What are some common electrical wire specifications?

Common wire specifications for household and industrial use are primarily categorized by nominal cross-sectional area (square millimeters, mm²), number of cores + core type, and insulation/sheath material. The nominal cross-sectional area is the core basis for selection, while the number of cores and material are chosen according to the application. The mainstream market uses copper core wires (aluminum core wires are only used for outdoor overhead lines/large cross-section engineering projects, and are basically not used in home decoration). The following is categorized by common home decoration and industrial/engineering applications, with applicable scenarios, directly corresponding to selection needs:

I. Core Specifications: Nominal Cross-sectional Area (Copper Core, Mainstream for Home Decoration/General Use)

The unit is square millimeters (mm², often abbreviated as "square"), and the larger the value, the higher the current carrying capacity (the current it can withstand), and the more suitable it is for higher-power appliances/circuits. For home decoration, 1.5, 2.5, 4, and 6 square millimeters are preferred. 10 square millimeters and above are mostly used for main lines in large houses/industrial use.

II. Common Matching Specifications: Number of Cores + Core Type (Combined with Cross-sectional Area)

Wire cores are divided into hard wires (single-core) and soft wires (multi-core). The number of cores is selected according to the circuit used, and combined with the cross-sectional area to form a complete model (such as BV 2.5mm², RVV 2×4mm²). The following four types are most commonly used in home decoration/daily life:

Single-core hard wire (single strand): Model such as BV (polyvinyl chloride insulation), the first choice for home wiring. It has high hardness, is not easily oxidized, and has firm connections. It is suitable for concealed/exposed wiring in conduits. Commonly used for single circuits (such as lighting/sockets);

Multi-core soft wire (multi-strand): Model such as BVR (insulation same as BV, soft core), more flexible than BV wire, suitable for scenarios with many bends (such as wiring in distribution boxes, appliance connection wires). The current carrying capacity is slightly higher than BV wire of the same cross-section, and the price is slightly higher;

Two-core sheathed soft wire: Model such as RVV 2×Xmm² (X is the cross-sectional area), with an outer sheath, waterproof/wear-resistant, suitable for exposed mobile wiring (such as desk lamps, small appliance extension cords);

Three-core sheathed soft wire: Model such as RVV 3×Xmm², including live wire/neutral wire/ground wire... Ground wire, commonly used for high-power household appliances (such as air conditioners and electric water heaters with exposed wiring), and also frequently used as a power supply cable in industrial applications.