For the main incoming power line, it is best to use copper-core wiring of the BVV 2×6mm² specification or larger. For lighting and general power circuits, the BVV 2×2.5mm² and BVV 2×4mm² specifications are recommended. As living standards rise, households are acquiring an increasing number of electrical appliances; consequently, the specifications of the wiring used in home renovations have become critically important. When selecting wiring for home renovation-specifically the BVV series-note that "BVV" is a national standard code designating copper-sheathed cables. The BVV 2×2.5mm² and BVV 2×4mm² specifications represent 2-core cables with cross-sectional areas of 2.5 square millimeters and 4 square millimeters, respectively.
Generally, BVV 2×4mm² wiring is utilized for main lines and trunk lines, while BVV 2×2.5mm² wiring is used for branch circuits serving individual appliances or for switch lines. For dedicated air-conditioning circuits, it is recommended to use wiring of the BVV 2×4mm² specification or larger, accompanied by a separate, dedicated ground wire. To ensure fire safety, ease of maintenance, and overall security, it is highly advisable to select "National Standard" (Guobiao) copper-core wiring that bears the "Great Wall Mark" certification. Regarding the cross-sectional area of the wiring within cable conduits: 1.5mm² wiring is typically selected for lighting circuits, while 2.5mm² wiring is selected for power outlets. Note that wiring for air conditioners must *not* be smaller than 2.5mm². For neutral/ground connections, it is best to use green-and-yellow bi-color wiring; for switch lines (live/hot wires), any color such as red, white, black, or purple may be used. Throughout a single home renovation project, the color coding and intended usage of the wiring must be applied consistently.
Important Considerations When Purchasing Wiring
When purchasing electrical wiring, the first step is to check the packaging of the wire spool to verify the presence of the "Great Wall Mark"-issued by the China Commission for Conformity Certification of Electrical Equipment-as well as a valid production license number.
Next, visually inspect the outer plastic sheath of the wire: it should appear bright in color and possess a dense, fine texture. You can perform a simple flame test using a lighter; if the material does not ignite into an open flame, it is likely a suitable product. Substandard products often utilize recycled plastics, resulting in a dull appearance and a loose texture; furthermore, they will typically ignite and burn with an open flame when exposed to heat. Secondly, one must examine the length and compare prices. Legitimate products typically come in rolls of 100 (±5) meters, whereas substandard products vary in length from 60 to 80 meters. Some manufacturers deliberately thicken the insulating sheath, making it difficult-even for industry professionals-to detect the discrepancy. In such cases, one can count the number of wire coils and multiply that figure by the radius of the entire roll to roughly estimate the total length.
Legitimate products utilize high-purity red copper, which features a bright, slightly soft exterior. In contrast, substandard products contain copper that appears dark and hard; this consists of recycled scrap copper, which possesses high resistivity and extremely poor conductivity. Such wiring poses a significant safety risk.