CEDIA ESPA EST Practice Test

Answer - B - The Joule is the unit used to measure the energy absorption capability of a surge suppressor.

Key Takeaway: The joule rating of a Surge suppressor is a measurement of the energy absorption capability of surge protective devices. Most Surge suppressors use a surge protection circuitry in the form of a Metal Oxide Varistor. A Metal Oxide Varistor is designed to create a short circuit across the line if the voltage across its terminals exceeds its breakdown point. At the breakdown point, the resistance of the MOV decreases from a normal level to a very low level. The transition from a high impendence state to short circuit takes place within just a few nanoseconds.