(2) The energized electrical conductors or circuit parts are insulated from the qualified person and from any other conductive object at a different potential. Typical working distances, primarily based on equipment type, are published in IEEE standard 1584 and used in studies to perform the incident energy calculations. Insulating gloves and sleeves are considered insulation only with regard to the energized parts upon which work is performed. An arc flash boundary is the distance at which the incident energy equals 1.2 cal/cm2, and arc-rated PPE is required for any employee within. (1) The qualified person is insulated or guarded from energized electrical conductors or circuit parts operating at 50 volts or more. No qualified person shall approach or take any conductive object closer to exposed energized electrical conductors or circuit parts than the restricted approach boundary set forth in Table 130.4(D)(a) and Table 130.4(D)(b), unless one of the following conditions applies: ![]() Under no circumstance shall unqualified person(s) be permitted to cross the restricted approach boundary. ![]() Where there is a need for an unqualified person(s) to cross the limited approach boundary, a qualified person shall advise the unqualified person(s) of the possible hazards and continuously escort the unqualified person(s) while inside the limited approach boundary. (3) Entering the Limited Approach Boundary. Where one or more unqualified persons are working at or close to the limited approach boundary, the designated person in charge of the work space where the electrical hazard exists shall advise the unqualified person(s) of the electrical hazard and warn him or her to stay outside of the limited approach boundary. (2) Working at or Close to the Limited Approach Boundary. Unless permitted by 130.4(E)(3), no unqualified person shall be permitted to approach nearer than the limited approach boundary of energized conductors and circuit parts. The shock protection boundaries and the arc flash boundary are independent of each other. Informational Note: In certain instances, the arc flash boundary might be a greater distance from the energized electrical conductors or circuit parts than the limited approach boundary. 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. ![]() Table 130.4(D)(b) is used for the distances associated with DC system voltages. The NFPA 70E defines three boundaries for electrical workers to observe.Table 130.4(D)(a) is used for the distances associated with AC system voltages.These boundaries are determined from using two separate tables: In the NFPA 70E, there are two shock protection boundaries that apply to personnel approaching exposed energized electrical conductors or circuit parts:
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