When Mains power supply fluctuates to your equipment, this switcher disconnects the power & reconnect after time set by wait timer. Nominal Voltage: 230 V AC Current Rating : 30 A Frequency: 50/60HZ Spike/Surge Protection: 160J Wait time between Switchover setting: 10 seconds or 10 minutes Application: Prevents damage to eletrical and electronic equipment / appliances such as Fridge, Air Conditioner, Photo copiers and business equipments from power fluctuations specifically over and under voltage level.