Arc Flash Hazard
An Arc-Flash Hazard Studies starts with collecting up-to-date equipment information, then performing a detailed studies will be done on load-flow analysis, short circuit analysis, and relay coordination study as well as an equipment evaluation to find that the current withstand rating is matchable as per NFPA 70E.
An electrical arc is formed any time when there is an insulation breakdown between phases or ground. It could happen when no one is around, someone walking in proximity, or someone working on the equipment. The most hazardous situation is when someone is working on or near energized equipment. They probably have the equipment doors open and are in close proximity to the equipment. When an electrical worker, while working inside an energized electrical panel, makes contact between phases or phase and ground with a conductive object like a screwdriver, or body parts, an electrical arc can form.