Table V-2 - AC Live-Line Work Minimum Approach Distance | | | | | |
The minimum approach distance (MAD; in meters) shall comform to the following equations. | | | | | |
For phase-to-phase system voltages of 50 V to 300 V: 1 | | | | | |
MAD = avoid contact | | | | | |
For phase-to-phase system voltages of 301 V to 5kV: 1 | | | | | |
MAD = M + D, where | | | | | |
D = 0.02 m | the electrical component of the minimum approach distance | | | | |
M = 0.31 m for voltages up to 750V and 0.61 m otherwise | the inadvertent movement factor | | | | |
For phase-to-phase system voltages of 5.1 kV to 72.5V: 1,4 | | | | | |
MAD = M + AD, where | | | | | |
M = 0.61 m | the inadvertent movement factor | | | | |
A = the applicable value from Table V-4 | the altitude correction factor | | | | |
D = 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 subpart | the electrical component of the minimum approach distance | | | | |
For phase-to-phase system voltages of more than 72.5 kV, nominal: 2, 4 | | | | | |
MAD = 0.3048(C+a)VL-GTA+M , where | | | | | |
C= | 0.01 for phase-to-ground exposures that the employer can demonstrate consist only of air across the approach distance (gap),
0.01 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
0.011 otherwise | | | | |
VL-G = | phase-to-ground rms voltage, in kV | | | | |
T = | maximum anticipated per-unit transient overvoltage; for phase-to-ground exposures, T equals TL-G, the maximum per-unit transient overvoltage, phase-to-ground, determined by the employer under paragraph (c)(1)(ii) of this section; for phase-to-phase exposures, T equals 1.35TL-G+0.45 | | | | |
A = | altitude correction factor from Table V-4 | | | | |
M = | 0.31 m, the inadvertent movement factor | | | | |
a = | saturation factor, as follows: | | | | |
Phase-to-Ground Exposure | | | | | |
VPeak = TL-GVL-G√2 | 635 kV or less | 635.1 to 915 kV | 915.1 to 1,050 kV | More than 1,050 kV | |
a | 0 | (VPeak-635)/140,000 | (VPeak-645)/135,000 | (VPeak-675)/125,000 | |
Phase-to-Ground Exposure3 | | | | | |
VPeak=(1.35TL-G+0.45)VL-g√2 | 630 kV or less | 630.1 to 848 kV | 848.1 to 1,131 kV | 1,131.1 to 1,485 kV | More than 1,485 kV |
a | 0 | (VPeak-630)/155,000 | (VPeak-633.6)/152,207 | (VPeak-628)/153,846 | (VPeak-350.5)/203,666 |