Key points
- The car decides the charging speed. Most accept 7.4kW on single-phase or 11kW on three-phase.
- Only a few cars take 22kW on AC, such as the Renault Zoe ZE50 and some Porsche, Audi and Mercedes models.
- A 7kW single-phase charger holds an 11kW car back to around 7kW. A 22kW three-phase socket lets it charge at its full 11kW.
- A 22kW charger needs a three-phase supply. Load management lets two sockets share it with the rest of your site.
- Overnight, almost any car gets a full charge on either type.
The honest answer
A 22kW charger won't charge most cars at 22kW. The car decides how fast it charges on AC, and most stop at 7.4kW or 11kW.
That doesn't make 22kW a waste. For a business, a dual 22kW pedestal still charges more cars, faster, than a 7kW unit. The detail is below, and our charger page has the full specification.
What the numbers mean
7kW usually means a single-phase charger. Its real maximum is about 7.4kW, the most a single-phase supply can give a car (bestchargers.co.uk). Most homes and many small sites are single-phase.
22kW means a three-phase charger. It can deliver up to 22kW per socket, but only to a car that can accept it. Many commercial premises already have a three-phase supply.
Both are AC chargers. If you're also weighing up rapid DC charging, see our AC vs DC guide.
The car decides the speed
Every EV has an onboard charger that converts AC power for the battery. Its size sets the AC charging limit, whatever the charger on the wall can offer.
"Most popular EVs cap at 11kW on three-phase," and 7.4kW is the single-phase ceiling (bestchargers.co.uk). Some examples:
| Car | Maximum AC charging |
|---|---|
| Kia EV6 | 11kW |
| Nissan Leaf (older models) | 6.6kW |
| Renault Zoe ZE50 | 22kW |
| BYD Atto 3, LEVC TX, some Nissan Ariya trims | 22kW |
| Porsche Taycan, Audi e-tron GT, Mercedes EQS and EQE | 22kW as an option on some versions |
Sources: Zapmap, Zapmap Renault Zoe guide, bestchargers.co.uk. Check the exact version, because specifications vary by trim and year.
Real-world speeds
Here is what different combinations actually deliver. "Miles per hour" is range added per hour of charging.
| Charger | Car's AC limit | Actual power | Range per hour | Time to add 40kWh |
|---|---|---|---|---|
| 7kW single-phase | 11kW | About 7kW | About 24 miles | About 5.7 hours |
| 7kW single-phase | 7.4kW | 7.4kW | About 25 miles | About 5.4 hours |
| 22kW three-phase | 6.6kW (older Leaf) | 6.6kW | About 22 miles | About 6 hours |
| 22kW three-phase | 11kW | 11kW | About 37 miles | About 3.6 hours |
| 22kW three-phase | 22kW | 22kW | About 75 miles | About 1.8 hours |
Range figures are derived from the LGA and Zapmap's implied efficiency of about 3.4 miles per kWh. Times are simple maths. Real sessions run a little longer, especially in cold weather or as the battery nears full.
The key row is the fourth one. The most common type of car charges around half as fast again on a 22kW socket as it would on a 7kW single-phase unit.
How long people stay changes the answer
Speed matters less the longer people stay.
- Hotels and holiday parks. Guests park overnight. The average usable battery is 73.4kWh (EV Database), so almost any car is full by morning on either charger.
- Wedding venues and days out. A six-hour stay at 11kW adds about 220 miles. At 7kW it adds about 145.
- Pubs and restaurants. A two-hour meal at 11kW adds about 74 miles. At 7kW it's about 48. Here the faster socket makes a real difference to the driver. Our pubs and restaurants page covers this.
What each needs from your supply
A 7kW charger draws about 32 amps on a single phase. A 22kW socket draws about 32 amps on each of three phases (derived).
Our pedestal has two 22kW sockets. With both running flat out, that's roughly 64 amps per phase. In practice it's often less, because most cars only take 11kW.
Optional dynamic load balancing lets the sockets share your supply with the kitchen, laundry or spa. When the building is busy, charging slows. When it's quiet, it speeds up. Our load management guide explains how.
The national application form for Northern Powergrid and other network operators sets out when you can "connect and notify" and when you must apply first. Demand above 60A per phase normally means applying first, unless the load is limited (ENA form). We handle that application.
What each costs
A 22kW post costs more than a 7kW wall unit. Part of that is the pedestal, and part is running a heavier three-phase cable underground to it.
Zapmap's workplace charging guide was last updated in May 2024. It gave about £1,500 for a fully installed 7kW double-headed unit, and £2,500 to £5,000 for a 22kW double-headed post (Zapmap). Treat those as old ballpark figures, not quotes.
Your own cost depends far more on groundworks and supply than on the 7kW or 22kW label. Our installation cost guide breaks it down.
Why a dual 22kW pedestal still makes sense
For most destination sites, we recommend 22kW sockets. The reasons are practical:
- Most cars charge faster. An 11kW car gets its full 11kW, instead of being held to around 7kW on a single-phase unit.
- Two cars at once. Two sockets on one pedestal means two guests charge at the same time, from one set of groundworks.
- The 22kW cars get full speed. Drivers of those cars get the fastest AC charge available.
- Shorter stays work better. At a pub, café or shop, an 11kW car gains an extra 12 or 13 miles every hour. That turns a token top-up into a useful one.
- You only dig once. Running three-phase cable now is simpler than digging up the car park again later.
- Load management keeps it in check. You don't need to reserve the full 44kW for the charger.
How to tell if you have three-phase power
You can often tell from your main fuse, known as the cut-out. A three-phase supply usually has three fuses side by side, one per phase. A single-phase supply has one.
Your electricity bill or supplier can also confirm it. Larger sites may have a current-transformer (CT) meter, which usually means a bigger three-phase supply.
If you're not sure, don't worry. We check the supply, the cut-out rating and the spare capacity as part of every survey. Our grid capacity guide explains what we look for.
When 7kW is enough
A 7kW charger can be the right choice in a few cases:
- a staff car park where cars sit all day
- a small B&B with one or two guest cars overnight
- a building with only a single-phase supply and no case for upgrading it
Next step
If you're unsure which suits your car park, a free site survey will check your supply and the cars your customers drive. Then compare the two packages to see how the costs would be shared.