The newly purchased tube-to-tube cable is sealed on both ends with a plastic gland.
But after a while, the remaining cable is not sealed and water vapor penetrates the cable.
When laying a cable, the cable head wrapped in plastic paper is sometimes submerged in water to allow water to enter the cable.
Occasionally the outer sheath breaks when towing and tubing.
Not in a timely manner cable production, so that a large number of water vapor into the cable.
In the cable head production, due to the preparation of the staff of the effect, the cable ends sometimes slip into the cable wells with water.
During the operation, the occurrence of intermediate joint breakdown and other failures, cable wells will be along the gap in the water into the cable.
In the construction site, the external force caused by cable damage or breakdown, cable water will occur.
Drying is very difficult once the water fill into the cable (such as pressurized nitrogen blowing heat), generally do not configure the appropriate equipment.
In practice, if the cable such as water, just saw the front a few meters, such as the entire cable has been into the water, it is not desirable.
Therefore, the prevention of water inflow cable, prevention should be based, using the following measures:
1. Cable head should be sealed. The cable ends that have been cut off must be sealed with plastic (using cable-specific glands) to prevent moisture ingress.
2. Cable laying in time for the production of cable head.
3. Strengthen the cable head production process management.
4. Using shrink cable head.
5. 10kV system with 8.7/10kV level of cable. At the same time to thicken the cable insulation.
6. Using PVC plastic double wall corrugated pipe.
The tube corrosion-resistant, smooth inner wall, good strength and toughness, so laying in the cable buried, can greatly reduce the damage to the outer sheath of the cable.
7. Cable trench (pipe) and cable well design.
Due to the restriction of the conditions, the cables are laid directly or in the form of cable ditches and are buried in direct burdens.
If they belong to coastal rainy areas, there is water in the cable ditches or cable wells for many years.
Due to the depth of the cable duct or cable well exceeding the depth of the sewer, drainage is difficult, so coordination should be made during planning to facilitate drainage of the cable duct (well).
If you can not do cable wells do not accumulate water, then the middle of the cable hole in the bracket propped up.
In addition, the design of the cable management, as straight as possible to reduce the elbow, the cable easy to lay.
The same time, in the production of cable wells, into a large cable and small cable wells, cable wells can be used to pull the cable.
Doing intermediate joints, and in the middle of the road is not easy to do wire wells, but it must be a corner of the place, changed to a small cable well, the cable well is only used in laying cables divert pulley.