Under no circumstance shall unqualified person(s) be permitted to cross the restricted approach boundary.ġ30.4(F) 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. Once there, click on the free access link to NFPA 70E. For the complete section, see the actual NFPA 70E text at NFPA.ORG. The shock protection boundaries and the arc flash boundary are completely different and independent of each other.īelow is a sample of NFPA 70E. It is critical to understand that 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. Table 130.4(D)(b) is used for the distances associated with DC system voltages.Table 130.4(D)(a) is used for the distances associated with AC system voltages.These boundaries are determined from using two separate tables: Verify results and send feedback if a discrepancy is found.In Section 130.4(D) of NFPA 70E, there are two shock protection boundaries that apply to personnel approaching exposed energized electrical conductors or circuit parts: Repeat Step 6 using the reduced arcing currents. Repeat Step 5 using the reduced arcing currents. Repeat Step 4, Reduced Intermediate Currents Repeat Step 4 using Reduced Arcing Current E arc_600, E arc_2400, or E arc_14300 (J / cm 2) Step 8: (To account for the arcing current variations)Īrcing Current Variation Correct Factor ( 1 - 0.5 VarC f )įinal Values of Arcing Current using the Correction Factor I arc (kA) and T (ms) Intermediate Value of Arc-Flash Boundary AFB 600, AFB 2400, or AFB 14300(mm)įinal Arc-Flash Boundary AFB 1, AFB 2 AFB 3, and AFB (mm) ![]() Intermediate Value of Incident Energy E arc_600, E arc_2400, or E arc_14300 (J / cm 2)įinal Value of Incident Energy E E 600, E 2700, E 14300 and E ≤600 (J / cm 2) data.Įnclosure Size Equivalent Height and Width Correction Factor CF, ESS
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