Wires and cables for electrical equipment are widely used and varied, including those for power, distribution, consumption, and weak current systems like control, signaling, instrumentation, and temperature measurement. However, China develops these cables domestically, but some high-end cables and materials are still imported.
Because the wide variety, this article covers only some types. Specifically, it focuses on wires and cables in construction engineering, transportation, mining, new energy, and industrial automation. Additionally, it summarizes and analyzes the localization of cable materials.
1. Wires and cables used in construction engineering fields
（1）Development status
Construction engineering mainly includes cloth wires, elevator cables, resistance and fire-resistant cables, pre-branch cables, aluminum alloy conductor cables, and medium and low-voltage power cables. These rely on urban and rural infrastructure and real estate development. Their usage has multiplied with improved living standards and advances in household electrification and informatization.
Two main types of wires exist polyvinyl chloride insulated wire, a CCC-certified product with standards GB/5023 (equivalent to IEC 60227) and JB/T8734, and cross-linked polyolefin insulated low-smoke, halogen-free, flame-retardant wires, which follow industry standards. However, due to non-standard product models, corporate standards are mainly implemented. As safety and environmental awareness increase, low-smoke halogen-free flame-retardant wires are increasingly used in public facilities and high-rise buildings, driving rapid market growth. Additionally, domestic companies have developed “long-life” wire and cable to meet individual building and home decoration needs.
Users highly value the simple structure of cloth wire, which offers good economic benefits. Many cable companies produce this type and continuously improve their production capacity to meet demand. Moreover, the materials and equipment used are domestically produced. High-speed extruders and packaging lines have recently improved cloth wire production efficiency to match foreign products. Technological developments like ultraviolet and silane cross-linking are now used in manufacturing cross-linked olefin-insulated low-smoke halogen-free flame-retardant wires. However, while popular in China, silane cross-linking technology is still in its infancy.
China’s elevator industry has overgrown, averaging 19% annually. Consequently, elevators increased from 285,000 units in 2001 to 5.66 million by the end of 2018, boosting the use of elevator cables. Domestic standards fall into four categories: IEC/GB, EN, UL/CSA, and JIS. Elevator cables comprise 70% to 80% of the market and are mainly copper core PVC insulated PVC sheathed cables with rated voltages of 450/750V and below, produced based on IEC/GB or EN standards.
Flame-retardant and fire-resistant cables are widely used in construction. Specifically, flame-retardant cables include halogen-containing and halogen-free types, which are increasingly used to prevent secondary fire hazards. Fire-resistant wires, designed to maintain safe operation under fire, come in various structures for different protection levels and applications. With improved fire safety awareness, these cables are now widely used in high-rise buildings, subways, malls, airports, power stations, critical industrial and mining enterprises, etc., closely related to fire safety, firefighting, and life-saving places. Therefore, fire-resistant cables that meet fire protection requirements must be used for firepower supply and fire protection facilities in buildings and public areas. Since 1994, building design codes have gradually included the use requirements for fire-resistant cables into mandatory provisions. In 2016, DGJ08-2048-2016 “Electrical Fire Protection Design Code for Civil Buildings,” “Electrical Design Code for Civil Buildings” Draft for Comments, (Gongxiao [2018] No. 57) “Enhancing Technology for Fire Protection Design of Civil Buildings with a Building Height Greater than 250 Meters” Standards such as “Requirements (Trial)” have begun to provide clear regulations on the fire resistance temperature and continuous power supply time of cables on fire protection lines.
Market demand has driven the rapid development of domestic low-voltage fire-resistant cable products, production equipment, and material technology. Consequently, domestic cable companies generally have the production capacity of low-voltage fire-resistant cables, and their products have been fully localized, and innovative products are constantly emerging. , such as 10,000-meter rolls of large-length mica tape, the application of new ceramic refractory materials, copper tape longitudinal wrapping argon arc welding equipment, and constant tension mica tape wrapping equipment, etc., have promoted the technological progress and quality improvement of low-voltage refractory cables. A wide variety of low-voltage fire-resistant cable structures have been produced: improved copper conductor + mica tape/cross-linked polyethylene insulation + flame-retardant outer sheath structure based on GB/T 12706, copper conductor + magnesium oxide insulation based on GB/T13033.1 +Copper sheath structure, GB/T 34926 copper conductor + mica tape insulation + filling + protective layer + copper sheath (+ plastic outer sheath) structure, and copper conductor + mica tape/cross-linked polyethylene insulation + mineral Filling (fireproof mud or ceramic polyolefin material) + low-smoke halogen-free outer sheath structure, copper conductor + mica tape/cross-linked polyethylene insulation + aluminum tube + fireproof mud filling + low-smoke halogen-free outer sheath structure, copper Conductor + ceramic silicone rubber insulation or cross-linked polyethylene insulation + ceramic silicone rubber filling + low smoke halogen-free outer sheath structure, etc. The fire resistance of the product can meet the requirements of British standards BS 6387 and BS 8491.
In recent years, construction engineering has increasingly used aluminum alloy conductors and pre-branch cables. Moreover, process technology advancements have enabled aluminum alloy conductors to replace copper cables effectively. At the same time, pre-branch cables have greatly facilitated electrical engineering installation. To reduce the loss of low-voltage power supply lines inside super-high-rise buildings, minimize the amount and space occupied by low-voltage cables, and improve power supply reliability, engineers now lay medium-voltage cables vertically to reach the substation room of the load center. Consequently, this approach reduces cable channel space and improves power supply quality. Engineers have applied this hanging medium-voltage cable in super-high-rise buildings and significant projects.