A wire is composed of one or several flexible wires, wrapped in a light and soft protective layer; A cable is composed of one or several insulated wires wrapped in a tough outer layer of metal or rubber. Cables and wires are generally composed of three components: core wire, insulation sheath, and protective sheath. The characteristics of commonly used cables are as follows: CEF - ethylene propylene rubber insulation chloroprene rubber sheath, and marine flame-retardant power cables. CVV - PVC insulated and PVC sheathed flame-retardant power cables for ships. Oxygen cabin wires often use BV, BX, RV, RVV series wires. Among them, BV - copper core polyvinyl chloride insulated wire, with a long-term allowable temperature of 65 ℃, a minimum temperature of -15 ℃, and a working voltage of 500V AC and 1000V DC. It is fixed and installed indoors and outdoors, and can be exposed or concealed. BX - Copper core rubber insulated wire, with a maximum operating temperature of 65 ℃, applied indoors. RV - PVC insulated single core flexible wire, with a maximum operating temperature of 65 ℃ and a minimum operating temperature of -15 ℃. The working voltage is 250V AC and 500V DC, used for internal wiring of instruments and equipment. RVV - Copper core PVC insulated and sheathed flexible wire, allowing long-term working temperature of 105 ℃, working voltage of 500V AC and 1000V DC, suitable for damp, high mechanical protection requirements, frequent movement and bending situations. In fact, there is no strict boundary between "wires" and "cables". Products with fewer cores, smaller product diameters, and simpler structures are usually referred to as wires, those without insulation are referred to as bare wires, and others are referred to as cables; The larger cross-sectional area of the conductor (greater than 6 square millimeters) is called a large wire, the smaller (less than or equal to 6 square millimeters) is called a small wire, and the insulated wire is also called a cloth wire. This statement is relatively simple and easy to understand. Cables generally have more than 2 layers of insulation, most of which are multi-core structures and are wound on cable reels, with a length generally greater than 100 meters. Electric wires are generally single-layer insulated, single core, rolled up to 100 meters in a coil, and wireless. Common cable models: VV represents: polyvinyl chloride insulation (first V), polyvinyl chloride sheath (second V) YJV22 represents: cross-linked polyvinyl chloride insulation (YJ), polyvinyl chloride sheath (V), steel strip Kaizhuang (22) models with "ZR" or "FR" are flame-retardant cables (wires). The model of aluminum wire with "L" is 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 flexible wire, BX - rubber insulated copper core wire, RHF - chloroprene rubber sheathed copper core flexible wire