The number of cables is the basis for determining the type of flame retardant to be used

When calculating the volume of non-metallic objects in the cable, the concept of the same channel refers to the space where the flame or heat of the cable can radiate unimpeded to the nearby wires and cables and ignite them. The number of cables is the basis for determining the category of flame retardant.
For example, if the trusses or slot boxes with fireproof boards are isolated from each other, the same channel should refer to each bridge or slot box. If there is no upper and lower or left and right fire isolation, if there is no fire isolation, the non-metallic volume of the cable should be included in the calculation of the non-metallic volume of the cable.