E20 displayed; charger shows 'Isolation Fault' or 'Insulation Resistance Low' (for units with DC components or advanced monitoring).

Safety first: An isolation fault can present a shock hazard. Do not use the charger until the cause is identified and corrected.

• Step 1 – Visual moisture check: Inspect the handle, cable entry, and bottom of the enclosure for signs of water or condensation. Dry thoroughly and allow 24 hours in a dry environment.
• Step 2 – Cable and handle inspection: Look for cracks, cuts, or discoloration on the cable jacket and handle body.
• Step 3 – Internal inspection (power OFF): Open the enclosure and inspect internal wiring and busbars for contamination, insect nests, or corrosion that could bridge conductors to ground.
• Step 4 – Insulation resistance test (qualified): A licensed technician should perform an insulation resistance test between live conductors and ground. Replace any wiring or components that fail.
• Step 5 – Isolation monitor check: If all insulation tests pass, the isolation monitoring device or its connection to the control board may be faulty and require replacement.