Mineral insulated cables are cables made of inorganic materials. The outer layer of the cable is a seamless copper sheath, and there is a layer of tightly compacted magnesium oxide insulating layer between the sheath and the metal core. Mineral cable is the main line of modern construction engineering, and it is an indispensable fireproof cable to ensure power transmission. It is suitable for power supply lines such as fire power supply, uninterruptible power supply, and emergency lighting power supply. Mineral cable bttz has subsequently extended a variety of new models such as BBTRZ cable, YTTW cable, BTLY cable, etc., all of which are developed and improved on the basis of bttz mineral cables. Cost-effective fireproof cables can be used in many projects. In the current building power distribution system, mineral insulated cables are being used more and more widely, and their fire resistance, durability, safety, reliability and economy cannot be replaced by traditional power cables. Under fire conditions, mineral insulated cables can not only ensure the power supply for firefighting within the duration of the fire (more than 180 minutes), but also will not delay combustion, produce smoke, or produce secondary disasters, thus gaining valuable time for fire rescue. It can be seen that mineral insulated cables are required for building fire protection. Compared with organic cables, mineral cables are resistant to high temperature, fireproof, explosion-proof, and non-combustible (it can run continuously for a long time at 250°C, and can run for a short time of 30min at the limit state of 1000°C), and has a large carrying capacity, small outer diameter, It has the advantages of high mechanical strength, long service life, and generally no need for independent grounding wires. Mineral insulated cables are widely used in nuclear power plants, metallurgy, chemical industry, mines, aerospace, high-rise buildings, airports, docks, underground railways and other places where passenger flow is concentrated, to protect fire pumps, fire elevators, important loads, emergency evacuation instructions, As well as electricity for important fire-fighting equipment such as fire prevention and smoke exhaust systems.(1) Fire resistance: Copper and magnesium oxide are inorganic materials used in mineral insulated cables. This kind of cable will not burn or support combustion, and it can still continue to operate when it is close to the flame. The copper sheath is melted at 1083 ℃, while the magnesium oxide insulating material is solidified at 2800 ℃. (2) High operating temperature Mineral insulated cables can withstand continuous operating temperatures up to 250 ℃. However, in an emergency, the cable can continue to operate for a short time at a temperature close to the melting point of the copper sheath. (3) Long life Inorganic materials used in mineral insulated cables can ensure the stability, long service life and fire resistance of cables. (4) Explosion proof The highly compacted insulating materials in mineral insulated cables can prevent the passage of steam, gas and flame between the equipment parts connected to the cables. (5) Small outer diameter The diameter of mineral insulated cable is smaller than that of other cables with the same rated current. (6) Waterproof If the mineral insulated cable is completely immersed in water, the mineral insulated cable can continue to operate with its seamless metal sheath. (7) High mechanical strength Mineral insulated cables are durable and can withstand severe mechanical damage without damaging their electrical performance. (8) Large current carrying capacity For cables with the same section, mineral insulated cables transmit higher current than other types of cables. At the same time, the mineral insulated cable can also withstand considerable overload. (9) Short circuit fault rating At the same temperature, the short circuit fault rating of mineral insulated cables is obviously higher than that of other types of cables. (10) Grounding For mineral insulated cables, an independent grounding conductor is not required, because the copper sheath used in this cable has played the role of grounding conductor and can provide excellent low grounding resistance. For grounding sheath loop (ESR) wiring, the outer copper sheath can be used as grounding and neutral conductor in the MEN (multiple grounded neutral) system. (11) High corrosion resistance The copper sheath of mineral insulated cable has high corrosion resistance. For most devices, it does not need to take additional protective measures. In places where the copper sheath of the cable is vulnerable to chemical corrosion or serious industrial pollution, the mineral insulated cable shall be protected with a plastic outer sheath.