Varistor protection is provided by the RAB-PD-X07-A1, RAB-PD-X08-A1, and RAB-PD-X51-X1 in power distribution panels, serving as the third level of overvoltage protection in compliance with the appropriate standards. These varistors are positioned directly in front of the devices they protect and are designed to eliminate any remaining voltage that previous steps of house wiring surge protection may have failed to interrupt. The surge protection is implemented as a detachable block capable of dissipating pulse overvoltages and diverting them to a protective earth conductor. Consequently, it is only compatible with three-wire distribution systems featuring a yellow-green protective conductor.

In the event of a substantial overvoltage, the surge protection module may become damaged, causing the control green light on the module to turn off. While the power distribution panel will continue to function, it will no longer provide protection against overvoltages, necessitating the replacement of the surge protection module.