6.1　General Principle

6.1.1　Optical cables shall be deployed and installed based on the environmental conditions of the locations to ensure that the cables remain undamaged.Artificial or mechanical installation method shall be adopted per the actual conditions.

6.1.2　During installation，special caution shall be exercised to avoid water from entering the optical cables and splice closures in order to maintain the integrity of optical cable sheath and ensure that the metal protection sheath of the buried optical cables is insulated.

6.1.3　The minimum installation curvature radius of optical cables shall be in accordance with those specified in Table 6.1.3.

Table 6.1.3　The minimum curvature radius allowed for optical cables

Note：D stands for diameter.

6.1.4　During installation，overlapping，increase of cable length and reserved length of optical cables can be determined per actual engineering practices，according to specifications in Table 6.1.4.

Table 6.1.4　Reference values for increased and reserved length of optical cables

6.1.5　The diameter of the cables through various types of pipes should not be more than 90% of the tube diameter.The nozzle shall be sealed tightly after installation.

6.1.6　Optical cables shall bear clear and permanent identity to be easily identified during operation and maintenance.In addition to characters，symbols and banners printed on the outer sheath of the optical cables，hanging signs shall be added to duct and aerial optical cables，and warning tapes may be added to directly buried cables.