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.
The electrical arc creates a pressure wave. The incident energy is the energy of this arc-flash coming into contact with a surface. Essentially an electric arc creates a radiation burn which accounts for the internal burns a person can receive when exposed to an electrical arc flash.
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.
Incident energy and arc-flash boundaries are calculated following the NFPA 70E and IEEE 1584 Standards.
Fire safety and Electrical Safety
Fire safety measures can be taken by NFPA standards. IEEE 1584 provides the formulas and tables needed to solve for the incident energy. IEEE 1584 provides techniques for designers and operators in determining the arc flash Hazard distance and incident energy.
Arc flash for Industries
VB Engineering performs the arc flash risk asseessment studies as per NFPA 70E 2015 standards and determines various boundaries like arc flash boundary, Limited Approach Boundary, Restricted Approach Boundary.