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24

2022

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08

How to prevent lightning damage in fiber optic cable wiring?


With the development of the network, optical fiber, as a medium used to transmit data in the integrated wiring system, is more and more used by people because of its advantages of high transmission rate and long distance. As we all know, the optical fiber is non-conductive and can be protected from inrush current. The optical cable also has good protection performance. The metal components in the optical cable have high insulation value to the ground, and the lightning current is not easy to enter the optical cable. The direct buried optical cable has an armoring layer, so when the optical cable line is struck by lightning, the optical cable can also be burned or damaged. So, how can we prevent lightning damage in fiber optic cable wiring?

 

Measure 1: For the lightning protection of the straight-type optical cable line: ① In the local grounding method, the metal parts in the optical cable should be connected at the joint part, so that the reinforcement core, moisture-proof layer and armor layer of the junction optical cable remain connected. ②According to the regulations of YDJ14-91, the moisture-proof layer, armor layer and reinforcing core should be electrically disconnected at the optical cable joint, and they are not grounded, and are insulated to the ground, which can avoid the accumulation of induced lightning current in the optical cable. It can avoid that the lightning current in the ground is introduced into the optical cable from the grounding device due to the difference in the impedance of the lightning protection drain wire and the metal component of the optical cable to the ground loop.

 

Measure 2: For the overhead optical cable: the overhead suspension wire should be electrically connected and grounded every 2km. When grounding, it can be directly grounded or grounded through a suitable surge protection device. In this way, the suspension wire has the protective effect of the overhead ground wire.

 

Measure 3: After the optical cable enters the terminal box, the terminal box should be grounded. After the lightning current enters the metal layer of the optical cable, the grounding of the terminal box can quickly release the lightning current and play a protective role. The direct buried optical cable has an armor layer and a reinforcing core, and the outer sheath is a PE (polyethylene) sheath, which can effectively prevent corrosion and rat bites.

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