What is the main purpose of a metallic sheath in a cable?

• A. To provide insulation
• B. To add flexibility
• C. To provide mechanical protection and current return path
• D. To reduce weight

Answer: (C)

The main purpose of a metallic sheath in a cable is to provide mechanical protection and a current return path. The metallic sheath helps safeguard the internal conductors from physical damage and environmental factors such as moisture or chemicals, which could compromise their integrity and performance. By enclosing the conductors, the sheath strengthens the overall structure of the cable and prevents issues that could arise from accidental impacts or abrasion.

Additionally, the metallic sheath often serves as a means for grounding and offers a return path for electrical current in certain configurations, which is crucial for safety and functionality in electrical systems. The presence of the metallic sheath ensures that any current leakage can be safely managed, enhancing the overall safety of the cable installation.

Options that focus on insulation, flexibility, or weight reduction do not accurately reflect the primary role of the metallic sheath. While a cable may have insulation layers and might be designed for flexibility or weight optimization, these factors are secondary to the sheath's fundamental functions of protection and providing a current return path.