3-Phase vs Single-Phase EV Charger UK: Which Do You Need?

UK domestic electricity is supplied at 230V nominal. A single-phase supply delivers that voltage on one live conductor, alongside a neutral and an earth — three wires entering the house. A 3-phase supply delivers 230V on each of three live conductors, alongside a shared neutral and earth — five wires entering the house. The voltage between any two of the three phases (the line-to-line voltage) is around 400V.

The power a circuit can deliver depends on voltage and current together. A 32A single-phase circuit caps at 230V × 32A = 7.36kW (rounded to 7kW in chargepoint marketing). A 32A 3-phase circuit delivers 230V × 32A × 3 phases ≈ 22kW. That is the entire reason home chargers come in those two main power ratings — they reflect what a single 32A circuit can carry on each supply type.

3-phase has a middle option too. A 16A 3-phase circuit delivers about 11kW. That is the rating you will see on most public AC chargers and on a lot of European home installations. In the UK it is uncommon for domestic use because, again, most homes do not have 3-phase to begin with.

Three checks tell you what you have without paying anyone for an answer.

Count the cables at the meter. Find your incoming supply head (the meter cabinet, usually external on newer builds, internal in older properties). Look at the cable feeding the meter from the cutout fuse. A single cable with two cores (live and neutral, plus a separate earth) is single-phase. A single cable with three live cores plus neutral is 3-phase. If there are three separate single-phase cables coming in side-by-side, that is also 3-phase (older installation style).

Look at the cutout fuse rating. Single-phase houses almost always have an 80A or 100A cutout fuse. 3-phase houses typically show three fuses (one per phase), each rated 60A, 80A or 100A. If you only see one big fuse, you are single-phase.

Ask your DNO. Distribution Network Operators (DNOs) own and operate the cabling between the substation and your meter. Each region has one — UK Power Networks, Northern Powergrid, SP Energy Networks, SSEN, National Grid Electricity Distribution, Electricity North West, NIE Networks. You can call or use their online enquiry forms; they will confirm your supply type from postcode and meter number, free of charge.

Marketing speaks in maximum power. Real-world charging speed is constrained by the slower of two things — the charger and the car's onboard AC charger. Most EVs sold in the UK accept far less than 22kW on AC, because the onboard rectifier is sized for typical use. Here is what each combination actually delivers, assuming a 60kWh usable battery and 10% to 80% charging (a 42kWh top-up):

This is the trap most 22kW conversations miss. Plugging a 22kW-capable wallbox into a car with an 11kW onboard AC charger gets you 11kW, not 22kW. The car decides the actual rate.

The list of cars accepting the full 22kW on AC is small. Renault Zoe (until production ended in 2024) is the headline example. Older Tesla Model S and Model X with the dual-charger option support 22kW. Most current Teslas, BMWs, VWs, Volvos, Polestars, Hyundais and Kias cap at 11kW on AC — some at 7.4kW. Confirm the spec on the manufacturer datasheet before assuming a 22kW install is worth it.

Where it does pay off: a household running two EVs that both accept 11kW, charging from a single 22kW wallbox with load-sharing logic — total 22kW shared across two cars, 11kW each, instead of either car getting 7kW or one waiting. That is the principal residential use case for 22kW. Single-EV households almost never break even.

UK chargepoint installation rules are governed by Engineering Recommendations G98 and G99, set by the Energy Networks Association. The thresholds matter because they decide whether installation is notify-and-go or wait-for-approval.

G98 covers connections up to 16A per phase. A 7kW single-phase wallbox and an 11kW 3-phase wallbox both fall under G98. The installer notifies the DNO after commissioning. No upfront approval, no delay.

G99 covers connections above 16A per phase. A 22kW 3-phase wallbox (32A per phase) falls under G99. The DNO must approve the installation before the wallbox is energised. Approval can take 4–12 weeks and the DNO may request supply or fuse upgrades at the homeowner's cost.

For the full process and timing expectations, see the DNO notification G98/G99 guide. Skipping the approval is not optional — installing a 22kW wallbox without DNO sign-off can void insurance, electrical compliance certificates, and the manufacturer warranty.

If you are single-phase today and want 3-phase, the DNO quotes for the upgrade and the homeowner pays. The bill depends on three things: distance from the nearest 3-phase cable, whether digging or trenching is required, and whether the substation has spare capacity. Typical quotes seen in 2025:

Quotes are bookings, not commitments. The DNO sends a non-contestable quote based on its design standards. Some elements (the cable pull, civil works) can be opened to competition under the connections market rules. For typical residential upgrades, that rarely changes the bottom line much, but the quote should always be checked for cost-categories you can challenge.

Even the cheap end of these numbers buys roughly 30 years of 7kW charging at average UK rates. The break-even for a 3-phase upgrade purely to charge faster is essentially never. The break-even cases for 3-phase are solar export, multi-EV households, home battery + EV combined, and commercial use of the property — not single-EV charging speed.

Three concrete scenarios make 3-phase pay off as a domestic install.

You already have 3-phase. Some new builds, farms, larger rural houses and converted commercial buildings already have it. In that case the incremental cost of an 11kW wallbox over a 7kW one is small (£200–£500 typically), and the faster charging is essentially free upside.

Two or more EVs sharing a single wallbox. A 22kW unit with load-sharing splits power between cars as they plug in. Two cars getting 11kW each beats two cars sharing 7kW. The use case is fleet drivers, families with both partners driving EVs, or households running an EV plus a PHEV.

Solar export plus EV plus battery. A 3-phase home with a sizeable solar array and a home battery can route surplus solar to the car at much higher rates than single-phase allows. For systems above 6kWp, this can shift meaningful chunks of summer solar from grid export (paid at flat rates) into the EV's battery. Most 7kW single-phase setups already do this fine for typical solar sizes.

If none of those describe your situation, single-phase 7kW is the right answer. The detailed power-vs-cost comparison sits in the 22kW vs 7kW home charger guide.

Beyond the supply itself, two install-specific factors matter for 3-phase.

Cable run length. 3-phase cabling is thicker and heavier than single-phase. Long runs (say, garage 20m+ from the consumer unit) become more expensive in materials and labour. Voltage-drop calculations get tighter, and the installer may need to upsize the cable to keep within the 3% drop allowed by BS 7671.

Consumer unit / load schedule. A 3-phase wallbox cannot share a single-phase consumer unit. The install needs either a 3-phase consumer unit (the standard approach in modern 3-phase homes) or a dedicated 3-phase tails-out feeding the wallbox direct from the meter. An installer who has only ever done single-phase domestic work may need to subcontract; getting a quote from someone qualified for industrial/commercial work is sensible. The general install steps and decisions are covered in the UK home EV charger installation guide.