This article focuses on the Nyy and Nyyhy models of 3X25mm copper core polyvinyl chloride (PVC) insulated power cables. Although both belong to low-voltage power transmission cables, they have significant differences in structural design and applicable scenarios, jointly providing reliable support for industrial, commercial, and civil power systems.​ In terms of specifications, "3X25mm" is the core identifier of both cables: "3X" indicates that the cable consists of 3 independent conductors, which is suitable for three-phase AC power transmission systems and can meet the power supply needs of most equipment without an additional neutral line; "25mm" refers to the cross-sectional area of a single conductor being 25 square millimeters. This specification determines its current-carrying capacity—at an ambient temperature of 30°C, the continuous current-carrying capacity can reach 95A, with an adapted power of approximately 47kW, which can meet the power supply needs of medium-sized motors, central air conditioners, elevators, and other equipment.​ 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 good 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), and can adapt to complex environments such as dry and dusty conditions. The core difference between the two lies in the sheath layer: Nyy cables only have an insulation layer without an outer sheath, suitable for indoor dry environments; Nyyhy adds a layer of PVC sheath outside the insulation layer, with better mechanical strength and weather resistance, and can be used for outdoor direct burial, pipe laying, or bridge laying scenarios.​ The difference in application scenarios stems from structural design: Nyy cables, due to the absence of a sheath and better flexibility, are often used in indoor fixed laying scenarios such as wiring in the ceiling of office buildings and connection of computer room equipment. During installation, contact with sharp objects should be avoided to prevent damage to the insulation layer; Nyyhy cables, relying on the protection of the sheath layer, are widely used in outdoor power distribution in industrial plants, underground direct burial lines in residential communities, and power supply systems in humid environments (such as basements and bathrooms), which can effectively resist soil corrosion, mechanical collision, and water vapor erosion.​ In addition, both cables comply with international low-voltage cable standards (rated voltage 0.6/1kV) 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 3-core integrated design reduces the number of cables, simplifies the wiring process, and lowers installation costs.​ In summary, the Nyy and Nyyhy 3X25mm copper core PVC power cables, with their suitable specifications, high-quality materials, and scenario-based design, have become ideal choices in the field of low-voltage power transmission, providing flexible and reliable solutions for the stability of power supply in different environments.