What is the highest degree of protection in valve-type arrestors?

The highest degree of protection in valve-type arrestors is found in the station class. This classification is designed for locations where the risk of overvoltage or transient surges is the greatest, such as substations or main service points in electrical distribution systems. The station class arrestors are built to handle substantial energy from lightning strikes or switching surges, ensuring robust protection for equipment and systems connected to the electrical distribution network.

In contrast, the other classes provide varying levels of protection suited for different applications with less severe conditions, making the station class the most reliable option for high-stakes environments where equipment damage must be minimized.