When people start looking into home EV charging, the question of charger size usually comes up early. The short answer for most UK homes is 7kW — but understanding why helps when you’re comparing quotes or checking specs.
The charging speeds available for home use
Home EV chargers in the UK typically run at either 3.6kW or 7kW on a standard single-phase supply. Some commercial properties and a small number of homes with a three-phase supply can access 22kW charging, but that’s genuinely uncommon in residential settings.
A 7kW charger over a standard overnight charge of around 10 hours delivers roughly 70kWh — more than enough to fill most current EVs from nearly empty, and well in excess of what most drivers actually use in a day.
The on-board charger: the factor most people miss
The speed at which a car actually charges is limited by its on-board charger — the component inside the vehicle that converts AC power from the wall into DC power for the battery. Many EVs have an on-board charger rated at 7.2kW or 7.4kW, which means they’ll charge at around 7kW regardless of what the wall unit delivers. Others are limited to 3.6kW or 3.7kW — common in some older or entry-level models.
Fitting a faster wall charger than the car can accept doesn’t speed anything up. If your car’s on-board charger is rated at 3.6kW, a 7kW unit will still charge it at 3.6kW. It’s worth checking your car’s spec before assuming a larger charger will make a difference.
What about 22kW?
22kW chargers require a three-phase electricity supply. Most UK homes have single-phase, so 22kW isn’t a realistic option without applying to your Distribution Network Operator for a supply upgrade — a process that can take months and comes at significant cost. For the vast majority of domestic installations, there’s no practical path to 22kW, and given how overnight charging works, no real need for one either.
Tethered or untethered?
Chargers come in two versions. Tethered units have a cable permanently attached — convenient if everyone in the household drives the same car type, since you never need to remember to bring a cable out. Untethered units have a socket instead, and you plug in your own cable. These suit households with different cable types, or where you might change car in the future.
The charging speed is the same either way. It’s a practical choice rather than a technical one.
What the installation involves
A standard home EV charger installation runs a dedicated circuit from the consumer unit to the charger location — usually an external wall or garage. It needs a correctly rated MCB, appropriate cable, and an enclosure suited to outdoor use. Most installations are completed in half a day. If your consumer unit is old or doesn’t have space for an additional circuit, that may need addressing first.
If you’re combining the charger with solar panels or a battery, the wiring layout needs a bit more thought — particularly around CT clamp placement, which affects how the charger and battery interact. We’ve covered that in our guide to wiring EV chargers and battery systems for Octopus Intelligent.
If you’re in Bristol or South Gloucestershire and want to talk through the right charger for your home, get in touch.
