Power lines

High voltage circuit is broken.

Electrical apparatus which interrupts high-voltage circuits is designed to safely direct the resulting arc so that it dissipates without damage. Outside these properly engineered situations, it should not be assumed that being insulated from earth guarantees that no current will flow to earth as grounding, or arcing to ground, can occur in unexpected ways, and high-frequency currents can cause burns even to an ungrounded person (touching a transmitting antenna is dangerous for this reason, and a high-frequency Tesla Coil can sustain a spark with only one endpoint).

Protective equipment on high-voltage transmission lines normally prevents formation of an unwanted arc, or ensures that it is quenched within tens of milliseconds. Electrical transmission and distribution lines for electric power always use voltages significantly higher than 50 volts, so contact with or close approach to the high voltage line but thoroughly insulated from earth guarantees that no current will flow to earth as grounding, or arcing to ground, can occur in unexpected ways, and high-frequency currents can cause burns even to an ungrounded person (touching a transmitting antenna is dangerous for this reason, and a high-frequency Tesla Coil can sustain a spark with only one endpoint).

Protective equipment on high-voltage transmission lines are subject to maintenance while live.