What is the primary function of a lightning arrester?

The primary function of a lightning arrester is to provide a low resistance path to earth ground. This component is designed to protect electrical equipment by diverting the surge of electricity caused by lightning strikes or switching operations down to the ground, minimizing the risk of damage to the system. When an overvoltage event occurs, the arrester activates, allowing the excess electrical energy to flow safely to the ground rather than through the electrical infrastructure. This effectively safeguards both the equipment and personnel from potential hazards associated with high voltage spikes, ensuring the integrity and reliability of the electrical system.

In contrast, the other options relate to functions that do not align with the purpose of a lightning arrester. Decreasing voltage levels or enhancing insulation strength involves different electrical components or systems. While increasing line current pertains to the flow of electricity through conductors under normal operating conditions, it does not reflect the protective purpose of the arrester related to handling transient overvoltage events.