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What is an Arc Flash Analysis?

By June 28, 2023No Comments3 min read

An arc flash is the rapid release of energy produced from an unintended fault (short circuit) in an electrical system. Huge currents form during an electrical arc fault and can cause copper and other metals to vaporize, resulting in an explosion! An arc flash analysis is a safety precaution used to find areas in the electrical system with the conditions for an arc flash to occur, and to suggest methods to reduce the risk of arc flash. Arc flash analyses are important for minimizing hazards and providing increased safety for workers, contractors, and the overall safety of a facility.

In the late 1800s, with electricity still new to most, people quickly learned that electrical shock was not the only hazard of electricity. They also found that if wires and equipment were not properly installed, electricity could start a fire. Since people had very limited knowledge of proper electrical installations, some form of guidance was needed. In 1896, a committee was formed to develop a single uniform electrical code. This was the birth of what is now known as the National Electrical Code (NEC).

Per the code, arc flash analyses are required for commercial, industrial, manufacturing, utility, and other facilities that have major electrical components. There is no danger of an arc flash in a normal home because relatively low voltage of home electricity is too small to sustain an arc long enough to cause an explosion. Per the code, arc flash calculations need to be reviewed every five years, or whenever there is a significant change in the electrical system.

The first phase of an arc flash analysis is data collection. Engineers and electricians visit the site and collect as much information as possible, such as wire sizes, types of equipment, settings, fuse sizes, etc. Those performing site investigations must be sure to wear the proper PPE (personal protective equipment) for the job and keep safe working distances from the electrical sources.

In the second phase engineers use the information gathered onsite to create a model of the electrical system using special software. There are several software options available for arc flash analysis; Encorus Group typically uses SKM software. When the model is complete, the software is used to perform short-circuit and arc-flash analysis which determines the level of danger at various points in the electrical system. The information from the analysis is presented in a report which must be prepared by a qualified and licensed professional engineer. The report includes a listing of the level of danger at each electrical component, as well as recommendations to reduce the risks of arc flash.

Phase 3 is the application of labels to the actual onsite equipment. Based on the engineer’s report from Phase 2, a label is prepared for each device telling the danger level and the PPE required to access the device. Engineers and electricians visit the site and install the labels.

Arc flash analyses are vital to the safety of people and equipment in industrial settings with large electrical equipment. If you require an electrical arc flash analysis, contact Director of Engineering Design and electrical engineer Tom Gilmartin, PE, PMP, LEED AP at (716) 592-3980 ext. 124 or