For a standard 7kW home EV charger, you need 6mm² twin and earth cable as a minimum, run from a dedicated 32A circuit. For longer cable runs over 25 metres, or higher-power 22kW three-phase chargers, 10mm² or larger may be required. Always use armoured cable (SWA) for outdoor or underground sections. Cable sizing must be calculated by a qualified electrician to account for current rating, voltage drop, and installation method under BS 7671. Never undersize — this is a fire risk.
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What Cable Size Do I Need for an EV Charger at Home?
Choosing the right cable for your EV charger is one of the most important parts of the installation. Using the wrong size can cause overheating, nuisance tripping, or in the worst case, a fire. Here is what you need to know in plain English.
The Most Common Answer: 6mm² Cable
For the vast majority of UK homes installing a standard 7kW single-phase home charger (the most popular type), a 6mm² twin and earth cable is used, protected by a 32A circuit breaker in your consumer unit.
Key factors that affect cable size:
Length of the cable run — The longer the cable, the more voltage is lost along the way. Runs over 25 metres may need 10mm² cable to stay within the 3% voltage drop limit
How the cable is installed — Cables buried in a wall, clipped to a surface, or buried underground all have different current-carrying capacities. Buried cables can carry more current; cables in thermal insulation carry less
Three-phase chargers (22kW) — These require a completely different circuit, typically 10mm² or larger, with a three-phase supply — not available in most UK homes
Other loads on the same supply — If your incoming supply is already heavily loaded, your electrician may need to install a load management device
What you can safely check yourself:
Check whether your home has a single-phase or three-phase supply (look at your meter or consumer unit — three-phase will have three live conductors)
Measure the rough distance from your consumer unit to where the charger will be fitted — this helps your electrician calculate the run length
Check whether you have a spare 32A slot in your consumer unit
When to call an electrician:
All EV charger installations in the UK must be carried out by a Part P registered electrician and notified to your local building control. The installer must also comply with OZEV (formerly OLEV) grant requirements if applicable. Do not attempt to wire this yourself — incorrect installation can void your home insurance and your car warranty.
Always get a site survey first. A qualified installer will calculate exact cable sizing for your specific property.