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 Code of Federal Regulations (Last Updated: November 8, 2024)
 Title 30 - Mineral Resources
 Chapter I - Mine Safety and Health Administration, Department of Labor
 SubChapter B - Testing, Evaluation, and Approval of Mining Products
 Part 18 - Electric Motor-Driven Mine Equipment and Accessories
 Subpart D - Machines Assembled With Certified or Explosion-Proof Components, Field Modifications of Approved Machines, and Permits To Use Experimental Equipment

  Appendix I to Subpart D of Part 18  

Latest version.

  • Appendix I to Subpart D of Part 18

    LIST OF TABLES

    Table No. Title
    1 Portable power cable ampacities - 600 volts.
    2 Portable cord ampacities - 600 volts.
    3 Portable power cable ampacities - 601 to 5,000 volts.
    4 Normal diameter of round cables with tolerances in inches - 600 volts.
    5 Nominal dimension of flat cables with tolerances in inches - 600 volts.
    6 Nominal diameter of heavy jacketed cords with tolerances in inches - 600 volts.
    7 Nominal diameter of three-conductor portable power cables with tolerances in inches - 601 to 5,000 volts.
    8 Fuse ratings or instantaneous settings of circuit breakers for short-circuit protection of portable cables.
    9 Specifications for portable cables longer than 500 feet.
    10 High voltage trailing cable ampacities and outside diameters.

    Table 1 - Portable Power Cable Ampacities - 600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature - 40 °C. Ambient)

    Conductor size - AWG or MCM Single conductor 2-conductor, round or flat 3-conductor, round or flat 4-conductor 5-conductor 6-conductor
    8 45 40 35 30 25 20
    6 60 50 50 40 35 30
    4 85 70 65 55 45 35
    3 95 80 75 65 55 45
    2 110 95 90 75 65 55
    1 130 110 100 85 75 65
    1/0 150 130 120 100 90 80
    2/0 175 150 135 115 105 95
    3/0 205 175 155 130 120 110
    4/0 235 200 180 150 140 130
    250 275 220 200 160
    300 305 240 220 175
    350 345 240 235 190
    400 375 280 250 200
    450 400 300 270 215
    500 425 320 290 230

    Table 2 - Portable Cord Ampacities - 600 Volts (Amperes Per Conductor Based on 60 °C. Copper Temperature - 40 °C. Ambient)

    Conductor size - AWG 1-3 conductor 4-6 conductor 7-9 conductor
    14 15 12 8
    12 20 16 11
    10 25 20 14

    Table 3 - Portable Power Cable Ampacities - 601 to 5,000 Volts (Amperes Per Conductor Based on 75 °C. Copper Temperature - 40 °C. Ambient)

    Conductor size - AWG or MCM 3-conductor types G-GC and SIIC-GC 2,000 volts 3-conductor type SHD-GC 2,001-5,000 volts
    6 65 65
    4 85 85
    3 100 100
    2 115 115
    1 130 130
    1/0 145 145
    2/0 170 170
    3/0 195 195
    4/0 220 220
    250 245 245
    300 275 275
    350 305 305

    Table 4 - Nominal Diameters of Round Cables With Tolerances in Inches - 600 Volts

    Conductor size - AWG or MCM Single conductor 2-conductor 3-conductor 4-conductor - Types W & G 5-conductor - Types W & G 6-conductor
    Types W & G twisted Type PG, 2 power Type PCG, 3 power, ground Types W & G Type PG, 3 power, ground Type PCG, 3 power, 2 control, ground Type w Tolerance
    8 0.44 0.81 0.84 0.94 0.91 0.93 1.03 0.99 1.07 1.18 ±0.03
    6 .51 .93 .93 .98 1.01 1.03 1.18 1.10 1.21 1.31 ±.03
    4 .57 1.08 1.08 1.10 1.17 1.20 1.29 1.27 1.40 1.52 ±.03
    3 .63 1.17 1.17 1.20 1.24 1.27 1.31 1.34 1.48 1.61 ±.03
    2 .66 1.27 1.27 1.29 1.34 1.34 1.39 1.48 1.61 1.75 ±.03
    1 .74 1.44 1.44 1.44 1.51 1.52 1.52 1.68 1.88 2.05 ±.03
    1/0 .77 1.52 1.52 1.52 1.65 1.68 1.68 1.79 1.96 2.13 ±.04
    2/0 .82 1.65 1.65 1.65 1.75 1.79 1.79 1.93 2.13 2.32 ±.04
    3/0 .87 1.77 1.77 1.77 1.89 1.93 1.93 2.07 2.26 2.49 ±.05
    4/0 .93 1.92 1.92 1.92 2.04 2.13 2.13 2.26 2.46 2.71 ±.05
    250 1.03 2.16 2.16 2.16 2.39 2.39 2.39 2.66 ±.06
    300 1.09 2.32 2.56 2.84 ±.06
    350 1.15 2.43 2.68 2.98 ±.06
    400 1.20 2.57 2.82 3.14 ±.06
    450 1.26 2.67 2.94 3.26 ±.06
    500 1.31 2.76 3.03 3.40 ±.06

    Table 5 - Nominal Dimensions of Flat Cables With Tolerances in Inches - 600 Volts

    Conductor size - AWG 2-conductor 3-conductor - Type G
    Type W Type G Major Minor
    Major Minor Major Minor O.D. Tolerance O.D. Tolerance
    O.D. Tolerance O.D. Tolerance O.D. Tolerance O.D. Tolerance
    8 0.84 ±0.04 0.51 ±0.03
    6 .93 ±.04 .56 ±.03 1.02 ±.04 0.56 ±.03 1.65 ±0.06 0.67 ±0.05
    4 1.05 ±.04 .61 ±.03 1.15 ±.04 .61 ±.03 1.85 ±.06 .75 ±.05
    3 1.14 ±.04 .68 ±.03 1.26 ±.04 .68 ±.03 1.99 ±.06 .77 ±.05
    2 1.24 ±.04 .73 ±.03 1.35 ±.04 .73 ±.06 2.10 ±.06 .81 ±.05
    1 1.40 ±.04 .81 ±.03 1.55 ±.04 .81 ±.03 2.43 ±.06 .97 ±.05
    1/0 1.51 ±.04 .93 ±.03 1.67 ±.04 .93 ±.03
    2/0 1.63 ±.04 .99 ±.03 1.85 ±.04 .99 ±.03
    3/0 1.77 ±.04 1.03 ±.03 2.00 ±.04 1.03 ±.03
    4/0 1.89 ±.04 1.10 ±.03 2.10 ±.04 1.10 ±.03

    Table 6 - Nominal Diameters of Heavy Jacketed Cords With Tolerances In Inches - 600 Volts

    Conductor size - AWG 2-conductor 3-conductor 4-conductor 5-conductor 6-conductor 7-conductor
    Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance
    14 0.64 ±0.02 0.67 ±0.02 0.71 ±0.02 0.78 ±0.03 0.83 ±0.03 0.89 ±0.03
    12 .68 ±.02 .72 ±.03 .76 ±.03 .83 ±.03 .89 ±.03 .98 ±.03
    10 .73 ±.03 .80 ±.03 .84 ±.03 .90 ±.03 1.00 ±.03 1.07 ±.03

    Table 7 - Nominal Diameters of Three-Conductor Portable Power Cables With Tolerances in Inches - 601 to 5,000 Volts

    Conductor size - AWG or MCM Type G-GC (nonshielded) 2,000 volts Type SHC-GC (shielded overall) 2,000 volts Type SHD-GC (individually shielded power conductors) 2,001-3,000 volts Type SHD-GC (individually shielded power conductors) 3,001-5,000 volts
    Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance
    6 1.25 + 0.10, −0.06 1.39 + 0.11, −0.07 1.62 + 0.13, −0.08 1.78 + 0.14, −0.09
    4 1.40 + .11, −.07 1.55 + .12, −.08 1.77 + .14, −.09 1.90 + .15, −.10
    3 1.48 + .12, −.07 1.62 + .13, −.08 1.84 + .15, −.09 1.98 + .16, −.10
    2 1.55 + .12, −.08 1.71 + .14, −.09 1.92 + .15, −.10 2.09 + .17, −.11
    1 1.74 + .14, −.09 1.89 + .15, −.09 2.04 + .16, −.10 2.18 + .17, −.11
    1/0 1.84 + .15, −.09 2.02 + .16, −.10 2.18 + .17, −.11 2.34 + .19, −.12
    2/0 1.99 + .16, −.10 2.16 + .17, −.11 2.29 + .18, −.12 2.46 + .20, −.12
    3/0 2.12 + .17, −.11 2.30 + .18, −.11 2.45 + .20, −.12 2.62 + .21, −.13
    4/0 2.30 + .18, −.12 2.48 + .20, −.12 2.62 + .21, −.13 2.76 + .22, −.14
    250 2.46 + .20, −.12 2.70 + .22, −.13
    300 2.63 + .21, −.13 2.84 + .23, −.14
    350 2.75 + .22, −.14 2.97 + .24, −.15

    Table 8 - Fuse Ratings or Instantaneous Setting of Circuit Breakers for Short-Circuit Protection of Portable Cables and Cords

    Conductor size - AWG or MCM Ohms/1,000 ft. at 25 °C. Maximum allowable fuse rating (amperes) Maximum allowable circuit breaker instantaneous setting (amperes)1
    14 2.62 20 50
    12 1.65 30 75
    10 1.04 40 150
    8 .654 80 200
    6 .410 100 300
    4 .259 200 500
    3 .205 250 600
    2 .162 300 800
    1 .129 375 1,000
    1/0 .102 500 1,250
    2/0 .081 1,500
    3/0 .064 2,000
    4/0 .051 2,500
    250 .043 2,500
    300 .036 2,500
    350 .031 2,500
    400 .027 2,500
    450 .024 2,500
    500 .022 2,500

    1 Higher circuit-breaker settings may be permitted for special applications when justified.

    Table 9 - Specifications for Portable Cables Longer Than 500 Feet1

    Conductor size - AWG or MCM Max. allowable length (feet) Normal ampacity at 60 °C. copper temperature (40 °C. ambient) Resistance at 60 °C. copper temperature (ohms)
    6 550 50 0.512
    4 600 70 .353
    3 650 80 .302
    2 700 95 .258
    1 750 110 .220
    1/0 800 130 .185
    2/0 850 150 .157
    3/0 900 175 .130
    4/0 1,000 200 .116
    250 1,000 220 .098
    300 1,000 240 .082
    350 1,000 260 .070
    400 1,000 280 .061
    450 1,000 300 .054
    500 1,000 320 .050

    1 Fuses shall not be used for short-circuit protection of these cables. Circuit breakers shall be used with the instantaneous trip settings not to exceed the values given in Table 8.

    Table 10 - High Voltage Trailing Cable Ampacities and Outside Diameters

    Power conductor Ampacity * Outside diameter **
    (inches)
    Size AWG or kcmil Amperes per conductor SHD-GC 2001 to 5000 volts SHD-CGC 2001 to 5000 volts SHD-PCG 2001 to 5000 volts
    6 93 1.56 1.62
    4 122 1.68 1.73
    3 140 1.78 1.82 1.94
    2 159 1.87 1.91 2.03
    1 184 1.95 1.98 2.12
    1/0 211 2.08 2.10 2.26
    2/0 243 2.20 2.20 2.40
    3/0 279 2.36 2.36 2.58
    4/0 321 2.50 2.50 2.76
    250 355 2.69 2.69
    300 398 2.81 2.81
    350 435 2.95 2.95
    500 536 3.31 3.31

    * These ampacities are based on single isolated conductor in air, operated with open-circuited shield for a 90 °C conductor temperature and an ambient temperature of 40 °C.

    ** Tolerances for the outside diameter are + 8%/−5%.

    [33 FR 4660, Mar. 19, 1968; 33 FR 6345, Apr. 26, 1968, as amended at 42 FR 8373, Feb. 10, 1977; 75 FR 17549, Apr. 6, 2010; 75 FR 20918, Apr. 22, 2010]