Home EV charging: cheaper, easier, sooner

Granny cable versus wallbox

The three-pin cable in the boot is known as a granny cable, named for the pace rather than the user. It draws about 2.3kW, adds roughly 8 miles of range per hour, and asks an ordinary socket to work near its limit for hours on end. Fine as an occasional backup; hard on ageing sockets and wiring as a daily habit.

If you do lean on one, plug straight into a healthy socket, never an extension lead or a coiled cable reel, and check the plug is not running warm. A 7kW wallbox is a different animal: its own circuit from the consumer unit, its own protection, and roughly three times the speed.

What the installer checks first

Fitting a charger is notifiable electrical work, so it is a job for a qualified installer who signs it off, not a weekend experiment. Before quoting, a good firm asks for photos of your consumer unit and main fuse, then runs a load check: a 100A main fuse usually carries a wallbox comfortably, while a smaller or busier supply (electric shower, electric heating) may need the network operator to upgrade the fuse first. Your installer arranges that.

They will also want the cable route from the board to where you park, and your choice of tethered (cable permanently attached) or untethered (a socket you bring a cable to). New home chargers are smart by law, able to schedule themselves into cheap hours. The rules that make garden power safe, proper outdoor kit and RCD protection, apply here with interest.

Night rates do the heavy lifting

The wallbox is half the product; the tariff is the other half. EV tariffs offer a cheap overnight window, and a smart charger fills the battery inside that window automatically, so the saving needs no willpower. You will need a smart meter sending half-hourly readings for one of these tariffs, which is a free box to tick.

A typical electric car covers 3–4 miles per kWh, so overnight units become cheap miles while you sleep. If there are panels on the roof, some chargers can divert surplus solar generation into the car instead of exporting it. In the wider bill-cutting order, the charger sits with the other big electric loads: after the cheap wins, and better for every fix that came before it.

Flats, rentals and the kerb

The honest bit: without off-street parking, a wallbox is rarely on the table. Trailing a cable across a pavement is a trip hazard most councils will not wear, though some now run kerbside and lamppost charging schemes, so ask yours. Renters need the landlord’s written permission, leaseholders the freeholder’s, and both are granted more often than people expect. Failing all that, public charging plus a workplace socket covers plenty of drivers until the parking situation changes.