Once the incident energy is equal to or greater than 1.2 cal/cm2, safety standards require PPE for any body part exposed to a potential second-degree burn. Outside the Arc Flash Boundary: Since a first-degree burn is a superficial injury, no PPE is required if the arc flash incident energy is less than 1.2 cal/cm2. (Per NFPA 70E Handbook, the restricted and limited boundaries and spaces within the arc flash boundary are not related to arc flash and incident energy and will be the subject of a future post.) At this distance, a person without arc flash PPE could receive a second-degree burn in the event of an arc flash. Inside the Arc Flash Boundary : NFPA 70E defines the arc flash boundary as the maximum distance from the arc source at which the incident energy equals 1.2 calories per square centimeter (cal/cm2). Arc-rated PPE is required to work within this boundary. At Pure Power Engineering, the arc flash boundary is the first piece of data that we report on an arc flash warning label. Arc Flash Boundaryĭefining the arc flash boundary is fundamental to an Arc Flash Risk assessment. This label includes all of the information that a qualified person needs in order to identify safe working practices and select personal protective equipment (PPE). As detailed in a previous blog post, the end result of an arc flash risk assessment is a warning label that is applied to each piece of electrical equipment. Arc Flash Risk Assessment (AKA Arc Flash Report)Īs part of a thorough power study, Pure Power Engineering routinely conducts an arc flash risk assessment, as required to meet National Fire Protection Association (NFPA) and Occupational Safety and Health Administration (OSHA) requirements. In a PV power system, personnel who perform electrical commissioning, acceptance testing, inspection, and operations and maintenance activities are at risk of arc flash exposure. All too often, arc flash conditions occur when workers are actively engaged with energized electrical equipment. The hazards associated with a flashover event include vaporized metal, molten metal, hot air, shrapnel, sound and pressure waves, and intense light.Īrc flash conditions can occur unexpectedly due to electrical equipment failure. Instead of following its intended path, electrical current passes through air between two conductors or between one conductor and ground. An arc flash is an explosive phenomenon that can occur during an electrical fault.
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