Electricity was used by both Kevin McCallister and Alex Pruitt as a booby trap.
Kevin used electricity against Marv Murchins when he connected the power and ground clamps from an AC/DC arc welder to the back of a sink of an old washing machine in Rob McCallister's brownstone house, sending a strong current of electricity through Marv when he touched the faucet. The shock was so strong that Marv briefly turned into a skeleton while screaming.[1]
Alex used electricity against Earl Unger and Burton Jernigan. For Burton, he sat on a chair that was wired to a golf cart battery and it fired the bullets in his battle suit and launched him towards the wall twice. For Earl, he tried to cut yarn that was wired by Alex and it was plugged into an outlet which made a current that electrocuted him.[2]