Incident energy plays a crucial role in Arc Flash Hazard Analysis as it determines the severity of an arc flash event and guides safety measures. Measured in cal/cm², incident energy represents the thermal energy a worker would be exposed to at a specific distance from the arc source. Higher incident energy levels indicate greater risk, leading to severe burns or injuries. It is used to establish the arc flash boundary, which is the safe distance beyond which incident energy drops to 1.2 cal/cm², the threshold for second-degree burns. Additionally, incident energy levels dictate the selection of Personal Protective Equipment (PPE), ensuring that workers wear the appropriate protection based on NFPA 70E guidelines. Engineers and safety professionals use incident energy calculations to design safer electrical systems by adjusting fault current levels, protective device settings, and equipment placement to reduce hazards. Compliance with OSHA, NFPA 70E, and IEEE 1584 relies on accurate Arc Flash Hazard Analysis, making incident energy a key factor in workplace safety and risk mitigation.