Fault Phenomenon: Time insulated bucket aerial work platform during annual electrical testing, the insulated bucket leakage current exceeds the limit.

Troubleshooting Process:
– Checked surface cleanliness: carbon powder adhered to surface.
– Checked metal inserts: cracks around inserts.
– After deep cleaning, retest still exceeded limit, determined insulation layer aged.

Root Cause: The fiberglass material of the insulated bucket aged or internal moisture ingress.

Required Parts: Insulated bucket assembly.