Do you know what an arc flash is? If not, just keep reading this article. The dictionary defines an arc flash as an electric luminous bridge that exist between distinctive electrodes. It occurs when a short circuit condition or a fault passes through this gap. Usually, an arc flash is initiated via accidental contact on underrated equipment at the available short circuit current, tracking or contamination over insulated surfaces. It can also be caused by deterioration or corrosion of an equipment or a part of it.
If an arc flash event occurs, an incredibly higher temperatures exceeding 30,000°F could be expelled. Such a deadly amount of energy causes ionization of air resulting to creation of surfaces that are hotter than the surface of the sun. Such kind of temperatures could severely destroy the human skin as well as set fire to clothes, plastics and leather kept within significant distance within fractions of seconds.
The extreme heat can also stimulate combustion of flammable compounds and fluids as well as solidify metals including Copper, Aluminum, and Zinc that are frameworks for various equipment in factories. Some of these metals may change their volume as they conform their state due to changes in temperature causing sound waves and explosive pressures. This may damage worker’s eardrum resulting to permanent or short-term hearing loss.
Arc Flash Studies
According to the National Electrical Code and the Occupation Safety and Health administration, there exist a specific arc hazard at a given piece of equipment within a facility. This arc flash hazard could exist every time a worker services an electrical gadget while still in its energized state. Though it is a requirement to de-energize that equipment before servicing it, it is always necessary for qualified personnel to work within energized equipment.
In order to identify an arc flash hazard, an arc flash evaluation is necessary. There exist many software packages available to facilitate the evaluation by a skilled professional electrical engineer. A complete evaluation requires that coordination and short circuit studies be performed or rather the results of these two studies must be provided to the engineer before performing an arc flash study.
One of the purpose of an arc flash study is that it categorizes arch flash hazards at particular equipment based on the identity of the Arc Flash Protection Boundary and the incidence energy. The Arc Flash Protection Boundary is the safest approach distance from an energized gadget or part of it. Normally, the default arch flash boundary for many electrical equipment is at 4 feet for lower voltage systems (less than 600V). While inside the Arch Flash Protection Boundary, a worker must be on protective clothing. These clothing is termed as Personal Protective Equipment (PPE). The function of the PPE is to regulate burns to the body resulting from a potential arc flash event to a survivable level.
An arc flash study ensure that all the fuse panels, motor control panels, breaker panels, switch panels and panel boards are surveyed and labeled with the American National Standards Institute arch flash warning labels. In addition, if any of these panels are to be used by a worker, they are required have a short circuit and coordination study performed.
Finally, an arc flash hazard analysis is performed to determine the available arc faults currents. Whenever you perform a comprehensive arc flash analysis by calculation, you are basically ensuring that your workers are using the proper safety equipment including footwear, gloves and face protection clothing. And when Occupation Safety and Health Administration (OSHA) want to determine whether you acted reasonably during an accidental event, then you will be absolutely safe. OSHA impose a fine of more than $500,000 for being non-compliant with the standard protective measures and regulations of arch flash hazards.
Therefore, if you’re involved in the design, implantation and evaluation of electrical system, you must have an understanding of the arc flash hazards as well as the arch flash evaluations to reduce or eliminate any danger posed to the electrical worker. OSHA also recommends you to consult an independent firm to conduct your arc flash analysis to reduce any bias that may occur when the process is done in-house.