Minimum Approach Distances (OSHA)

How close qualified employees may come to exposed energized parts during power generation, transmission and distribution work.

72.5 kV and less — Table R-6 worksites at 900 m (3,000 ft) or lower

Nominal voltage, phase to phase (kV)	Phase-to-ground	Phase-to-phase
0.050 to 0.300	Avoid contact
0.301 to 0.750	0.33 m · 1.09 ft	0.33 m · 1.09 ft
0.751 to 5.0	0.63 m · 2.07 ft	0.63 m · 2.07 ft
5.1 to 15.0	0.65 m · 2.14 ft	0.68 m · 2.24 ft
15.1 to 36.0	0.77 m · 2.53 ft	0.89 m · 2.92 ft
36.1 to 46.0	0.84 m · 2.76 ft	0.98 m · 3.22 ft
46.1 to 72.5	1.00 m · 3.29 ft	1.20 m · 3.94 ft

More than 72.5 kV — Table R-7 worksites at 900 m (3,000 ft) or lower

Nominal voltage, phase to phase (kV)	Phase-to-ground	Phase-to-phase
72.6 to 121.0	1.13 m · 3.71 ft	1.42 m · 4.66 ft
121.1 to 145.0	1.30 m · 4.27 ft	1.64 m · 5.38 ft
145.1 to 169.0	1.46 m · 4.79 ft	1.94 m · 6.36 ft
169.1 to 242.0	2.01 m · 6.59 ft	3.08 m · 10.10 ft
242.1 to 362.0	3.41 m · 11.19 ft	5.52 m · 18.11 ft
362.1 to 420.0	4.25 m · 13.94 ft	6.81 m · 22.34 ft
420.1 to 550.0	5.07 m · 16.63 ft	8.24 m · 27.03 ft
550.1 to 800.0	6.88 m · 22.57 ft	11.38 m · 37.34 ft

Altitude correction — Table R-5 multiply the distances above by A

Altitude above sea level	A
0 to 900 m	1.00
901 to 1,200 m	1.02
1,201 to 1,500 m	1.05
1,501 to 1,800 m	1.08
1,801 to 2,100 m	1.11
2,101 to 2,400 m	1.14
2,401 to 2,700 m	1.17
2,701 to 3,000 m	1.20
3,001 to 3,600 m	1.25
3,601 to 4,200 m	1.30
4,201 to 4,800 m	1.35
4,801 to 5,400 m	1.39
5,401 to 6,000 m	1.44

How this is generated

Values are the alternative minimum approach distances in the federal OSHA power-work standard, generated from the regulation text. Federal regulations are not subject to copyright (17 U.S.C. §105).

The tables apply at worksites 900 m (3,000 ft) above sea level or lower. Higher up, multiply the distances by the altitude correction factor.
For single-phase systems of 72.5 kV and less, use the voltage to ground.
Above 72.5 kV, the phase-to-phase distances apply only when no insulated tool spans the gap and no large conductive object is in it; the clear live-line tool distance must be at least the value shown.
These alternative distances are the conservative table values; the regulation also allows distances calculated from the maximum transient overvoltage (Table R-3 equations), which an engineering analysis may justify.
Voltage ranges are nominal phase-to-phase.

Working space in front of equipment · Maintenance checklist