Electrical soft copper stranded wire
Electrical soft copper stranded wire is a flexible conductive wire made from multiple strands of high-purity soft copper wire. It boasts excellent conductivity, flexibility, and fatigue resistance, making it widely used in power systems, electrical equipment, and communications engineering. Its primary function is to transmit current or signals. Its multi-strand structure offers improved bending and vibration resistance compared to single-strand copper wire, making it adaptable to complex installation environments and frequent movement, making it a crucial material for electrical connections. Electrical soft copper stranded wire comes in a variety of sizes, ranging from 0.5 square millimeters to over 1000 square millimeters, depending on cross-sectional area, to meet varying current load requirements.
The production of soft copper stranded electrical wire requires a rigorous series of steps to ensure its performance and quality. First, high-purity electrolytic copper rods (copper content of 99.95% or more) are used as raw material. Through the wire drawing process, the copper rods are drawn into soft copper wires of varying diameters. The drawing process requires careful control of the drawing speed, die precision, and lubricant to ensure uniform copper wire size and a smooth surface, with diameter deviations within ±0.01 mm. Subsequently, multiple strands of soft copper wire are twisted together according to specific twisting rules. Twisting methods include regular twisting, bundle twisting, and multiple twisting. Regular twisting involves twisting the copper wires in layers, with each layer twisted in opposite directions, which improves the wire’s stability and strength. Bundle twisting involves twisting multiple copper strands in parallel, resulting in greater flexibility. Multiple twisting involves first twisting several copper wires into strands, then twisting the strands together into a wire, suitable for large-cross-section stranded wires. During the stranding process, the twist pitch must be carefully controlled. A pitch that is too large or too small will affect the performance of the stranded wire. The typical pitch is 10-20 times the outer diameter of the stranded wire. After stranding, the stranded wire undergoes annealing. This involves heating to 300-500°C under an inert gas atmosphere, holding the temperature for a period of time, and then slowly cooling. This eliminates the internal stress generated during the twisting process and improves the wire’s flexibility and conductivity. Surface treatments such as tinning and silver plating are also required for stranded wire with special requirements to enhance corrosion resistance and weldability. Finally, after inspection and packaging, the finished electrical soft copper stranded wire must ensure that indicators such as conductor resistance, cross-sectional area, and flexibility meet standard requirements.
Electrical soft copper stranded wire offers a range of outstanding performance characteristics, giving it distinct advantages in the field of electrical connections. First, its core characteristic is its exceptional conductivity, reaching over 95% IACS. This allows for efficient current transmission, minimizes energy loss, and is suitable for a variety of high-current transmission applications. Second, its exceptional flexibility allows for easy bending and folding, with a bend radius as small as 3-5 times the stranded wire’s outer diameter, facilitating installation and wiring in confined spaces. It also resists breaking after repeated bending. Third, its excellent fatigue resistance allows it to withstand long-term vibration and shock, maintaining stable conductivity in vibrating environments such as motors and automobiles, with a fatigue life exceeding hundreds of thousands of cycles. Fourth, its large heat dissipation area, due to its multi-strand twisted structure, offers greater surface area than single-strand copper wire of the same cross-sectional area, resulting in better heat dissipation and effectively reducing temperature rise during current transmission. Fifth, its excellent solderability and connectability facilitate connection to other electrical components, enabling reliable connections through crimping, welding, and other methods, with low contact resistance.
Electrical soft copper stranded wire is widely used in a wide range of applications. In power systems, it’s often used in transformer lead-out cables, busbar expansion joints, and grounding devices. For example, large-section soft copper stranded wire is used for the low-voltage side of transformer lead-out cables, accommodating thermal expansion and contraction during transformer operation, ensuring stable current transmission. In electrical equipment, such as internal connections in high- and low-voltage switchgear and motor lead-out cables, its flexibility facilitates assembly and maintenance. In telecommunications engineering, it serves as the conductor of communication cables, transmitting electrical signals and ensuring communication quality. In rail transit, such as in subway and light rail overhead contact lines and pantograph connections, soft copper stranded wire adapts to vehicle vibration and displacement during operation, ensuring a continuous power supply. In the new energy sector, such as in electric vehicle battery cables and charging station cables, large-section soft copper stranded wire meets the high-power and high-current transmission requirements. With the development of the power industry, communications technology, and the new energy sector, the application range of electrical soft copper stranded wire continues to expand.
Industry trends indicate that the production of electrical soft copper stranded wire is trending toward larger cross-sections, higher performance, and composite materials. To meet the high-current transmission demands of ultra-high voltage (UHV) transmission and renewable energy generation, the research and development and production capacity of large-section electrical soft copper stranded wire are continuously expanding. Currently, stranded wires with cross-sectional areas exceeding 1000 square millimeters are produced. Optimized stranding structures and processes ensure flexibility and conductivity. The development of high-performance stranded wires is a hot topic. For example, high-conductivity stranded wires achieve conductivity exceeding 98% IACS by increasing copper purity (99.99%+) and optimizing the annealing process. Weather-resistant stranded wires utilize surface coatings or the addition of alloying elements to extend their service life in humid and corrosive environments. The application of composite electrical soft copper stranded wires, such as copper-clad aluminum stranded wire and carbon fiber-reinforced copper stranded wire, is increasing. Copper-clad aluminum stranded wire combines the high conductivity of copper with the lightweight characteristics of aluminum, reducing cost and weight. Carbon fiber-reinforced copper stranded wire offers increased strength and fatigue resistance, making it suitable for applications requiring high strength. Furthermore, the industry is actively promoting green production, reducing environmental impact through measures such as the use of environmentally friendly lubricants and the recycling of scrap copper. In the future, with the rapid development of high-end equipment manufacturing and new energy industries, the performance and specification requirements for electrical soft copper stranded wire will continue to increase, driving the industry to achieve greater progress in material research and development, process innovation, and other areas.
