Injuries are usually caused by the explosive effect of arcing current, and by any associated fire or flames that may result when a live cable is penetrated by a sharp object such as the point of a tool. Such effects can also occur when a cable is crushed severely enough to cause internal contact between the conductors, or between metallic sheathing and one or more conductors. Typically, injuries are severe — potentially fatal — burns to the hands, face and body; electric shock is possible but less likely.
Incidents may also arise from cables, connections and terminations which have been damaged but left unreported and unrepaired, or which have deteriorated with age.