Nyy Copper Power Cable 4×50mm², 4×70mm² are two types of copper core power cables suitable for low-voltage power distribution systems. With stable conductive performance, excellent insulation protection and flexible laying characteristics, they are widely used in industrial power distribution, building power supply, municipal engineering and other fields, providing efficient and safe power transmission support for various electrical scenarios.​ In terms of structural design, both cables adopt a 4-core copper conductor configuration, corresponding to cross-sectional specifications of 50mm² and 70mm² respectively. The conductors are made of high-purity electrolytic copper (purity ≥99.95%) through a multi-strand stranding process, which not only improves the mechanical strength of the conductor, enabling it to withstand external forces such as stretching and bending during laying, but also reduces the skin effect loss during current transmission, with a conductivity of over 58MS/m. In the 4-core design, 3 cores are phase lines and 1 core is a neutral line, adapting to the three-phase four-wire power distribution system without the need for additional neutral line laying, simplifying the wiring process and reducing installation costs.​ The insulation and sheath system is the core advantage of this series of cables. The insulation layer is made of polyvinyl chloride (PVC) material with excellent temperature resistance, and the thickness is designed differently according to the cross-sectional specifications: the insulation layer thickness of 4×70mm² cable is 1.4mm-1.6mm, and that of 4×50mm² is 1.2mm-1.4mm. The PVC insulation layer has excellent electrical insulation performance, with insulation resistance ≥1000MΩ·km and breakdown strength ≥10kV/mm, which can operate stably for a long time under the rated voltage of 0.6/1kV, effectively blocking current leakage between conductors. The outer sheath is also made of PVC material. The sheath thickness of 4×70mm² is 1.6mm-1.8mm, and that of 4×50mm² is 1.4mm-1.6mm. After modification with a special formula, it has acid and alkali resistance, UV resistance, wear resistance and other characteristics, which can resist oil pollution, chemical corrosion in industrial environments and climate erosion during outdoor laying. At the same time, the sheath has certain flame retardancy (oxygen index ≥30), meeting relevant flame retardant standards, which can delay the spread of flame and reduce the risk of fire.​ In terms of performance parameters, both cables meet the 0.6/1kV voltage level requirements, with significant differences in current-carrying capacity: the 4×70mm² cable has a current-carrying capacity of about 180A-200A when laid in air at an ambient temperature of 30℃, and 150A-170A when directly buried, suitable for power supply of high-power equipment clusters; the 4×50mm² has a current-carrying capacity of about 140A-160A in air and 110A-130A when directly buried, suitable for medium-power load scenarios. The bending radii are 12 times and 10 times the cable outer diameter (about 250mm and 200mm respectively), facilitating laying in narrow spaces. The long-term operating temperature range is -15℃ to 70℃, and it can withstand 160℃ high temperature during short circuits (within 5 seconds), ensuring safety in fault situations.​ In application scenarios, 4×70mm² cables are often used in power trunk lines of production lines in industrial plants, power supply of central air conditioning systems in large shopping malls, incoming cables of residential communities, etc., which can meet high-load power demand; 4×50mm² are suitable for distribution branches in office buildings, municipal street lamp systems, power supply of small workshop equipment and other scenarios. Both support various laying methods such as open laying, pipe threading and direct burial, and can maintain stable performance in humid, dusty and large temperature difference environments, with a designed service life of more than 20 years.​ In terms of construction and maintenance, excessive bending or extrusion should be avoided during cable laying. For direct burial, a sand cushion should be laid and warning signs should be set to prevent external damage; special sealing accessories should be used at joints to ensure waterproof and moisture-proof. In daily maintenance, the operating temperature can be monitored by infrared temperature measurement, and the aging degree can be evaluated in combination with insulation resistance testing to early warn potential faults and ensure long-term reliable operation of the cable.​ In summary, Nyy Copper Power Cable 4×50mm², 4×70mm², with their characteristics of high-efficiency conductivity, environmental corrosion resistance, safety and flame retardancy, have become an ideal choice in the low-voltage power distribution field, providing a solid guarantee for power transmission in various construction and industrial scenarios.