Minimum Approach Distance Calculator Text-Version

This page is a copy of Table V-2, Table V-4, Table V-6, and Table V-8 in 29 CFR 1926.960, with references to applicable portions of 29 CFR Part 1926, Subpart V, and, for the public’s convenience, certain corresponding portions of 29 CFR 1910.269 added in brackets. The minimum approach distance calculator is for use with phase-to-phase system voltages exceeding 72.5 kilovolts only. However, Table V-2 includes information relevant for lower voltages.

Table V-2 – AC Live-Line Work Minimum Approach Distance
The minimum approach distance (MAD; in meters) shall conform to the following equations.

For phase-to-phase system voltages of 50 V to 300 V: 1

For phase-to-phase system voltages of 301 V to 5 kV: 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 750 V and 0.61 m otherwise the inadvertent movement factor

For phase-to-phase system voltages of 5.1 kV to 72.5 kV: 1, 4

 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 [29 CFR 1910.269 and Appendix B to 29 CFR Part 1926, Subpart V.] [See 29 CFR 1926.960.] 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 that 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 [29 CFR 1926.960 or paragraph (l)(3)(ii) of 29 CFR 1910.269]; 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 Exposures
VPeak = TL-GVL-G2 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-Phase Exposures3
VPeak = (1.35TL-G+0.45)VL-G2 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

1Employers may use the minimum approach distances in Table V-5. [See 29 CFR 1926.960.] If the worksite is at an elevation of more than 900 meters (3,000 feet), see footnote 1 to Table V-5.

2Employers may use the minimum approach distances in Table V-6, except that the employer may not use the minimum approach distances in Table V-6 for phase-to-phase exposures if an insulated tool spans the gap or if any large conductive object is in the gap. If the worksite is at an elevation of more than 900 meters (3,000 feet), see footnote 1 to Table V-6. Employers may use the minimum approach distances in Table 7 through Table 14 in Appendix B to [29 CFR Part 1926, Subpart V or Table 14 through Table 21 in Appendix B to 29 CFR 1910.269], which calculated MAD for various values of T, provided the employer follows the notes to those tables.

3Use the equations for phase-to-ground exposures (with VPeak for phase-to-phase exposures) unless the employer can demonstrate that no insulated tool spans the gap and that no large conductive object is in the gap.

4Until March 31, 2015, employers may use the minimum approach distances in Table 6 in Appendix B to [29 CFR Part 1926, Subpart V, or Table 6 through Table 13 in Appendix B to 29 CFR 1910.269].

Table V-4 – Altitude Correction Factor
Altitude above Sea Level (m) A
0 to 900 1.00
901 to 1,200 1.02
1,201 to 1,500 1.05
1,501 to 1,800 1.08
1,801 to 2,100 1.11
2,101 to 2,400 1.14
2,401 to 2,700 1.17
2,701 to 3,000 1.20
3,001 to 3,600 1.25
3,601 to 4,200 1.30
4,201 to 4,800 1.35
4,801 to 5,400 1.39
5,401 to 6,000 1.44

Table V-6 – Alternative Minimum Approach Distances (in Meters or Feet and Inches) for Voltages of More Than 72.5 kV 1, 2, 3
Voltage Range Phase to Phase (kV) Phase-to-Ground Exposure Phase-to-Phase Exposure
m ft m ft
72.6 to 121.0 1.13 3.71 1.42 4.66
121.1 to 145.0 1.30 4.27 1.64 5.38
145.1 to 169.0 1.46 4.79 1.94 6.36
169.1 to 242.0 2.01 6.59 3.08 10.10
242.1 to 362.0 3.41 11.19 5.52 18.11
362.1 to 420.0 4.25 13.94 6.81 22.34
420.1 to 550.0 5.07 16.63 8.24 27.03
550.1 to 800.0 6.88 22.57 11.38 37.34

1Employers may use the minimum approach distances in this table provided the worksite is at an elevation of 900 meters (3,000 feet) or less. If employees will be working at elevations greater than 900 meters (3,000 feet) above mean sea level, the employer shall determine minimum approach distances by multiplying the distances in this table by the correction factor in Table - 4 corresponding to the altitude of the work.

2Employers may use the phase-to-phase minimum approach distances in this table provided that no insulated tool spans the gap and no large conductive object is in the gap.

3The clear live-line tool distance shall equal or exceed the values for the indicated voltage ranges.

Table V-8 – Assumed Maximum Per-Unit Transient Overvoltage
Voltage Range (kV) Type of Current (ac or dc) Assumed Maximum Per-Unit Transient Overvoltage
72.6 to 420.0 ac 3.5
420.1 to 550.0 ac 3.0
550.1 to 800.0 ac 2.5
250 to 750 dc 1.8

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