EO charger displays E03 and refuses to start charging; often occurs immediately after power‑up.

Safety first: Do not repeatedly reset a device that is tripping on earth leakage. There may be a genuine shock hazard. Isolate power at the breaker before opening the unit.

• Check external RCD/RCBO: If your EO charger is fed via an upstream RCD/RCBO, verify it has not tripped. Reset it once only. If it trips again immediately, disconnect the EV and try powering the charger without a vehicle connected.
• Test without vehicle: With the charger powered and no EV plugged in, check if E03 appears. If the error only occurs when a specific vehicle is connected, the leakage may be in the vehicle and you should consult the vehicle manufacturer.
• Inspect for moisture: Open the EO enclosure (power off) and look for signs of water ingress: condensation, rust, water tracks, or dampness around cable glands and the Type 2 socket. Dry the interior thoroughly with a lint‑free cloth and allow several hours of ventilation before re‑energizing.
• Check residual current sensor: Locate the toroidal current sensor (often around the line and neutral conductors). Ensure all required conductors pass through the core and that no earth conductor is incorrectly routed through it. Look for cracks or physical damage.
• Insulation resistance test (qualified electrician only): Perform an insulation resistance test between line/neutral and earth on the charger output circuit (with the EV disconnected) to confirm there is no low‑resistance fault path.
• Replace RCD/RCM module if faulty: If no external leakage is found and E03 persists, the internal residual current detection circuit on the main PCB or dedicated RCM module may be defective and should be replaced with the EO‑approved part.