how can voltage fluctuation arm electrical appliances....
say fluctuation on a stormy night...
Small dips or surges in the amplitude of the AC Mains waveform generally will not cause much harm. If your PC resets due to an AC Mains voltage dip, well, that can be bad if you're in the middle of typing!
More harmful are large transients on the AC Mains, like from lightning hits nearby, etc. Most electronic devices have some power supply input clamping circuitry to try to keep these powerline transients from causing harm ("Surge Suppressors"), but depending on the size of the spike coming in, and the quality of the surge suppression circuitry, the device may be damaged.
Here is some more reading for you:
You can also refer to ITIC (CBEMA) curve which states the AC input voltage range which can be tolerated by most computers and other business equipments. Any voltage variations above the specified range may result in malfunctioning/failure of IT equipments.
Separate names with a comma.