Precautions for quality acceptance of prefabricated branch cables

In order to ensure accurate processing and manufacturing of prefabricated branch cables and meet product quality requirements, the cables must undergo the following project acceptance.

1. Check the certificate of conformity, relevant technical documents, and product certification marks produced according to national standards.

2. Verify whether the models, specifications, lengths, and voltage levels of the main and branch cables meet the design requirements.

3. The appearance of the cable is intact, without flattening or twisting, the sheath is not aged or cracked, and the cable head is tight.

4. The outer protective layer of heat-resistant and flame-retardant cables should have clear markings and manufacturer labels.

5. Conduct insulation shake test on the cable using an insulation resistance meter with a range of 1000V and a resistance value of ≥ 10 megohms.

Precautions for installation and laying of prefabricated branch cables

When prefabricated branch cables leave the factory, they are tied to the main cable. After the main cable is installed and fixed, the branch cable can be untied.

2. Before installation, the top of the cable should be waterproofed with a sealing cap, and then reinforced with a heat shrink tubing.

During the installation process, attention should be paid to fixing the branch cables to avoid shaking and ensure good contact between the internal crimping parts of the branch joints.

4. The buried laying of ice flat cables is the same as that of ordinary cables. It is worth noting that the branch joints are inconvenient to pass through pipes, so they should be avoided from being laid in environments that are susceptible to mechanical external forces.

5. The vertical laying of prefabricated branch cables is different from the laying of ordinary cables, and requires the installation of accessories, including hangers (also known as crossarms), cable brackets, cable fixing clamps, and hanging head devices for upper end fixation.

6. To prevent eddy current effects, it is strictly prohibited to use iron clamps for single core cables, and saddle plastic wire clamps should be used for fixation; Single core cables cannot be threaded through a single steel pipe. When threading through a pipe, four cables A, B, C, and N must be threaded through a single steel pipe.

7. Before laying, check the cable channel to confirm whether the branch cable can safely pass through the hole, and develop detailed preventive measures to prevent damage to the branch part when passing through the hole during the lifting process.

8. During the lifting process, do not apply tension to the branch lines. Use lifting ropes with a strength of more than 4 times the weight of the cable. After the cable is lifted, immediately fix the hanging head at the top of the cable to the hanger, and fix the main cable with a fixed clamp every 1.5>2m. The weight of the prefabricated branch cable should be evenly distributed on the bracket as soon as possible to prevent local stress and damage from falling.

9. After installation, seal the cable openings with fireproof materials and hang cable signs at the ends and branches of prefabricated branch cables.

Conclusion

The emergence of prefabricated branch cables has changed the history of making cable heads on construction sites for a long time, and is a major breakthrough for wires and cables used in low-voltage distribution systems. It has excellent power supply reliability, good earthquake resistance, air tightness, waterproofing, convenient construction, low environmental requirements, and maintenance free characteristics. The application of prefabricated branch cables in China has been rapidly promoted. With the acceleration of various infrastructure construction and real estate development in China, the market's requirements for the types of applications of prefabricated branch cables are constantly increasing, and the performance requirements are constantly improving. For example, from ordinary cables to flame retardant, fire-resistant, halogen-free low smoke flame retardant requirements, from small cross-section to large cross-section, from single core to multi-core, etc., the application prospects of prefabricated branch cables are very broad. After all, prefabricated branch cables are a new member of the cable family. In order to adapt to the further development needs of prefabricated branch cables, understanding and mastering prefabricated branch cables and their usage precautions is crucial for their promotion and application.