Wallbox shows 'Error 08' and refuses to charge; often related to supply voltage issues.

Safety first: Only a qualified electrician should measure live voltages. Turn off the breaker before tightening any terminals.

• Check other loads: Verify if lights or other appliances in the building flicker or behave abnormally, which may indicate a supply problem. If so, contact your utility or electrician.
• Verify breaker and wiring rating: Confirm that the breaker size and cable gauge match the Wallbox model’s requirements. Undersized wiring can cause voltage drop under load.
• Terminal inspection (electrician): With power off, open the Wallbox and inspect the input terminal block. Tighten all phase and neutral screws to the specified torque. Look for discoloration or melted insulation indicating overheating.
• Measure supply voltage: With power on and charger idle, measure line‑to‑line and line‑to‑neutral voltages at the Wallbox terminals. Compare with the acceptable range in the installation manual. If outside range, correct the supply or wiring.
• Phase configuration check: Ensure that a three‑phase Wallbox is wired correctly (L1, L2, L3, N, PE) and that jumpers or settings for single‑phase operation (if applicable) are correctly configured.

If supply voltage is within spec and Error 08 persists, the internal grid monitoring circuit on the main control board may be defective and should be replaced by a service technician.