Should your voltage levels are unstable (ie: power stays on, but the particular voltage amount may differ quite a bit with the 220V regular), then I think that's the type of situation where by an AVR is helpful. The Main class couldn't be loaded when The category cannot be initiated. https://byd14702.pointblog.net/the-smart-trick-of-uninterruptible-power-supply-ups-that-no-one-is-discussing-77387069