What are the performance characteristics of mineral insulated cables?
Mineral insulated cables are basically composed of a highly conductive conductor core (melting point 1083°C), insulating material (melting point 2800°C), and a copper sheath (melting point 1083°C). If the cable requires corrosion protection, a layer of polyvinyl chloride may be added.
As can be seen above, mineral insulated cables have excellent fire and high-temperature resistance. The cable itself cannot burn, nor will it ignite a fire. Even under external flames, the cable will continue to operate normally. Furthermore, as long as the flame temperature is below the melting point of copper, the cable can continue to function normally after the fire is extinguished without replacement. This is why mineral insulated cables are used in fire protection systems.
However, mineral insulated cables also have significant disadvantages. Magnesium oxide easily absorbs moisture, which causes the insulation resistance to drop sharply, rendering the mineral insulated cable ineffective. For mineral insulated cables, the intermediate connectors and terminals are crucial for moisture resistance. Proper treatment of these two key points ensures the performance of the mineral insulated cable.
Furthermore, mineral insulated cables have poor flexibility, making it difficult to maintain straight lines during construction.
Furthermore, because super-high-rise buildings tend to deflect with wind, using mineral insulated cables in their vertical trunk lines will subject the cable connectors and terminals to constant vibration, potentially impacting the cables' moisture resistance.
