In the UK, many homes have a PME (TN-C-S) earthing arrangement. If the combined neutral and earth (PEN) conductor in the supply breaks, exposed metal on a car connected outdoors could reach a dangerous voltage. BS 7671 therefore requires EV charge points on PME supplies to be protected against this, either by a charger with built-in open-PEN detection, a separate earth electrode (TT arrangement), or another compliant method. Whether a particular Tesla Wall Connector installation meets this depends on the model’s UK specification and the installer’s design, so check Tesla’s UK documentation and ask your installer.
Common Ways to Provide Protection
| Method | How it works |
|---|---|
| Charger with built-in open-PEN detection | Monitors supply voltage and disconnects if a PEN fault is likely |
| Earth rod (TT system) for the charger | Charger earth is separated from the PME earth |
| Separate protective device | External unit that monitors and disconnects |
Questions to Ask Your Installer
- Is my supply PME, and how will the charger be protected against an open PEN fault?
- Does the charger model include built-in detection?
- What RCD protection is included? See RCD protection for EV chargers.
- Will I receive an Electrical Installation Certificate?
The IET Code of Practice for EV charging equipment installation explains the options in detail. For supply cable choices, see does an EV charger cable need to be armoured. UK-market wallboxes such as the EVDANCE EV-ACT3204E 22 kW wallbox are installed with the earthing arrangement the installer specifies.
Frequently Asked Questions
What is a PEN fault?
A break in the combined neutral and earth conductor of a PME supply.
Do I need an earth rod for my EV charger?
Not if the charger or another device provides compliant open-PEN protection.
Does every UK charger have PEN protection?
Many do; check the specific model and installation design.
Related Reading
- Does an EV Charger Cable Need to Be Armoured?
- RCD Protection for EV Chargers
- UK VAT on EV Charger Installation
Key Takeaways
- PME supplies need open-PEN protection for EV charge points.
- Options include built-in detection or an earth rod.
- Confirm the model and design with your installer.