California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 5 - Electrical Safety Orders
Group 2 - High-Voltage Electrical Safety Orders
Article 36 - Work Procedures and Operating Procedures
Section 2940.2 - Minimum Approach Distances
Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) The employer shall establish minimum approach distances using one of the following methods:
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, shall provide for five standard deviations between the statistical spark over voltage of the gap and the statistical withstand voltage corresponding to the electrical component of the minimum approach distance. The employer shall make any engineering analysis conducted to determine maximum anticipated per unit transient overvoltage available upon request to employees and to the Chief of the Division or designee for examination and copying.
NOTE to subsection (a)(2): Approach distances in Table 2940.2-3 and Table 2940.2-4 assume a maximum anticipated per-unit transient overvoltage in Table 2940.2-5.
(b) No employee shall be permitted to approach or take any conductive object without an approved insulating handle closer to exposed energized parts than the employer established minimum approach distances unless one of the following is met:
(c) Type of Insulation.
(d) Working Position.
Table 2940.2-1 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 601V to 5 kV:1 | |||||
MAD = M + D, where | |||||
D = 0.02 m | D is the electrical component of the minimum approach distance | ||||
M = 0.31 m for voltages up to 750V and 0.61 m otherwise | M is the inadvertent movement factor | ||||
For phase-to-phase system voltages of 5.1 kV to 72.5 kV:1 | |||||
MAD = M + AD, where | |||||
M = 0.61 m | M is the inadvertent movement factor | ||||
A = the applicable value from 2940.2-7 | A is the altitude correction factor | ||||
D = the value from 2940.2-2 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 A to this article | D is the electrical component of the minimum approach distance | ||||
For phase-to-phase system voltages of more than 72.5 kV, nominal:2 | |||||
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 subsection (a)(1)(A) of this section; for phase-to-phase exposures, T equals 1.35TL-G+0.45 | ||||
A = | altitude correction factor from 2940.2-7 | ||||
M = | 0.31 m, the inadvertent movement factor | ||||
a = | saturation factor, as follows: | ||||
Phase-to-Ground Exposure | |||||
VPeak = TL-GVL-GY2 | 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 Exposure3 | |||||
VPeak=(1.35TL-G+0.45) | |||||
VL-gY2 | 630 kV or less | 630.1 to 848 kV | 848.1 to 1,131 kV | 1,131.1 to 1,485kV | 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 |
1 Employers may use the minimum approach distances in Table 2940.2-3. If the worksite is at an elevation of more than 900 meters (3,000 feet), see footnote 1 to Table 2940.2-3. | |||||
2 Employers may use the minimum approach distances in Table 2940.2-4 except that the employer may not use the minimum approach distances in Table 2940.2-4 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 2940.2-4. Employers may use the minimum approach distance in Table 6 through Table 13 in Appendix A to this article, which calculated MAD for various values of T, provided the employer follows the notes to those tables. | |||||
3 Use 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 objects is in the gap. |
TABLE 2940.2-2 ELECTRICAL COMPONENT OF THE MINIMUM APPROACH DISTANCE (D; IN METERS) AT 5.1 TO 72.5 kV |
||
Phase-to-ground exposure |
Phase-to-phase exposure |
|
Nominal voltage (kV) phase-to-phase |
D(m) |
D(m) |
5.1 to 15.0 | 0.04 | 0.07 |
15.1 to 36.0 | 0.16 | 0.28 |
36.1 to 46.0 | 0.23 | 0.37 |
46.1 to 72.5 | 0.39 | 0.59 |
TABLE 2940.2-3 ALTERNATIVE MINIMUM APPROACH DISTANCES (IN METERS OR FEET) FOR VOLTAGES OF 72.5 kV AND LESS 1 |
||||
Distance |
||||
Phase-to-ground exposure |
Phase-to-phase exposure |
|||
Nominal voltage (kV) phase-to-phase |
m |
ft |
m |
ft |
0.601 to 0.7502 | 0.33 | 1.09 | 0.33 | 1.09 |
0.751 to 5.0 | 0.63 | 2.07 | 0.63 | 2.07 |
5.1 to 15.0 | 0.65 | 2.14 | 0.68 | 2.24 |
15.1 to 36.0 | 0.77 | 2.53 | 0.89 | 2.92 |
36.1 to 46.0 | 0.84 | 2.76 | 0.98 | 3.22 |
46.1 to 72.5 | 1.00 | 3.29 | 1.20 | 3.94 |
1 Employers 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 2940.2-7 corresponding to the altitude of the work. | ||||
2 For single-phase systems, use voltage-to-ground. |
TABLE 2940.2-4 ALTERNATIVE MINIMUM APPROACH DISTANCES FOR VOLTAGES OF MORE THAN 72.5 kV 1,2,3 |
||||
Phase-to-ground exposure |
Phase-to-phase exposure |
|||
Voltage range phase to phase (KV) |
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 |
1 Employers 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 2940.2-7 corresponding to the altitude of the work. | ||||
2 Employers 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. | ||||
3 The clear live-line tool distance shall equal or exceed the values for the indicated voltage ranges. |
TABLE 2940.2-5 ASSUMED MAXIMUM PER-UNIT TRANSIENT OVERVOLTAGE |
||
Voltage range (kV) |
Type of current (AC or DC) |
Assumed maximum perunit 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 |
TABLE 2940.2-6 DC LIVE-LINE MINIMUM APPROACH DISTANCE WITH OVERVOLTAGE FACTOR1 |
||||||||||
Maximum Anticipated Transient Overvoltage |
Maximum Line-To-Ground Voltage (kV) |
|||||||||
250 (kV) |
400 (kV) |
500 (kV) |
600 (kV) |
750 (kV) |
||||||
m |
ft |
M |
ft |
m |
ft |
m |
ft |
m |
ft |
|
1.5 or less | 1.12 | 3.67 | 1.60 | 5.25 | 2.06 | 6.76 | 2.62 | 8.59 | 3.61 | 11.84 |
1.6 | 1.17 | 3.84 | 1.69 | 5.54 | 2.24 | 7.35 | 2.86 | 9.38 | 3.98 | 6.37 |
1.7 | 1.23 | 4.03 | 1.85 | 6.07 | 2.42 | 7.94 | 3.12 | 10.23 | 4.37 | 14.33 |
1.8 | 1.28 | 4.20 | 1.95 | 6.40 | 2.62 | 8.59 | 3.39 | 11.12 | 4.79 | 15.71 |
1 The distances specified in this table are for air and live-line tool conditions. 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 2940.2-7 corresponding to the altitude of the work. |
TABLE 2940.2-7 ALTITUDE CORRECTION FACTOR |
||
Altitude (m) | Altitude (ft) | Correction Factor |
0 to 900 | Sea level to 3000 | 1.00 |
901 to 1,200 | 3,001 to 4,000 | 1.02 |
1,201 to 1,500 | 4,001-5,000 | 1.05 |
1,501 to 1,800 | 5,001-6,000 | 1.08 |
1,801 to 2,100 | 6,001-7,000 | 1.11 |
2,101 to 2,400 | 7,001-8,000 | 1.14 |
2,401 to 2,700 | 8,001-9,000 | 1.17 |
2,701 to 3,000 | 9,001-10,000 | 1.20 |
3,001 to 3,600 | 10,001-12,000 | 1.25 |
3,601 to 4,200 | 12,001-14,000 | 1.30 |
4,201 to 4,800 | 14,001-16,000 | 1.35 |
4,801 to 5,400 | 16,001-18,000 | 1.39 |
5,401 to 6,000 | 18,001-20,000 | 1.44 |
1. Amendment filed 12-10-87; operative 1-9-88 (Register 88, No. 1).
2. Amendment of subsection (b) and Table filed 12-12-94; operative 1-11-95 (Register 94, No. 50).
3. Editorial correction of Table (Register 95, No. 32).
4. Amendment of subsection (a)(1), table and table note filed 11-25-97; operative 12-25-97 (Register 97, No. 48).
5. Amendment filed 7-26-2000; operative 8-25-2000 (Register 2000, No. 30).
6. Amendment filed 4-28-2014; operative 7-1-2014 (Register 2014, No. 18).
7. Amendment of section heading and section filed 2-27-2018; operative 4-1-2018 (Register 2018, No. 9).
8. Amendment of Table 2940.2-1 filed 12-5-2019; operative 4-1-2020 (Register 2019, No. 49).
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.