Charger shows E04 and will not energize; often associated with incorrect supply voltage or wiring.

Safety first: This fault involves mains wiring. Only a qualified electrician should remove covers and test live voltages.

• Verify supply type: Confirm whether your EO model is designed for single‑phase or three‑phase operation and that the installed wiring matches the product specification (e.g., 230 V single‑phase vs 400 V three‑phase).
• Measure incoming voltage: With appropriate test equipment, measure line‑to‑neutral and line‑to‑line voltages at the EO charger input terminals. Compare with EO installation manual limits. Persistent over/undervoltage should be reported to your utility.
• Check terminal tightness: With power isolated, inspect and re‑torque the line, neutral, and earth terminals in the charger according to EO torque specifications. Look for heat discoloration or melted insulation indicating a poor connection.
• Confirm neutral presence: Many EO chargers require a solid neutral connection. Verify that neutral is present, correctly sized, and continuous back to the distribution board.
• Phase configuration on PCB: Some EO models have jumpers or configuration settings for 1‑phase vs 3‑phase. Ensure these are set correctly per the installation manual.
• Reset and monitor: After correcting wiring or supply issues, restore power and observe whether E04 clears. If the error persists with correct voltages, the voltage sensing circuit on the main PCB may be defective and require replacement.