- A 16 A reinforced socket (3.2 kW) adds about 140 km overnight, enough for most commuters.
- A 7.4 kW wallbox adds about 330 km overnight and costs €1,000–2,000 installed.
- Home charging costs €2–4 per 100 km, three to four times less than public fast charging.
- Never charge from an ordinary extension lead: continuous 10 A loads are outside its design.
Three ways to charge at home
The standard socket (2.3 kW). Available everywhere, but designed for intermittent loads. Charging a car for eight hours at 10 A pushes a circuit that was never meant for it. Acceptable occasionally, not as a routine.
The reinforced socket (3.2 kW). A dedicated 16 A circuit with its own protection, often called a “green’up” socket in France. It adds about 25 kWh overnight, or 140–160 km. Installation costs €300–600. For a driver covering 40–60 km a day, it is the cheapest adequate solution.
The wallbox (7.4 to 22 kW). A fixed charging point with integrated protection, scheduling and, often, load management. At 7.4 kW single-phase it adds 50–60 kWh overnight, or 320–380 km. Installed cost: €1,000–2,000, before any subsidy.
How much range each option adds
| Solution | Power | kWh in 8 hours | Kilometres added | Typical installed cost |
|---|---|---|---|---|
| Household socket | 2.3 kW | ~17 kWh net | ~105 km | €0 |
| Reinforced socket | 3.2 kW | ~23 kWh net | ~145 km | €300–600 |
| Wallbox single-phase | 7.4 kW | ~53 kWh net | ~330 km | €1,000–2,000 |
| Wallbox three-phase | 11 kW | ~79 kWh net | ~495 km | €1,500–2,500 |
The kilometre figures assume 16 kWh/100 km and 10 % charging losses. A more efficient car gains more kilometres from the same energy.
What it costs to charge at home
Take a consumption of 16 kWh/100 km and a tariff of €0.18/kWh off-peak:
- 16 × 0.18 = €2.88 per 100 km.
- For 15,000 km a year: about €430, plus 10 % losses, so roughly €475.
On a flat tariff at €0.25/kWh, the same distance costs about €660. On a public fast charger at €0.60/kWh, it would cost €1,600 — which is why home charging, when available, dominates the economics of electric driving.
Choosing between 7.4 and 11 kW
The useful question is not “how fast can I charge?” but “how many hours is the car actually parked?” Most cars sit still for 10–12 hours a night. A 7.4 kW wallbox delivers 60–70 kWh in that window, more than any normal daily need.
An 11 kW unit makes sense if:
- you have three-phase power already;
- two electric cars share the same charging point;
- you need to recharge a large 100 kWh battery overnight after a long trip.
Otherwise, 7.4 kW is the sweet spot, and cheaper to install.
Safety and paperwork
- Use a qualified installer. In most European countries, a dedicated charging circuit requires a certified electrician and, often, a declaration to the grid operator.
- Check the protection. A dedicated 30 mA type-A or type-B residual current device, plus a DC fault detector, is standard for mode 3 charging.
- Do not daisy-chain extension leads. A 10 m extension reel at 10 A can overheat; it is the most common cause of home charging incidents.
- Load management matters. A wallbox that communicates with the meter avoids tripping the main fuse when the oven and the car charge at the same time.
Charging on off-peak hours
Most suppliers offer a cheaper overnight window, typically 8 hours. With a connected wallbox or the car’s own scheduler, you can align charging with that window and cut the energy cost by 30–50 %. For a 15,000 km year, that is €150–250 saved annually — enough to pay back part of the wallbox.
When home charging is impossible
Without a private parking space, the calculation changes. Public slow charging (7–22 kW) at €0.30–0.50/kWh costs €5–8 per 100 km, still below petrol but far from the home figure. Some workplaces offer cheap charging, and a few cities provide residential on-street permits. Before buying an electric car, map the chargers within a five-minute walk and check their reliability, not just their presence.
Frequently asked questions
Can I charge an electric car from a normal household socket?
Technically yes, at 2.3 kW (10 A), but it is not recommended for daily use. A standard socket is not designed for a continuous 10 A load over eight hours, and extension leads add risk. Use a dedicated reinforced socket or a wallbox.
How long does it take to charge at home?
A 50 kWh battery goes from 20 % to 100 % (40 kWh) in about 13 hours on a 3.2 kW reinforced socket, six hours on a 7.4 kW wallbox and four hours on 11 kW three-phase. In practice you charge overnight, not from empty to full.
Do I need a three-phase supply for an 11 kW wallbox?
Yes. Most homes have single-phase power, which caps charging at 7.4 kW. Check your meter and main fuse before buying; upgrading the supply is possible but adds cost and paperwork.
Are there grants for installing a home charger?
Several countries and regions subsidise installation, often 30–50 % of the cost up to a cap, sometimes limited to rural areas or specific income brackets. Check your national energy agency and local authority before signing a quote.