The process of quantifying arc-flash hazards for electrical equipment has been evolving ever since the 1980s. Ultimately, PPE is selected and enforced by the owner of the electrical equipment, and NFPA 70E serves to provide recommendations only. For example, HRC 3 recommends PPE with a system arc rating of at least 25 cal/cm², which may include an arc-rated suit jacket, pants, hood, gloves, leather work shoes, a hard hat, safety glasses, and hearing protection. NFPA 70E offers tables that correlate specific ranges of incident energy to a hazard/risk category (HRC), which link to a recommended PPE. Rated by the manufacturer (based on incident energy in cal/cm² ), PPE is selected by a facility to protect its personnel from an arcing fault. It represents the point at which personnel need to wear personal protective equipment (PPE) t o safeguard against a potential arc-flash hazard. working distance) the fault current available and the expected duration of the fault.Īrc-flash boundary is the distance at which the incident energy equals 1.2 cal/cm ². Incident energy exposure changes based on a variety of factors, including: the type and voltage of equipment how far a person is away from the equipment (i.e. In either case, a hazard exists if a person may be exposed to an arcing fault on energized electrical equipment.Īccording to the NFPA 70E-2012 Standard, an arc-flash hazard analysis is determined by:Ī quantitative calculation of the thermal energy to which a person may be exposed, incident energy is measured in calories per square centimeter (cal/cm² ). Copyright 2012)Ĭalculations for arc-flash hazards on wind farms differ from many other applications in that they can be ascertained from two sources: the utility system external to the wind farm, or from the wind turbine generators. NFPA 70E-2012 defines an arc-flash hazard as: “A dangerous condition associated with the possible release of energy caused by an electric arc.” (Source: Handbook for Electrical Safety in the Workplace, 3rd Edition. NFPA 70E-2012, Standard for Electrical Safety in the Workplace, is the standard that explains and provides guidance for arc-flash hazard analyses. OSHA has since aimed to reduce uncertainties and increase jobsite safety, thanks to their new ruling. Because there are several methods for calculating incident energy, different organizations provided inconsistent calculations for different types of equipment. Until 2014, OSHA offered no regulations or recommendations on a preferred calculation method. The magnitude of a potential arc-flash hazard can be quantified in terms of incident energy. One important standard set by the organization requires employers to mark electrical equipment with signs, warning personnel of potential risks, including arc flashes. Without proper training and safeguards in place, one wrong move could lead to thermal burns, electrical shock, and falls as a result.Īs a regulatory body, the Occupational Safety and Health Administration (OSHA) is the main federal agency responsible for the enforcement of safety and health legislation in the United States. W orkers in the wind power industry face several potential hazards that include arc flashes, electrical discharges that occur upon opening energized circuits. The foresightful worker is attired in personal protective equipment to safeguard against the arc-flash.
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