What does a shield wire do in electrical installations?

In electrical installations, a shield wire is specifically designed to protect the power lines and associated equipment from the destructive effects of lightning. By being positioned above the conductors, the shield wire acts as an interceptor for lightning strikes, reducing the risk of direct hits to the power lines. When lightning strikes the shield wire, the electrical energy is directed safely to the ground, thereby preventing damage to the insulation of the conductors or electrical equipment and minimizing the risk of outages or fires.

The primary function of the shield wire is to serve as a protective mechanism against lightning, which is critical in ensuring the reliability and safety of the electrical distribution system. This protective feature is essential, especially in regions prone to thunderstorms and lightning activity, and is a standard practice in overhead power line installations for enhanced safety.

Additional context about the other choices highlights their distinct roles: enhancing power carrying capacity is not a function of a shield wire; rather, it pertains to conductor size and type. Support for overhead lines typically comes from physical structures like poles or towers, not the shield wire itself. While a fuse link is vital for circuit protection, it does not relate to the function of a shield wire, which is focused on lightning protection. Thus, the choice that best encapsulates the purpose of