Factory-Direct Supply of Certified Wires and Conductors for Diverse Industrial Applications
Stranded Soft Drawn Bare Copper Naked Copper Cable
Standard: ASTM B8 / ASTM B3 (Soft wire) / IEC 60228 Class 2 / BS EN 60228
Conductor Material: Soft-drawn (annealed) electrolytic-grade copper (≥ 99.9% Cu)
Temper: Soft / Annealed
Conductivity: 100% IACS
Construction: Solid (small AWG) / Concentric-lay stranded (7 or 19 wires)
Size Range (ASTM): 14 AWG solid to 250 MCM stranded
Size Range (IEC): 1.5–120 mm² Class 2 on request
Surface Finish: Bare (standard); Tinned available (ASTM B33)
Optional Tempers: Medium-hard (B2) / Hard-drawn (B1) on request
Product Overview
Stranded Soft Drawn Bare Copper Conductor is a concentric-lay or unilay stranded overhead and grounding conductor manufactured from soft-drawn (annealed) electrolytic-grade copper to ASTM B8 (Concentric-Lay-Stranded Hard, Medium-Hard or Soft Copper Conductors) and IEC 60228 / BS EN 60228 Class 2. The soft-drawn (annealed) temper delivers the highest flexibility and ductility of all bare copper conductor types — conductors can be bent, coiled, and routed around obstacles without risk of work-hardening or strand breakage, making soft copper the preferred choice wherever the conductor must be handled, repositioned, or terminated repeatedly in the field.
Copper's inherently high conductivity — 100% IACS (International Annealed Copper Standard) — makes bare copper the highest-conductivity overhead and grounding conductor available. For a given cross-section, bare copper carries approximately 60% more current than aluminium of the same area. Soft-drawn copper conductors are available as solid wire (small AWG sizes, for rigid applications) and concentric-lay stranded (all sizes, for flexible applications). Standard range: 14 AWG solid to 250 MCM stranded (ASTM B8); equivalent IEC/metric sizes from 2.5 mm² to 120 mm² also available on request.
100% IACS Conductivity
Annealed copper achieves 100% IACS — the reference standard for electrical conductivity. For any given cross-section, soft copper carries more current than hard-drawn copper, aluminium, or any other common conductor material. The conductivity of all other conductors is expressed as a percentage of soft copper.
Maximum Flexibility — Annealed Temper
Annealing (controlled heat treatment) removes work-hardening from the copper wire, restoring full ductility. Soft copper conductors can be bent to tight radii, coiled on reels, and repositioned in service repeatedly without fatigue — essential for hook-up wires, jumpers, and portable ground leads.
ASTM B8 & IEC 60228 Compliant
Manufactured to ASTM B8 (North American projects) and IEC 60228 / BS EN 60228 Class 2 (international projects) — accepted by utilities globally for overhead grounding, earthing electrode connections, and neutral conductors.
Corrosion Resistant
Copper forms a stable protective patina (copper oxide / verdigris) on outdoor exposure — resisting atmospheric corrosion without galvanic risk. No bimetallic interface concerns when connected to copper hardware, lugs, and terminals of the same metal family.
Solid or Stranded — Application Matched
Small AWG sizes (14, 10, 8, 6, 4) available as solid wire for rigid terminations in switchgear and panel boards. Medium and large sizes (AWG 4 and above) supplied as 7-wire or 19-wire stranded for flexibility in overhead jumpers, grounds, and grounding electrode conductors.
Tinned Option Available
Tin-coated (tinned) variants available in select AWG sizes per ASTM B33 — tinning prevents surface oxidation and greatly improves solderability, preferred for terminations subject to repeated make/break connections and for use in humid or marine environments.
Technical Specifications
Basic Parameters
| Standards | ASTM B8 (Concentric-Lay-Stranded Copper); ASTM B3 (Soft or Annealed Wire); IEC 60228 Class 2; BS EN 60228 |
|---|---|
| Conductor Material | Electrolytic-grade soft-drawn (annealed) copper — minimum 99.9% Cu purity |
| Temper | Soft / annealed (maximum ductility and flexibility) |
| Conductivity | 100% IACS (annealed copper reference standard) |
| Density | 8.89 g/cm³ |
| Construction | Solid (small AWG) or concentric-lay stranded (standard); unilay available on request |
| Size Range (ASTM) | 14 AWG solid / 14 AWG–250 MCM stranded |
| Size Range (IEC/metric) | 1.5 mm² to 120 mm² (Class 2 stranded, on request) |
| Surface Finish | Bare (standard); Tinned (select AWG sizes, per ASTM B33) |
| Optional Tempers | Medium-hard (ASTM B2); Hard-drawn (ASTM B1) available on request |
| Packaging | Coil, reel, or drum; standard lengths 500 m / 1000 m; custom lengths available |
Parameter Table — ASTM B8 Soft Drawn Bare Copper (Hongda Data)
| AWG Size | Construction | Individual Wire Ø (in.) | Individual Wire Ø (mm) | Approx. Area (mm²) | Weight (kg/km) | DC Resistance (Ω/km, 20°C) |
|---|---|---|---|---|---|---|
| 14 | Solid | 0.064 | 1.63 | 2.08 | 19 | 8.450 |
| 10 | Solid | 0.102 | 2.59 | 5.27 | 46 | 3.330 |
| 8 | Solid | 0.129 | 3.28 | 8.37 | 73 | 2.097 |
| 6 | Solid | 0.162 | 4.11 | 13.30 | 104 | 1.320 |
| 4 | Solid | 0.202 | 5.13 | 20.65 | 188 | 0.8488 |
| 14 | 7 strands | 0.071 | 1.80 | 2.08 (×7) | 21 | 8.450 |
| 12 | 7 strands | 0.089 | 2.26 | 3.31 (×7) | 30 | 5.310 |
| 10 | 7 strands | 0.113 | 2.87 | 5.26 (×7) | 48 | 3.330 |
| 8 | 7 strands | 0.142 | 3.61 | 8.37 (×7) | 76 | 2.097 |
| 6 | 7 strands | 0.178 | 4.52 | 13.30 (×7) | 121 | 1.320 |
| 4 | 7 strands | 0.225 | 5.72 | 21.15 (×7) | 192 | 0.8488 |
| 3 | 7 strands | 0.252 | 6.40 | 26.67 (×7) | 249 | 0.6734 |
| 2 | 7 strands | 0.283 | 7.19 | 33.63 (×7) | 305 | 0.5354 |
| 1 | 19 strands | 0.322 | 8.18 | 42.41 (×19) | 385 | 0.4237 |
| 1/0 | 19 strands | 0.362 | 9.19 | 53.50 (×19) | 485 | 0.3360 |
| 2/0 | 19 strands | 0.405 | 10.29 | 67.43 (×19) | 612 | 0.2665 |
| 3/0 | 19 strands | 0.456 | 11.58 | 85.03 (×19) | 771 | 0.2116 |
| 4/0 | 19 strands | 0.512 | 13.00 | 107.2 (×19) | 957 | 0.1678 |
| 250 MCM | 37 strands | 0.558 | 14.17 | 126.7 (×37) | 1149 | 0.1418 |
Soft Drawn vs Hard Drawn vs Medium Hard — Temper Comparison
| Property | Soft Drawn / Annealed (this product) | Medium Hard Drawn | Hard Drawn |
|---|---|---|---|
| ASTM standard | B3 (wire) / B8 (stranded) | B2 (wire) | B1 (wire) / B8 class H |
| Conductivity | 100% IACS (highest) | 97% IACS | 97% IACS |
| Tensile strength | ~220–250 MPa (lowest) | ~280–320 MPa | ~345–415 MPa (highest) |
| Flexibility / ductility | Excellent (most flexible) | Good | Low (stiff, brittle at bends) |
| Sag resistance | Low (creeps under load) | Medium | High |
| Best for | Grounding, jumpers, hook-up, portable leads | Overhead service drops | Long-span overhead transmission |
Key Features & Material Advantages
Highest Conductivity of Any Common Conductor
Annealed copper at 100% IACS is the reference point for all other conductor conductivities. AAC aluminium is 61% IACS; AAAC is 52.5% IACS; steel is approximately 17% IACS. For grounding applications where minimum impedance is the design objective, soft copper is irreplaceable.
Excellent Termination Properties
Soft copper's high ductility allows lug crimp, compression joint, and mechanical clamp terminations to form gas-tight, low-resistance connections without conductor damage. Harder tempers can crack or spring-back at termination points; soft copper compresses cleanly and stays put.
Long Fatigue Life in Dynamic Applications
Annealed copper resists fatigue fracture under repeated flexing — critical for jumper conductors on overhead lines that are subject to wind-induced vibration, and for portable grounding sets that are connected and disconnected hundreds of times over their service life.
Low DC Resistance for Fault Current Capacity
Grounding conductors must carry fault current for the duration of a protective relay operation (typically 0.1–3 seconds). Low DC resistance and high copper mass give bare soft copper superior fault current capacity per unit cross-section compared to all alternative conductor materials.
Universal Hardware Compatibility
Bare copper is compatible with all standard copper-compatible hardware: copper lugs, bronze clamps, stainless steel compression fittings, and copper-bearing alloy connectors. No bimetallic compatibility concerns as long as aluminium hardware contact is avoided or separated by a suitable bi-metal pad.
Tinned Option for Wet & Soldered Applications
ASTM B33 tinned copper provides a solderable, oxidation-resistant surface — essential for terminations in humid environments (coastal installations, underground vaults), and for any connection that uses solder rather than compression crimping as the joint-making method.
Certifications & Standards
Typical Applications
Overhead Jumper Conductors
Flexible connections between adjacent spans, around insulators, and across switches on overhead distribution lines — soft copper flexibility essential for repeated repositioning during maintenance.
Grounding Electrode Conductors
Connection from electrical system neutral or equipment frame to grounding electrodes (rods, plates, buried grids) — ASTM B8 soft copper is the most commonly specified GEC material in NEC and IEC-standard installations.
Substation Grounding Grid
Buried bare copper grounding grid conductors in substations and switchyards — soft copper's flexibility facilitates installation in trenches and around concrete foundations.
Portable Protective Grounds
Temporary safety grounds applied to de-energised lines before maintenance work — soft copper withstands the repeated clamp/unclamp cycles and fault current duties of portable grounding sets.
Residential & Commercial Wiring
Uninsulated hook-up wire and grounding conductors in switchboards, panel boards, and distribution boards — small AWG soft copper (14–4 AWG) for short-circuit rated grounding connections.
Industrial Earthing Systems
Equipment bonding conductors, earthing busbar connections, and bonding rings in industrial facilities — bare copper for permanent low-impedance earthing throughout the plant.
Lightning Protection Down Conductors
Bare copper down conductors connecting lightning air terminals to earthing electrodes — soft copper bends around building corners without kinking, maintaining continuous electrical path.
Railway Earthing & Bonding
Track bonding conductors, return current bonds, and traction earthing connections in railway electrification systems — bare soft copper for reliable, low-resistance rail bonding.
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Frequently Asked Questions
As a factory, we offer flexible MOQ depending on the cable type. For standard stock items, MOQ is low; for customized specifications, please contact our sales team for a detailed quote.
Yes, Qiangli cables are manufactured in compliance with international standards such as UL, CE, TUV, and VDE. We provide full test reports and certificates upon request.
Absolutely. We have a dedicated R&D team that can customize cable structure, material, color, and printing to meet your specific project needs.
For standard products, lead time is usually 7-15 days. For large-scale project orders or customized products, it typically ranges from 20 to 30 days.
Yes, we provide free samples for most standard cables. You only need to cover the international courier costs. Contact us to arrange your sample shipment.