What is Incident Energy?

• A. The voltage of the arc.
• B. The duration of the arc event.
• C. The amount of heat impressed on a surface (person) generated during an arcing event, measured in cal/cm2.
• D. The current in amperes.

Answer: (C)

Incident energy is the heat energy that would be transferred to a surface, such as skin, during an arc flash, expressed in calories per square centimeter (cal/cm^2). This thermal measure captures the potential burn risk from the arc and is the basis for selecting PPE and setting arc-flash protection boundaries. While the amount of incident energy depends on factors like arc current, duration, and fault energy, the fundamental idea is the heat flux to a surface, not the voltage or current alone. So the concept describes the heat impressed on a surface during an arcing event, measured in cal/cm^2.