Which of the following is NOT a type of section insulator?

• A. Fibreglass
• B. Porcelain
• C. Steel
• D. Wood

Answer: (C)

Section insulators are meant to stop the flow of electricity and keep different parts of the line electrically separate. They’re made from non-conductive materials that resist current, like porcelain or fibreglass composites, and historically even wood. Steel, on the other hand, is a metal that conducts electricity very well, so using it as an insulator would create a path for current instead of blocking it. That’s why steel is not used as a section insulator. The other materials listed are typical insulator materials, while steel is a conductor, not an insulator.