A 2.5 square meter wire is mainly used for lighting wiring and socket wiring of ordinary household appliances. 4 square meters of wires are mainly used for high-power electrical appliances such as kitchens, bathrooms, and air conditioners. The installation precautions for household electrical wires are generally used for lighting fixtures with a single core wire of 1.5 square meters, for sockets with a single core wire of 2.5 square meters, for air conditioners or high-power appliances with a capacity of 3 horsepower or more with a single core wire of 4 square meters, for main incoming wires with a single core wire of 6 square meters, and for grounding wires with two colors.