The Schneider Electric (Square D) SDSA3650 Surge Protector 480/277V 3PH is a three-phase surge protective device designed to help protect electrical equipment from damaging voltage spikes and transient surges. It works by diverting excess transient voltage away from connected circuits, reducing the risk of electrical damage. In HVAC applications, it can help protect compatible air con... https://www.partshnc.com/sdsa3650-schneider-electric-square-d-480277v-3ph-surge-protector