WHAT IS AN OPEN PEN FAULT?
An open PEN fault happens when the combined Protective Earth and Neutral (PEN) conductor in a property’s electrical supply becomes damaged or disconnected. This is a serious safety issue because it can make metal parts in your home, like water pipes, appliances, or even an electric car, carry dangerous live voltages. Open PEN faults can be caused by things like cable damage, corrosion, or loose connections in the network outside your home — and they often happen without warning. That’s why modern EV chargers, such as the Myenergi Zappi, are designed with built-in PEN fault detection. They automatically cut off the power if a problem is detected, keeping your home, family, and vehicles safe while charging.
📈 How frequently do they occur?
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According to a Freedom of Information request, reported broken PEN incidents climbed from 57 cases in 2003 to 474 cases in the UK in the most recent year—an almost 8× increase CEF+15mfame.guru+15zaptec.com+15.
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However, this likely underestimates the true scope, as many faults go unreported. A single PEN fault may affect up to 50 properties at once, meaning the real scale of incidents could be significantly larger .
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Industry statistics from the Health & Safety Executive note around 400 open PEN faults reported annually, with roughly 10% causing injuries CEF+9myenergi GB+9mfame.guru+9.
🛡️ Why is it a concern?
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When the PEN conductor breaks, metalwork tied to protective earth can float at dangerous voltages—sometimes up to 230 V—relative to true Earth The FPA+10IET Electrical+10myenergi GB+10.
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With such broken PEN faults, diverted neutral currents may flow through water or gas pipes, overheating them and potentially causing fires proteusswitchgear.com+13mfame.guru+13IET Electrical+13.
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For electric vehicle (EV) charging installations, this is particularly hazardous, since metal EV bodies can become live. Consequently, new standards (BS 7671‑722 and IET 01:2024) mandate PEN-fault detection in EV charge points YouTube+9IET Electrical+9media.umbraco.io+9.
📊 Summary
Years Reported Cases Estimated True Scale Notes
200357 Likely higher FOI data
2024~474 Tens of thousands One fault may hit 50 homes
Annual~400~40 injuries/year HSE stats (10% cause injury)
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Overall, around 400–500 reported incidents per year, with actual incidence likely much higher, potentially affecting thousands of homes annually and causing dozens of injuries.
✅ What you can do?
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🧰 Install a PEN-fault detection device or EV charger compliant with IET 01—these devices monitor supply voltage and disconnect the charger if a fault occurs mfame.guru+1IET EngX+1IET EngX+1mfame.guru+1The FPA+2myenergi GB+2mfame.guru+2zaptec.com+2IET Electrical+2media.umbraco.io+2.
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💼 Network operators and electricians are required to report any open PEN faults to the DNO/HSE.
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📞 Report suspected faults immediately by calling 105 in the UK YouTube+5zaptec.com+5IET Electrical+5media.umbraco.io+2IET Electrical+2zaptec.com+2.
🔚 Bottom line
Open PEN faults are regularly reported—hundreds of times annually—but the true number of affected installations across UK homes is likely far greater. They carry serious risks, especially around EV charging. Ensuring installations comply with the latest standards and reporting any faults promptly is essential for safety.