The third chapter processing and laying cable pipe
The 3.0.1 cable pipe should not have perforation, crack and obvious uneven, wall should be smooth; metal cable pipe should not have severe corrosion. Hard plastic pipes shall not be used in places where the temperature is too high or too low.
In susceptible to mechanical injury and local stress in the relatively large buried, enough strength pipe should be used. Article 3.0.2 cable tube processing should meet the following requirements:
A nozzle should be free of burrs and sharp edges, should be made of horn shaped orifice.
Second, the cable pipe after bending, should not have cracks and significant concavity phenomenon, with its curved flat degree should not be larger than the pipe diameter of 10%; cable tube bending radius should not be less than the cable penetration of the minimum allowable bending radius.
Three, metal cable pipe should be coated on the outer surface of anticorrosive paint or coated with asphalt, galvanized zinc layer exfoliation should also be painted with anticorrosive paint. The 3.0.3 cable tube inner diameter and outer diameter of cable ratio shall not be less than 1.5; concrete pipe, clay pipe, asbestos cement pipe in addition should meet the above requirements, the diameter is not less than 100mm.
Article 3.0.4 the elbows of each cable duct shall not be more than 3, and the right angles shall not exceed 2.
Article 3.0.5 the cable duct shall meet the following requirements:
First, the cable pipe should be installed firmly; the distance between the cable pipe support point, when the design is not specified, it should not be more than 3m. Two, when the linear length of the plastic pipe is more than 30m, it is advisable to install the expansion joint. Article 3.0.6 the connection of a cable pipe shall meet the following requirements:
A metal cable pipe should be firmly connected, seal should be good, two nozzle should be aligned. The length of the sleeve joint of the short sleeve pipe or the threaded pipe shall not be less than 2.2 times of the diameter of the cable pipe. Cable pipe should not be directly butt welding.
Two, a hard plastic tube in the socket or plug, the insertion depth of the inner diameter of the pipe should be 1.1 ~ 1.8 times. The seal should be coated with adhesive glued in the plug surface is sheathed; the two ends of the sleeve should be sealed.
The cable section 3.0.7 to the mouth of the pipe equipment, and equipment should be easy to disassemble and import equipment does not hinder the connection. Cable laying parallel pipe should be neat.
Article 3.0.8 use cable protection pipe for grounding wire, welding good ground wire; threaded pipe joints, welding application jumper, cable laying.
Article 3.0.9 the laying of concrete, clay, asbestos cement cable pipe, the foundation should be solid, smooth, there should be no subsidence. Cable duct laying shall meet the following requirements:
A cable, pipe laying depth shall not be less than 0.7m; when laid under the sidewalk, should not be less than 0.5m. Two, the cable duct drainage slope should be not less than 0.1%.
Three, cable pipe connection, pipe holes should be aligned, the joints should be strict, there shall be no groundwater and slurry infiltration.