E08
Mercedes-Benz
AC Residual Current Device Trip / Leakage Detection
Wallbox shows E08; charging stops unexpectedly; may coincide with upstream RCD tripping.
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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
Insulation fault in internal wiring of Mercedes-Benz wallbox, Moisture ingress causing leakage to earth, Damaged Type 2 cable insulation, Faulty vehicle causing excessive AC leakage current
How to Fix / Troubleshooting
Safety first: Do not repeatedly reset a tripping RCD without finding the cause. Turn off the wallbox breaker and RCD.
- Inspect cable and plug: Check the entire length of the attached or detachable Type 2 cable for cuts, abrasions, or crushed sections. Replace the cable if any damage is found.
- Check for moisture: Open the wallbox and look for signs of water ingress, especially around cable glands and the lower part of the housing. Dry the interior thoroughly and correct any sealing issues.
- Isolate the wallbox: Have an electrician disconnect the wallbox and test the RCD with other loads. If the RCD only trips with the wallbox connected, the fault is likely in the charger or cable.
- Insulation testing (technician): A qualified technician should perform insulation resistance tests on the wallbox internal wiring and cable. Components with low insulation resistance must be replaced.
- Vehicle check: If possible, test another EV on the same wallbox. If only one vehicle causes E08 and RCD trips, the vehicle’s onboard charger may be faulty.
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Repair Difficulty
Professional Required
5/5
Required Part
Type 2 Charging Cable or Internal Wiring Harness
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