What characterizes an arc in electrical terms?

An arc in electrical terms is characterized by a high-temperature electrical discharge. This phenomenon occurs when current flows through the air or another medium in a form of plasma rather than through a solid conductor. The intense heat generated by the arc can reach temperatures sufficient to melt metals and ignite combustible materials, contributing to fire incidents.

In the context of electrical systems, arcs usually arise from faults, such as insulation failure or short circuits, where the electrical energy seeks the easiest pathway to ground. The result is a rapid release of energy, which is responsible for the visible light and the considerable heat associated with an arc. The high temperature created during an arc can cause significant damage, making it crucial for fire investigators to recognize and understand this characteristic in the context of fire origin and cause analysis.