Charger shows E09; internal self-test reports 'isolation fault' or 'insulation resistance too low'

Safety first: An insulation fault can present a shock hazard. Immediately take the charger out of service by switching off the upstream breaker and locking it out if possible.

Step-by-step checks:

• 1. Inspect housing and seals: Look for cracks, missing gaskets, or open cable glands that could allow water into the KEBA unit, especially on outdoor installations.
• 2. Open and inspect interior (power off): Carefully open the housing and look for signs of moisture, corrosion, or dirt tracks on PCBs and wiring. Dry any moisture with a lint-free cloth and allow the unit to air dry completely.
• 3. Check cable entries: Ensure that all cable glands are properly tightened and that unused openings are sealed with approved plugs.
• 4. Visual wiring check: Examine all internal conductors for nicks, crushed insulation, or contact with sharp metal edges. Repair or replace damaged wiring harnesses.
• 5. Board cleaning: If light contamination is present on the main control board, clean with appropriate electronics cleaner and a soft brush. Severe corrosion usually requires board replacement.
• 6. Insulation test (qualified person): Perform an insulation resistance test between live parts and earth according to KEBA and local standards. If values are below specification and not due to external wiring, replace the main control board or affected wiring.

Do not return the charger to service until the cause of the insulation fault is clearly identified and corrected.