What is a key function of arrestors in line protection?

The primary role of arrestors in line protection is to safeguard electrical equipment from voltage surges, which can occur due to various factors, including lightning strikes or switching operations. When a surge occurs, arrestors act as a protective element by redirecting the excessive voltage to the ground, thus preventing potential damage to sensitive electrical components. This function is crucial in maintaining the longevity and reliability of electrical systems, as it helps to avoid costly repairs and downtime that could result from unprotected voltage spikes.

In this context, the other options do not fulfill the function of an arrestor. Increasing current, for instance, is not a protective role, and the purpose of decreasing resistance is not relevant to the functionality of arrestors in managing surges. Ensuring line buoyancy is unrelated to the electrical aspects of line protection and more focused on physical support structures rather than electronic safety.