The possible duration of the arc is determined by the settings of the protection devices upstream of the network point including all sources.įrom this data the incident energy is calculated in Joules per square centimetre, J/cm 2 (or cal/cm 2). The calculation involves an assessment of the maximum bolted short circuit current available at a given location, the possible maximum duration of the arc, the distance from the arc source, the line voltage (if above 600V) and the conductor spacing. Since then this standard has been updated to IEEE1584-2018 and details how to calculate the amount of energy that is released in an arc flash incident. In 2002, there was a standard for measuring the energy released in an arc flash incident called IEEE1584-2002. A proper workplace safety audit that includes Arc Flash incident energy calculations and risk assessment can suggest electrical equipment settings to reduce the probability of a serious arc flash related incident from occurring in the workplace. This can also cause the electric network to shut down and cause expensive downtime. Arc flash incidents can cause damage to the electrical networks on the site by overloading parts of the electrical grid on site. Arc Flash Standards and the LawĪrc Flash is a workplace electrical hazard and therefore there are laws and standards governing the measurement and mitigation of the risks associated with arc flash incidents as the safety of the people in the workplace is paramount. The incident energy in an arc flash incident does not necessarily depend on the system voltage because the lower the voltage, the more current there can be in the system and the higher current levels create the high amounts of energy that is dissipated in an arc flash incident in an electrical system. Critically, most Arc Flash incidents happen when the electrical system is being worked on and “live” and thus Arc Flash presents a serious risk to the employees. The injuries can range from burns, blindness, hearing loss, impact injury, psychological trauma and even death. This amount of energy is sufficient to cause severe injury to anyone within the blast radius. The explosion causes shrapnel and vapourised conductors to escape the blast site at 1600 km/hr. The temperatures inside an Arc Flash incident can reach 19,000☌ (sun’s surface temperature is 6000☌) causing conductors especially copper to evaporate. The sudden discharge of electrical energy causes a brilliant explosion of light and sound. An Arc Flash is an explosive release of energy caused by an electrical short circuit between 2 energised conductors or an energised conductor and earth.
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