![]() Limited Approach Boundary is the normal “stay-back” distance for unqualified persons (that is, people without any special training or equipment). Two shock protection boundaries are intended to protect workers from this second hazard. However, the two hazards need to be addressed separately. Most equipment that poses an arc flash hazard also presents a risk of electric shock. Failure to use the right PPE can lead to injuries. If workers must cross this boundary to work on the equipment while it is still powered, they need specific personal protective equipment (PPE) to protect them from burns. ![]() Unqualified workers, who may not be prepared to protect themselves to the same degree, should stay away they should not cross the Arc Flash Boundary. Qualified workers, who have the training to safely perform the task in question, should use the information on the equipment’s arc flash label to identify the PPE they need. The type of required PPE will depend on the work being done, the nature of the equipment, and the available power. If workers must cross this boundary to work on the equipment while it is still powered, they need specific personal protective equipment (PPE) to protect them from burns. ![]() In this case, the Arc Flash Boundary offers another related benefit it tells workers when they need specific gear. Staying away from the equipment is an easy way to keep safe, but sometimes a worker must get closer to do their work. Staying outside the Arc Flash Boundary is a way to reduce or eliminate injuries from an arc flash. The Arc Flash Boundary helps him to determine a safe distance. The electrical worker has to be able to determine his relative risk, according to the distance from the equipment. The Arc Flash Boundary was developed at OSHA’s request by the NFPA to help companies, electrical workers, and employees avoid workplace injuries and fatalities due to shock, electrocution, arc flash, and arc blast, when working in proximity to energized electrical equipment. The Arc Flash Boundary determines the distance from the equipment at which the Incident Energy of an arc flash would be 1.2 cal/cm². The Arc Flash Boundary marks the distance from the equipment at which the Incident Energy of an arc flash would be. These burns are caused by the extreme heat given off by the runaway arc the radiant heat that spreads out in all directions.Īs a result, NFPA 70E includes a “stay-back” distance intended to limit these burns. Refer to NFPA 70E Table 130.In an arc flash, the most common and most severe injuries are burns. If any one of the above are not known, then Table 130.7(C)(15)(a) cannot be used and an incident energy analysis must be performed instead of using the Table. The needed working distance in order to perform the task.The maximum fault clearing time of the overcurrent device protecting the equipment being worked on.The maximum available fault current at the equipment being worked on.The voltage of the equipment being worked on while energized.In order to even begin to use this table, the qualified person must already know several key pieces of information: On the right side of the table is the arc-flash boundary.In the middle of the table is the arc-flash PPE category.On the left side of the table is the description of the equipment.Table 130.7(C)(15)(a) is used to determine the arc-flash PPE category and the arc-flash boundary. The results of an incident energy analysis to specify an arc flash PPE category in Table 130.7(C)(15)(c) shall not be permitted.Īs mentioned above, 130.7(C)(15) can be used instead of performing an incident energy analysis. (2) The arc flash PPE category method in accordance with 130.7(C)(15)Įither, but not both, methods shall be permitted to be used on the same piece of equipment. (1) The incident energy analysis method in accordance with 130.5(G) In the 2018 NFPA 70E ( Standard for Electrical Safety in the Workplace), section 130.5(F) allows two options for selecting the proper level of PPE:
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