What design features help insulators resist pollution and tracking?

• A. Shorter creepage paths.
• B. Non-hydrophobic surface coatings.
• C. Optimized shed geometry, hydrophobic surface or coatings, and longer creepage paths.
• D. Solid metal cores with no housing.

Answer: (C)

Pollution and tracking resistance comes from keeping the surface dry and making leakage paths harder to form. The best design combines longer creepage paths with optimized shed geometry and hydrophobic surfaces or coatings. A longer creepage path forces leakage current to travel a longer distance along the surface, which reduces the likelihood of a flashover under polluted and humid conditions. Optimized shed geometry helps water shed away more effectively and prevents continuous water films from forming, while hydrophobic surfaces repel moisture and resist the formation of conductive films. Together, these features maintain insulation performance during pollution events. Shorter creepage paths invite easier leakage; non-hydrophobic coatings fail to shed water; and solid metal cores with no housing are not insulating and don’t resist pollution or tracking.