1. It has a strong hygroscopicity. Fire-resistant cables usually employ mineral insulating materials such as magnesium oxide, which have a high melting point and excellent fire resistance. However, one drawback of mineral insulating materials is their strong hygroscopicity, which makes them prone to absorbing moisture from the air. When the insulation layer of a cable absorbs a large amount of moisture, its insulation performance will be affected, which may reduce the fire resistance and electrical performance of the cable
2. Some components of the cable were not sealed tightly. Moisture or water will enter the cable insulation layer from the cable end or the cable protective layer, and then seep into each accessory of the cable, thereby damaging the entire power system.
