Do surge protectors fail?
For the most part, no. Failure of a properly designed and appropriately applied surge protector is rare and usually caused by the protector being operated outside of its limits. For example, if the power system Neutral wire connection becomes undone, excessive AC voltage may appear across the protector. This sustained AC voltage will cause the protection components to overheat, and eventually the protector will disconnect itself from the power line. But a common cause of protector failure, whether it be an AC line protector, or a data line protector, is misapplication.
