1.5mm², 2.5mm² and 4mm² 450/750V PVC insulated copper cables are three widely used products in low-voltage electrical systems. With a unified rated voltage standard and their respective adapted cross-sectional areas, they meet the power demand in different scenarios and all comply with relevant industry specifications, providing stable and reliable guarantees for electrical connections.​ In terms of specification parameters, all three cables have a rated voltage of 450/750V, which means that in an AC system, the rated voltage between conductors is 450V, and the rated voltage between conductors and the ground is 750V, making them safely applicable to low-voltage distribution networks. The difference in cross-sectional area is their most significant distinction: the current-carrying capacity of the 1.5mm² cable is usually 10-16 amperes, the 2.5mm² cable is about 16-25 amperes, and the 4mm² cable can reach 25-32 amperes. The conductors are all made of high-purity electrolytic copper, and the multi-strand stranded structure enhances flexibility, facilitating bending and laying, while reducing the risk of breakage due to mechanical stress. The thickness of the outer PVC insulation layer increases slightly with the increase of cross-sectional area. The insulation thickness of 1.5mm² is about 0.6-0.8mm, 2.5mm² is about 0.8-1.0mm, and 4mm² is about 1.0-1.2mm, ensuring good electrical insulation performance, which can effectively isolate current and prevent short circuits and leakage.​ In terms of performance, the PVC insulation layers of the three cables all have excellent chemical corrosion resistance, which can resist the erosion of acids, alkalis, oils and other substances, and prolong their service life. At the same time, they have certain wear resistance and flame retardancy, so they are not easy to be damaged by friction in daily use, and can delay combustion in case of fire, improving safety. The working temperature range is -15℃ to 70℃, which can adapt to the climate conditions of different regions and seasons. In addition, the low resistance characteristic of the conductor reduces energy loss during current transmission, ensuring the efficiency of power transmission.​ In terms of application scenarios, the three cables have their own focuses and complement each other. The 1.5mm² cable is suitable for home lighting lines, ordinary socket circuits and power supply of small household appliances (such as televisions and computers). Its small size and good flexibility allow it to easily pass through narrow conduits. The 2.5mm² cable plays a role in scenarios with slightly higher power, such as power supply for air conditioners (1.5 horsepower and below), electric water heaters (below 1500W) and other household appliances, as well as lighting main lines and socket circuits in commercial places. The 4mm² cable has strong current-carrying capacity and is mainly used for high-power equipment, such as air conditioners of 2 horsepower and above, electric ovens, bathroom heaters, etc. It is also suitable for the main incoming line of residences, and special line power supply for kitchens and bathrooms, which can meet the needs of multiple high-power electrical appliances working at the same time.​ During installation and use, it is necessary to select the corresponding specification of cable according to the specific load power to avoid overload. During laying, excessive bending and stretching should be avoided to prevent damage to the insulation layer; keep away from high-temperature heat sources to prevent accelerated aging of PVC materials. Regularly check the appearance and connection of the cable, and timely handle problems such as insulation layer damage and conductor oxidation, which can further ensure the safe and stable operation of the electrical system.