Fault Phenomenon: Aichi SR166 insulated aerial work platform during insulation testing, the instrument indicates insulation failure, prohibiting live-line work.

Troubleshooting Process:
– Checked boom surface: surface dirty, damp, or cracked.
– Checked metal inserts: inserts corroded, reducing creepage distance.
– Checked test electrodes: electrodes poor contact.
– Checked ambient humidity: excessive humidity.

Root Cause: The insulated boom surface is dirty and damp, or there are micro-cracks in the fiberglass layer, causing reduced insulation performance.

Required Parts: Insulated boom cleaning and drying or boom section replacement.