Installation and testing of shielded cabling systems

With the development of the economy and the dependence on information technology, the requirement for the confidentiality and security of networks is higher. Therefore, the network system must have the least electromagnetic radiation and the strongest anti-electromagnetic interference capability. In order to protect the network from interference from any external sources and prevent information from being intercepted in the middle, A shielded structured cabling system consisting of Shielded Cables and shielded components will be the best choice.

The shielded Wiring System adds a metal shielding layer to the external of a common unshielded wiring system. It uses the reflection, absorption, and skin effect of the metal shielding layer to prevent electromagnetic interference and electromagnetic radiation. The advantages of the shielded wiring system are mainly reflected in its strong ability to resist external electromagnetic interference and RF interference, and it can also prevent the energy radiation from internal transmission signals to the outside world, provides good system security. For a shielded cabling system, we need to pay attention to the following two points during design and construction:

1. The function of the shielded cabling system requires that all connected hardware use shielded products, including transmission cables, distribution frames, modules, and jumpers.

2. The shielded cabling system must be correctly and properly grounded. If the shielding layer of each connection element of the transmission channel is discontinuous or poorly grounded, the transmission performance may be worse than that provided by the unshielded system.

Part 1 Installation

The installation of the shielded wiring system mainly involves two aspects: the floor wiring room and the work area shielding cable terminal and system grounding.

In view of the particularity of the shielding system, it is necessary to ensure that the Screen Layer of the cable is in good contact with the Screen Layer of the module and the distribution frame in the range of 360 degrees, rather than connecting at some points, at the same time, the shield layer cannot break between the same link.

Step 2: Use a dedicated terminal tool to remove the outer skin of the shielded cable

Step 2: Separate the four pairs of twisted pair wires. Do not split the core wires. Follow the color sequence indicated on the information module and pull the two wires to a small segment, place the wires one by one in the corresponding cable trough with a slight force.

Step 2: After all the core wires are embedded, you can press the core wires into the trough with a plug-in. Align the cutter ports of the wire logging tool with the wire slots and wires of the information module, and cut off the extra wires outside the module. Repeat this operation and connect the streamline in the cable to the metal slice behind the module.

Step 2: add the plastic dust-proof sheets of the information module to the twisted pair wire along the gap and fix them on the information module. Then, stamp the module with an iron and press it to complete the whole process of making the module. Then, put the created information module into the information outlet.

Step 2: After the information module is created, you can also test whether the connection is good. You can use a multimeter to measure the connection. Place the Multimeter in the resistance position of x10, and contact one watch needle of the wanzhi beads with the corresponding core wire at the other end of the network cable, another 10 thousand use the table pen contact information module card into the corresponding color core line of the card trough edge note not contact core line), if the resistance is small, it proves that the information module is connected well, otherwise use the wire clamp to press the corresponding core line, until smooth. You can also use professional testers, such as FLUKE, to select different shielding testing standards based on different objects. A complete shielding system must be shielded everywhere. A continuous and complete blocking path can achieve the expected results. If you choose to use a shielding system, in addition to cables, modules, distribution frames and other connectors need to be shielded, supplemented by metal trays and pipelines. The principle of Electrostatic shielding is to allow the interference current to flow into the Earth through the shielding outer layer. Therefore, it is very important to properly ground the shielding layer.

Part 2 grounding

It is very important to shield the ground properly. Otherwise, the interference will not be reduced, but will increase. When the grounding point is incorrectly arranged, the grounding resistance is too large, and the grounding potential is not balanced, it will cause grounding noise, that is, the potential difference is generated at a certain two points in the transmission channel, in this way, the interference current is generated on the metal shielding layer. At this time, the shielding layer itself forms the largest interference source, resulting in far inferior performance to the non-shielded transmission channel. Therefore, to ensure screen effect, the screen must be properly and reliably grounded.

The grounding fittings in the shielded distribution frame are bus bars for grounding. They can connect all the shielding modules to a unified grounding body to form a grounding channel in the distribution frame.

There are two main types of grounding fittings used to shield distribution frames:

1. grounding parts installed in the Distribution Frame

The grounding parts installed in the distribution frame are flexible. When the shielding module is inserted into the distribution frame, the metal housing automatically forms a good connection with the grounding parts, and completes the grounding of the shielding module.

2. Independent grounding parts

Independent grounding fittings can be switched from a special unshielded distribution frame to a shielded distribution frame. Such shielding modules generally contain grounding interfaces for cabling. After the shielding module is inserted into the distribution frame, connect the grounding fittings to the grounding interface of the shielding module to form the Grounding Connection of the shielding module.

Grounding piles should be installed on the distribution frame so that the grounding wires from the cabinet can be overlapped.

The traditional shielding distribution frame is grounded by a metal column in the Cabinet, which is no longer used.

The following methods can be used to shield the grounding of the distribution frame:

1. Each shield distribution frame is connected to the consortium copper strip of the Cabinet through its own grounding wire to form a star grounding structure;

2. grounding copper strip is installed at the bottom of the Cabinet, and an independent grounding wire is used to connect the grounding copper strip to the grounding copper strip of the Telecommunications room of the wiring room) to form a star grounding structure between cabinets;

3. The cross-sectional area of the grounding wire should be greater than 6mm2;

4. Cold-Rolled welding pieces commonly used by electricians should be used at both ends of the grounding wire to avoid a short circuit formed by the split of the wire head;

5. In order to improve the Discharge Capability of high-frequency interference signals, it is recommended that the grounding wire be knitted to meet the skin effect requirement of high-frequency current with a larger surface area.

In the shielded cabling project, in addition to high-quality cables and connectors, good construction skills and meticulous work attitude are essential. Pay attention to the details in the construction process, and do a good job in shielding all the grounding links in the system. We believe that we will be able to make high-quality shielding projects.

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