Cable laying 1 Scope This process standard is applicable to the laying of power cables for electrical installations of general industrial and civil buildings of 10 kV and below. 2 Construction Preparation 2.1 Equipment and Material Requirements:

2.1.1 All material specifications, models and voltage levels should meet the design requirements and have product certification.

2.1.2 The cable size, type, voltage grade, length, and date of manufacture should be indicated on each axis cable. The cable shaft should be intact.

2.1.3 The appearance of the cable is intact, the armor is free of rust, no mechanical damage, and the light is significantly wrinkled and distorted. The oil-immersed cable should be well sealed without oil leakage and oil seepage. Rubber sheath and plastic cable sheath and insulation show no aging and cracks.

2.1.4 All kinds of metal steel should not have obvious corrosion, and there is no burr in the tube. All fastening bolts should be galvanized.

2.1.5 Other ancillary materials: Cable cover plates, cable marking piles, cable signs, paint, gasoline, lead seal, stearic acid, white cloth tapes, rubber bag cloths, black bag cloths, etc. shall all meet the requirements.

2.2 main equipment:

2.2.1 Motors, brackets for laying cables and shafts, cable rollers, turning guide wheels, hanging chains, pulleys, wire ropes, hemp ropes, and jacks.

2.2.2 Insulation rocker, tape measure, hacksaw, hand hammer, wrench, electric welding tool, electrician tool.

2.2.3 radio walkie-talkies (or simple telephone), hand-held loudspeakers (conditional multi-function amplifiers can be used for communication).

2.3 Operating conditions:

2.3.1 The civil works should meet the following conditions: Reserve holes, embedded parts meet design requirements, embedded parts are firmly installed, and strength is acceptable. The floor and finish of cable trenches, tunnels, shafts, and manholes are completed and the drainage of cable trenches is smooth without water accumulation. The demolition of the equipment such as the cable along the template is completed. The site is clean, the road is unimpeded, and the trench cover is complete. The erection of the scaffold for placing the cable is completed and the safety requirements are met. Illumination along the cable satisfies the construction requirements. Directly bury the cable trench and dig well according to the plan. The cable well is plastered and plastered. The sand is laid and the debris in the trench is removed. The cover and sand are transported to the ditch.

2.3.2 The following conditions shall be met for the installation of the equipment: All electrical equipment and electrical equipment distribution cabinets in the power distribution room shall be installed. Cable trays, cable trays, cable brackets, and wire and tube protection tubes are installed and inspected. 3 Operation process 3.1 Process flow: buried cable laying → sand-covered brick → backfill soil → buried stake → preparations → horizontal laying → cable along the bracket, bridge laying → hanging signs → vertical laying → buried stakes → nozzle Waterproofing → Peeling brush oil → Hanging sign 3.2 Preparation:

3.2.1 Conduct a detailed inspection of the wires before construction; specifications, models, cross-sections, and voltage levels all meet the design requirements, and the appearance is free from distortion, damage, oil leakage, and oil leakage.

3.2.2 Insulation shake test or pressure test before cable laying. For cables below 1kV, use a 1kV megger to shake the line and the insulation resistance to ground shall not be less than 10M. 3 to 10 kV cables shall be tested in advance for pressure and leakage, and the test standards shall comply with the provisions of national and local power supply departments. If necessary, the insulation resistance must be measured with a 2.5kV megger before laying. Paper-insulated cables. If the test is unqualified, the core should be checked for moisture. If it is wet, it can be sawed off and then tested until it is qualified. The inspection method is: peel off a piece of core insulation paper and point it with a fire. If the sound is batter, the cable is wet. After the cable test is completed, the oil-impregnated paper-insulated cable shall be immediately sealed with solder (lead-tin alloy). Other cables are covered with a rubberized cloth and then wrapped with black cloth.

3.2.3 Installation of cable-laying equipment: When using mechanical-displacement cable, the machine should be installed in a proper position and the steel wire rope and pulley should be installed. When installing the cable manually, install the roller in advance.

3.2.4 Setting of temporary liaison command system: Short-circuit or outdoor cable laying can be communicated with radio walkie-talkies and controlled by handheld loudspeakers. The cable laying in high-rise buildings can be used as a directional link with a radio walkie-talkie. The simple telephone is used as a full-line liaison and is commanded by a hand-held loudspeaker (or a multi-purpose amplifier, which is a special device for commanding and placing cables).

3.2.5 When laying multiple cables on a bridge or a bracket, arrange the cables in advance according to the actual situation on the site and use a table or drawing. In case of cable crossover and confusion.

3.2.6 When the cable is laid in winter and the temperature does not meet the requirements of the code, the cable should be warmed in advance.

3.2.7 Cable Handling and Bracket Installation: Cables are transported at short distances. The method of rolling the cable shaft is generally used. When scrolling, scroll in the direction indicated by the arrow on the cable axis. If there is no arrow, it can be rolled in the direction of winding the cable, and must not be rolled in the opposite winding direction to avoid loose cable. The installation location of the cable bracket shall be selected so as to facilitate the laying of the cable bracket. Generally, it shall be straight near the start and end points of the cable. When erecting, pay attention to the direction of rotation of the cable axis. The cable outlet should be above the cable axis (Figure 2-1).

3.3 buried cable laying:

3.3.1 Remove impurities from the trenches, and lay down the bottom sand or fine soil.

3.3.2 Cabling Figure 2-1 Cable laying can be pulled manually or mechanically. The use of mechanical traction can be achieved with electric winch or dragging (dry ship method) (see Figure 2-2) and (Figure 2-3). When laying the cable, it should be noted that the cable bending radius should meet the requirements of the specification. Figure 2-2 Manual traction diagram Figure 2-3 Mechanical traction (dropper) diagram The cable should be laid in the trench with a proper amount of serpentine bends. The two ends of the cable, the middle connector, the cable well, the tube, and the vertical There should be an appropriate margin of redundancy.

3.3.3 sand cover brick: After laying the cable, the quality inspection department of the construction unit, the supervision unit and the construction unit shall be required to jointly perform the inspection of the concealed project. Acceptance of concealed works Pass the cable up and down with 10cm sand or fine soil, and then cover the cable with a brick or cable cover. The cover width should exceed 5cm on both sides of the cable. When using the cable cover, the cover should point in the direction of power reception.

3.3.4 Backfill soil. Before backfilling the soil, another hidden project inspection shall be conducted. After passing the inspection, the soil shall be backfilled and compacted.

3.3.5 Buried stakes: Cables shall be provided with apparent bearing stakes in corners, joints, crossings, and entrances and exits of buildings. Lines should be properly set up stakes. It is advisable that the stake be exposed to the ground with 15cm.

3.3.6 Directly buried electric wires in and out of the building, where the indoor pipe outlet is lower than the outdoor ground, waterproof treatment shall be performed on the pipes according to design or standard drawings (Figure 2-4). Figure 2-4

3.3.7 When a cable with a protective layer of hemp skin enters the indoor part, the hemp skin shall be stripped off and painted with anti-corrosion paint.

3.4 Cables are laid along the brackets and bridges:

3.4.1 Horizontal laying The laying method may be manual or mechanical. When laying cables along bridge or trays, they shall be laid in a single layer and arranged in order. There must be no crossover. The bend radius should be based on the maximum allowable bending radius of the cable. Cables of different grade voltages shall be laid in layers, and high voltage cables shall be laid in the upper layer. When installing the cable with the same voltage level along the bracket, the horizontal distance shall not be less than 35. Mm

3.4.2 Vertical laying. Vertical laying, the best conditions for the laying of the top down. Lift the cable to the top of the floor before building the crane. When laying, the same section cable should be laid on the lower floor, after the laying of high-rise, pay special attention, near the cable shaft and some floors should take anti-skid measures. When laying from bottom to top, low-layer small-section cable can be laid by human traction of a large rope pulley. High-level, large-section cable should be used mechanical traction laying. When laying along the bracket, the distance between the brackets shall not be more than 1.5 meters. When laying along bridges or pallets, install at least two clip brackets on each floor. When laying, you should put a piece of it immediately. When the cable passes through the floor, the casing shall be installed. After laying, the casing shall be tightly sealed with fireproof material.

3.5 hanging signs:

3.5.1 The specifications of the signboard should be consistent, and have anti-corrosion performance. The mounting should be firm.

3.5.2 The cable number, specification, model and voltage rating should be indicated on the signboard.

3.5.3 Directly buried cables shall enter and exit the building, cable wells and both ends of the board.

3.5.4 Cables shall be placed at the ends, corners and intersections along the bracket bridges. Signs shall be added to the straight sections. 4 Quality Standard 4.1 Guaranteed Project:

4.1.1 The withstand voltage test results, leakage current and insulation resistance of the cable must comply with the provisions of the construction specification.

Inspection method: check the test record.

4.1.2 The laying of cables must comply with the following provisions: The cable must not be twisted, flattened, broken, or severely scratched on the surface of the sheath. When laid directly, it must not be laid parallel to the top or bottom of the pipe.

Inspection method: Observe and inspect the concealed project records.

4.2 Basic items:

4.2.1 Coordinates and elevations are correct, neatly arranged, signposts and signs are set up accurately; the cable protection measures required for fire protection, heat insulation and corrosion protection are complete.

4.2.2 When laying on the bracket, it is fixed and reliable. The cable on the same side bracket is arranged in the correct order. The control cable is under the power cable. The power cable below 1kV should be placed under the power cable above 1kV; the depth of buried cable buried, The requirements for backfilling, protective measures and the minimum distance between the cables and between the cable and the underground pipe network are to comply with the requirements of the construction regulations.

4.2.3 Cable turns and branches are not disordered, neat and clear, cable sign piles and signs are clear and complete, and hidden construction records and coordinate diagrams of buried cables are complete and accurate.

Inspection method: Observe and inspect the concealed project records and coordinate diagrams.

4.3 The minimum bending radius of the cable and the test method shall comply with the requirements of Table 2-l. Cable minimum bending radius and test method Table 2-1 Item Bending Radius Inspection Method Single core multi-core cable ≥ 20d ≥ 15d Minimum rubber or PVC sheath ≥ 10d1 Permissible rubber insulation Power cable bare lead sheath ≥ 15d lead bend Sheathed steel tape armored ≥20d check radius Plastic insulated power cable ≥ 10d Control cable ≥ 10d Note: d is the outer diameter of the cable. 5 Finished product protection 5.1 The construction of buried cables should not be too early, generally after other outdoor projects are basically completed, to prevent damage to the cables during construction of other underground projects. If the cable has been laid ahead of schedule, other underground constructions should be stepped up.

5.2 Immediately after the buried cable is laid, it should be sanded, covered or bricked and backfilled to prevent other heavy objects from damaging the cable. The as-built drawings shall be drawn in time to indicate the actual azimuth coordinates and laying depth of the cables.

5.3 The trench cover should be covered immediately after the construction of the cable laid along the cable trench.

5.4 Indoor laying of cables along bridge trays or pallets should be carried out after the basic construction of the pipeline and air-conditioning works is completed to prevent damage to cables during construction of other specialties.

5.5 The doors and windows at both ends of the cable are installed and locked to prevent the cable from being lost or damaged. 6 Quality problems that should be noted 6.1 Directly burying cables Covering tiles or bricks should prevent the removal of impurities in the trenches, the absence of fine sand or fine soil, and the lack of cover or bricks, and missing parts. The person in charge of construction should strengthen inspections.

6.2 When the cable enters the inner cable channel, it prevents the casing from being treated with water and the water in the ditch. Should be strictly in accordance with specifications and process requirements.

6.3 oil-immersed cable to prevent the end of the head seal is not tight, there is oil leakage phenomenon. Technical training for construction operators should be conducted to improve the operation level.

6.4 When laying cables along brackets or bridges, prevent the cables from being misaligned and having serious crossovers. Before the cable construction, arrange the cables in advance, draw out the arrangement chart, and perform the construction according to the chart. When the cable is laid, it should be laid one by one and fixed one.

6.5 The cable with hemp protective layer enters the room to prevent the anti-corrosion treatment of the stripping oil.

6.6 Cables laid along trays or trays should be prevented from having insufficient bending radius. During the construction of the bridge or pallet, the construction personnel should consider meeting the requirements for the bending radius of the largest cross-section cable laid on the bridge or pallet.

6.7 Preventing the cable sign from hanging out neatly or missing. Should be reviewed by someone else. 7 Quality Record 7.1 Quality Assurance Information;

7.1.1 cable product certification.

7.1.2 Cable insulation shake or pressure test records.

7.1.3 concealed project acceptance records.

7.1.4 All kinds of metal profile material certification, certificate.

7.2 Construction Record:

7.2.1 Self-check record 7.2.2 Cable engineering sub-item quality inspection and assessment records.

7.2.3 The project acceptance record.

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