How does a cap-and-pin insulator differ from a simple pin insulator?

• A. A cap-and-pin insulator uses a cap and pin mounting method, typically for certain configurations, whereas a pin insulator is mounted directly on a cross-arm pin.
• B. A cap-and-pin insulator is used for DC lines, while pin insulators are for AC lines.
• C. A cap-and-pin insulator is made of glass; pin insulator is porcelain.
• D. A cap-and-pin insulator is mounted on the cross-arm without any cap, whereas a pin insulator uses a cap.

Answer: (A)

The main idea tested is how insulators are mounted and how the conductor is attached on a line. In a cap-and-pin setup, the insulator sits on a pin on the cross-arm, and the conductor connects to a cap at the top of the insulator. The cap provides the connection point for the line, while the insulator body is carried by the pin on the cross-arm. In a simple pin insulator, the insulator is mounted directly on the cross-arm pin and the conductor connection relies on the top end of the insulator but without a separate cap assembly used for the conductor connection. This difference in how the conductor is attached and how the insulator is mounted is what distinguishes cap-and-pin from a plain pin insulator. The other statements aren’t about how the mounting and conductor connection are arranged, so they don’t describe what actually sets cap-and-pin apart.