Which of the following best describes a "flashover"?

A "flashover" refers to an electrical discharge that occurs between conductors, often due to a buildup of voltage. This phenomenon happens when the voltage exceeds the dielectric strength of the insulating material between the two conductors, causing an arc or spark to jump across the gap. This is significant in various contexts such as electrical engineering, circuits, and safety protocols since flashovers can lead to equipment damage and safety hazards.

Understanding why electrical discharge between conductors is central to the concept of flashover helps clarify why this option is the best choice. In contrast, the other options—power failure, temporary circuit disruption, and excessive heat generation—do not capture the specific nature of flashover. They may relate to electrical systems but do not define the process of an electrical discharge happening between two conductors.