– Flash hazard analysis: A method to determine the risk of personal injury as a result of exposure to incident energy from an electrical arc flash. – Arc-flash hazard: A dangerous condition occurred due to electric arc produced by release of energy. – Electrical shock: Physical stimulation that occurs when electrical current passes through the body. – Electrical hazard: A dangerous condition as a consequence of shock, arc-flash bum, thermal bum, or blast due to unintentional contact or failure of equipment. – Shock hazard: A dangerous condition associated with the release of energy. – Available fault current: It is the fault current that can be provided by the serving grid or utility, owned generators and large electric motors, subjected to the impedance of the path. – Fault current: A current that flows from one conductor to another conductor or one conductor to ground due to an abnormality produced in the system. – Bolted fault current: Short circuit current flows between conductors at different potentials having zero or negligible impedance. – Arcing fault current: Fault current flows through an electrical arc plasma. Some important terminologies used for arc flash analysis and mitigation through IEEE Std. Due to the aforesaid hazard, a person exposed to arc flash may suffer severe burns, lung damage, vision loss, eardrum ruptures and even death. During this event, intense light with sound waves, shrapnel, molten metal with toxic gases and smoke are generated which become components of the arc flash as shown in Figure 1. An arcing fault usually occurs between phase bus bars or from phase to neutral or ground. Superheated ambient air produces a rapid volumetric expansion known as arc blast and consequently an explosion. When an arc flash occurs, large amount of energy dissipates from conductive plasma. Basically, arc is a flow of electricity through ionized gases. The basic phenomena of the arc flashes, arc blast, electric arc, electrical explosion are the same. Day by day in the electrical safety world its understanding is gaining significant importance. Therefore, to recognize and understand Arc flash phenomena and its significant threats, IEEE and NFPA are applying efforts to support research and development.Īrc flash, a type of electrical explosion, is one of the most complex e-Hazard in the workplace. According to NFPA 70E, every year more than 2000 workers are hospitalized in extensive injured condition caused by arc flash accidents.
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