Bosch EV charger displays E102 and refuses to start charging when the vehicle is connected.

Safety first: Do not use the charger if you see sparks, smoke, or melted plastic. Turn OFF the breaker immediately. Ground fault conditions can be hazardous.

• Check for moisture: Inspect the J1772 handle and the vehicle inlet for visible moisture, condensation, or road salt. If wet, disconnect power at the breaker and allow everything to dry for at least 24 hours in a warm, dry area.
• Inspect cable jacket: Look along the entire Bosch cable for cuts, deep abrasions, or crushed sections that could expose conductors. If any damage is visible, do not use the charger.
• Verify proper grounding: Have a qualified electrician confirm that the charger’s circuit has a solid equipment ground and that the ground and neutral are correctly separated in the panel, as required by code.
• Reset and retest: After drying and inspection, reset the breaker, reconnect the vehicle, and see if E102 clears. If the error returns immediately with multiple vehicles, the internal ground fault detection module or main PCB may be defective.
• Professional service: Replacement of the internal ground fault detection circuitry or main control board should be performed by a Bosch-authorized service technician.