Wallbox shows E05 and refuses to charge; vehicle may show ‘Incorrect supply voltage’ or ‘Charging station fault’.

Safety first: Only perform voltage measurements if you are trained and have appropriate test equipment. Otherwise, contact a licensed electrician.

• Check supply configuration: Confirm whether your Mercedes-Benz wallbox is configured for single-phase or three-phase operation. Compare with the actual supply from your distribution board.
• Measure voltage: With the cover removed and power ON (electrician only), measure L–N and L–L voltages at the wallbox terminals. Ensure they are within the range specified in the installation manual (typically around 230 V single-phase or 400 V three-phase).
• Inspect neutral and earth: Verify that the neutral (N) and protective earth (PE) conductors are correctly connected and secure. A loose neutral can cause E05 and damage equipment.
• Correct wiring errors: If phases are miswired or missing, have the electrician correct the connections at the distribution board and wallbox terminal block.
• Grid issues: If the supply voltage is unstable or outside tolerance, contact your utility provider. Do not attempt to operate the wallbox until the supply is corrected.