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When does an integrated cabling call for a shielded cabling system?(II)

  • 2018-04-16
It stands as the other part of the previous article“When does an integrated cabling call for a shielded cabling system?(I)” Today, let’s continue to talk about the principle of shielded wiring system.
2.Principle of shielding
Separate stranded wire pairs or 4-line pairs both can be outfitted with a metal shield layer. Different wire pairs or 4-line pairs can be placed together after metal shielding. Shielding is designed to increase the distance from the electromagnetic outside. As far as shielding itself is concerned, it minimizes crosstalk between wire pairs or 4-line pairs. These will be accomplished by reflection and absorption according to the skin collection response.
     (1) Metal shielding can effectively reflect a large number of electromagnetic fields from inside and outside.   
(2) When the intensity of the alternating signal generated by the interference source is gradually increased from the AC200V to the AC3500V, there is no error in the data signal transmitted in the FTP5 system. In class 5 UTP systems, the situation is not so favorable: when the voltage rises to AC200V, data errors and losses begin to occur. In practical application, AC 200V AC becomes an important interference source affecting the performance of cabling system.
(3) When the intensity of electromagnetic interference in the area of integrated wiring system is higher than that of 3V/m, a shielded cabling system is suggested to be taken for protection.
(4) When users have high requirements for EMC (electromagnetic interference and information leakage prevention) or network security and confidentiality are taken into consideration, shielded cabling system shall better be adopted.
     (5) When the non-shielded cabling system can not meet the requirements of cable spacing in the installation site, the shielded cabling system should be adopted.
(6) The cables, connectors, jumpers, and equipment cables used in the shielded wiring system shall be shielded and shall maintain the continuity of the shield layer.
To sum up, when the network wiring is located around the strong electromagnetic field (such as power plant, substation, etc.), the wiring system can adopt shielded system to ensure the normal transmission of network information.
 Depending on the intensity of electromagnetic interference , different shielding measures can usually be taken at 3 levels :
1.In the case of normal electromagnetic interference, shielding of metal bridges and pipes can be adopted, that is, all cables are enclosed in pre-laid metal bridges and pipelines, and metal bridges and pipes are kept well grounded. In this way, the interference current can be introduced into the earth and a better shielding effect can be obtained.
2.In the presence of sources emitting the strong electromagnetic interference, the shielded system of shielded twisted pair wire and shielded connection can be used, accompanied with the metal bridge and pipe. As such, good shielding effect can be obtained generally.
  3. In the case of strong electromagnetic interference, optical fiber cabling can be employed. Despite high cost of optical fiber cabling, the shielding effect is quality, with relatively higher bandwidth and transmission rate. The network with optical fiber cabling can boast its advancement for the next 20 years, and the network will not be eliminated because of the backwardness of the cabling system.
This article comes from Jiangsu Hansheng Cable Technology Co., Ltd., Please reprint with the source indicated!
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