A 22kW EV charger sounds like the obvious choice if you want the fastest possible home charging. However, a 22kW charge point is only worthwhile when both the property and the vehicle can support it.
For most homes, a 7kW single-phase charger remains the most practical and cost-effective option. Three-phase charging can make excellent sense for high-mileage drivers, multiple-EV households and commercial premises, but upgrading a typical domestic supply can involve substantial work and cost.
This guide explains the difference between 7kW, 11kW and 22kW charging, what a three-phase upgrade involves in Redhill and Surrey, and when the investment is genuinely justified.
The difference between 7kW, 11kW and 22kW EV charging
Most UK homes have a single-phase 230V electricity supply. A standard domestic EV charger connected to this supply typically delivers:
- 7.4kW at approximately 32A
- Around 25–30 miles of range per hour, depending on the vehicle
- Enough charging capacity for most cars when charging overnight
A three-phase supply uses three live phases at approximately 400V between phases. This allows higher AC charging rates without placing the entire load on a single phase:
| Charger rating | Supply arrangement | Current | Typical use |
|---|---|---|---|
| 7.4kW | Single-phase | 32A | Most homes and everyday overnight charging |
| 11kW | Three-phase | 16A per phase | Homes or businesses with a suitable vehicle and supply |
| 22kW | Three-phase | 32A per phase | Fleets, high-mileage users and short-dwell commercial charging |
An important point is that the vehicle determines the actual charging speed. A 22kW wallbox cannot force a car to accept 22kW.
Many battery electric vehicles have a single-phase 7kW on-board charger. If that is the case, connecting the car to an 11kW or 22kW three-phase unit may still only provide approximately 7kW. Many plug-in hybrid vehicles accept even less, often between 3.6kW and 7kW.
Always check the vehicle manufacturer’s specification for its AC on-board charger rating before paying for a three-phase supply upgrade.
Why most Redhill homes are better suited to 7kW charging
Victorian and 1930s semi-detached and terraced homes around Redhill town centre, Earlswood and St John’s are generally supplied with single-phase electricity. Service fuse ratings of 60A to 100A are common.
That does not automatically prevent you from installing an EV charger. A qualified electrician can assess the existing supply, calculate the property’s demand and install a suitable 7kW charge point with the correct protective equipment.
For a typical commuter:
- The car may arrive home with 30–50 miles of driving used
- A 7kW charger can usually replace that energy comfortably overnight
- Smart off-peak tariffs can reduce the cost of charging
- The installation is usually considerably simpler than a three-phase conversion
A 22kW charger connected to a single-phase supply will normally operate at a reduced rate, usually around 7kW. In that situation, there is no charging-speed advantage over a correctly specified 7kW charger.
Newer estates and larger detached homes may already have a three-phase supply, particularly where the property has significant electrical demand. The only reliable way to confirm this is to inspect the service head and distribution equipment, then verify the supply arrangement with the network operator.
When is a three-phase supply worth considering?
A three-phase EV charging installation may be worth the investment in the following situations.
1. You drive very high annual mileage
If your work involves long daily journeys, a 22kW charge point can reduce the time needed to replenish the battery, provided the vehicle supports 22kW AC charging.
This may be particularly useful for drivers who return home between journeys or need to prepare the car for another long trip during the day.
2. You have two electric vehicles
Two-EV households can quickly place extra demand on a single-phase installation. Options may include installing two 7kW charge points with appropriate charging management, but a three-phase supply may provide more flexibility where both vehicles need regular charging.
It is still important to compare the cost of a supply upgrade with the actual charging pattern. If both cars are usually parked overnight, two intelligently managed 7kW points may be sufficient.
3. You operate electric vans or a small fleet
Small businesses with electric vans often need dependable charging between shifts. Faster charging can reduce vehicle downtime and make fleet scheduling easier.
This is relevant to businesses around Holmethorpe Industrial Estate in Redhill and Merstham, as well as premises near Salfords and the A23 and A25 corridors.
4. Vehicles have short dwell times
Gyms, hospitality venues, showrooms, offices and other businesses may benefit when customers, staff or fleet vehicles are only parked for a few hours.
A 22kW dual-socket unit can be practical where vehicles need meaningful battery replenishment during a working day, particularly when the premises already has three-phase electricity.
5. You plan to provide paid or staff charging
Landlords, commercial property operators and businesses monetising charge points may find that faster charging improves the usefulness and commercial return of the installation.
For Redhill town-centre retail and hospitality premises, gyms, offices, schools and healthcare buildings, three-phase charging is often more achievable than it is in a domestic property because the existing electrical infrastructure may already include three-phase distribution.
What does upgrading a home to three-phase involve?
A domestic three-phase upgrade is more than replacing the wallbox. It normally requires an application to UK Power Networks, the local Distribution Network Operator for Redhill and the surrounding Surrey area.
Depending on the property and local network, the work may involve:
- A supply and load assessment
- A new or upgraded DNO connection
- A replacement service cut-out
- Metering changes
- A three-phase and neutral, or TP&N, distribution board
- New cabling between the service head, distribution board and charger
- Per-phase RCD or RCBO protection
- Suitable DC leakage protection for the vehicle circuit
- Testing, certification and commissioning
The DNO element of a three-phase connection can typically range from around £1,500 to £5,000 or more, depending on the distance to the nearest three-phase main, available network capacity, excavation requirements and whether reinforcement is needed.
Internal distribution work and the charger itself are additional costs. As a broad planning figure, a complete domestic project may cost several thousand pounds and can reach £8,000–£10,000 or more in difficult cases. A straightforward property with three-phase infrastructure nearby may cost substantially less.
Lead times can range from several weeks to several months. UK Power Networks confirms that the cost and timescale depend on the specific work required. You can find its current guidance on EV connection costs and timescales.
Alternatives to a three-phase upgrade
Before applying for a new supply, ask whether one of these options meets your needs:
- Install a standard 7kW single-phase charger and charge overnight
- Install a second 7kW charger with suitable load sharing or charging management
- Use a smart off-peak electricity tariff
- Choose a charger that can be upgraded or configured later
- Install a 22kW-capable unit on an existing three-phase supply, if the vehicle supports it
A 22kW-rated charger on single-phase electricity will not provide 22kW. It will simply operate at the maximum rate allowed by the supply and vehicle, normally around 7kW for a typical home installation.
A sensible decision-making process
A professional assessment should establish:
- Whether the property is single-phase or three-phase
- The service fuse rating and available capacity
- The vehicle’s AC on-board charger rating
- The condition and capacity of the existing consumer unit
- Earthing and bonding arrangements
- The proposed cable route and cable length
- Whether one or more charge points are required
- Whether charging management is appropriate
- Whether UK Power Networks approval is needed
At completion, you should receive an Electrical Installation Certificate and relevant test results. These documents confirm that the installation has been inspected and tested correctly.
For businesses, the assessment should also consider operating hours, vehicle movements, parking duration and future fleet requirements. A three-phase installation may be easier to justify at a warehouse, gym, restaurant, office or healthcare premises than at a typical family home.
Is 22kW charging a good investment?
For most commuter households with one EV, the answer is usually no. A 7kW charger is normally sufficient, particularly when the car is parked overnight and the vehicle has a 7kW on-board charger.
A three-phase upgrade is more likely to make financial and operational sense when:
- The vehicle accepts 11kW or 22kW AC charging
- You drive high daily mileages
- Several EVs need frequent charging
- Electric vans must return to service quickly
- Customers or staff need charging during short visits
- The property already has a suitable three-phase supply
The best approach is to compare the expected time saved with the cost of the DNO and internal electrical work, rather than assuming that the highest charger rating is automatically the best option.
EV charger installation in Redhill and Surrey
ADS Electrical provides EV charger installation and wider electrical services for homeowners, landlords and commercial clients across Redhill and Surrey, including Reigate, Merstham, Earlswood, Meadvale, Nutfield, Salfords, Whitebushes, South Park and Woodhatch.
As an NICEIC Approved Contractor, we can assess your supply, review your vehicle’s charging capability, plan cable routes and advise whether a 7kW, 11kW or 22kW solution is appropriate. We offer a free site survey, free lighting and charging design consultation, and aim to provide free quotes within 24 hours.
If you are planning a domestic installation, contact ADS Electrical about a home charging point Surrey property can rely on. For workplaces, landlords and fleet operators, we can design practical EV charging solutions Redhill businesses can use every day.
Frequently asked questions
Can any EV use a 22kW charger?
No. The vehicle must have an 11kW or 22kW three-phase AC on-board charger. If it only accepts 7kW single-phase charging, it will charge at approximately 7kW.
Is 11kW charging faster than 7kW?
Yes, provided the property has three-phase electricity and the vehicle supports 11kW AC charging. An 11kW charger uses approximately 16A on each phase.
Does a 22kW charger need three-phase electricity?
Yes, to deliver its full rating. A 22kW charger requires approximately 32A per phase on a three-phase supply.
Can a typical Redhill terrace house be upgraded to three-phase?
It may be possible, but this depends on the local network, service arrangement and the distance to suitable three-phase infrastructure. UK Power Networks must assess and approve the supply upgrade.
How long does a three-phase EV charger upgrade take?
A straightforward project may take several weeks. More involved DNO work, roadworks or network reinforcement can extend the process to several months. Internal charger installation is normally arranged after the upgraded supply is available.
What is the best charger for most homes?
For a typical single-EV household, a smart 7kW single-phase charger is usually the most cost-effective choice. The correct specification depends on the car, property supply and how many miles you drive each day.