Fault Phenomenon: Aichi insulated boom aerial work platform during preventive testing, the insulation arm leakage current exceeds the limit.

Troubleshooting Process:
– Checked arm surface: surface contaminated and damp.
– Checked fiberglass layer: delamination and cracks present.
– After cleaning and drying, retest still exceeded limit, confirming internal moisture or damage.
– Repaired and cured cracks or replaced boom section.

Root Cause: The fiberglass layer of the insulated arm was damaged or internally damp.

Required Parts: Insulation repair material or boom section assembly.