The arc flash boundary is3/11/2024 ![]() Note: A individual undergoing on-the-job training who has demonstrated the ability to perform duties safely at his or her level of training, and who is under the direct supervision of a qualified person, is considered to be a qualified person for the purpose of those duties. ![]() Only qualified persons may place or remove locks and tags on energized electrical systems. An individual may be qualified to work, for example, on circuits up to 600 volts, but may be unqualified to work on higher voltages. Qualified persons are those who have received specific training and have demonstrated the skills necessary to work safely on or near exposed energized parts. The training offered by Environmental Health and Safety associated with this program covers personal safety issues regarding work on electrical systems and includes relative information to be gathered while analyzing electrical-related hazards, which safe work practices may apply, and selection, use and care of appropriate electrical-related personal protective equipment. This program provides a system for ensuring that personnel performing energized electrical work, including voltage testing and diagnostics, are trained in the safety aspects of such work and have been qualified by their supervisor to perform the task assigned. This takes into account various system variable beyond knowing the system voltage in order to accurately determine the proper distance for the Arc Flash Boundary.Occupational Safety and Health Program for Animal Handlers The Arc Flash Boundary is only determined through a detailed power system analysis referred to as an Arc Flash Analysis. Know your voltage and have access to the table is all that is needed to determine the shock boundaries.ĭetermining the Arc Flash Boundary is not nearly as easy as determining the three shock boundaries. The boundaries are directly related to their voltage levels and do not change based upon various system attributes. The boundaries that focus on protecting workers from electrical shock and electrocution Limited Approach, and Restricted Approach, are determined by referencing the NFPA 70E Tables 130.4(C)(a) for AC systems and 130.4(C)(b) for DC systems. An approved work permit where applicable is needed to cross this boundary, with some form of documentation in place at a minimum. Qualified workers must don applicable arc flash PPE as well as shock PPE appropriate for the voltage a worker is exposed to. Non-qualified workers are prohibited from crossing the restricted approach boundary and entering the restricted space. The Restricted Approach Boundary may only be crossed by a qualified worker. ![]() ![]() However, when the arc flash boundary is larger, be sure proper arc flash PPE is worn within the limited approach boundary. In many cases the limited approach boundary is the farthest electrical boundary that exists. To cross the limited approach boundary a worker must be qualified or otherwise escorted by a qualified person. No matter who crosses the Arc Flash Boundary, proper PPE is required that meets the requirements of the NFPA 70E.ĭistance from an exposed live part within which a shock hazard exists. Detailed formulas for determining the arc flash boundary can be found in the NFPA 70E and IEEE 1584.īoth Qualified and Non-qualified can cross the Arc Flash Boundary as long as long as Qualified personnel supervision is present. This boundary is calculated based upon specific system information, and can apply when exposed energized conductors or circuit parts are present, or with doors and equipment closed if interacting in a manner that could cause an arc. It is defined as the distance at which a worker is exposed to 1.2 calories/cm2 of incident energy, which represents the onset of a second degree burn. The Arc Flash Boundary deals specifically with arc flash hazards and determines when arc flash PPE shall be required. These boundaries are not calculated and apply only when exposed energized conductors or circuit parts are present. The Limited, and Restricted approach boundaries deal strictly with shock prevention and are based upon nominal system voltage. The arc flash boundary has a primary purpose of preventing burn injury due to arc flash incidents. The third boundary is the arc flash boundary. Two boundaries deal specifically with shock hazards and are intended to prevent shock and electrocution. The NFPA 70E defines three boundaries for electrical workers to observe.
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