging point needs its own suitable RCD protection, not exceeding 30 mA, that disconnects all live conductors. Smooth DC fault current can impair some RCDs. The completed design therefore also needs the appropriate DC residual-current protection, either through a suitable RCD type or a recognised combination with an RDC-DD (residual DC detecting device).
An RDC-DD is not automatically the complete RCD function. RCD, RDC-DD and open-PEN protection are separate functions even where one product houses more than one of them. The RCD protection for EV chargers entry explains the evidence to expect for integrated equipment.
On a PME (protective multiple earthing) supply, a broken PEN (protective earth and neutral) conductor can create a dangerous voltage on connected metalwork without producing the imbalance that a conventional RCD detects. An outdoor charging design must use a protective approach permitted by the current standard.
The assessment follows the connected car and lead, not only the wall unit. A chargepoint fixed inside a garage can still supply a vehicle outside. The final records identify the earthing arrangement, open-PEN measure, product declaration, commissioning method and any electrode purpose. Do not test the function by deliberately creating a dangerous network condition.
DNO registration and connection route
An EV chargepoint is a significant electrical load and must be registered with the DNO in Great Britain. This is a demand-connection process. A one-way charger is not generation equipment and should not be described as a G98 or G99 installation.
The installer assesses the chargepoint, supply and maximum demand to establish whether the DNO needs an application before connection or notification after installation. ENA Connect Direct is the current common submission route. Network work or an agreed limit may be required in some cases.
The owner remains responsible for making sure the DNO has received the required submission and, where approval is needed before connection, granted it. Ask for:
- the submitted equipment and load information
- any declared maximum-demand or load-management setting
- the DNO acknowledgement or authorisation
- details of any fuse, meter or service work
- confirmation that the installed model and setting match the submission
In Northern Ireland, NIE Networks is the DNO. At the 23 July 2026 review, ENA Connect Direct included NIE Networks and required the suitably qualified contractor to submit the low-carbon technology application before installation, then wait for an approved response. The NIE Networks EV Drivers Guide still showed the older form-based Connect and Notify and Apply to Connect routes. The contractor should use the current Connect Direct route and retain its response. The Great Britain GOV.UK registration route does not apply.
Smart charging and tariff controls
Private domestic and workplace chargepoints sold in Great Britain fall within the EVs (Smart Charge Points) Regulations where the statutory scope applies. These are product-sale rules, separate from the electrical installation. They cover matters including smart functionality, supplier interoperability, user information, default scheduling, randomised delay, security and continued basic charging without a communications network.
The seller’s statement of compliance belongs with the product records. Supplier interoperability means the chargepoint should retain smart functionality when the electricity supplier changes. It does not guarantee that every supplier tariff, third-party app or vehicle integration will support it.
The control architecture assigns scheduling to one of:
- the chargepoint
- the vehicle
- the electricity supplier
- a separate home-energy controller
Two active schedules can conflict unless their interaction has been tested. The commissioned record includes the ready time, charge limit, default schedule, randomised-delay override, manual-charge method and fallback behaviour when the internet, vehicle API or tariff instruction is unavailable.
Solar charging depends on the meter or CT position, minimum charging current, battery priority and response to short changes in export. A “solar compatible” label does not establish how the system measures or controls surplus.
Grants, planning and permissions
EV chargepoint grant schemes are restricted by property, parking, applicant, vehicle, product and installer conditions. The portfolio and amounts can change. Check the current GOV.UK scheme before installation and follow its application order. Some routes require eligibility confirmation before work starts.
Leasehold, rented and shared-parking installations may need written permission from the landlord, freeholder, property manager or parking-space owner. A listed building or unusual mounting position may need a specific planning check.
Planning rules differ across the UK. In England, some wall-mounted chargepoints and electrical outlets can be permitted development where the current conditions are met. That does not remove the need for land rights, Building Regulations compliance or permission for work in a pavement.
Part S of the Building Regulations in England deals with EV infrastructure in specified new buildings, major renovations and changes of use. It is not a general replacement for the electrical and building-control checks on every existing-home installation.
Installation and commissioning
The fixed electrical work should be completed and tested by people competent for the work. Commissioning checks the circuit and the end-to-end charging functions against the installed design.
The commissioning record should cover as applicable:
- circuit inspection and electrical test results
- RCD and DC residual-current protective functions
- open-PEN protective measure
- isolation and labelling
- chargepoint configuration and site limit
- load-management sensor direction, phase coverage and throttling
- fail-safe behaviour after a sensor or communications fault
- communication with an EVSE (EV supply equipment) simulator
- a controlled charge with the vehicle
- smart schedule, app and owner access
An EVSE simulator and the actual car prove different parts of the system. The first checks defined chargepoint states. The second confirms that the installed charger, cable, vehicle and control setup work together.
Handover records and owner access
The final record set includes:
- chargepoint make, model and serial number
- final circuit route and protective-device schedule
- Electrical Installation Certificate or applicable electrical record
- Building Regulations compliance evidence
- DNO submission and response
- commissioning and functional-test results
- smart-chargepoint statement of compliance
- product, cable and protective-device declarations used by the design
- chargepoint warranty and workmanship cover
- app ownership, administrator access and account-transfer method
- configured site limit, schedules and load-management settings
- user instructions, isolation procedure and fault contacts
Set up the owner account while the installer is present. Confirm that the owner, rather than only the installer, can see charging sessions and change permitted settings. Record the manual charging method and recovery process if the app, internet connection or vehicle integration stops working.
After the first normal charging sessions, compare the observed power and timing with the commissioned settings. A lower rate may be correct if the car, site limit or load balancing is restricting power. Persistent unexplained throttling, failed schedules, unusual heat, damage or repeated protective-device operation should be referred back to the installer rather than worked around.