SAGEM 3P@C

3.2.3.Avoiding Laser Damage

„While the equipment installed with a fiber interface module is operating, please do not expose your eyes directly to these optical interfaces, lest the laser ray from the interfaces cause eye damage.

„It is suggested that protection covers for optical interfaces be placed on those optical interfaces if they are not in use.

„Wear safety glasses to protect your eyes if condition permits.

3.2.4.Lightning Protection Requirements

The equipment room building, if higher than 15 m, should be designed in accordance with the lightning protection requirements for Class II civil buildings and structures.

During the anti-lightning design, measures should be taken to guard against the incursion of direct stroke and the lightning current. In the areas where lightning occurs frequently, there is also the phenomenon of side flash. So, some preventive measures against the side flash should be adopted according to the actual situation during the design. For example, connect the outer metal windows of the building with the lightning protection down lead. Along the height of the building, set horizontal metal lightning protection straps on the outer wall at a certain interval to prevent the lightning.

The following lightning protection measures shall be taken for the main building body of the equipment room.

„Install anti-lightning nets or anti-lightning straps on the parts of the building that are subject to lightening.

„Equipment the protruding objects such as the chimney, antenna with an overhead conductor or arrester.

„Ensure the sectional area of the downlead of the anti-lightning device is no less

than 2 mm2, and their spacing is no more than 30 m.

The grounding resistance of the building’s lightning protection grounding device should be no more than 10 ohm. Before external cable and metal pipes etc. enter the building, they should be grounded. When outdoor aerial cables directly enter a room, lightning arrester should be installed at the point of entry. At the top of chimneys or antennas etc., lightning rods or lightning protection rings should be added. For buildings and structures, it is advisable to use the steel reinforcement of the reinforced concrete building slabs, beams, pillars and foundation as the discharge line for lightning-protection devices.

In the past, the lightning protection ground of the building was separated from the ground of telecom and power supply systems, and large distances were required between various grounding devices. However, due to such reasons as small building sites, most of these requirements of distance were not satisfied. In fact, they can not be separated in many circumstances, so it is advisable to employ joint grounding systems for the lightning protection of the buildings. The joint grounding system connects the operating ground and protection ground for telecom use and the lightning protection ground of the building as well as the ground of the industrial frequency AC power supply system together. The grounding resistance of joint grounding should be quite high. Since the grounding resistance required for telecom is far less than 10 ohm, while the grounding requirements for various telecom equipments are different, the joint grounding resistance shall be determined according to the minimum resistance value of the various grounding devices.

It is advisable to employ the metal components of the building itself (such as reinforcing steel bars inside walls and pillars) as the lead wires for lightning protection grounding, and these lead wires should be electrically connected, so that the electric potentials inside the building are equilibrated.

3P@C Installation Manual

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