Annotated Bibliography: Copper Conductor Cross-Section of Electric Wires and Cables

Scope and purpose: This bibliography is intended for cable-industry engineers, electrical engineers, graduate students and academic writers. It compiles the core standards, Chinese journal papers, foreign literature and textbooks on the cross-section of copper conductors, with entries given in GB/T 7714 reference style and brief annotations, ready to be cited in academic papers and technical reports. Coverage: nominal vs. effective conductive cross-section, conductor classes, compacted stranding, large-cross-section segmented conductors, AC/DC resistance, and engineering selection checks.

1. Core Standards

1.1 National Standards (China)

1.2 International Standards

2. Chinese Journal Papers (with Annotations)

Zhai Y H. Design and key manufacturing technology of segmented conductor for a 3000 mm² high-voltage power cable[J]. Electric Wire & Cable, 2025.

Annotation: Under power-frequency AC, a large solid round copper conductor exhibits a marked skin effect, with current concentrated near the surface; simply enlarging the geometric cross-section cannot linearly raise ampacity. The 3000 mm² conductor uses a five-sector Milliken segmented structure, dividing the conductor into mutually insulated sectoral elements to weaken eddy currents. The paper derives formulas for the controlling cross-section and the outline cross-section of a single element, requires the finished DC resistance ≤ 0.0060 Ω/km and out-of-roundness < 0.8 mm, and studies the influence of compacting-die grading and stranding tension on effective cross-section uniformity.

Mei W J. Structural design of large round compacted submarine-cable conductors[J]. Electric Wire & Cable, 2025.

Annotation: Builds a cross-section geometric model for 630 mm² and 1800 mm² compacted copper submarine-cable conductors, and studies how the compaction degree and lay length affect the uniformity of the effective cross-section. Submarine-cable conductors require an extremely small circumferential resistance variation to prevent local overheating. An iterative method is given for single-wire diameter, number of layers and compacting dies, with the effective cross-section verified by finished-conductor resistance.

2.1 Conductor Structure and AC/DC Resistance

Ning G K. Structure design and process control of a round-wire / trapezoidal-wire mixed-strand large copper conductor[J]. Electric Wire & Cable, 2024.

Annotation: A conventional all-round-wire stranded copper conductor has a low filling factor, while an all-trapezoidal profiled conductor requires expensive tooling. A mixed-strand construction is proposed: round wires in the centre and trapezoidal wires on the outer layers. For 300 mm² and 400 mm² copper conductors the compacting factor reaches 0.97–0.98 with a stable DC-resistance margin, reducing copper consumption by about 2–3% compared with a conventional round-wire compacted conductor. Lay-length-to-diameter ratio ranges are given (inner layers 23–30, outer layers 14–16), together with the elongation requirement for annealed copper wire.

Dong Y Z. Influence of high-voltage cable conductor structure on AC and DC resistance[J]. Electric Wire & Cable, 2026.

Annotation: For the same effective cross-section, the number of wires, single-wire diameter and compacting factor directly affect the AC resistance. Finer wires reduce intra-wire eddy-current loss, but closely stranded fine wires strengthen the proximity effect. Temperature changes alter copper resistivity and skin depth, so the cross-section utilisation varies nonlinearly with temperature.

2.2 Cross-Section Concepts and Selection

On the role and significance of the nominal cross-section of a solid conductor for cables[J]. Electric Wire & Cable.

Annotation: Clarifies a common industry misconception: the nominal cross-section is not equal to the measured geometric cross-section. Stranding gaps, compaction deformation and the lay factor all make the geometric area larger than the effective conductive cross-section; the sole acceptance criterion for a conductor is its 20 °C DC resistance. Using measured data for several sizes, the paper compares the geometric area with the effective cross-section back-calculated from resistance, and analyses the mechanism behind 'undersized' (short-measure) conductors.

Selection and optimisation of cross-section for long-distance low-voltage power cables[J]. Electrical Application, 2022.

Annotation: Presents a complete selection procedure for low-voltage distribution copper conductors (ampacity, voltage drop, thermal stability, economic current density, mechanical strength), including the economic-current-density selection formula; suitable as a reference for electrical engineering design.

2.3 Comparison of Chinese and Foreign Standards

Dou H C. Analysis of key technical differences between Chinese and US copper conductors for cables — based on structural classification and resistance calculation[J]. Electric Wire & Cable, 2025.

Annotation: Compares the GB/T 3956 copper conductor (metric nominal cross-section) with the US AWG copper-conductor system. The Chinese standard uses 'fixed nominal cross-sections plus maximum resistance limits', whereas AWG defines the cross-section by single-wire diameter. Their resistivity references and stranding correction factors differ, so copper conductors of the same geometric area are judged against different DC-resistance limits; cross-section conversion must be watched in export selection.

3. Foreign Literature and International Reports

Deng Y, et al. Influence of copper conductor structure on AC and DC resistance of high-voltage power cables[J]. Wire & Cable, 2026.

Annotation: Studies the effects of copper-conductor cross-section, single-wire structure and compacting factor on AC and DC resistance, quantifying the reduction of the effective current-carrying cross-section under the skin effect.

CIGRE WG D1.54. Basic principles and practical methods to measure the AC and DC resistance of conductors of power cables and overhead lines: Technical Brochure 894[R]. Paris: CIGRE, 2023.

Annotation: An authoritative CIGRE technical report systematically presenting the principles, methods and uncertainty analysis for measuring the AC/DC resistance and effective cross-section of copper conductors; suitable as a reference for test methods.

4. Complete Reference List (GB/T 7714 Style)

Standards:

1. GB/T 3956-2008, Conductors of cables[S]. Beijing: China Standards Press, 2008.

2. GB 50217-2018, Standard for cable design of electric power engineering[S]. Beijing: China Planning Press, 2018.

3. GB 51348-2019, Standard for electrical design of civil buildings[S]. Beijing: China Architecture & Building Press, 2019.

4. GB/T 12706.2-2020, Extruded solid insulation power cables and accessories for rated voltages from 1 kV up to 35 kV — Part 2: Cables of rated voltages 1 kV and 3 kV[S]. Beijing: China Standards Press, 2020.

5. IEC 60228:2023, Conductors of insulated cables[S]. Geneva: International Electrotechnical Commission, 2023.

6. IEC 60287-1-1:2014, Electric cables — Calculation of the current rating — Part 1-1: Current rating equations (100% load factor) and calculation of losses — General[S]. Geneva: IEC, 2014.

Journal papers:

7. Zhai Y H. Design and key manufacturing technology of segmented conductor for a 3000 mm² high-voltage power cable[J]. Electric Wire & Cable, 2025.

8. Mei W J. Structural design of large round compacted submarine-cable conductors[J]. Electric Wire & Cable, 2025.

9. Ning G K. Structure design and process control of a round-wire / trapezoidal-wire mixed-strand large copper conductor[J]. Electric Wire & Cable, 2024.

10. Dong Y Z. Influence of high-voltage cable conductor structure on AC and DC resistance[J]. Electric Wire & Cable, 2026.

11. On the role and significance of the nominal cross-section of a solid conductor for cables[J]. Electric Wire & Cable.

12. Selection and optimisation of cross-section for long-distance low-voltage power cables[J]. Electrical Application, 2022.

13. Dou H C. Analysis of key technical differences between Chinese and US copper conductors for cables — based on structural classification and resistance calculation[J]. Electric Wire & Cable, 2025.

Foreign literature and reports:

14. Deng Y, et al. Influence of copper conductor structure on AC and DC resistance of high-voltage power cables[J]. Wire & Cable, 2026.

15. CIGRE WG D1.54. Basic principles and practical methods to measure the AC and DC resistance of conductors of power cables and overhead lines: TB 894[R]. Paris: CIGRE, 2023.

Textbooks:

16. Qu X Q. Stranding Technology[M]. Shanghai: Shanghai Scientific & Technical Publishers, 2001.

5. Quick Reference: Key Concepts

5.1 Nominal Cross-Section vs. Effective Conductive Cross-Section

The nominal cross-section is only a size designation and is not a dimensional acceptance criterion; the effective conductive cross-section is back-calculated from the 20 °C DC resistance according to Ohm's law of resistance:

S = ρ₂₀ · L / R₂₀

where ρ₂₀ is the resistivity of annealed copper at 20 °C (about 0.017241 Ω·mm²/m), R₂₀ is the 20 °C DC resistance per unit length (Ω/km), and L is the conductor length. A stranded conductor contains internal gaps, so its geometric area is larger than its effective conductive area; the aim of compacting, profiled wires and segmented construction is to raise the filling factor, increase the effective cross-section and reduce the resistance.

5.2 Short-Circuit Thermal Stability Check

S ≥ I∞ · √t / √C

where I∞ is the steady-state short-circuit current (A), t is the short-circuit duration (s), and C is the thermal-stability coefficient of the copper conductor (commonly taken as 143 in engineering practice).

6. Literature Search and Verification Guide

17. Chinese journal papers: use CNKI (China National Knowledge Infrastructure) and Wanfang Data to search the journals Electric Wire & Cable and Electrical Application; locate by author or title and complete the volume, issue and page numbers.

18. Chinese national standards: the National Public Service Platform for Standards Information (std.samr.gov.cn) provides the status and bibliographic information of standards.

19. IEC standards: obtain the current version from the IEC Webstore (webstore.iec.ch).

20. Suggested search keywords: copper conductor cross-section, compacting factor, filling factor, lay factor, segmented conductor (Milliken), skin effect, DC resistance, nominal cross-section, economic current density.