How is leakage current typically assessed in the field?

• A. Visual inspection for wetting/marks and using instruments to measure surface leakage or partial discharge if available; otherwise cleaning or replacement.
• B. Measuring surface leakage using a handheld scope without any visual checks.
• C. Visual inspection for wetting/marks only, with no measurement performed.
• D. Visual inspection for wetting/marks and applying protective coatings.

Answer: (B)

Measuring leakage current with a portable instrument provides a direct, quantitative assessment of the insulation’s condition. Leakage current is an electrical symptom, not something you can reliably judge from appearance alone, so using a handheld scope or leakage meter gives real numbers to compare against acceptable limits or prior readings. Visual checks can signal possible contamination or moisture, but they don’t tell you how much current is actually leaking or whether that leakage is within safe levels. When available, more advanced diagnostics like partial discharge can add insight, but the essential step in the field is to quantify surface leakage current with a portable instrument. This objective data guides maintenance decisions far more reliably than visuals alone.