Do you need single-phase or three-phase power for EV charging?

Your charging requirement decides whether a supply upgrade is useful. Energy Saving Trust says 22 kW AC charging needs a three-phase supply, but your vehicle can limit the speed [S2]. Check spare capacity and parking time before committing to an upgrade. Load management may let you serve more vehicles on your existing connection. Checked October 2026.

Last checked 16 October 2026

What is the difference between single-phase and three-phase supply?

Your supply is the connection bringing electricity into your site. UK Power Networks describes single-phase as the smaller supply and recommends an electrician’s assessment of the equipment you intend to run [S1].

For a charging project, start with the vehicles and their departure times. A larger connection is useful only when the charging plan needs it. A hotel with cars parked overnight and a delivery business with vehicles returning between shifts should not order the same arrangement without checking their needs.

Kilowatts, written kW, measure power: how fast energy is transferred. Kilowatt-hours, written kWh, measure energy: how much you buy or deliver. Use our power and energy guide when reading equipment schedules. A distribution network operator, or DNO, manages the local electricity network. It is different from the supplier that bills you for electricity.

How do you check whether your business has three-phase power?

Ask your electrician to record the incoming supply arrangement, protective devices, distribution boards and existing loads. UK Power Networks says the service head’s fuse arrangement can provide a visible indication: single-phase commonly has a single fuse, while three-phase has a set of three [S1]. Do not remove covers or seals to investigate it yourself.

Collect a recent bill, any connection agreement and a site plan before the visit. Ask the survey report to distinguish the equipment rating from the spare capacity actually available while your business is operating. That distinction makes it easier to compare offers on the same basis.

Keep a list of equipment likely to run alongside charging: refrigeration, ovens, workshop machinery or heating. Record seasonal events and planned additions. A quiet-day visit should not become the sole design assumption for a busy trading day. See how much power your site has.

Do you need three-phase power for a 22 kW charger?

Energy Saving Trust says 22 kW alternating current, or AC, charging requires a three-phase supply. It also explains that the vehicle’s onboard charger can restrict the power accepted [S2]. Buying a higher-rated post does not remove that vehicle limit.

Use the following as a purchasing checklist, rather than an equipment recommendation:

Compare AC and DC chargers before assuming a supply upgrade is the answer to a short parking window. Direct current, or DC, charging is a different equipment decision.

How fast do your vehicles actually need to charge?

Use energy required divided by usable charging time as a first calculation. This is a planning calculation; your designer must allow for losses and operating restrictions before using it as a specification.

For illustration, assume a van needs 28 kWh and stays for 8 hours. Average delivery would need to be 28 ÷ 8 = 3.5 kW before losses. Change the stay to 2 hours and the same energy requires 14 kW. These are assumptions, not typical van consumption or a forecast of charging performance.

Repeat this calculation for the busiest credible day. Include early departures and vehicles that return late. Ask whether charging should follow a queue, share capacity equally or prioritise vehicles due to leave. The point is to specify completed journeys, rather than purchase the largest charger on a product sheet.

Could load management avoid a supply upgrade?

Energy Saving Trust describes load management as distributing available power without exceeding the site’s spare capacity [S2]. Ask for a comparison between a controlled charging layout and a connection upgrade.

Make the comparison practical. Request the delivered energy at each departure time, the behaviour when communications fail, and who can change the power limit. Ask your electrician to consider individual phase loading as well as the overall site figure. Put those requirements in the survey brief rather than attempting to set electrical limits yourself.

Our load management versus grid upgrade guide helps organise that comparison. Include a fallback operating plan for a vehicle that misses its intended charging window, such as reallocating a departure or using another charging location.

What should a three-phase upgrade quote include?

Request separate lines for network work, metering, your distribution equipment, cable routes, reinstatement and charger installation. UK Power Networks distinguishes upgrading the supply from changing the meter [S3]. Ask each party to identify its scope so that an apparent all-in price does not leave work unallocated.

Do not apply a residential upgrade price to your business without a survey. A car park cable route, trading access and excavation arrangements belong in the specification. Request a programme showing dependencies and the proposed electricity interruption, then compare the disruption with your opening hours.

For fully funded proposals, ask who pays for that work and whether it changes the lease or income share. For part funded and self funded proposals, identify the host’s contribution separately. Ask your solicitor to check access rights, redevelopment options and removal obligations before signing any land agreement.

What should you do next?

Prepare your vehicle list, parking windows and existing electricity information. Then get matched with an installer that covers your area for a supply and charging assessment.

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