Surge voltage arrester with ventsafe feature.

摘要

A surge voltage arrester assembly comprises a primary gas tube surge arrester (22) and an air gap secondary arrester that provides surge protection should the gas tube become vented to atmosphere. The secondary arrester has the air gap (42) defined by a rim (40) of one of the gas tube electrodes and a metallic cup (36) into which the gas tube is positioned. In a three element version of the invention wherein the gas tube has two line electrodes (70,70) and a ground electrode (72), metallic cups (80,80) are provided at opposite ends of the gas tube to cooperate with the ground electrode for forming secondary air gaps (86) for each line electrodes. An 0-ring (53,88) and a sealing compound (90) seals each secondary air gap (86) against the entrance of contaminants.