Lightning arresters are devices use to protect electric equipment or instruments from lightning. Lightning arrester is usually installed adjacent to the equipment so that when lightning occurs, the arrester diverts the voltage to the group thus protecting the surroundings. There are around ten well known types of lightning arresters.Some of them include, electrolytic arresters, impulse protective gap, oxide film arrester, metal oxide lightning arrester and among other types of arresters. Before one decides on which type of the arrester they wish to employ they'll consider some factors like the voltage of the arrester and reliability and at times the cost.How does an arrester work?Take an instance of oxide film arrester. This type of an arrester contain lead peroxide arranged in a tube.This tube contains spark gap.When there's over voltage, an arc tends to pass through the spark gap and additional voltage is applied to the column and there's discharge. During the process, resistance increases until only less amount is passing through. This will be finally interrupted by a space gap. Lightning arrester isn't harmful to it's surrounding as long as its directed well especially where it discharges the high voltage.