Construction matters, selection and core number of optical cable

A, optical cable outdoor construction:

The most important thing for long distance optical cable laying is to choose a suitable path. Here is not necessarily the shortest path is the best, but also pay attention to the right to use the land, the possibility of erection or buried.

Must have a very complete design and construction drawings, so that the construction and future inspection convenient and reliable. During the construction, we should always pay attention not to make the cable under heavy pressure or be punctured by hard objects.

When the cable turns, the turning radius is greater than 20 times the diameter of the cable itself.

1. Outdoor aerial optical cable construction:

A. Hoisting overhead method, which is simple and cheap, is the most widely used method in China, but hoisting and finishing is more time-consuming.

B. Hanging wire winding overhead mode, which is stable and less maintenance work. But you need a special wrapping machine.

C. Self-bearing overhead mode has high requirements for line trunk, difficult construction and maintenance, and high cost, which is rarely used in China at present.

D. When overhead, guide device shall be added to the dry spot of the cable lead, and the cable shall be avoided to mop the floor. Pay attention to reduce the friction when cable traction. A stretch of cable should be left on each trunk for telescoping.

E. Pay attention to the reliable grounding of metal objects in optical cables. Especially in mountainous areas, high voltage power grid areas and many areas generally have 3 ground points per kilometer, and even choose non-metallic optical cables.

2, outdoor pipeline cable construction:

A. Before construction, check the occupation of pipes, clean and place plastic sub-pipes, and put traction wires in at the same time.

B. Calculate the cable length and ensure that the reserved length is sufficient.

C. Do not lay out the cable too long (generally 2KM), and the cable should be pulled from the middle to both sides.

D. The traction force of the cable is generally not more than 120kg, and the strengthening center of the cable should be pulled, and the waterproof treatment of the cable head should be done.

E. Cable leading and leading must be added to the device, can not directly mop the floor.

D. The pipeline optical cable should also be reliably grounded.

3, directly buried optical cable laying:

A. The depth of the directly buried optical cable trench should be excavated according to the standard, which is shown in the following table:

B. Where ditches cannot be dug, pipes can be laid overhead or drilled.

C. The bottom of the trench should be flat and firm. If necessary, a portion of sand, cement or support can be pre-filled.

D. Manual or mechanical traction can be used for laying, but attention should be paid to guiding and lubrication.

E. After laying, cover and tamp the soil as soon as possible.

4, the laying of optical cable in the building:

A. When laying vertically, special attention should be paid to the bearing problem of the optical cable. Generally, every two layers should be fixed once.

B. When the cable passes through the wall or floor, protective plastic tubing with mouth guard should be added, and the tube should be filled with flame retardant filler.

C. A certain amount of plastic pipe can also be laid in advance in the building, and traction or vacuum fiber optic cable will be used when the fiber optic cable is applied in the future.

Two, the selection of optical cable:

The choice of optical cable in addition to according to the number of fiber cores and fiber types, but also according to the use of optical cable environment to choose the outer sheath of optical cable.

1. Armored optical cable should be selected when outdoor optical cable is directly buried. When overhead, a black plastic sheath cable with two or more stiffeners can be selected.

2. The optical cable used in the building should pay attention to its flame retardant, poison and smoke characteristics when choosing. Generally, flame retardant but smoky type (Plenum) can be selected in pipes or forced ventilation, and flame retardant, non-toxic and smokeless type (Riser) should be selected in exposed environments.

3. Vertical Cables in the building can be selected from Distribution Cables; Breakout Cables can be used for horizontal cabling.

4. If the transmission distance is within 2km, multi-mode optical cable can be selected, and over 2km, relay or single-mode optical cable can be selected.

Three, the number of cable core determination method:

The number of glass fibers contained in each cable is the number of fiber cores. The following Xiaobian to introduce you to the number of cable core determination method.

According to the IBDN standard, it is generally recommended that the communication room in each building should be 12 cores, and the inter-building should be 24 cores.

First, know the number of wiring points at this layer, figure out the number of switches, and whether the switches are stacked or not stacked. If the switches are stacked and the core switches are redundant for dual-system hot backup, six cores are sufficient (two cores are redundant for each core). If a switch needs four cores without stacking, multiply the number of switches by four plus the redundancy of four cores.

Experience: Set an optical fiber in the distribution room of each floor (horizontal cabinet).

Generally six cores: two cores for use, two cores for reserve, two cores for redundancy; There are also ones that use eight-core fiber.

Redundancy: as long as more than used, more is called redundancy;

Master/standby: one used and the other identical for backup;

Hot backup: both are working at the same time;

Cold backup: The backup device is in standby state.

The minimum specification configuration is 2 cores per 48 points. Of course, 48 points can choose 4 cores, because 2 cores is the smallest unit of optical cable, more than 2 cores as a spare part is more appropriate.

The above is the cable core number of methods to determine the introduction, you can understand. Backup can be selected because of people, so out of the cable core number difference is more, according to the standard selection is only to ensure a minimum selection and a backup core number can be.