M = 0.31 m for voltages up to 750V and 0.61 m otherwiseįor phase-to-phase system voltages of 5.1 kV to 72.5V: 1,4ĭ = the value from Table V-3 corresponding to the voltage and exposure or the value of the electrical component of the minimum approach distance calculated using the method provided in Appendix B to this subpartįor phase-to-phase system voltages of more than 72.5 kV, nominal: 2, 4Ġ.01 for phase-to-ground exposures that the employer can demonstrate consist only of air across the approach distance (gap),Ġ.01 for phase-to-phase exposures if the employer can demonstrate that no insulated tool spans the gap and the no large conductive object is in the gap, or The electrical component of the minimum approach distance The minimum approach distance (MAD in meters) shall conform to the following equations.įor phase-to-phase system voltages of 50 V to 300 V: 1įor phase-to-phase system voltages of 301 V to 5kV: 1 Table V-2 - AC Live-Line Work Minimum Approach Distance Table V-2 - AC Live-Line Work Minimum Approach Distance The employer shall ensure that devices used by employees to close circuits under load conditions are designed to safely carry the current involved.

For example, the employer could estimate the heat energy just outside a substation feeding a radial distribution system and use that estimate for all jobs performed on that radial system. The employer may make broad estimates that cover multiple system areas provided the employer uses reasonable assumptions about the energy-exposure distribution throughout the system and provided the estimates represent the maximum employee exposure for those areas. Note 2 to paragraph (g)(2): This paragraph does not require the employer to estimate the incident heat energy exposure for every job task performed by each employee. An employer may choose a method of calculating incident heat energy not included in appendix E to this subpart if the chosen method reasonably predicts the incident energy to which the employee would be exposed. The Occupational Safety and Health Administration will deem employers following the guidance in appendix E to this subpart to be in compliance with paragraph (g)(2) of this section. Note 1 to paragraph (g)(2): Appendix E to this subpart provides guidance on estimating available heat energy. For each employee exposed to hazards from electric arcs, the employer shall make a reasonable estimate of the incident heat energy to which the employee would be exposed.

Note to paragraph (c)(1)(ii): See Appendix B to this subpart for information on how to calculate the maximum anticipated per-unit transient overvoltage, phase-to-ground, when the employer uses portable protective gaps to reduce maximum transient overvoltages.Įstimate of available heat energy. The employer shall make any engineering analysis conducted to determine maximum anticipated per-unit transient overvoltage available upon request to employees and to the Assistant Secretary or designee for examination and copying. When the employer uses portable protective gaps to control the maximum transient overvoltage, the value of the maximum anticipated per-unit transient overvoltage, phase-to-ground, must provide for five standard deviations between the statistical sparkover voltage of the gap and the statistical withstand voltage corresponding to the electrical component of the minimum approach distance. No later than April 1, 2015, for voltages over 72.5 kilovolts, the employer shall determine the maximum anticipated per-unit transient overvoltage, phase-to-ground, through an engineering analysis or assume a maximum anticipated per-unit transient overvoltage, phase-to-ground, in accordance with Table V-8.

Arc flash boundary working distance