Hole design requirements for laying pipeline cables

প্রথম, the pipeline cable laying

The hole position of the laying pipeline cable should meet the design requirements
1. In cement pipes, steel pipes or plastic pipes with a hole diameter of 90 mm or more, three or more sub-pipes shall be laid at one time between the two (hand) holes according to the design regulations.
2. The sub-tube must not be laid across the hole of the person (hand). The sub-tube must not have a joint in the pipe.
3. The extension length of the sub-tube in the hole of the person (hand) is generally 200-400mm; the tube hole and the tube hole of the sub-tube that are not used in this project should be sealed in time according to the design requirements.
4. When the optical cable is put in all kinds of pipes, the inner diameter of the pipe should be not less than 1.5 times the outer diameter of the cable.
5. artificial laying of optical cable must not exceed 1000m. The airflow of the cable is generally not more than 2000m.
6. The cable after laying should be straight, no twist, no cross, no obvious scratches and damage. After laying, it should be fixed according to the design requirements.
7. Do not bend the cable out of the pipe hole within 150mm.
8. The sub-tube or silicon core tube occupied by the optical cable is sealed with a special plug.
9. The overlapping length of the cable laying on both sides of the cable joint shall meet the design requirements. After the connection is completed, the remaining length of the cable shall be placed and fixed in the manhole according to the design requirements.
10. Pipeline cable shall be reserved for the manhole according to the design requirements according to the access requirements.

Second, direct buried cable laying
● The buried depth of direct buried optical cable should meet the relevant requirements of the engineering design requirements for communication optical cable lines. The specific buried depth should meet the requirements of the above table. The cable should be naturally tiled at the bottom of the ditch, and there should be no tension.

Buried optical cable laying should also meet the following requirements:

1. The radius of curvature of the direct buried cable should be greater than 20 times the outer diameter of the cable.
2. The optical cable can be laid in the same trench as other communication optical cables. When laying in the same trench, it should be arranged in parallel, and should not overlap or cross. The parallel clearance between cables should be ≥100mm.
3. When the direct buried optical cable is parallel or cross-over with other facilities, the spacing shall not be less than the above table.
4. When the cable is laid in a terrain with large terrain (such as mountains, terraces, dry trenches, etc.), it should meet the requirements of the specified depth and radius of curvature.
5. Slopes with slopes greater than 20° and slope lengths greater than 30 m should be laid in “S” shape. When the cable ditch on the slope surface is likely to be washed by the water flow, measures such as blockage reinforcement or diversion should be taken. On the slope
When laying on longer slopes with a degree greater than 30°, special structural cables (generally steel wire armored cables) should be used.
6. The pipe buried directly through the protection pipe should be tightly sealed.
7. Directly bury the cable into the hole of the person (hand) should be provided with a protective tube. The cable armor protection layer shall extend to approximately 100 mm from the first support point in the manhole.
8. The various signs of the direct cable should be installed as required by the design.
9. The protective measures when directly burying the cable through the obstacle should meet the design requirements.

Backfill should meet the following requirements:
1. Fill the fine soil first, then fill the ordinary soil, and do not damage the optical cable and other pipelines inside the trench.
2. After the 300mm fine soil is backfilled in the urban area or suburb, the red brick is covered. Every time the backfill is about 300mm, it should be compacted once, and the residual soil cleaning work should be done in time.
3. After the soil is compacted, the cable trench should be flush with the road surface on the pavement or floorwalk. The soil should not be sunken before the road surface is repaired; the dirt road can be 50~100mm higher than the road surface, and the suburbs can be high.
Out of 150mm or so.
When the microchannel optical cable is needed, the cable trench should be cut straight. The width of the slot should be determined according to the outer diameter of the cable. সাধারণত, it should be less than 20mm. The height of the topmost cable in the channel should be greater than the height of the road.
80মিমি, the total depth of the channel should be less than 2/3 of the thickness of the road; the groove bottom of the cable trench should be flat, no hard ridge (step), no debris such as gravel; the angle of the groove should meet the cable laying Curvature

Radius requirement. At the same time, you need to comply with the following requirements:
1. Before laying the optical cable, it is advisable to lay 10mm thick fine sand on the bottom of the groove or place a foam strip with a diameter close to the width of the groove for buffering.
2. After the cable is placed in the groove, the buffer protection material should be placed above the cable according to the characteristics of the material recovered from the road surface.
3. The restoration of the road surface should meet the requirements of the competent department of the road. The repaired pavement structure should meet the requirements of the service function of the corresponding road section.

Third, overhead cable laying
● Pay attention to the safety of aerial work.
● The aerial cable should be naturally straight after being laid, and it should be free from tension, stress, no twist, and no mechanical damage.
● The hook program of the optical cable should be selected according to the design requirements. The spacing of the cable hooks should be 500mm and the tolerance is ±30mm. The hooking direction of the hook should be the same on the hanging wire. The hooking plate should be installed completely. The first hook on both sides of the pole should be 500mm away from the pole. The allowable deviation is ±20mm.
● Deploy the overhead aerial cable to make a telescopic reserve on every 1~3 rods. The telescopic reserve is reserved for 200mm between the straps on both sides of the pole. The requirements for the installation of the telescopic reserve are as follows. A protective tube shall also be installed at the cross-height or T-shaped wire of the cable.
● Deploy the overhead aerial cable to make a telescopic reserve on every 1~3 rods. The telescopic reserve is reserved for 200mm between the straps on both sides of the pole. The telescopic reserve installation method should meet the requirements of Figure 2. A protective tube shall also be installed at the cable, cross sling or T-shaped wire.
● The method of hoisting the overhead cable at the suspension joint shall comply with the requirements of Figure 3.

Fourth, lead the cable laying
● The material, specifications and installation location of the protective tube should meet the design requirements.
●Import the protective tube in the way of cementing rods, wood poles and walls.
●Installation of the upper part of the protective tube on the optical cable

Fifth, the wall cable laying

The laying of wall cables shall meet the following requirements:
1. It is not advisable to lay armor or linoleum cable on the wall.
2. The height of the wall cable should be no less than 3m from the ground. The crossing of the street and the access to the courtyard should be carried out by steel strands. The lowest point of the cable should meet the design requirements.
3. The minimum distance between the wall cable and other pipelines should meet the design specifications.
4. The horizontally laid suspension wire shall be fixed at the terminal on the wall and the intermediate support shall meet the requirements of the above two figures.
5. The distance between the wall supports should be 8~10m, and the distance between the terminal fixture and the first intermediate support should be ≤5m.
6. The hanging wire laid vertically shall be on the wall and its terminal shall meet the requirements of the above figure.
7. The hook spacing requirement of the wall overhead cable is the same as the spacing requirement of the overhead hook of the pole. The spacing between the hooks on both sides of the wall overhead cable shall be 150-250mm (as shown in the above figure), and the distance between the two sides shall be equal.

Sixth, the corridor cable laying
Cables are laid in the corridors. সাধারণত, there are two types of wire troughs and concealed pipes. They should meet the following requirements:
1. The specifications of the pre-embedded trunk and concealed pipe should meet the requirements of the design documents.
2. It is advisable to use the mark on both ends of the pre-embedded wire trough and the dark pipe to indicate the number and other contents and spray the construction party mark.
3. The pre-embedded wire trough should adopt metal wire trough, and the cross-section utilization rate of the pre-embedded or sealed wire trough should be 30% to 50%.
4. It is advisable to use steel pipes or flame-retardant PVC rigid pipes for laying dark pipes. When laying more than 4 কোর, the diameter of the straight pipe should be 50% to 60%, and the curved pipe should be 40% to 50%. When the inner tube is laid with 4 cores and below, the cross-section utilization ratio of the pipe should be 25% to 30%.

The laying of optical cables in the line slots shall comply with the following requirements:
1. The cable in the sealed cable slot should be placed straight and should not be crossed as much as possible. The cable should be bundled and fixed at the turn-in and groove. It is not advisable to cross the power cable. If it cannot be met, the corresponding protective measures must be taken.
2. When laying the optical cable in the horizontal and vertical trunking, the cable should be bundled. When laying vertically, the spacing should not be greater than 1.5m, the spacing should be uniform, it should not be tied too tightly or the cable should be squeezed; the horizontal spacing is 5~10m.
3. The cable laying is not allowed to exceed the maximum cable tensile force and crushing force, and the outer sheath of the cable should not be obviously damaged.
4. The optical cable shall not be placed in the elevator or the shaft of the water supply, gas supply and heating pipes; it shall not be placed in the strong electric shaft.

The minimum clearance between the corridor cable and other equipment rooms and pipelines shall comply with the following requirements:
1. The minimum clearance between the cable of the table and the distribution box, the transformer room, the elevator machine room and the air-conditioning room meets the requirements of the following table.
2. The minimum clearance between cable laying and other pipelines in the corridor is as specified in the following table.

Seven, optical cable connection
Key points of each process:

1. Construction preparation:
The connection environment should be dustproof, waterproof and shockproof. It is best to choose to connect to the car. If it is unconditional, it should use the connection tent and set the work table and work chair.
2 Arrange the continuation points and test point personnel in place.

2. Optical cable stripping:
●Check whether the cable connected to the cable is damaged or deformed before opening.
● straighten out the optical cable and make a reservation according to the regulations;
●Wipe the end of the cable with 3000mm cotton yarn, and cut off the end of the cable 200-300mm;
●sets of heat shrinkable sleeves suitable for the outer diameter of the cable;
●Confirm the A and B ends of the cable;
●to do the shield line;
●clean the grease;
●testing the insulation of the metal components of the optical cable with an insulated shaker;
●Note the depth of the infeed.

3. The cable is fixed in the connector:
● Ensure that the cable does not loosen, and the tightening screw should make the reinforcing core have a bending phenomenon;
● The fixing of the reinforcing member should pay attention to its length, so that the distance between the clamping plate of the fixing cable and the fixing reinforcement screw should be equivalent to the remaining length.

4.optical cable bundle tube stripping:
● Determine the position of the beam tube opening and stripping, pay attention to smoothing;
● cut the beam tube, pay attention to the knife;
●remove the beam tube, pay attention to uniform speed;
● wipe the grease, pay attention to clean;
● Put the bundle tube into the storage tray, and fix the ends with nylon straps. Be careful not to pull the strap too tightly;
●pre-disc fiber, so that the joint point after the connection can be placed in the fixing groove of the fiber protection tube, and the excess fiber is cut off.

5. optical cable core welding:
●Keep the workbench and the fusion splicer clean throughout the entire process;
●The optical fiber connection shall be connected one by one in order, and shall not be cross-connected.

6. continuous indicator test:
● After receiving 2 কোর, notify the test point test, pay attention to test two directions, two windows;
●After the test indicators are qualified, notify the connection point to thermally melt the 2-core fiber one by one.

7. Fiber protection tube heating: Move the protection tube to the middle of the fiber connector; after the tube is cooled, remove the protection tube and confirm that there are no air bubbles in the tube. The subsequent fiber fusion and hot melt are performed one by one according to the above method.

8.fiber storage:
1 step by step, pay attention to each tube immediately received;
2Fixed fiber protection tube, pay attention to safety and firmness;
3 Check after containment, pay attention to bending radius, extrusion, and force;
4 After the cover is closed, notify the test point to retest.

9. the cable connector box packaging:
The importance of sealing (1 to prevent the joint box from entering the water 2 directly buried joint box anti-ant);

Sealing operation (1 cable and joint box, pay attention to the sealing of the upper and lower covers of the joint box, pay attention to the uniform placement of the sealing tape).

Cable splicing considerations:
Splicingis also calledopening the skylight”, that is, a cable is longitudinally sectioned to expose the bare fiber, and several of the cores are disconnected from the branch cable, and the remaining cores are not damaged. point:

● “Splicing” should use indoor branch cable or center bundle tube cable.
●The length of the longitudinal section of the cable must be favorable for the core of the core.
●When the fiber is connected from the cable, the through fiber must not be damaged. When the fiber is to be reserved at the connection of the cable, it should be separated from the fiber with different connections.

Eight, the cable ends
Key points of each process

The requirements for the key points of the cable end are the same, and some of the processes are the same as the cable connection. The following explains the differences:
1. Full-test test: The test method is divided into two types: optical time domain reflectometer (OTDR) and light source optical power meter;
2. Label sticking: The end label of the optical cable mainly includes the tail fiber head label and the terminal terminal diagram. The label needs to indicate the direction of the optical cable, the number of cores and the position occupied by the terminal, etc., requiring clear writing, stable sticking and over-plastic protection.

Post time: 2019-10-19
ইনকয়েরি এখন