If you’re installing an EV charger or upgrading a supply, the same question keeps cropping up: do you still need to bang in an earth rod if you’ve got a PME fault detection device?
The short answer is: not usually. The 18th Edition Amendment 2 (BS 7671:2018+A2:2022) sets out clear rules on when a rod is needed, and modern PME fault protection devices are designed specifically to remove that requirement in most EV installations.
Quick Answer: In most EV installs, a PME fault detection device means you don’t need an earth rod. Only in TT systems or special DNO cases will a rod still be required.
What PME Fault Protection Does
PME (Protective Multiple Earthing) fault detection devices monitor the supply and disconnect all live conductors and the earth if a PEN (Protective Earth and Neutral) fault is detected.
- Prevents dangerous touch voltages on exposed metalwork.
- Removes the need for a separate earth electrode in many EV installs.
- Available for single-phase and three-phase setups — e.g. IP65 PEN Fault Detection Unit and 3-Phase PME Boards.
Installer’s Pick: The IP65 PEN Fault Detection Unit trips faster and more reliably than rods, saving you time on site.
When You Still Need an Earth Rod
There are cases where PME alone isn’t enough:
- TT systems — no PME available, so you must provide a local electrode.
- Certain DNO conditions — some still require a rod as belt-and-braces.
- Legacy installs — older boards without PME detection.
- Outdoor non-EV circuits — e.g. garden supplies where PME isn’t allowed.
For most EV charger installs, a compliant PME fault device removes the earth rod requirement entirely.
PME vs Earth Rod – Why It Matters for EV
Earth rods have always been unreliable:
- Soil conditions vary (clay, sand, chalk).
- Resistance values change with weather and moisture.
- Testing adds time and cost.
PME devices solve this with a self-contained, regulation-compliant disconnect that satisfies BS 7671 and DNOs. That’s why they’re now the go-to option for EV installs needing fast sign-off.
Products That Deliver
- PEN/PME fault detection units – e.g. IP65 PEN Unit
- PME-ready consumer units with RCBOs + RCDs – e.g. PME Plastic Consumer Unit (40A RCBO + SPD)
- Load balancing PME boards and 3-Phase PME units for multiple chargers
Final Word
So, do you still need an earth rod with PME fault protection?
- Most modern EV installs – no.
- TT or non-PME systems – yes.
The key is matching the board or PME device to the supply type and making sure it’s 18th Edition A2 compliant. That way you’ll pass inspection first time and cut callbacks.
👉 Next step: Explore our PME fault detection range and EV-ready consumer boards to spec your install with confidence.