May 02, 2023

Specification Requirements for Pigtail Wiring for Optical Transmitter Boxes in Low Current Projects

Specification Requirements for Pigtail Wiring for Optical Transmitter Boxes in Low Current Projects

Strictly adhere to product quality control and project evaluation standards during construction process to check actual work quality one by one. After completion of project, an assessment of quality of construction will be carried out, and materials will be prepared to confirm quality. ensure that delivered project exceeds design concept. Defines and takes into account role of application.

One. Laying electrical equipment routes

①Usually required

1. Before laying cables (lines), perform an external inspection.

2. The route is laid out centrally to least extent, horizontal and vertical, neat and graceful, not suitable for crossing.

3. Routes should not be laid in places subject to mechanical damage, emissions of aggressive substances, humidity, strong magnetic and electric fields, if necessary, take effective protection or shielding measures.

4. If air temperature around route is above 65°C, thermal insulation measures must be taken, in presence of a fire that can lead to a fire, fire safety measures must be supplemented.

5. The route is not suitable for parallel laying in high-temperature processes above pipelines and processes with aggressive liquid substances directly below pipelines.

6. An appropriate margin must be left for wiring of terminal equipment of route and places for its passage through expansion joints of building and foundation settlements.

7. The line should not have a middle connector. If it is unavoidable, it should be connected to a junction box or terminal, and connector should be inserted into socket, a non-corrosive flux should be used when welding. For compensating wires, coaxial cables with connectors should be used, and for high-frequency cables, special connectors should be used.

8. When laying roads, it is not recommended to drill mounting holes on concrete beams and columns.

9. After completing route, you should draw a school line and a serial number.

10. When measuring line insulation, connected equipment and components must be disconnected.

②Cable laying

1. The working temperature when laying cable should not be lower than -7℃.

2. When laying cable, it must be laid scientifically, and it is not suitable for crossing; when laying it is necessary to avoid friction between cable and between cable and other solid objects; when it is fixed, tightness must be appropriate.

3. The bending of semi-core of a multi-core cable must be at least 6 times its diameter.

4. When shielded cables (wires) intersect with wires and cables, they must form oblique angles; when they are laid on parallel surfaces, distance between them must comply with requirements of design solution.

5. Cables with different data signals and different voltage ratings in oneoh and same bridge frame must be classified and laid; for AC circuit lines and franchise lines, use barriers to separate and route unshielded data lines.

6. The cable must be fixed and firmly secured when routed along support frame or free line trough.

7. When installing bridge vertically, cables must be sorted from top to bottom in accordance with following requirements: dashboard data path; franchise chain safety route; route of DC and AC power supply system;

8. The clear distance between installed data line and electrical equipment with a strong magnetic field and a strong electrostatic field must exceed

1.5 m, when used for laying shielded cables or cable protection tubes with metallic materials and free line grooves, it must exceed 0.8 m.

9.When laying cable in a trench, it should be laid on support frame or in frame of bridge. When a cable enters a building, cable duct and building must be protected and sealed.

③Other rules

1. The cable protection tube must be cleaned before cable is passed through tube, and transmission line must not be damaged when passing through tube.

2. Separate cable protection tubes must be selected for data signal path, power system path, chain franchise path and required instrument panel data signal path.

3. The routes on both sides of terminal block in instrument panel (box) in vehicle must be numbered in accordance with technical drawings.

4. When transmission line is connected to terminal block, instrument panel, electrical equipment, etc., an appropriate margin should be left.

two. Installation of switching power supply equipment

①Installation of power supply and distribution system

1. The power supply equipment of low-voltage projects should check appearance and specifications of equipment before installation.

2.Automotive relays, AC contactors and switches must be movable in motion, inseparable in contact, free of rust and damage.

3.Standard parts and terminal blocks must be intact, free of debris and rust.

4. The notes on machines and equipment are complete and specifications are in accordance with requirements of installation manual.

②Installation of switching power supply equipment

1. The installation of machinery and equipment must be strong, neat and beautiful. The serial number of terminal, main purpose plate and other signs must be complete and written correctly and clearly.

2. For large equipment, it must be evenly supported by equipment.

3. The distance between open charged parts of power equipment installed in instrument box, andthere must be at least 4 mm between other exposed conductors. When it is not running, there must be an insulating layer between them.

4. When power supply is installed on a concrete wall, column or foundation, it must be fixed with expansion screws, and following requirements must be met: (1) The height ratio between center of case and height of ground should be 1.3-1.5 m. (2 ) Power supply system boxes installed in shade should be neatly arranged.

5.After installing UPS equipment, it is necessary to check reliability of its automatic conversion equipment.The conversion time and value of conversion working voltage should be consistent with requirements of design concept.

6. Before using a regulated power supply, check characteristics of its zener diode, and operating voltage fluctuation value must comply with requirements of installation and use manual.

7. The output operating voltage of ballast must be checked before use, and operating voltage value must comply with requirements of manual before installation.

8. The ground resistance between inductive electrification part of power supply equipment and metallic material case must be at least 5 MΩ when accurately measured with a 500 V megger. If installation manual contains unique requirements, these requirements must be met.

9. Before closing power supply and distribution system, switches of all power supply equipment in system must be in "relay" position, and fuse size must also be checked.

Thirdly, grounding device of integrated electrical wiring system

①Usually required

1. The earthing device of integrated wiring system is divided into protective earthing device and multifunctional earthing device according to main purpose. The protective earthing device is divided into: high-voltage electric shock protection earthing device, lightning protection earthing device, anti-static earthing device and electrical corrosion protection earthing device; multifunctional grounding device is divided into: working grounding, logical grounding device, shielding grounding device. and a data signal grounding device. Different earthing devices have different requirements, and earthing device must be designed according to design concept.

2. The grounding system of an integrated electrical wiring system to be grounded must meet following requirements:

(1) When using hot-dip galvanized wire pipe for piping, except where specifically specified in design, there is no need for wire jumpers after connecting plumbing andwater pipes, water pipes and small metal boxes, but following requirements must be observed:

When using bolts to connect water pipes, length of male thread at end of pipe should be at least 1/2 length of tee connection. The surface of male thread should be smooth, without rust and damage. Or conductivity anti-corrosion grease. Once connected, outer thread should expose 2-3 buckles.

When connecting water pipes to waterproof casings containing mounting screws, screws must be tightened; in places with vibrations, fixing screws must be secured against loosening.

Plastic sleeves should not be used for connection between water pipe and small box, but conductive metal sleeves should be used.

If there is a PE line in water pipe of low current installation, each terminal is connected to PE line.

(2) If hot-dip galvanized wire pipes are selected for pipeline, and design concept requires bridging between water pipes, following requirements must be observed:

Arc welding jumper wires cannot be used for open piping and special buckle jumper wires designed to specific design concepts should be used. For cable ducts directly buried or routed through concrete, arc welding jumpers can be used instead of line card jumpers. If there is bare soft polyethylene copper wire on outside of tube, no jumper is required. This PE wire must be connected to each terminal through which it passes. When piping is made of black iron pipe, if design concept does not require bridging, then no bridging is required. If jumper wires are specified, spring steel wire jumpers can be used in middle of black iron pipe and between black iron pipe and terminal. When PVC pipes are used for both high current and low current, low current installation piping should be run as little as possible parallel to low current piping to prevent interference. When laying bridges for strong and weak currents, high and low wire troughs should be separated; When it needs to be laid on same bridge, use metal baffles to separate high and low currents.

②Pre-construction environmental survey

Before starting equipment installation project, finish checking design and environmental conditions of handover room and equipment room, and construction can be started under following conditions:

1. The work transfer room, machinery and equipment room, and general construction work in work area have been completed. The floor of house is flat and smooth, height and width of door should not interfere with transportation of equipment and equipment, there are anti-theft locks andkeys.

2. The location, number and size of pre-buried earthen ditches, dark holes and openings in house must comply with requirements of project.

3. A reliable building power supply and grounding system must be provided in work acceptance room and control room.

4. The total area of ​​the work acceptance room and control room, temperature and humidity of environment must comply with design requirements and relevant requirements.

③Inspection of equipment before construction

Device testing typically includes:

(1) Before starting construction, construction company must check specifications, models, G codes, numbers, and quality of cables and equipment commonly used in project. do not correspond to design concept, cannot be used in project.

(2) Tested devices should be well-registered, and components with unqualified certificates should be kept independently for review and resolution.