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EV chargingHome EV charger types and speeds, explained properly
There are three ways to put electricity into a car on your own driveway, and only one of them is a real answer for daily driving. Here is what each delivers in miles per hour, and where the ceiling actually sits.
Updated 4 August 2026 · written by the Clearline guidance team
The three options, side by side
Home charging comes down to three formats. A portable cable into a normal socket, a wall mounted unit on a dedicated circuit, or the same wall unit running at higher power because the house has a three phase supply. The gap between them is large, and it is the gap that decides whether charging is something you think about or something you forget about.
| Method | Power | Range added per hour | What it is for |
|---|---|---|---|
| 3-pin granny cable | around 2.3kW (10A) | roughly 8 to 15 miles | Emergencies and occasional top-ups |
| 7kW wall unit, single phase | up to 7.4kW (32A) | approximately 25 to 35 miles | Daily charging in almost every UK home |
| 22kW wall unit, three phase | up to 22kW | capped by the car, most cap at 11kW or less on AC | Homes that already have a three phase supply |
Figures from manufacturer and guide sources checked August 2026. Real world miles vary with the car, the temperature and how you drive.
The granny cable is an emergency tool
A granny charger is a portable lead that plugs into a standard UK 3-pin socket and draws around 2.3kW, adding roughly 8 to 15 miles of range an hour. For a car parked overnight at a relative's house once a quarter, that is genuinely useful. For every night, it is the wrong tool.
The reason is not the speed, it is the socket. A 3-pin plug pulling a continuous 2.3kW for ten hours or more is a sustained load that most domestic sockets and the wiring behind them were never designed to carry, and overheating is a real risk. If you want to charge from a socket regularly rather than from a wall unit, BS 7671 (the 18th Edition wiring regulations) points to a dedicated outdoor 13A or 16A socket on its own circuit with appropriate RCD protection, which is an installation job in its own right.
Keep the granny cable, just do not rely on it
Almost every EV ships with one, and it is worth keeping in the boot. Treat it the way you treat a spare wheel: fine to get you home, not something you plan your week around.
What 7kW actually means for a night
A 7kW home charger adds approximately 25 to 35 miles of range per hour, roughly three times what the granny cable manages. On single phase the practical ceiling is 7.4kW at 32A, and that is what almost every home unit on the UK market is built to deliver.
Put that against a normal overnight window and the arithmetic is not close. Seven hours at 7kW is around 49kWh, which is a full charge for the large majority of cars on UK roads. A 7kW unit is enough to fully charge any UK EV overnight, which is why the debate about faster home charging is mostly a debate about something you will never use.
You are not charging against the clock, you are charging against a cheap window
The number that matters at home is not how fast the charger goes, it is how much energy you can move inside the hours your tariff is cheap. Most off-peak windows run five to seven hours, and 7kW fills a car comfortably inside that. Anything faster is spending money to finish early on a job that had all night.
Where 22kW comes in, and why it usually does not
22kW charging requires a three phase electricity supply, and around 97% of UK homes are single phase. Getting three phase installed is a Distribution Network Operator job costing roughly £3,000 to £4,000 where a three phase main is already close by, and £7,000 to £15,000 or more once trenching, road works or network reinforcement enter the picture.
Even where three phase already exists, most UK EVs cap AC charging at 11kW or less, so the full 22kW frequently cannot be used by the car sitting on the drive. We have broken the trade-off down properly in 7kW or 22kW home charging, including the cases where three phase genuinely is the right answer.
Every new unit is a smart unit now
Since the Electric Vehicles (Smart Charge Points) Regulations 2021 came into force on 30 June 2022, any new domestic charge point sold and installed in Great Britain has to be smart. That means it arrives pre-configured to charge in default off-peak hours, which you can change, and it applies a randomised delay of up to ten minutes at the start of a schedule. Non-smart units can no longer legally be newly installed. The detail sits in the smart charger rules.
The practical effect is that the speed question and the tariff question are the same question. A smart unit paired with an off-peak rate is what turns 7kW into cheap miles, and our tariff guidance covers which windows are currently on offer.
Not sure whether your supply, your parking and your car add up to a straightforward install? The free remote design call works it out in twenty minutes, with no obligation.
Get your free quote →How to choose, in order
- Assume 7kW unless something specific rules it out. It covers every UK EV overnight.
- Check what your main fuse is rated at, because that decides whether load balancing is needed rather than a supply upgrade.
- Only look at 22kW if the property already has three phase, and check your car's AC charging limit before you do.
- Keep the granny cable for emergencies, and do not build a routine around it.
- Pick the tariff and the charger together, because charger-side tariff integration is what unlocks the cheapest rates.
If you are weighing a charger alongside solar panels or battery storage, the sizing conversation changes again, because a charger is a large flexible load that a battery and an array can both feed. Every county page on this site carries a local calculator, and you can find yours through our coverage map.
Clearline gives independent guidance and does not install. Installations are carried out by an MCS-certified installation team for your area.
Charging speed questions, answered
How many miles does a 7kW charger add per hour?
Approximately 25 to 35 miles of range per hour, against roughly 8 to 15 miles from a 3-pin granny cable. The exact figure depends on the car's efficiency and the conditions. Over a normal overnight window that is a full charge for the large majority of UK EVs.
Is it safe to charge from a 3-pin plug every night?
It is not what a standard domestic socket was designed for. A granny cable pulls a continuous 2.3kW for ten hours or more, and most sockets and their wiring were not built for that sustained demand, which brings a real overheating risk. For regular socket charging, BS 7671 points to a dedicated outdoor 13A or 16A socket on its own circuit with appropriate RCD protection.
Do I need a 22kW charger?
Almost certainly not. 22kW requires a three phase supply and around 97% of UK homes are single phase, and even on three phase most UK EVs cap AC charging at 11kW or less. A 7kW unit fully charges any UK EV overnight.
What does 7.4kW mean compared with 7kW?
7.4kW is the maximum a single phase 32A circuit can deliver at UK voltage, and it is what most modern home units are rated at. 7kW is the round number people use in conversation for the same class of charger. The difference in charging time is a matter of minutes, not hours.
Can I install a charger myself?
No. Charger installation is notifiable electrical work, which means it must be carried out by a registered competent person such as an NICEIC or NAPIT registered electrician, or notified to your local building control. It also needs the correct notification to your Distribution Network Operator.
Does a faster charger cost more to run?
No. You pay for the energy you move, not the rate you move it at, so a full charge costs the same whether it took four hours or eight. What changes the cost is the time of day you charge and the tariff you are on.
See the numbers next: Tesla Powerwall 3, installed, or what a battery costs.
Figures and specifications in this guide are sourced below and were checked on the date shown. Rates and product specifications change; we confirm the current picture on your free design call.
Sources
- myenergi Zappi v2.1 datasheet Rev 2.1.5, charging current and single phase power ratings myenergi.com
- Granny charger power output and range added per hour electriccarscheme.com
- 3-pin daily charging safety and the BS 7671 dedicated outdoor socket requirement mackie-electrical.co.uk
- 7kW range added per hour compared with granny charging proev.co.uk
- Three phase requirement for 22kW, proportion of UK homes on single phase, and DNO upgrade cost ranges solargridcheck.co.uk
- Vehicle AC charging caps and why 7kW is sufficient overnight evtariff.co.uk
- Electric Vehicles (Smart Charge Points) Regulations 2021 legislation.gov.uk
- Charger installation as notifiable work requiring a registered competent person elec-mate.com
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