Do I Need a 3 Phase Supply for a 22kW Home Charger?

Yes. Around 95% of UK domestic properties have a single phase electricity supply, which caps home EV charging at 7.4kW regardless of which charger you buy. A 22kW charger only reaches its full speed on a 3 phase supply, and upgrading to one typically costs £3,000 to £15,000 through your Distribution Network Operator (DNO).

• 95% of UK homes are single phase, which caps EV charging at 7.4kW regardless of the charger fitted
• 22kW needs a genuine 3 phase supply,  a DNO upgrade typically costs £3,000–£15,000
• Your car may not accept 22kW anyway: many EVs cap onboard AC charging at 7.4kW or 11kW
• Worth it mainly if you already have 3 phase, charge multiple EVs, or have a genuinely short daily charging window

The Difference Between Single Phase and 3 Phase

A single phase supply delivers power through one live conductor at 230V, and this is what almost every standard UK house has. It supports a maximum EV charging rate of 7.4kW (32A), which is the standard home charger size fitted across the country.

A 3 phase supply uses three live conductors at 400V, and it is mainly found in larger new build homes, farms, converted commercial properties, and some rural properties. It allows a charger to draw 32A across each of the three phases, adding up to 22kW in total.

Crucially, fitting a 22kW charger on a single phase supply will not get you 22kW. Most 3 phase specific units simply will not operate at all on a single phase supply, while some hybrid units will run but fall back to roughly 7.4kW. The charger cannot create three phase power out of a single phase connection. The supply has to be there first.

Does Your Car Even Use 22kW?

This is the detail most people miss. Even with a genuine 3 phase supply, many electric cars cannot accept a full 22kW of AC power because their onboard charger caps it lower, often at 7.4kW or 11kW. Fitting a 22kW wallbox to a car limited to 7.4kW AC will not speed anything up. It is worth checking your specific vehicle's onboard charger rating before paying for a faster unit or a supply upgrade.

When 3 Phase Charging Is Actually Worth It

For the large majority of drivers, a 7kW single phase charger is genuinely enough. An overnight 7 to 8 hour charge adds roughly 200 miles of range, comfortably covering the average UK daily driving distance. A 3 phase 22kW setup tends to make financial sense in narrower cases, such as:

• Properties that already have a 3 phase supply, so no costly upgrade is needed
• Households charging more than one EV, or running a small fleet from a single driveway
• Cars with large batteries and genuinely limited charging windows, such as a short lunchtime top up rather than an overnight charge
• Vehicles whose onboard charger can actually accept above 7.4kW AC

Checking What Supply You Already Have

You can get a rough idea by looking at your fuse box. A single phase supply has one main fuse where power enters the property. A 3 phase supply typically shows three separate 100A fuses. An electrician can confirm this properly during a site survey, along with whether an upgrade through your DNO is realistic and what it is likely to cost for your specific property.

What This Looks Like With Fit Solar

As part of every EV charge point installation, Fit Solar carries out a full electrical survey to confirm your supply type and check whether a standard 7.4kW charger is suitable, which it is for the vast majority of the homes we visit across Stroud, Gloucestershire, and the wider Cotswolds. If you do have 3 phase power, or a genuine case for upgrading, we can talk you through charger options such as the myenergi Zappi, which is available in both single phase and 3 phase versions and also supports solar matching. For a full breakdown of what a typical installation costs either way, see our guide on home EV charger installation costs.

Not sure which supply you have, or whether 7kW or 22kW is right for your home? Book a free EV charger site survey with Fit Solar and we'll check your electrics and give you a straight answer.