Mercedes-Benz Nuisance or Genuine Earth Leakage Trip

Wallbox trips the household RCD/RCBO as soon as charging starts, but no specific wallbox error is displayed.

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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

Combined leakage from multiple circuits exceeding RCD threshold, Incompatible RCD type with Mercedes-Benz wallbox (e.g., Type AC instead of Type A or B), Internal insulation fault in wallbox, Faulty Type 2 cable

How to Fix / Troubleshooting

Safety first: Do not repeatedly reset a tripping RCD without investigation.

  • Check RCD type: Verify that the RCD protecting the wallbox is of the type recommended by Mercedes-Benz (often Type A or B). Replace if incorrect.
  • Dedicated circuit: Ensure the wallbox is on its own dedicated circuit, not shared with other large loads.
  • Test cable and vehicle: Try a different EV and, if possible, a different cable to see if the trip still occurs.
  • Insulation test: An electrician should perform insulation resistance tests on the wallbox and cable to identify any leakage paths.
  • Component replacement: Replace any component (cable, internal wiring, control board) that shows low insulation resistance.
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Repair Difficulty

Hard 4/5

Required Part

RCD Protection / Wallbox Internal Wiring
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