How can moisture ingress on porcelain insulators be detected?

• A. Visual moisture or moisture marks, salt deposits from pollution, and infrared thermography to spot hotspots.
• B. Only audible crack detection.
• C. Replacing the insulator without inspection.
• D. Relying solely on external color change.

Answer: (A)

Moisture ingress on porcelain insulators shows up best when you combine surface signs with a non-contact thermal check. Visual wet patches or moisture marks indicate water on or inside the surface film, which lowers surface resistance and promotes leakage. Salt deposits from pollution, known as efflorescence, form as moisture dissolves salts and then leaves conductive crystals on the surface, highlighting damp areas. Infrared thermography adds a powerful diagnostic angle by spotting hotspots where leakage current concentrates, even if the wet area isn’t obvious to the eye.

Other approaches miss important pieces: audible crack detection alone doesn’t reliably reveal moisture in many cases; replacing the insulator without inspection sacrifices safety and can miss underlying leakage paths; relying solely on external color change is not dependable since discoloration can arise from aging or pollution unrelated to moisture.