The 4mm² single core copper cable with PVC insulation focused on in this abstract is a standardized electrical wire specifically designed for low-voltage power distribution scenarios in houses and buildings. Equipped with a rated voltage of 450/750V, high-purity copper conductor, and flame-retardant PVC insulation, it has obtained dual international certifications (CE and RoHS). It is widely suitable for medium-power electrical circuits such as residential kitchen sockets, electric water heaters, and wall-mounted air conditioners, as well as small equipment power supply systems in commercial buildings. Relying on the advantages of safety compliance, stable current-carrying capacity, and easy installation, it has become a preferred product for home improvement electricians, building contractors, and electrical project procurement, providing a reliable medium-power power transmission solution for house and building electrical systems. In terms of voltage rating and certification compliance, the rated voltage of 450/750V accurately matches the common electricity demand in house and building scenarios: "450V" refers to the insulation voltage between the conductor and the ground or neutral wire, and "750V" is the insulation voltage between two conductors. It can not only stably carry 220V single-phase (such as kitchen sockets, electric water heaters) and 380V three-phase (such as small commercial air conditioners) power supplies, but also reserves a 20%-30% safety margin to cope with voltage fluctuations during peak electricity usage (e.g., multiple air conditioners running simultaneously in summer), avoiding the risk of insulation breakdown. More importantly, the cable has passed CE certification (complying with the EU Low Voltage Directive 2014/35/EU), which means its electrical safety, mechanical performance, electromagnetic compatibility and other indicators all meet the European market access standards, and it can be directly used in building projects exported to Europe; at the same time, it meets the requirements of RoHS certification, with the content of six hazardous substances such as lead, cadmium, and mercury in the insulation layer and conductor accessories lower than the limit value, no heavy metal pollution, suitable for scenarios with high environmental protection requirements such as residential bedrooms, children's rooms, and office spaces in commercial buildings, ensuring indoor air quality and human health. In the core design of the conductor and insulation layer, the cable conductor is made of high-purity electrolytic copper (purity ≥99.95%), which has significant performance advantages compared to copper-clad aluminum or recycled copper conductors: Firstly, it has extremely low resistivity (≤0.017241Ω·mm²/m at 20℃), resulting in low current transmission loss, and is not easy to cause insulation aging due to heating during long-term use, which is especially suitable for equipment such as electric water heaters that run 24 hours a day in houses and buildings; Secondly, the conductor adopts a single-core solid or multi-strand stranded structure (selectable according to installation needs). The solid structure has strong rigidity, suitable for scenarios such as in-wall piping and fixed laying, and is not easy to shift due to vibration; the multi-strand stranded structure has better flexibility, which can be repeatedly bent at a bending radius of 5× the cable outer diameter, facilitating installation environments that require direction changes such as ceiling wiring and equipment terminals, reducing the probability of construction damage. Tests show that the long-term allowable current-carrying capacity of this 4mm² copper conductor is about 32A (20℃ environment, single-core laying), which can stably support medium-power equipment below 7.0kW (such as 80L electric water heaters and 1.5-ton wall-mounted air conditioners), avoiding conductor overheating or insulation softening caused by overload. The insulation layer is made of modified flame-retardant PVC (polyvinyl chloride) material, with optimized performance for house and building environment characteristics: Firstly, the flame-retardant grade meets the GB/T 18380.1-2008 Class C standard, with an oxygen index ≥24%. It can self-extinguish within 60 seconds in the vertical combustion test, and there are no molten drips, which can effectively prevent flames from spreading along the cable, reducing the risk of electrical fires in flammable areas such as kitchens and equipment rooms; Secondly, it has excellent electrical insulation performance, with a volume resistivity ≥1×10¹²Ω·cm and a dielectric loss tangent ≤0.08 at 50Hz. Even in the humid and oily environment of the kitchen, it can isolate the conductor from the external environment, avoiding electric leakage accidents; Thirdly, the temperature resistance performance is stable, with a long-term operating temperature of 70℃, and short-term overload can withstand 160℃ (for 5 seconds), which can cope with local high temperatures during electric water heater heating and temperature changes such as equipment heat dissipation in summer, and is not prone to insulation cracking or hardening; In addition, the surface of the PVC insulation layer is smooth, with low friction during piping, which can improve construction efficiency. At the same time, it has good chemical corrosion resistance, which can resist erosion from common cleaning agents, coatings in houses and weak acid-base substances in commercial buildings, extending the service life of the cable to more than 20 years. In terms of product positioning and scenario adaptability, this 4mm² single-core cable takes "exclusive for medium-power circuits" as its core positioning, and its detailed design meets practical needs: Firstly, the color identification is standardized, with red/yellow/green for live wires, blue for neutral wires, and yellow-green for ground wires, complying with international wiring standards. Electricians can quickly identify the purpose of wiring, reducing the probability of wrong connection (such as avoiding equipment burnout caused by confusing live wires and neutral wires); Secondly, it has strong specification adaptability. The 4mm² cross-sectional area is between 2.5mm² (low power) and 6mm² (high power), which exactly fills the wiring gap of medium-power equipment, and there is no need to choose a thicker 6mm² cable to adapt to 3-7kW equipment, resulting in cost waste; Thirdly, it has wide compatibility, and can be seamlessly adapted to common electrical accessories such as copper terminal blocks, PVC/metal conduits, and residual current devices. It can be integrated into the existing house and building electrical systems without additional modification, reducing the complexity of project construction. In addition, the product production process strictly follows international quality control standards. Each batch of cables undergoes multiple tests: conductor resistance test (to ensure the resistivity meets the standard), insulation thickness test (standard thickness 0.8mm, tolerance ±0.1mm), voltage resistance test (1.5kV/1min no breakdown), and flame-retardant performance test (vertical combustion self-extinguishing) to ensure stable and consistent performance. Whether it is the wiring of medium-power equipment circuits in the kitchen and bathroom during new house decoration, the replacement of old 2.5mm² cables to adapt to new home appliances during old house circuit transformation, or the equipment power supply in convenience stores and small offices in commercial buildings, this 4mm² single-core copper conductor PVC insulated cable can rely on its safety compliance, stable current-carrying capacity, environmental protection and durability to become a reliable power transmission carrier. Overall, this 4mm² single core copper cable with PVC insulation (450/750V CE & RoHS Certified) perfectly meets the medium-power electricity demand in houses and buildings through accurate voltage adaptation, authoritative international certification, high-quality material combination, and scenario-based design. It can not only ensure the safe and stable operation of medium-power equipment, but also meet the compliance requirements of domestic and foreign building projects, while taking into account environmental protection and durability, laying a solid electrical foundation for the comfortable life of houses and the efficient operation of buildings, and is an ideal choice in the field of medium-power building wiring.