4.3 Copper Cable Selection
4.3.1 The cable structure may be in accordance with Table 4.3.1，and shall be selected in consideration of engineering conditions and application scenarios.
1 Insulation layer type shall be adopted according to the user requirements.
2 Aluminum and plastic composite sheath shall be adopted when all plastic cables are used.
3 Fire retardant cables shall be adopted when laying indoor terminal cables and distribution cables.
4 The diameter of duct cables shall be suitable for installation in the duct.
5 The working environment temperature of all plastic cables shall be between-30℃to+60℃whilst special need shall be considered per actual working environment when temperature goes beyond the specified range.
Table 4.3.1 Usage scenarios for main cable types
4.3.2 The types of the cables in engineering design should not be too many.
4.3.3 Considering with the existing cable network conditions and the actual local situations，all plastic cables should be selected for new cable lines whilst the inflatable type shall be applied to duct primary cables，filling type may be applied to buried and distribution duct cables，and self-supporting type shall be applied to aerial and wall-mount cables.
4.3.4 Aerial cables should not exceed 400 pairs.Multi-core cables with over 400 pairs and important or special cables shall adopt the underground laying method.
4.3.5 The underground laying method may use the plastic outer sheath cables laid in ducts，with one cable in each duct.When the capacity of the only cable needed is less than 400 pairs and conditions are not suitable for building ducts，the buried method can be adopted.The use of culvert or the method of adding protective pipes may also be adopted according to actual circumstances.
4.3.6 According to specific project situations，distribution cables may adopt the block，street，or indoor distribution method，and shall be gradually incorporated into the Customer Premises Network construction and the overall urban planning scheme.Distribution cables should adopt the duct laying method.
4.3.7 Non-filled primary cables shall adopt inflating maintenance and install pressure monitoring system.Pressure sensors shall be installed in the cable sleeves.