22kW three-phase AC charging

A nominal 22kW AC chargepoint normally makes 32A available on each phase of a 400V three-phase supply. The electrical relationship is approximately:

power = √3 × line voltage × current × power factor

At a power factor close to one, 400V and 32A per phase produce about 22kW. The figure is a three-phase equipment rating, not something a single-phase property can obtain through a setting or cable change.

Three things must all support it

Full-rate charging requires:

a three-phase site supply with enough capacity on each phase
a chargepoint, circuit and cable rated for the duty
a vehicle with an onboard AC charger able to accept three phases at that current

The third point is often missed. Many three-phase-capable vehicles accept a lower AC power than 22kW. Others charge on one phase only. A 22kW wall unit then supplies the lower rate the vehicle requests.

Check the exact vehicle variant and market specification. DC rapid-charging capability does not establish its AC onboard-charger rating.

Charge-time estimates

Use energy required divided by average accepted power. If a vehicle needs 30kWh and actually accepts an average 10.5kW from a nominal 11kW onboard charger, the session takes about 2.9 hours. Connecting that vehicle to a 22kW point does not halve the time.

The value of 22kW therefore depends on dwell time and vehicle turnover. It can be useful where several compatible vehicles need meaningful energy during short stops. It may add little at a home where one car remains parked overnight.

Assessing the three-phase supply

The presence of three meter tails or a three-phase consumer unit does not prove 32A per phase is spare. The installer must confirm the connection capacity, cut-out arrangement, phase loading and maximum demand.

Other three-phase and single-phase loads matter. Poor distribution of single-phase loads can constrain one phase before the total site demand looks excessive. A load-management system must therefore respect per-phase limits, not just a summed power figure.

Where the property is currently single-phase, conversion to three-phase is a network project, not part of the chargepoint setting. Feasibility, scope, disruption and charges are site-specific. Before seeking an upgrade, compare its complete cost with the actual vehicle energy needed during the available parking window.

Network process

Every EV chargepoint installation must be reported through the current network-operator process. A high-demand or three-phase proposal may need assessment before installation, particularly where the existing connection or local network cannot support the additional demand.

A one-way chargepoint remains demand equipment and is not a G99 generator merely because it is three-phase or rated at 22kW. If the equipment can export from a vehicle, the embedded-generation function has a separate G98 or G99 connection assessment.

Retain the demand-connection decision, supply capacity, phase allocation and commissioned limits in the handover record.

Load management across several outlets

At a workplace, car park or multi-vehicle home, the site’s connection may be smaller than the sum of every chargepoint rating. That is not automatically a design failure. A managed system can allocate available current between connected vehicles.

Specify what “22kW chargepoint” means when several outlets operate:

22kW available to each simultaneously
22kW shared across a group
a site limit divided dynamically
a priority or queue based on user, departure or state of charge

Also define the minimum useful allocation and what happens when communications with the management system fail. A system that falls back to every outlet at full power can breach the site limit; one that stops all charging may fail its operational purpose.

Circuit, connector and protection

The installation uses Mode 3 control and normally a Type 2 interface. A detachable cable must itself be three-phase and correctly rated. The familiar Type 2 shape alone does not prove that all phase conductors are present.

The circuit must meet the current BS 7671 requirements, which as at 22 July 2026 means BS 7671:2018+A4:2026. Cable rating and voltage drop, protective devices, RCD and DC residual-current functions, earthing and PEN-fault measures all need to cover the actual equipment and route.

When 22kW is justified

It is strongest where compatible vehicles have short dwell times, the site already has suitable three-phase capacity and the operational value of faster turnaround exceeds the extra infrastructure cost.

It is weaker where vehicles accept only single-phase or lower-power three-phase AC, remain parked for many hours, or would require a major supply conversion solely to shorten an already adequate overnight session.

Three-phase charging boundaries

vehicle three-phase AC rating for the exact variant
site capacity and spare current on each phase
simultaneous or shared outlet rating
three-phase cable and Type 2 equipment rating
DNO assessment and any supply work
maximum-demand and communications-failure strategy
actual energy needed during dwell time
whether bidirectional operation is separately supported and approved