Single-phase and three-phase supplies explained simply
The electricity coming into your home arrives either as a single-phase supply — one live conductor, which is what the overwhelming majority of UK houses have — or as three-phase, which is more common in commercial premises and some larger or rural properties.
A single-phase domestic supply supports a charge point of around 7kW. Three-phase is what allows a 22kW unit. You cannot simply choose 22kW; the supply has to be there first, and upgrading a single-phase supply to three-phase is usually expensive and rarely justified for home charging.
What 7kW actually gives you
A 7kW charger delivers substantially more than a three-pin lead and will replenish a typical family EV overnight. For a household covering ordinary daily mileage, the car is full every morning regardless of whether the charger is 7kW or 22kW — you are asleep either way.
| Method | Typical home use |
|---|---|
| Three-pin lead (around 2.3kW) | Slow — best as an occasional backup only |
| 7kW dedicated charger | The standard for UK homes; full charge overnight |
| 22kW charger | Needs three-phase supply; only faster if the car supports it |
Your car may be the limit anyway
Every EV has a maximum AC charging rate set by its onboard charger. Many popular models accept a maximum of around 7kW or 11kW on AC. Fitting a 22kW unit to a car that can only take 7kW achieves nothing at all.
Rapid public charging works differently — it uses DC and bypasses the car's onboard AC charger, which is why motorway charging is so much faster than anything possible at home.
When 22kW is worth considering
- The property already has a three-phase supply
- The vehicle genuinely accepts 11kW or 22kW AC
- Several vehicles need charging in a short window
- There is a business or high-mileage use case attached to the property
Not sure what supply you have?
You do not need to work it out yourself. We check the incoming supply as part of the assessment and tell you exactly what your property can support.
Frequently asked questions
How can I tell if I have three-phase?
It is usually visible at the intake and meter position — three fuses rather than one. An electrician can confirm it in seconds.
Can I upgrade to three-phase for faster charging?
Technically yes, via your network operator, but it is often costly and rarely worthwhile purely for home charging.
Is 7kW enough for a large EV?
For overnight charging, generally yes. Even a large battery will gain a very significant amount of range across a full night.