Comment by lazide

Over voltage protection is not provided by caps (generally), but MOV’s, Zenier Diodes, spark gaps, etc. [https://en.m.wikipedia.org/wiki/Surge_protector].

Essentially, components that kick in when a voltage exceeds a certain limit to allow that excess voltage to shunt to ground instead of continue to build up in the circuit.

Similar devices in pneumatics or hydraulics are pressure relief valves [https://en.m.wikipedia.org/wiki/Relief_valve], and they provide similar functionality - giving a easier/lower resistance path for the high voltage/pressure, so delicate things downstream don’t fail.