A surge arrester (1) includes varistor elements (2) forming a stack (3) and having opposed end surfaces (4a, 4b). The varistor stack is electrically connected via the opposed end surfaces to end terminals (7a, 7b) having circumferential ridges (32a, 32b), which, in the event of failure of the varistor elements, are designed to relocate the resulting arc and direct it in a manner which reduces or minimizes damage to the surge arrester. The ridges serve as damage-tolerant sacrificial rooting points for an arc in the event of varistor element failure by presenting a substantial metal mass for the arc to erode away.