Steel pins have lead threads to prevent what on the insulator?

Steel pins have lead threads to prevent what on the insulator?

• A. Creeping
• B. Grounding
• C. Localized pressure
• D. Uplift

Answer: (C)

The idea being tested is how mounting hardware protects the insulator by distributing load rather than concentrating it. Steel pins would press into the insulator surface at the thread contacts, creating high, localized stresses that can crack or chip the ceramic material. Lead threads are softer and malleable, so they deform to fill gaps and spread the clamping force over a larger area. This cushions the bearing surface and reduces the risk of damage from tight fastening or vibration, effectively preventing localized pressure on the insulator.

The idea being tested is how mounting hardware protects the insulator by distributing load rather than concentrating it. Steel pins would press into the insulator surface at the thread contacts, creating high, localized stresses that can crack or chip the ceramic material. Lead threads are softer and malleable, so they deform to fill gaps and spread the clamping force over a larger area. This cushions the bearing surface and reduces the risk of damage from tight fastening or vibration, effectively preventing localized pressure on the insulator.