Shielded Cabling System Installation and Grounding Methods

Fibermart
Thursday 04 September, 2014
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Shielded cabling system is installed in the general unshielded cabling system with metal shielding layer on the outside of a metallic shield reflection, absorption and skin effect of preventing electromagnetic interference and electromagnetic radiation function. The major advantage of shielded cabling system is it has a strong resistance to external electromagnetic interference and radio frequency interference ability. Besides it also can prevent the internal energy of the transmitted signal to the outside world radiation and has a good system security. Shielded cabling system must be properly installed and grounded. If the transmission channel of the shield connection element is not continuous or poorly grounded, it may perform even worse than unshielded cabling system. Shielded cabling system installation and grounding methods will be provided in this article.

Shielded Cabling System Installation

Shielded cabling system installation mainly involves two aspects: the shield cable termination and system grounding of the floor area and working area.Based on the particularity of the shielding system, you need to ensure that the cable shielding layer of the range of 360 degrees with the module and patch panel with good contact shield, rather than at some point to connect. At the same time, the shielding layer can not be broken in the same link. Usually, there are five steps to install a shielded cabling system:

Step 1: Use special clamping tool to remove the sheath of the shielded cable.

Step 2: Separate the peeled four twisted pair, but do not open the core wire pairs. According to the core line color indicated by the information module to sort cable. Pull the corresponding cores flatly with both hands, then put the wire into corresponding line slot.

Step 3: After all core wires being embedded then use a wire clamp to press the core wire into the groove. Aligning blade of wire clamp to the line slot and wire on the information module. Cut off the wire which exceeds the module. Repeat this operation, and connect the drain wire and metal pieces behind the module.

Step 4: Penetrate plastic dust film of the information module into twisted pair along the gap, and fixed on information module. Then cover the iron covering of the module, the module can be produced after pressing it. Finally put the completed information module into information outlet.

Step 5: After information module being produced, you can test the connection with multimeter. If the resistance is small, it indicates information module connections are good. If not, press corresponding core line with wire clamp until it smooths. Professional testers can also be used. Choose different shielding test standards according to different objects.

A complete shielded wiring system installation requires shielding everywhere. Only a continuous and complete shielding path can reach users' expected result. If you choose to use shielding system, cable, module, ODF as well as metal bridge and pipeline all need to be shielded. The principle of electrostatic shielding is to make the interference shielding outer into the earth, thus properly grounded shielding layer is also very important.

Shielded Cabling System Grounding

Properly grounded shield is very important, otherwise it not only will not reduce interference, but will make interference increase. Because when ground point is not properly arranged , the ground resistance is too large and the ground potential is not balanced, which may cause ground noise. Then it may generate potential differences between two points of transmission channel, which makes interference current produce on the metal shielding layer. At this time, the shield itself forms a big interference source, causing its performance much poor than unshielded transmission channel. To guarantee the screen effect, proper shielded cabling system grounding becomes particularly important.

Shielded Distributing Frame

The grounding accessories of the shielded distributing frame are bus-bar used to ground. Shielded module can connect to the grounding body through them, forming a grounding passage in the distributing frame. There are two main type shielded distributing frame grounding accessories:

1. Ground accessories installed within the distributing frame
Ground accessories installed within the distributing frame have flexibility. When shielded cabling system installation module is inserted into the patch panel, its metal shell forms a good connection with grounding accessories automatically, then complete the shielded module grounding work.

2. Independent grounding accessories
Independent grounding accessories can transform the unshielded distributing frame into shielded distributing frame. These shielded modules generally contain grounding connector which can be pluged with lap line. After inserting shielded modules into distributing frame, then plug the lap line into the shielded modules' grounding connector, forming the shielded modules' grounding connection. Distributing frame should be fitted with ground piles, so the ground wire from the cabinet can overlap with them. The traditional distributing frame uses metal post in the cabinet to ground. This approach is no longer used.

Shielded Distributing Frame Grounding

The shield grounding of distributing frame can be used in the following ways:

1. Each distributing frame through the respective ground wire to connect the cabinet's copper bar, forming a star-ground structure;

2. Install the copper bar in the bottom of cabinet, then use independent grounding wire to connect copper bar and ground piles, so that the ground between the various cabinet formed star-ground structures;

3. Ground wire cross-sectional area should be greater than 6mm2;

4. Electrical ground wire ends should use common cold solder pieces, so as not to spread the thread composed of short circuit;

5. In order to improve the discharge capacity of high frequency interference signals, we suggest grounding wires should use braided lines. Greater surface area can meet the demand of skin effect of high frequency current.

Conclusion

To install a shielded cabling system, in addition to high quality wire and plug parts, good construction techniques and meticulous work attitude are essential. Focus on the details of the construction process and do every step carefully, then you are sure to make a good shielding project.