What does a surge arrester do?
A surge arrester, or surge diverter, acts like a trapdoor to excess electrical energy. Sometimes called over-voltages, or transients, or surges, unwanted bursts of electricity are lured to the trapdoor by what is called a low-impedance path to ground. The trapdoor is a metal oxide varistor, or MOV, which opens or “clamps” when the overvoltage exceeds a certain level, and safely diverts most of the excess energy to the ground rod. When the over-voltage or transient is over, the MOV automatically resets and is ready for the next one. It is important to note that with lightning or other fast acting impulses, the leading edge of the impulse will pass the first MOV, even as the majority of the surge is racing to, and through, the trapdoor, hence the need for a second stage “point of use” plug-in type surge arrester inside the home or business.
