Best Construction Standards & Techniques for Structured Cabling

The cabling construction strictly adheres to the relevant building cabling installation standards and local regulations. The main regulations to be followed in this construction detail include:

"Code for Design of Generic Cabling System for Buildings and Building Groups" (GB/T 50311-2016)

"Acceptance Code for Generic Cabling System Engineering" (GB/T 50312-2016)

Before the installation work begins, the construction and environmental conditions of the wiring closet and equipment room should be inspected.

 

1.The civil engineering of the wiring closet, equipment room, and work areas has been fully completed. The floor should be flat and smooth, the height and width of the doors should not hinder the movement of equipment and materials, and the doors should be equipped with locks and keys.

2.The positions, quantities, and dimensions of the pre-installed floor slots, concealed holes, and openings should meet the design requirements.

3.Special attention should be given to the inspection of the raised floor in the equipment room. The floor panels should be tightly and firmly installed, with a horizontal tolerance of no more than 2mm per square meter. The floor supports should be secure, and the grounding of the anti-static measures for the raised floor should comply with the design and product specifications.

4.The wiring closet and equipment room should provide reliable construction power and grounding devices.

5.The area, environmental temperature, and humidity of the wiring closet and equipment room should meet the design requirements and relevant regulations.

 

(1) Before construction, the construction team must verify the specifications, models, quantities, and quality of the cables and equipment used in the project. Equipment without factory inspection certification or that does not match the design cannot be used in the project.
(2) The inspected equipment should be recorded, and defective components should be stored separately for further inspection and handling.

 

(1) The material, specifications, and models of various profiles should comply with the design documents. The surface should be smooth and flat, without deformation or fracture.
(2) When using steel pipes, rigid polyvinyl chloride pipes, or glass fiber reinforced plastic pipes, the pipe body should be smooth without scars, and the pipe hole should not be deformed. The bore and wall thickness should meet the design requirements.

 

(1) The specifications, models, and types of twisted pair cables and optical cables used in the project should comply with the design and contract requirements.
(2) The markings and labels attached to the cables should be complete and clear.
(3) The outer sheath of the cable should be intact, and the cable should be accompanied by a factory quality inspection certificate. If required by the user, a report on the electrical performance test of the batch of cables should be provided.
(4) The electrical performance of the cable should be tested by sampling 100m from any three reels of the batch of cables.
(5) When cutting the cable head, the A and B ends should be identified if required, and the type and sequence number should be marked on the outer end of the cable.
(6) After opening the optical cable, the outer appearance should be inspected for damage, and the sealing of the cable end should be checked.
(7) When using 62.5/125μm or 50/125μm multimode graded-index optical fibers and single-mode optical fibers in the structured cabling system, on-site testing should include the attenuation constant and fiber length.

Attenuation Test: It is recommended to use an Optical Time Domain Reflectometer (OTDR) for testing. If the test results exceed the standards or differ significantly from the factory test values, an optical power test should be performed for comparison to determine whether the deviation is due to testing errors or excessive fiber attenuation.

Length Test: Each optical fiber should be tested, and the results should be consistent. If there is a significant difference in fiber length within the same optical cable, testing should be performed from the other end or a light transmission check should be conducted to determine if there is a broken fiber. The inspection of fiber optic patch cords should comply with the following regulations:

The fiber optic patch cords should have a fire-resistant optical fiber protective sheath, and both ends should be equipped with suitable protective caps for the active connectors.

The type of optical fiber in each jumper cable should be clearly marked, and the selection should comply with the design requirements.

 

(1) The plastic material of the patch panel, information outlet, and other connectors should be flame-retardant.
(2) The overvoltage and overcurrent protection indicators of the security patch panel should comply with the relevant regulations of the Ministry of Posts and Telecommunications.
(3) The type and quantity of optical fiber outlet connectors and their locations should match the design.
(4) The optical fiber outlet panel should have clear markings for transmission (TX) and reception (RX).

 

(1) The model and specifications of the cable distribution equipment should comply with the design requirements.
(2) The arrangement and labeling of the optical and cable distribution equipment should match the design. All label names should be consistent, and label positions should be accurate and clearly visible.
(3) The specific technical indicators and requirements for the electrical performance, mechanical properties, optical cable transmission performance, and connectors of the UTP cables should comply with the design specifications.

 

:(1) After the network rack installation is complete, the horizontal and vertical tolerances should comply with the manufacturer's specifications. If no manufacturer specifications are available, the vertical deviation should not exceed 3mm.
(2) Various parts on the rack should not fall off or be damaged. If the paint falls off, it should be repainted, and all labels should be complete and clear.
(3) The rack installation should be secure and should be reinforced according to the construction drawing requirements.
(4) The rack panel should be installed with a front clearance of 1.5m and a rear clearance of more than 0.8m from the wall to facilitate installation and construction.
(5) The bottom of the wall-mounted rack should be 300~800mm above the ground.

(1) When using a bottom cable routing method, the rack's bottom position should align with the cable entry holes.
(2) The vertical tilt error of each vertical column should not exceed 3mm, and the horizontal error of the base should not exceed 2mm per square meter.
(3) All labels on the terminal blocks should be complete.
(4) The patch panel or concealed cable box should preferably be installed inside the wall. The bottom of the box should be 500~1000mm above the ground.

 

(1) The terminal block equipment should be complete, installed in place, and labeled.
(2) The installation screws must be tightened, and the panels should be kept in a horizontal plane.

 

(1) Installed on the raised floor or ground, it should be fixed in the junction box, and the outlet panel can have vertical and horizontal forms; the junction box cover can be opened and should be tightly waterproof and dustproof. The junction box cover should be flush with the ground.
(2) When installed on the wall, it should be 300mm above the ground. If the ground uses a raised floor, the internal height of the raised floor should be added.
(3) The fixing method of the information outlet base should be determined by the construction site conditions, preferably using expansion screws, nail guns, etc.
(4) The fixing screws must be tightened to avoid looseness.
(5) The information outlet should have a label, indicated by color, graphics, or text, to represent the type of terminal equipment connected.
(6) The installation position should comply with the design requirements.

 

(1) The installation position of the cable tray and aisle should comply with the construction drawing, with a left-right deviation not exceeding 50mm.
(2) The horizontal deviation of the cable tray and aisle should not exceed 2mm per square meter.
(3) The vertical cable tray and aisle should be perpendicular to the ground without tilting, and the vertical deviation should not exceed 3mm.
(4) The horizontal deviation at the splice of the two channels should not exceed 2mm.
(5) The suspension bracket installation should be vertical, neat, and secure, without tilting.
(6) The metal cable tray and channel should have good contact with the joints and be securely installed.

 

 

(1) Before laying the cables, the specifications, models, routes, and positions should be checked to ensure they comply with the design requirements.
(2) The cables should be laid straight without twisting, loops, or external force damage.
(3) Labels should be attached to both ends of the cable before laying, indicating the start and end positions. The labels should be written clearly, neatly, and correctly.
(4) Power cables, signal cables, UTP cables, optical cables, and other weak system cables in the building should be laid separately. The minimum clearance between the cables should comply with the design requirements.
(5) Cable laying should have redundancy. In the wiring closet and equipment room, the UTP cable reserve length is generally 36m, and in the work area, it is 0.30.6m; the optical cable reserve length at the equipment end is generally 510m. Special requirements should follow the design requirements.
(6) The bending radius of the cable should comply with the following regulations:
① The bending radius of unshielded 4-pair UTP cables should be at least 4 times the outer diameter of the cable, and at least 8 times during construction.
② The bending radius of shielded UTP cables should be at least 610 times the outer diameter of the cable.
③ The bending radius of backbone UTP cables should be at least 10 times the outer diameter of the cable.
④ The bending radius of 2-core or multi-core horizontal optical cables should be greater than 25mm; the bending radius of other multi-core horizontal optical cables, backbone optical cables, and outdoor optical cables should not be less than 10 times the outer diameter of the optical cable.
⑤ To avoid stress and twisting during cable laying, a qualified traction head should be made. If mechanical traction is used, centralized or distributed traction methods should be selected based on the cable traction length, laying environment, and traction tension.
⑥ When laying optical cables, the rotation of the optical cable reel should be synchronized with the cable laying, and the cable laying speed is generally 15m/min. The optical cable outlet should maintain a relaxed arc and reserve a buffer margin, but not too much, to avoid cable back-bending.

(1) The two ends of the buried pipe should have markings indicating the room number, sequence number, and length.
(2) When laying concealed pipes, steel pipes or flame-retardant rigid PVC pipes should be used. The pipe diameter utilization rate for straight pipes should be 5060%, and for curved pipes, it should be 4050%. When laying 4-pair UTP cables in concealed pipes, the cross-sectional utilization rate of the pipe should be 25~30%. The pre-buried cable trench should preferably use metal cable trenches, and the cross-sectional utilization rate of the trench should not exceed 40%.
(3) When laying optical cables and cables in the same pipe, a plastic pipe should be pre-installed inside the concealed pipe to lay the optical cables separately, ensuring that the optical cables and cables are laid separately. The inner diameter of the pipe should be 1.5 times the outer diameter of the optical cable.

(1) The cable tray should preferably be more than 2.2m above the ground, and the top of the cable tray should be at least 0.3m away from the ceiling or other obstacles. The width of the cable tray should not be less than 0.1m, and the fill rate of the cross-section inside the cable tray should not exceed 50%.
(2) When laying cables vertically in the cable tray, they should be fixed to the cable tray bracket at the top and every 1.5m. When laying horizontally, they should be reinforced at the beginning, end, turns, and every 3~5m.
(3) The cable trench should preferably be 2.2m above the ground. When installed in the ceiling, the opening surface of the trench cover should maintain a vertical clearance of 80mm, and the cross-sectional utilization rate of the trench should not exceed 50%.
(4) When laying cables in the cable trench, they do not need to be bundled. The cables in the trench should be straight and  try to avoid crossing, and the cables should not overflow the trench. At the cable entry and exit points of the trench and the turns, they should be bundled and fixed. Vertical cable trenches should fix the cables every 1.5m on the cable bracket.
(5) When laying cables in horizontal and vertical cable trays and vertical cable trenches, the cables should be bundled. 4-pair UTP cables should be bundled in 24-cable bundles, and 25-pair or more backbone UTP cables, optical cables, and other signal cables should be bundled according to the cable type, diameter, and number of cores. The bundling interval should not be greater than 1.5m, and the buckle interval should be uniform, with moderate tightness.

The support and protection methods for cable laying in the distribution subsystem should comply with the following requirements:

 

① Pre-buried cable trenches in buildings can be of different sizes, set in one or two layers, and should have at least two pre-buried trenches, with a cross-sectional height not exceeding 25mm.
② When the straight buried length exceeds 6m or when the cable trench route crosses or turns, a pull box should be set to facilitate cable laying and maintenance.

 

① Concealed pipes should preferably use metal pipes or flame-retardant rigid PVC pipes. The inner diameter of the concealed pipes pre-buried in the wall should not exceed 50mm, and the inner diameter of the concealed pipes in the floor should be 15~25mm. A concealed cable box should be set every 30m of straight pipe.
② The turning angle of the concealed pipe should be greater than 90 degrees, and there should be no more than two turns per pipe, without S-bends. A concealed cable box should be set every 15m when bending the pipe.
③ The bending radius of the concealed pipe should not be less than 6 times the outer diameter of the pipe. If the outer diameter of the concealed pipe is greater than 50mm, it should not be less than 10 times.

① When laying horizontally, the support interval is generally 1.5~3m, and when laying vertically, it should be fixed to the building structure at intervals of less than 2m.
② Metal cable trenches should be equipped with brackets or hangers in the following cases:
A. At the cable trench joint;
B. Every 3m;
C. 0.5m from both ends of the cable trench;
D. At the turn.
③ The fixed point interval of the plastic cable trench bottom is generally 1m.

 

the net clearance inside the raised floor should not be less than 150mm. If the raised floor is used as an air duct for the ventilation system, the net height inside the raised floor should not be less than 300mm.

 

or when laying cables under the carpet in the work area, a patch panel should be installed.

 

The grounding of the metal cable trench should comply with the design requirements.

 

(1) Cables should not be laid in elevator or pipeline shafts.
(2) The backbone channel should be connected. The hole in the shaft that passes through each floor should be either rectangular or circular. The size of the rectangular hole should not be less than 300mm×100mm, and at least three circular steel pipes should be installed at the circular hole, with a diameter not less than 100mm.

 

During the structured cabling process, various record tables should be kept for future reference and analysis.