These arresters are for protection against switching, which act as secondary protection against overvoltage and eliminate the leakage voltage from class B arresters and also transfer the voltages caused by switching on the power grid to ground.
The Class C surge arrester is designed to be the interface between the conductor of the electrical system and the ground and reduce the amount of overvoltage in the electrical device. The Class C surge arrester is single-pole and is used to protect electrical equipment during voltage changes caused by lightning. This surge arrester has a high discharge capacity because it has a metal oxide varistor.