Hard Drawn Bare Copper (HDBC) Conductor – Overhead Transmission & Traction – BS 7884, ASTM B8, JIS C 3105

Overhead Line
Description

Product Overview

Hard drawn bare copper conductors are used for:

  • Overhead transmission systems

  • Overhead traction systems

  • Transformer earthing (occasionally)

Standards: BS 7884, ASTM B8, JIS C 3105:1994, AS 1746

Technical Data:

  • Voltage Rating: 450 Volts

  • Temperature Limits: -15°C to +70°C

Specifications

Property Details
ROHS Compliant ✓
Voltage Level Low Voltage (450V)
Working Temperature 70°C
Conductor Stranded plain annealed compacted circular copper
Insulation/Sheath None (bare)

Construction

Conductor: Stranded plain annealed compacted circular copper conductor, non‑insulated and non‑sheathed.

Technical Parameters

Table 1 – BS 7884 (HDBC Conductor)

Nominal Area (mm²) Stranding (No./mm) Approx. Overall Diameter (mm) Nominal Mass (kg/km) Max. DC Resistance at 20°C (Ω/km) Minimum Breaking Load (kN) Current Rating* (A)
10 7/1.35 4.05 89.82 1.82900 3.752 80
14 7/1.60 4.80 126.20 1.30300 5.267 99
16 3/2.65 5.70 148.30 1.10600 6.194 112
16 7/1.70 5.10 142.40 1.15400 5.946 106
25 7/2.10 6.30 217.30 0.75630 9.073 138
32 3/3.75 8.06 296.90 0.55200 12.400 171
32 7/2.46 7.38 298.20 0.54970 12.442 168
35 7/2.50 7.50 308.00 0.53370 12.860 171
50 7/3.00 9.00 443.50 0.37060 18.520 215
50 19/1.80 9.00 435.80 0.38190 17.700 212
70 7/3.55 10.65 621.10 0.26460 25.930 264
70 19/2.10 10.50 593.20 0.28060 24.090 256
95 19/2.50 12.50 840.70 0.19800 34.140 317
100 7/4.30 12.90 911.20 0.18100 36.540 334
120 19/2.80 14.00 1055.00 0.15780 42.830 364
125 19/2.90 14.50 1131.00 0.14710 45.940 380
150 19/3.20 16.00 1377.00 0.12080 55.940 429
150 37/2.25 15.75 1334.00 0.12640 53.880 418
185 19/3.55 17.75 1695.00 0.09815 68.860 486
185 37/2.50 17.50 1647.00 0.10240 66.490 475

* Current ratings for guidance only.

Table 2 – JIS C 3105:1994 (HDBC Conductor)

Size Area (mm²) Number / Dia. of Wire (No./mm) Calculated Cross Section (mm²) Approx. Overall Diameter (mm) Approx. Weight (kg/km) Calculated Breaking Load (kN) DC Resistance at 20°C (Ω/km) Standard Length per Reel (m)
0.9 7/0.4 0.9 1.2 8 0.36 20.7 2,000
1.4 7/0.5 1.4 1.5 12 0.56 13.2 2,000
2 7/0.6 2 1.8 18 0.81 9.18 2,000
3.5 7/0.8 3.5 2.4 32 1.43 5.17 2,000
5.5 7/1.0 5.5 3.0 50 2.23 3.31 2,000
8 7/1.2 7.9 3.6 71 3.2 2.30 2,000
14 7/1.6 14.1 4.8 127 5.64 1.29 2,000
22 7/2.0 22 6.0 198 8.71 0.818 2,000
30 7/2.3 29.1 6.9 262 11.4 0.618 2,000
38 7/2.6 37.2 7.8 335 14.5 0.484 2,000
50 19/1.8 48.3 9.0 438 19.2 0.376 2,000
60 19/2.0 59.7 10.0 541 23.6 0.301 2,000
80 19/2.3 78.9 11.5 715 31.1 0.228 2,000
100 19/2.6 100.9 13.0 914 39.4 0.178 2,000
125 19/2.9 125.5 14.5 1,137 48.7 0.143 2,000
150 37/2.3 153.7 16.1 1,396 60.5 0.118 2,000
200 37/2.6 196.4 18.2 1,783 76.7 0.092 2,000
250 61/2.3 253.4 20.7 2,305 99.7 0.0715 2,000
325 61/2.6 323.9 23.4 2,946 126 0.056 1,000
400 61/2.9 402.9 26.1 3,665 156 0.045 1,000
500 61/3.2 490.6 28.8 4,462 189 0.37 1,000
600 91/2.9 601.1 31.9 5,478 233 0.0303 500
725 91/3.2 731.9 35.2 6,670 281 0.0248 500
850 127/2.9 838.9 37.7 7,645 325 0.0217 500
1000 127/3.2 1021.4 41.6 9,309 393 0.0179 300

Table 3 – AS 1746 (HDBC Conductor) – Electrical & Thermal Ratings

Cross Sectional Area (mm²) Stranding (mm) Nominal Conductor Diameter (mm) Mass (kg/km) Breaking Load (kN) Calculated DC Resistance at 20°C (Ω/km) Reactance at 50Hz with 300 mm Spacing (Ω/km) Current Rating Still Air (A) Current Rating 1 m/s Wind (A)
6 7/1.04 3.12 53.6 2.51 3.03 0.365 44 87
10 7/1.35 4.05 90.2 4.17 1.80 0.349 61 120
16 7/1.70 5.10 143 6.50 1.13 0.334 82 160
25 7/2.14 6.42 227 10.1 0.716 0.320 110 212
35 19/1.53 7.65 314 14.1 0.516 0.306 135 260
50 19/1.83 9.15 451 20.0 0.361 0.295 169 323
70 19/2.14 10.7 617 26.8 0.264 0.285 206 392
95 37/1.83 12.8 882 39.0 0.186 0.273 256 486