Summary:
PEN (Protective Earth and Neutral) fault detection is a must-have for EV charger safety in the UK. This post explains what a PEN fault is, why it’s dangerous, and how Eco Harmony’s PME protection devices — including Tesla-compatible 3-phase models — help installers stay compliant and protect their clients’ chargers.
What Is a PEN Fault?
A PEN fault occurs when the combined neutral and earth conductor (common in TN-C-S or PME systems) becomes disconnected or broken.
This can lead to:
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Dangerous voltage rise on exposed metal parts
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Electric shock risk for users
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Damage to chargers and vehicles
Under BS 7671:2018 Amendment 2, EV chargers on PME systems must include protection against PEN faults — unless the site has its own earth electrode and verified disconnection system.
Why PEN Fault Detection Is Critical for EV Installations
As EV charging expands into residential and commercial sites, most locations use PME supplies. Without proper PEN protection, installers risk non-compliance — and potential safety hazards for customers.
That’s where automatic PEN fault detection devices come in.
They constantly monitor voltage between live, neutral, and earth conductors.
If an imbalance is detected, they isolate the supply within milliseconds, preventing electric shock.
The Tesla-Compatible 3-Phase Solution
For multi-phase EV chargers — such as Tesla Wall Connectors, MyEnergi Zappi, or Easee — Eco Harmony’s
3-Phase PEN Fault Detection & Surge Protection Device (Tesla-Compatible) offers the ideal all-in-one solution.
Key benefits:
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✅ Full 3-phase PEN fault detection with automatic disconnection
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✅ Built-in Type 2 surge protection for transient voltage control
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✅ Tesla-compatible – tested for use with Tesla 3-phase chargers
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✅ Compliant with BS 7671 Amendment 2
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✅ Compact design – easy to install beside any distribution board
This makes it a perfect fit for installers working with EV chargers that lack built-in PME protection.
When to Use Standalone vs. Integrated Devices
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Standalone units (like Eco Harmony’s PEN Fault Detection Device) are ideal for retrofitting existing charger setups.
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Integrated models with RCBO and SPD are best for new installations or 3-phase charger networks.
Both ensure compliance and user safety, giving you peace of mind and your customers long-term reliability.
Installation Tips
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Mount close to the charger or consumer unit.
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Follow manufacturer wiring diagrams carefully.
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Test isolation function after installation.
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Combine with Type 2 SPD where needed to protect against surges.
Conclusion
A PEN fault can be catastrophic — but with the right protection, it’s easily prevented.
Eco Harmony’s range of PME protection devices keeps EV installations safe, compliant, and compatible with today’s top charging brands.
👉 Explore PEN Fault Protection Solutions:
https://ecoharmony.co.uk/collections/surge-protection-pme