Overhead cable manufacturers: What are the characteristics of insulated cables?
Overhead cable manufacturers believe that the resistivity of metal conductors in insulated cables is very small; the resistivity of insulators is very high. The reason why insulators can insulate is because the positive and negative charges in the insulator molecules are tightly bound, there are few charged particles that can move freely, and the resistivity is high. Therefore, in general, the macroscopic current generated by the movement of free charges under the action of an external electric field can be ignored, and it is considered to be a non-conductive substance. For insulators, there is a breakdown voltage that gives electrons enough energy to excite them. Once the breakdown voltage is exceeded, the material is no longer insulating.
Aerial cable manufacturers believe that mineral insulated cables are the main line fire protection cables for modern construction projects to ensure power transmission, and are suitable for power supply lines such as fire power supplies, uninterruptible power supplies, and emergency lighting power supplies.
Aerial cable manufacturers believe that the characteristics of mineral insulated cables are as follows:
1. High operating temperature: Mineral insulated cables can withstand continuous operating temperatures up to 250°C. But 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;
2. Fire resistance: The two materials used in mineral insulated cables, copper and magnesium oxide, are inorganic. This kind of cable will not burn or support combustion, and can continue to work under conditions close to the flame;
3. Explosion-proof: overhead cable manufacturers believe that the highly dense insulating material in mineral insulated cables can prevent steam, gas and flame from passing between the equipment components connected to the cable;
4. Long service life: The mineral insulated cable adopts inorganic materials, which can ensure the stability, long life and fire resistance of the cable;
5. Waterproof: If the mineral insulated cable is completely submerged in water, the mineral insulated cable can continue to run with its seamless metal sheath;
6. Small outer diameter: overhead cable manufacturers believe that the diameter of mineral insulated cables is smaller than other cables with the same rated current;
7. High mechanical strength: The mineral insulated cable is sturdy and durable, and can withstand severe mechanical damage without destroying its electrical properties;
8. Large current carrying capacity: For cables of the same cross-section, the current transmitted by mineral insulated cables is higher than other types of cables. At the same time, mineral insulated cables can withstand considerable overloads.
9. High corrosion resistance: Overhead cable manufacturers believe that the copper sheath of mineral insulated cables has high corrosion resistance. For most devices, it does not require additional protection. Where the copper sheath of the cable is susceptible to chemical corrosion or severe industrial pollution, a mineral insulated cable wrapped in a plastic sheath should be used for protection.
10. High short-circuit failure rate: overhead cable manufacturers believe that at the same temperature, the short-circuit failure rate of mineral insulated cables is significantly higher than other types of cables.
11. Good grounding: Aerial cable manufacturers believe that a separate grounding conductor is not required for mineral insulated cables, because the copper sheath used in this cable has already played the role of grounding conductor, which can provide excellent low grounding resistance.