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S12700 and S12700E Series Agile Switches Hardware Installation and Component Replacement

This document describes hardware installation procedures of the S12700 series switches, troubleshooting methods for common hardware faults, and switch maintenance instructions.

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Environmental Requirements for an Equipment Room

Environmental Requirements for an Equipment Room

Requirements for Selecting a Site for an Equipment Room

When designing a project, consider the communication network planning and technical requirements of the equipment. Also consider hydrographic, geological, seismic, power supply, and transportation factors.

Construction, structure, heating and ventilation, power supply, lighting and fire-proof construction of the equipment room should be designed by specialized construction designers to suit the environmental requirements of devices. The equipment room should also follow local regulations concerning the industrial construction, environmental protection, fire safety, and civil air defense. Construction must conform to government standards, regulations, and other requirements.

The equipment room should be located in a place free from high temperature, dust, toxic gases, explosive materials, or unstable voltage. Keep the equipment room away from significant vibrations or loud noises, as well as power transformer stations.

The specific requirements for selecting a site for an equipment room are as follows:
  • The room should be located at a distance of at least 5 km (3.11 mi.) from heavy pollution sources such as smelting and coal mines. It should be located at a distance of at least 3.7 km (2.30 mi.) from moderate pollution sources such as chemical, rubber, and galvanization factories. It should be located at a distance of at least 2 km (1.24 mi.) from light pollution sources such as packinghouses and tanyards. If these pollution sources cannot be avoided, ensure that the equipment room is upwind of the pollution sources. In addition, use a high-quality equipment room or protection products.
  • The room should be located away from livestock farms, or be upwind of the livestock farms. Do not use an old livestock room or fertilizer warehouse as the equipment room.
  • The equipment room must be far away from residential areas. An equipment room that is not far away from residential areas must comply with equipment room construction standards to avoid noise pollution.
  • The room should be located far away from industrial and heating boilers.
  • The room should be at least 3.7 km (2.30 mi.) away from the seaside or salt lake. Otherwise, the equipment room should be airtight with cooling facilities. In addition, alkalized soil cannot be used as the construction material. Otherwise, equipment suitable for wet conditions must be used.
  • The doors and windows of the equipment room must be kept closed to maintain an airtight room.
  • Using steel doors to ensure sound insulation is recommended.
  • No cracks or openings are allowed on the walls or floors. The outlet holes on the walls or windows must be sealed. Walls must be constructed such that they are smooth, wear-resistant, dustproof, flame retardant, sound insulated, heat absorptive, and have electromagnetic shielding.
  • The air vent of the room should be far from the exhaust of city waste pipes, big cesspools and sewage treatment tanks. The room should be in the positive pressure state to prevent corrosive gases from entering the equipment room and corroding components and circuit boards.
  • It is recommended that the room be on or above the second floor. If this requirement cannot be met, the ground for equipment installation in the room should be at least 600 mm (23.62 in.) above the maximum flood level.
  • The equipment room should be strong enough to resist winds and downpours.
  • The room should be located away from dusty roads or sand. If this is unavoidable, the doors and windows of the equipment room must not face pollution sources.
  • Do not place air conditioning vents near the equipment so that they blow directly on the equipment because condensation may be blown into the equipment.
  • Do not use decorative materials that contain sulfur in the equipment room.

Equipment Room Layout

An equipment room usually contains mobile switching equipment, telecommunications equipment, power supply equipment, and other auxiliary equipment. To ensure easy maintenance and management, place the equipment in different rooms. Figure 14-19 shows the layout of the equipment room.
Figure 14-19 Layout of the equipment room

The general layout principles of the equipment room are as follows:
  • It should meet requirements for laying out and maintaining communication cables and power cables.
  • It should reduce the cabling distance, which facilitates cable maintenance, reduces potential communication faults, and maximizes efficiency.
  • To ensure normal operation of equipment in the equipment room when the mains supply is disconnected, configure an emergency power generation system for the equipment room.

Construction Requirements for the Equipment Room

Table 14-8 describes the construction requirements for the equipment room.
Table 14-8 Construction requirements for the equipment room

Item

Requirements

Area

The smallest area of the equipment room can accommodate the equipment with the largest capacity.

Net height

The minimum height of the equipment room should not be less than 3 m (9.84 ft). The minimum height of the equipment room is the net height below overhead beams or ventilation pipes.

Floor

The floor in the equipment room should be semi-conductive and dustproof. A raised floor with an ESD covering is recommended. Cover the raised floor tightly and solidly. The horizontal tolerance of each square meter should be less than 2 mm (0.08 in.). If raised floors are unavailable, use a static-electricity-conductive floor material, with a volume resistivity of 1.0 x 107 ohms to 1.0 x 1010 ohms. Ground this floor material or raised floor. You can connect them to ground using a one megohm current-limiting resistor and connection line.

Load-bearing capacity

The floor must bear loads larger than 150 kg/m2 (0.21 bf/in.2).

Door and windows

The door of the equipment room should be 2 m (6.56 ft) high and 1 m (3.28 ft) wide. One door is enough. Seal the doors and windows with dustproof plastic tape. Use double-pane glass in the windows and seal them tightly.

Wall surface treatment

Paste wallpaper on the wall or apply flat paint. Do not use pulverized paint.

Cable trays

Use cable trays to arrange cables. The inner faces of the cable trays must be smooth. The reserved length and width of the cable trays, and the number, position and dimensions of the holes must comply with the requirements of device arrangement.

Water pipe

Do not pass service pipes, drainpipes, and storm sewers through the equipment room. Do not place a fire hydrant in the equipment room, but place it in the corridor or near the staircase.

Internal partition wall

Separate the area where the equipment is installed from the equipment room door. The partition wall can block some outside dust.

Installation position of the air conditioner

Install air conditioner vents so that the air does not blow directly on equipment.

Other requirements

Avoid the proliferation of mildew, and keep out rodents (like mice).
Figure 14-20 Internal partition wall inside the equipment room

Equipment Room Environment

Metal dust may cause short circuit or startup failure of electronic equipment. Ensure that the equipment room is free from conductive metal dust.

Dust on devices may cause electrostatic discharge and result in poor contact for connectors or metal connection points. This problem can shorten the life span of devices and cause faults.

The equipment room must be free from explosive, conductive, magnetically-permeable, and corrosive dust. Table 14-9 lists the requirement for dust concentration in the equipment room.
Table 14-9 Requirements for dust particles in the equipment room

Mechanical active material

Unit

Concentration

Dust particle

Particle /m3

≤ 3x 104

(no visible dust accumulated on a workbench in three days)

Suspending dust

mg/m3

≤0.2

Precipitable dust

mg/m2·h

≤1.5

Description

  • Dust particle diameter ≥ 5 µm
  • Suspending dust diameter ≤ 75 µm
  • 75 µm ≤ precipitable dust diameter ≤ 150 µm
Take the following measures to meet the requirements:
  • Use dustproof materials for ground, wall, and ceiling construction.
  • Use screens on the door and windows facing outside. The outer windows should be dust-proof.
  • Clean the equipment room regularly and clean the air filter monthly.
  • Wear shoe covers and ESD clothing before entering the equipment room.
  • Install a door with an air filter in the cabinet where the device is located.

Requirements for Corrosive Gases

The room should be free from dusts and corrosive gases, such as SO2, H2S, and NH3. Table 14-10 lists the requirements for the corrosive gas concentration.
Table 14-10 Requirements for corrosive gas concentration

Chemical active material

Unit

Concentration

SO2

mg/m3

≤0.30

H2S

mg/m3

≤0.10

NOx

mg/m3

≤0.50

NH3

mg/m3

≤1.00

Cl2

mg/m3

≤0.10

HCl

mg/m3

≤0.10

HF

mg/m3

≤0.01

O3

mg/m3

≤0.05
Take the following measures to meet the requirements:
  • Avoid constructing the room near a place where the corrosive gas concentration is high, such as a chemical plant, breeding farm, or sewage plant.
  • Ensure the air intake vent of the room is in the prevailing upwind direction from any pollution source.
  • Place batteries in different rooms.
  • A professional service should monitor the corrosive gas conditions regularly.

Requirements for ESD Prevention

The absolute value of electrostatic voltage must be less than 1000 V.

Take the following measures to meet this requirement:
  • Train operators about ESD prevention.
  • Keep the correct humidity level in the equipment room to reduce the impact of static electricity.
  • Lay out an ESD floor in equipment rooms.
  • Wear ESD shoes and clothing before entering equipment room.
  • Use ESD tools, such as wrist straps, tweezers, and pullers.
  • Ground all conductive materials in the room, including computer terminals. Use ESD worktables.
  • Keep non-ESD materials (such as common bags, foam, and rubber) at least 30 cm (11.81 in.) away from boards and ESD-sensitive components.

Electromagnetism Requirements for the Equipment Room

All interference sources, inside or outside the equipment room, can cause equipment problems with capacitive coupling, inductive coupling, electromagnetic wave radiation, and common impedance (including grounding system) coupling. Prevent the interference using these approaches:

  • Take effective measures against electrical interference from the power supply system.
  • Do not use the working ground of the equipment as the same ground for surge protection. Separate them as far as possible.
  • Keep the equipment far away from high-power radio transmitters, radar units, and high-frequency and high-current equipment.
  • Use electromagnetic shielding if necessary.

Requirements for Lightning Proof Grounding

Table 14-11 lists the requirements for lightning proof grounding.
Table 14-11 Requirements for lightning proof grounding

Item

Requirements

Capital construction

  • Use reinforced concrete to construct the equipment room.

  • Install a lightning proof device like a lightning rod outside the room.

  • The lightning proof ground shares the same grounding body with the protective ground of the room.

Power cables leading in the equipment room need to be equipped with a surge protector

  • After the low-voltage power cables are led into the room, install the surge protector for the power cables in the AC voltage stabilizer and the AC power distribution panel (box). Correctly ground the surge protector nearby.

  • For an equipment room in urban area, install a power supply surge protector with the nominal discharge current of no less than 20 kA. For an equipment room that is built in a suburb and subject to lightning strikes, install a power supply surge protector with the nominal discharge current of more than 60 kA. For an equipment room that is built in a mountain area and subject to frequent lightning strikes, or in a separate high-rise building in a city, install a power supply surge protector with the nominal discharge current of more than 100 kA.

  • The ground cable of the surge protector should be no longer than 1 m (3.28 ft).

Grounding for DC power distribution

  • Connect the DC working ground (positive pole of the -48 V DC power supply or the negative pole of the 24 V DC power supply) with the indoor collective ground cable nearby. The total ground cable should meet the maximum load of the equipment.

  • The power equipment must have a DC working ground cable, which can connect the power equipment to the collective ground cable of the telecommunication site (or the protective ground bar of the equipment room).

Equipotential connection

  • Properly ground the devices and auxiliary devices in the room such as mobile base station, transmission, switching equipment, power supply equipment, and cable distribution frame. Connect all PGND cables to the collective protective ground bar. Connect all PGND cables in one equipment room to one protective ground bar.

  • Apply joint grounding to the working ground and protective ground of devices, which means the two share one grounding network.

  • The cable tray, rack or shell, metal ventilation pipe, metal door or window of the equipment should be grounded for protection.

General requirements for grounding

  • Do not connect the neutral line of the AC power cable with the protective ground of any telecom equipment in the equipment room.

  • Do not install a fuse or switch on the ground cable.

  • All ground cables should be as short as possible, and arranged in a straight line.

Grounding resistance

  • The grounding resistance must be lower than 1 ohm.

  • The upper end of the grounding body should be at least 0.7 m (2.30 ft) over the ground. In cold areas, bury the grounding body below the frozen ground.

  • Measure the grounding resistance periodically to ensure effective grounding.

Routing of signal cable

  • Do not arrange the signal cables overhead in the equipment room. All signal cables must be led into the site underground.

  • Use the cables with a metal jacket or place them into a metal pipe if they come out/in the equipment room.

  • Ground the idle lines inside the cable in the equipment room.

  • Signal cables should be deployed on internal walls. Do not deploy outdoor aerial cables.

  • Keep signal cables away from power cables and surge protection devices.

Collective ground cable

  • Use a ground ring or ground bar for the collective ground cable.

  • Do not use aluminum cables as ground cables. Adopt measures to prevent electrification corrosion when connecting different metal parts together.

  • Use a copper busbar as the collective ground cable with a cross-sectional area of no less than 120 mm2 (0.19 in.2), or use the galvanized flat steel of the same resistance. Insulate the collective ground cable from the reinforcing steel bars of the building.

Grounding lead-in

The grounding lead-in should be a maximum of 30 m (98.42 ft) long. Use the galvanized flat steel with cross-sectional area of 40 mm x 4 mm (1.58 in. x 0.158 in.) or 50 mm x 5 mm (1.97 in. x 0.197 in.).
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Updated: 2023-10-23

Document ID: EDOC1000069460

Views: 142181

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