The wire is composed of one or several soft wires, which are covered with a light and soft protective layer; The cable is composed of one or several insulated conductors, which are covered with a tough outer layer made of metal or rubber. Cables and wires are generally composed of three parts: core wire, insulating sheath and protective sheath. The characteristics of common cables are as follows: CEF - ethylene propylene rubber insulation, neoprene sheath, marine flame retardant power cable. CVV - PVC insulated, PVC sheathed marine flame retardant power cable. BV, BX, RV and RVV series wires are often used for oxygen cabin wires. Among them, BV - copper core PVC insulated wire, with long-term allowable temperature of 65 ℃, minimum temperature of - 15 ℃, working voltage of AC 500V and DC 1000V, can be fixed indoors and outdoors, and can be laid in open or dark. BX - copper core rubber insulated wire, maximum service temperature 65 ℃, applied indoors. RV - PVC insulated single core flexible wire, with maximum service temperature of 65 ℃, minimum service temperature of - 15 ℃, working voltage of AC 250V and DC 500V, used as internal wiring of instruments and equipment. RVV - copper core PVC insulated and sheathed flexible wire, with allowable long-term working temperature of 105 ℃, working voltage of AC 500V and DC 1000V. It is used in wet, high mechanical protection requirements, frequent movement and bending. In fact, there is no strict boundary between "wire" and "cable". Generally, products with few cores, small diameter and simple structure are called wires, those without insulation are called bare wires, and others are called cables; The larger conductor cross-sectional area (greater than 6 mm2) is called large wire and the smaller one (less than or equal to 6 mm2) is called small wire, and insulated wire is also called cloth wire. This is relatively simple and easy to understand! Cables generally have more than 2 layers of insulation, most of which are multi-core structure, wound on the cable reel, and the length is generally more than 100 meters. Wires are generally single-layer insulation, single core, 100 meters in a roll, and wireless reel. Common model of cable: VV means PVC insulation (the first V), PVC sheath (the second V); yjv22 means: cross connected polyethylene insulation (YJ), PVC sheath (V), steel strip kaizhuang (22) model. Add "Zr" or "fr" for flame retardant cable (wire). Add "L" It is aluminum wire. The models of wires are relatively simple: BVV - PVC insulated and sheathed copper core wire, BV - PVC insulated copper core wire, BYJ - copper core cross-linked polyolefin insulated wire, BVR - PVC insulated copper core wire, BX - rubber insulated copper core wire, RHF - neoprene rubber sheathed copper core wire.