6.4 Installation Requirements for Aerial Optical Cables
6.4.1 Aerial optical cable lines shall adopt different construction intensity levels based on different load areas.Division of load zones shall be determined according to the meteorological conditions described in Table 6.4.1.
Table 6.4.1 Meteorological conditions for division of line load zones
Notes：1 The ice density is 0.9g/cm3.For ice and frost mixtures，ice thickness may be converted as 1/2 of its thickness.
2 The maximum wind speed shall be the calculated by the average value of maximum wind speed in 10 minutes，as automatically recorded by meteorological stations.
3 The maximum ice thickness and maximum wind speed shall be determined according to the meteorological data in the construction areas and shall be based on average data for a 10-year period as a cycle.
6.4.2 For exceptional regions where the ice is severe or the wind speed exceeds 25m/s，the building standards shall be upgraded for this specific line section as opposed to the whole line，according to the actual weather conditions.
6.4.3 Aerial optical cables may be used for light and medium load zones and areas where terrains are relatively even.For overweight load zones，areas where winter temperature is below-30℃，or regions where large span terrains，sandstorms and hazardous winds are prevalent，aerial optical cables should not be considered.
6.4.4 Laying of aerial optical cables shall give priority to sharing of the existing poles.
6.4.5 The intensity of aerial optical cable pole lines shall be in accordance with the relevant requirements under the current professional standard YD 5148 Design Specifications for Pole Line of Optical（Copper）Cable Communication Engineering.The pole intensity shall be checked and verified to ensure architecture safety when using existing poles to hang optical cables.
6.4.6 Aerial optical cables should adopt suspension wire hanging method and the self-supporting method can also be used according to engineering requirements.Each suspension wire usually should hang an optical cable only.Hanging two cables on one suspension wire，in the cases of short distance laying，shall ensure line safety and not affect operation and maintenance.Optical cables on suspension wires may be installed with cable hooks or spiral binding.
6.4.7 Installation of suspension wires shall meet the following requirements：
1 The selection of suspension wire shall be in accordance with the following requirements：
1）The suspension wire may be determined through calculation of such factors as the load zone differences of the installation regions，optical cable loads，standard spans between poles etc.As a general practice，steel galvanized strands with 7/2.2 and 7/3.0 specifications usually should be selected.
2）In general，the commonly used pole span shall be 50m.Appropriate pole span of different steel strands for various load zones shall be selected in accordance with Table 6.4.7.The main and auxiliary suspension wires device should be adopted when the pole span goes beyond the specifications outlined in the Table below.
Table 6.4.7 Selection for suspension wire specifications
2 The installation and reinforcement of suspension wires shall be in accordance with the following requirements：
1）Suspension wires may be installed with bolt（wooden pole），suspension arms hook（cement pole）or three holes single-bend-slot，and suspension wire arms and pressure plates may also be considered.
2）Installation positions of suspension wires shall consider the requirements of other cables on the pole，and ensure that after hanging the cables，the clearance between the optical cable and other facilities under circumstances of temperature and load changes shall be in accordance with the relevant requirements for spacing distance.
3）The ending，false ending，discharge nodes，elevation and depression auxiliary devices of suspension wires and the protective devices for angle pole suspension wires shall be arranged according to relevant requirements.
6.4.8 When aerial lines are near or crossed with certain facilities，the spacing distance shall be in accordance with the following requirements：
1 The minimum horizontal clearance between the poles and other infrastructures shall be in accordance with the requirements outlined in Table 6.4.8-1.
Table 6.4.8-1 Minimum horizontal clearance between poles and other infrastructures
Note：In narrow areas，when parallel laying of aerial optical cables and the existing aerial lines is being planned and spacing distance between the two lines cannot meet the above requirements，poles can be shared.Alternatively，other laying methods of optical cable lines can be used and the requirements for spacing distance shall be meet.
2 The height of aerial optical（copper）cables under all circumstances shall not be lower than specifications outlined in Table 6.4.8-2.
Table 6.4.8-2 Height of aerial optical（copper）cables
Table 6.4.8-2（continued）
3 The minimum vertical clearances shall not be less than specifications outlined in Table 6.4.8-3，when aerial optical（copper）cables cross with other infrastructures.
Table 6.4.8-3 The minimum vertical clearances for aerial optical（copper）cables when crossing with other infrastructures
Notes：1 If power supply lines are coating lines，optical（copper）cables may also cross above power supply lines.
2 When optical（copper）cables have to cross above，installation for poles and suspension wires on both sides of the crossing span shall be strengthened with protective devices.
3 Communication lines shall be set up below power lines and above the tram trolleys and catenary.
6.4.9 Optical cable joint closure may be installed on suspension wires or poles and shall be fixed firmly.
6.4.10 Optical cable suspension wires shall use pole ground wires or guys for grounding every 300m-500m，insulators should be installed every 1km for electric disconnection.
6.4.11 Optical cables shall avoid the possibly impacted areas.When these areas are inevitable，protective measures such as longitudinal cutting hard plastic pipes shall be adopted at the vulnerable point.Steel pipes for protection shall be used for the optical cables from ground to pole.
6.4.12 When crossing below aerial power lines，optical cable shall be wrapped by insulating material to ensure insulation whilst grounding devices or high voltage insulators shall be installed on both sides of the suspension wire crossovers to ensure electric disconnection.
6.4.13 Measures for fire protection shall be taken when crossing or approaching is inevitable for optical cables to facilities that may cause fire.
6.4.14 The installation of wall-mount optical cables shall meet the following requirements.
1 Armored optical cables should not be mounted on walls.
2 The height of wall-mount optical cables from the ground shall not be less than 3m.
3 Steel stands wire hanging methods shall be adopted for cables that go across blocks or courtyards and the distance from the lowest point of optical cables to the ground shall be in accordance with those specified in Table 6.4.8-2.