What is an electrical spark caused by differences of potential between conductive metal bodies known as?

The phenomenon described is known as "side flash." This occurs when there is a difference in electrical potential between two conductive metal bodies, which leads to a discharge of electricity through the air. In the case of side flash, one of the conductive bodies is struck by lightning or experiences a high voltage, and the electrical current can jump to a nearby conductive object, creating a spark. This is particularly dangerous as it can occur near structures or equipment that are not directly struck by lightning but are close enough to receive the energy transfer.

Understanding this concept is crucial for ensuring adequate lightning protection measures are in place, as side flashes can cause significant damage or injury, even in the absence of a direct lightning strike.