Jul 18, 2019 - 03:22 AM
All surge protectors are good for a certain number of joules. MOV is rated in Joules. The MOV is basically full of tiny LEDs that, when a spike happens, xxxx the excess voltage off the line and burns out dissipating the voltage once they are all used up the surge protection is gone. At this point, a new unit would need to be purchased. The joules can be used up by many smaller spikes or one big spike. All surge protectors use the same concept.