Sagem 4450E - Manual (Page 53)

SAGEM 3P@C
3P@C Installation Manual
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SAGEM SA
3.2.3. 3.2.3. 3.2.3. 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. 3.2.4. 3.2.4. 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 mm
2 , 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.