The short answer is yes. A 22kW EV charger requires a three-phase electricity supply, and there is no way around it — the power simply is not available on a standard single-phase connection. What confuses people is that many 22kW chargers will happily work on single phase, they just deliver 7.4kW when they do. You have bought a 22kW unit and installed a 7kW charge point.
How to tell what supply you have
Most UK commercial premises, offices, industrial units and larger retail sites already have three phase. Most houses do not — the standard domestic supply in the UK is single phase, typically rated at 60A to 100A. The quickest check is the incoming supply at the meter: a single-phase supply has one live conductor and one main fuse; three phase has three, usually with three fuses side by side. Your electrician will confirm it in a minute, and it is worth confirming before you specify anything, because it is the single fact that determines what you can install.
If you have single phase and want 22kW, you can apply to your distribution network operator for a three-phase supply. It is possible, it is not cheap, and the timescale is measured in months rather than weeks.
What actually changes between 7kW and 22kW
A 7.4kW charger adds roughly 25 to 30 miles of range per hour. A 22kW charger adds roughly 75 to 90. Over an eight-hour working day or a twelve-hour overnight stop, both fill almost any vehicle — which is why dwell time, not power, should drive the decision.
There is a second limit that catches people out: the car. Many EVs have an onboard AC charger capped at 7kW or 11kW, and a vehicle limited to 7kW will draw 7kW from a 22kW charger. Paying for 22kW hardware to serve a fleet of vehicles that cannot accept it is a common and expensive mistake. Check the maximum AC charging rate of the vehicles that will actually use the bays.
When 22kW is worth it
Three situations justify it. Vehicles that turn over during the day — pool cars, visitor bays, shift changeovers, hotel day guests — because a 22kW bay serves three cars in the time a 7kW bay serves one. Mixed fleets where a few high-mileage vehicles need topping up between runs. And sites where you want the flexibility to concentrate available capacity on fewer vehicles at busy times, which load management makes possible.
Where cars sit still all day or all night, more 7kW sockets almost always beat fewer 22kW ones for the same money and the same supply. Read our guide to EV charging for workplaces for how that plays out on a staff car park.
The switchable middle ground
Several chargers can be configured either way, which is useful if your supply might change or if you are specifying across multiple sites. The Sevadis MaxiCharger Gen 2 Digital runs at 22kW or 11kW on three phase, or 7.4kW on single phase. The MyEnergi Zappi is available in both variants. Specifying a switchable unit costs a little more upfront and saves replacing hardware later.
Will your supply carry it?
Having three phase is not the same as having spare capacity. A 22kW charger draws around 32A per phase continuously, and several of them on top of an existing building's load will find the limit quickly. Load management is what resolves this: it monitors the site's total draw and reduces charger output when the building is busy, so charging gives way rather than tripping the main fuse. In practice it usually allows several times more charge points than the raw headroom suggests — and it is dramatically cheaper than a supply reinforcement.
Where to start
Confirm the supply, check the vehicles' AC limits, then decide the socket count. If the answer is 22kW, our 22kW commercial range starts at £469. If it is 7kW, the 7kW range starts at £312. Either way the Workplace Charging Scheme can return up to £350 per socket at a business site. Not sure which way to go? Tell us about the site and we will help you size it.