Electric cars
Single-phase vs three-phase home EV charging
Why most home EV chargers run at around 7kW, when three-phase charging helps, and why a faster charger rarely matters on an overnight tariff.
Edited by Rob Gibbs. Published: . Guidance reviewed: .
Short answer
Most UK homes have a single-phase supply, and the home chargers Octopus offers are rated at around 7kW. Three-phase supplies can allow faster chargers, but only if your car can accept the extra power. On an overnight tariff, 7kW for six hours already adds around 40kWh, which is enough for most daily driving.
What a 7kW charger gives you
At about 7kW, each hour of charging adds roughly 7kWh. Over Intelligent Go’s six-hour off-peak window that is around 40kWh, or more than 100 miles for a typical EV, before charging losses.
When three-phase helps
A three-phase supply can feed a faster charger, but the car decides how fast it actually charges. Many EVs’ onboard chargers accept less than a fast three-phase charger can deliver on alternating current. Upgrading a home to three-phase is arranged with the local network operator and can be expensive.
What to ask before you pay for more
Check these with your installer:
- Your car’s maximum AC charging rate.
- Whether your supply and fuse can take the charger alongside the rest of the house.
- How many miles you actually need to add overnight.
Questions people ask
Do I need three-phase power for an EV?
No. Most homes charge on a single-phase supply, at around 7kW, which suits overnight charging.
Will a faster charger save money?
Not on the price per kWh. It only helps if you regularly need more energy than the off-peak window can deliver.
Tariffs in this guide
Related guides
- EV chargepoint grants: who can still claimThe government EV chargepoint grant for renters and flat owners: how much it pays, who qualifies and how it changed on 1 April 2026.
- Keeping gas on a fix while electricity is on Intelligent GoCan your gas stay on a fixed tariff while your electricity moves to Octopus Go or Intelligent Go? How the two fuels work separately.
- Two electric cars on Intelligent Octopus GoWhat to check when two EVs share one home on Intelligent Octopus Go: device control, charging time and the whole-home window.
- Which cars and chargers work with Intelligent Octopus Go?How to check whether your car or charger works with Intelligent Octopus Go, what happens if it does not, and the Go tariff that works with any EV.
- Charging a company EV at home on an Octopus tariffWhat to sort out when you charge a company or salary-sacrifice EV at home on Octopus Go or Intelligent Go: records, reimbursement and the whole-home cost.
- Plug-in hybrids on Octopus Go and Intelligent GoWhether a plug-in hybrid (PHEV) can use Octopus EV tariffs, and why a smaller battery changes whether they save you money.
Primary sources
- EV home charger installation FAQs — Octopus Energy; checked 2026-10-30. Home chargers Octopus offers are rated at around 7kW.
- How does Intelligent Octopus Go work and how can I join? — Octopus Energy; checked 2026-10-30. The 23:30 to 05:30 whole-home window, smart charging billed at the off-peak rate and eligibility checks.