As the fire-resistant cable is now used more and more widely, so many manufacturers are producing, but often the quality is not guaranteed. So in general, enterprises in the development of fire-resistant cable products, are the first trial production of a section of the product, sent to the relevant national testing organizations, to obtain a test report, on the batch production, there are a small number of cable manufacturers to set up their own fire-resistant test room, we all know that the fire-resistant test is for the production of the cable process results of the test, the same process program, in different periods of time the performance of the cable production there is a certain degree of variability, for the production of fire-resistant cable enterprises if the fire-resistant cable pass rate of 99%, but often the quality can not be guaranteed. A certain degree of variability, for the production of fire-resistant cable for the enterprise if the fire-resistant cable fire-resistant test pass rate of 99%, the fire-resistant cable there is a 1% risk of hidden safety hazards, which is 100% of the danger for the user. So how to improve the fire-resistant cable fire-resistant test rate, from raw materials, conductor selection, production process control and other aspects to do a description:

　　1. Mica tape with three kinds, synthetic mica, gold mica, white mica, their respective quality performance is the best synthetic mica, white mica is the worst, for small specification cables must be selected synthetic mica tape for wrapping, mica tape delamination can not be used, long term storage of mica tape is prone to hygroscopicity, so in the storage of the mica tape must be considered in the storage of the surrounding environment, temperature and humidity.

　　2. When mica tape wrapping equipment is selected, it should be used with good stability, the best wrapping angle is 300-400 wrapping, the mica tape is wrapped evenly and tightly, all the guide wheels and rods that are in contact with the equipment must be smooth, neatly lined up, the tension is not too big, and the side plates of the take-up wheels and barrels are flat and smooth.

　　3. For the axial symmetry of the round core of the mica tape wrapped tight in all directions, so for the conductor structure of the fire-resistant cable should be used in the round tightly compressed conductor. The reasons are as follows:

　　① Some users proposed conductor for the bundle stranded soft structure conductor, which requires enterprises to use the reliability of the cable from the user to communicate with the user to change to a round tightly compressed conductor, the soft structure of the bundle, compound stranding easy to cause damage to the mica tape as a conductor for fire-resistant cables is not desirable, but there are manufacturers believe that the user needs to be what kind of fire-resistant cables, manufacturers should meet the user's needs, I think that after all, the user of the cable related to the details of the problem and not very understand, the cable is with the human being, the cable is not very understand, the cable is the same as a human being. I think the user after all the details of the cable is not very understand, the cable is closely related to human life, so the cable manufacturing enterprises must be related to technical issues with the user to make it clear.

　　② fan-shaped conductor should not be used, because the fan-shaped conductor of its mica tape winding pressure is unevenly distributed, as shown in the figure, as can be seen in the figure fan-shaped core wrapped around the mica tape of its three fan-shaped corner of the pressure is the largest, due to the mica is a lamellar silicate polymers, the molecular attraction of the interlayer is much weaker than the bonding force of the s1-0 covalent bonds within the crystal. The interlayer is easy to slide and bonded by silicon, but the bonding strength is also low, and it is very easy to fall off and crack when scraped and extruded, especially when the fan-shaped structure is used, the cores after winding and wrapping are easy to be scraped and bruised when they pass through the guide wheels, wire dividing rods, and the rows of wires to the edges of the side panels of the work wheels and when they are extruded and wrapped with the insulations of the subsequent processes into the mold core, which will result in the degradation of the electrical properties. In addition, from the cost point of view of the fan-shaped conductor structure of the cross-section circumference is greater than the circumference of the round conductor cross-section, which increases the precious material mica tape, although the round structure of the cable outside diameter has increased. Although the outer diameter of the circular structure cable has increased and the amount of PVC sheathing material has increased, the overall cost of the product material compared to the total cost of the circular structure cable is still economical. Based on the above explanation, from the technical and economic analysis, the conductor of fire-resistant power cable adopts round structure as the best.