E05
Zaptec AC Supply Overvoltage Protection

Charger shows E05; app indicates ‘Overvoltage on supply’ and charging is blocked

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Utility grid overvoltage, Incorrect supply configuration (e.g., 400 V single-phase miswired), Faulty voltage sensing circuit on main board, Neutral disconnection in TN system causing phase-to-neutral overvoltage

How to Fix / Troubleshooting

Safety first: Overvoltage can damage the charger and vehicle. Do not bypass this protection.

Steps:

  • Check other devices: If lights flicker or other electronics behave abnormally, there may be a grid or neutral issue. Contact your utility or electrician.
  • Verify supply voltage (technician): Measure phase-to-neutral and phase-to-phase voltages at the charger’s terminal block. Confirm they are within Zaptec’s specified range.
  • Inspect neutral connection: Ensure the neutral conductor is securely connected and not shared incorrectly with other circuits.
  • Power-cycle: After any wiring correction, turn the breaker OFF for 2 minutes, then ON, and check if E05 clears.
  • If measured voltage is normal but E05 persists: The voltage sensing circuit on the main control board may be defective and require board replacement.
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Repair Difficulty

Professional Required 5/5

Required Part

Main Control Board (Voltage Sensing Circuit)
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