Portions of the mechanical linkages connected to movable contacts must be constructed of __________ materials to prevent energizing the CB components such as the tank and controls.

• A. Nonconductive
• B. Conductive
• C. Semiconductive
• D. Metallic

Answer: (A)

The moving parts that connect to the contacts must be nonconductive so they don’t provide a current path to the rest of the breaker. Keeping these linkages insulated prevents energy from feeding into the tank, control circuits, or frame when the contacts move, reducing shock risk and the chance of unintended energization or arcing along the linkage. If the linkage were conductive, it could become energized during operation and energize surrounding components, which is unsafe. Nonconductive materials such as insulating polymers or phenolic composites are used precisely because they isolate the moving parts from live metal, while still withstanding the mechanical demands of switching.