This article focuses on two Nyy type copper core polyvinyl chloride (PVC) insulated power cables with 1kV voltage level, namely 3X1X120mm² triple-core cable and 2X1X10mm² duplex cable. Although both products belong to the Nyy series, due to differences in structure and specifications, they perform different functions in power transmission systems, jointly providing efficient and safe power solutions for industrial, commercial and civil fields.​ In terms of specifications, the identifiers of the two cables contain clear technical implications. In "3X1X120mm²", "3X1" indicates that the cable consists of 3 individually insulated single-core conductors, forming a triple-core structure, which is suitable for three-phase AC power systems; "120mm²" is the cross-sectional area of a single conductor, and this specification enables it to have a strong current-carrying capacity. At an ambient temperature of 30°C, the continuous current-carrying capacity can reach 210A, with an adapted power of about 105kW, which is sufficient to meet the needs of high-power scenarios such as large industrial equipment (such as injection molding machines, air compressors) and workshop main line power distribution. In "2X1X10mm²", "2X1" means that it is composed of 2 individually insulated single-core conductors to form a duplex structure, suitable for single-phase AC or DC circuits; the cross-sectional area of "10mm²" determines its current-carrying capacity characteristics. At the same ambient temperature, the continuous current-carrying capacity is about 55A, with an adapted power of about 11kW, which is often used for residential indoor wiring, small household appliance power supply and lighting system circuits.​ In terms of materials, both cables use high-purity electrolytic copper (purity ≥99.95%) as the conductor core to ensure low resistance and high-efficiency conductivity, reducing energy loss during transmission. The insulation layer is made of temperature-resistant PVC material, which has excellent insulation strength (power frequency withstand voltage of 3kV/5min without breakdown), corrosion resistance and flame retardancy (self-extinguishing time after leaving the fire ≤10 seconds). Among them, the insulation layer thickness of the 120mm² conductor is 1.4mm, and that of the 10mm² conductor is 0.7mm, both of which can meet the insulation requirements of 1kV voltage level, and can adapt to the working environment of -15℃ to 70℃, resisting the influence of complex conditions such as dryness and dust.​ The difference in application scenarios stems from the design of specifications and structures. The 3X1X120mm² triple-core cable, with its characteristics of large cross-section and high current-carrying capacity, is mainly used for main line power distribution in industrial plants, low-voltage side outgoing lines of transformers in large commercial complexes and main incoming lines of high-rise buildings. For example, in large manufacturing workshops, the cable can connect the workshop main distribution box and the junction boxes in each production area, stably supporting the simultaneous operation of multiple large-scale equipment. Its flexibility (bending radius ≥12 times the cable outer diameter) also facilitates laying in cable trays or underground pipe galleries. The 2X1X10mm² duplex cable, due to its small cross-section and flexible and lightweight characteristics, is widely used in socket circuits, lighting branches in residential interiors and power supply for equipment in small commercial places (such as convenience stores, offices). In residential building decoration, the cable is often concealed in wall or floor conduit，and its smooth insulation surface reduces friction with pipes, reducing the risk of damage during construction.​ In addition, both cables comply with international low-voltage cable standards and have passed strict factory tests (including DC resistance, insulation resistance, mechanical performance, etc.) to ensure safety and reliability. In terms of construction convenience, the multi-core integrated design reduces the number of cables, simplifies the wiring process, and lowers installation costs.​ In summary, the 1kV 3X1X120mm² Nyy triple-core cable and 2X1X10mm² Nyy duplex cable, with their suitable specifications, high-quality materials and scenario-based design, meet the needs of high-power and medium-low power transmission respectively, and have become indispensable key components in low-voltage power distribution systems, providing a strong guarantee for the stability of power supply in different scenarios.