Disaster Protection SurgeArrest components such as MOVs and overtemperature fuses ensure that there is an immediate response to lightning strikes and wiring faults. If the protection components are damaged due to power spikes or surges, excess power no longer reaches the connected equipment. Unlike APC SurgeArrest products, most surge protectors still have power flowing after circuits are damaged, and equipment is subsequently exposed to further surges. Protection Indicator SurgeArrest alerts you when its circuit has been damaged by a severe impact or surge in the power line and can no longer provide 100% protection. If protection remains, APC will replace your damaged SurgeArrest at no charge. Wiring Problem Indicator This LED indicates potentially dangerous wiring problems in the in-wall wiring.