Describe the typical construction of a suspension insulator string.

• A. A single long rod with glazing.
• B. A series of disc-shaped insulators connected by metal hardware and suspended from the cross-arm to carry the line voltage.
• C. A metal shell with a ceramic core.
• D. Several cylindrical insulators in parallel.

Answer: (B)

The suspension insulator string is built from a series of disc-shaped insulators (usually porcelain or toughened glass) connected end-to-end with metal hardware to form one long string. The top of the string is attached to the cross-arm with a suspension clamp, while the bottom attaches to the conductor via a line clamp or hook. This arrangement lets the insulator stack carry the mechanical tension of the line while providing the necessary electrical insulation from the support. Having multiple discs in series increases the overall voltage rating by dividing the voltage across each unit and extends the creepage path, helping to prevent leakage. The metal fittings also allow easy assembly, maintenance, and the needed flexibility to handle wind and sway. The other descriptions don’t reflect this structure: a single long rod isn’t a suspension string, a metal shell with a ceramic core isn’t how suspension insulators are built, and several cylindrical insulators in parallel wouldn’t reliably withstand high voltage or provide the required series insulation.