EV Charger Installation: A Practical Guide
A clean EV charger install comes down to four things: enough supply capacity, the right cable, correct earthing, and a proper commissioning certificate.
Domestic EV charging is one of the fastest-growing areas of electrical work. A typical 7 kW charge point draws around 32 A continuously, so the install is as much about the existing supply and earthing as it is about the unit on the wall.
This guide runs through the practical steps — surveying the supply, sizing the cable, handling the PME earthing question, and commissioning — to install a domestic charge point to Section 722 and the IET Code of Practice.
Key takeaways
- A 7 kW single-phase point draws about 32 A continuously — check the supply and maximum demand first.
- Run a dedicated circuit; size the cable for the continuous load and volt drop over the run.
- Address PME/PEN fault risk with open-PEN protection or a TT earth electrode.
- Use load management where the supply can't take the full charge current on top of existing demand.
- Certify with an EIC and an EV charge point commissioning certificate.
Survey the supply first
Before quoting, check the main fuse rating, the existing maximum demand and the earthing arrangement. A 7 kW charger on top of a house with electric heating and a shower can exceed an 60 A or 80 A main fuse, which is where load management or a supply upgrade comes in.
Confirm the earthing arrangement — most supplies are PME (TN-C-S), which drives the PEN fault protection decision later.
Check the headroom
Work out the existing maximum demand with diversity before you add 32 A — TradePlanr's max demand calculator makes that a two-minute check.
Cable sizing and the circuit
Run a dedicated radial from the consumer unit or a suitable point. Size the cable for the continuous 32 A load, applying the installation reference method and any grouping or thermal correction factors, and check volt drop over what can be a long run to a driveway or garage.
Protect the circuit appropriately and provide the 30 mA RCD protection with DC fault current capability that Section 722 requires.
Earthing and PEN fault protection
On a PME supply you must protect against an open-PEN condition, because a lost network neutral can make the car and charger body live. Most modern charge units include open-PEN protection that disconnects on out-of-range voltage; where they don't, install a separate earth electrode and run the point as TT.
Whichever route you take, verify it works at commissioning, not just that it is wired in.
Load management and commissioning
Where the supply can't carry the charger on top of peak demand, a load-management device (CT clamp on the tails) throttles the charge current so the main fuse is never overloaded. This often avoids a costly supply upgrade.
Commission the unit, test the circuit and RCD, confirm the earthing protection, then certify. The circuit gets an EIC and the charger gets its commissioning certificate.
Handover pack in one go
TradePlanr issues the EIC and the EV charge point commissioning certificate together, signed on site, so the customer leaves with a complete record.
Frequently asked questions
Can any house take a 7 kW charger?
Not always. A 7 kW point adds about 32 A of continuous load. If existing maximum demand plus the charger exceeds the main fuse, you either fit load management to throttle the charge current or arrange a supply upgrade with the DNO.
What cable size for a 7 kW EV charger?
It depends on the installation method and run length, but 6 mm² is common for a typical clipped or buried run, with 10 mm² used where volt drop or thermal factors demand it. Always size for the specific job rather than a rule of thumb.
Does an EV charger need its own certificate?
Yes — the new circuit is certified with an EIC and the charge point is recorded on a commissioning certificate. Installing the circuit is also notifiable under Part P.
From guidance to action
Related guides
Section 722: EV Charging Requirements
The Section 722 rules for EV charge points — RCD types, PEN fault protection and earthing arrangements.
The IET Code of Practice for EV Charging
What the IET Code of Practice adds on top of BS 7671 for EV charging equipment installations.
How to Calculate Maximum Demand (with Diversity)
Applying diversity to work out realistic maximum demand for a domestic installation.
