Cable branch box quality appraisal

Cable branch box is a power system component used for branching, connecting and protecting cables in high or low voltage cable networks. Cable branch boxes usually consist of a metal or plastic shell with insulating parts, connection terminals, cable joints, etc. inside, which are used to branch, connect and protect cables.
In cable networks, cable branch boxes are used to distribute power from one main cable to multiple branch cables to supply different loads or areas. The cable branch box is an important part of the stable operation of the power system. It not only improves the flexibility and reliability of the cable network, but also facilitates the maintenance and management of the power system.
In the case of cable branch box quality appraisal, Zhongke Testing can provide cable branch box quality appraisal services.

cable branch boxes are divided into power distribution cabinets and lighting control boxes according to functions;
is divided into fixed (detachable) and mobile types according to structure;
can be divided into fixed and wall-mounted types according to installation methods;
can be divided into AC and DC types according to power supply.

GB/T 3906-2020 3.6 kV～40.5 kV AC metal-enclosed switchgear and control equipment
GB/T 11023-2018 High-voltage switchgear sulfur hexafluoride gas sealing test method
GB/T 28811-2012 High-voltage switchgear and control equipment based on IEC Digital interface for 61850
GB/T 28537-2012 Use and handling of sulfur hexafluoride (SF6) in high-voltage switchgear and control equipment
GB/T 28810-2012 High-voltage switchgear and control equipment Application of electronics and related technologies in auxiliary equipment for switchgear and control equipment
GB/T 28534-2012 Environmental and health impacts of the release of sulfur hexafluoride (SF6) gas in high-voltage switchgear and control equipment
GB/T 24836-2018 1100kV gas insulated metal-enclosed switchgear
GB/T 4208-2017 Enclosure protection grade (IP code)
GB 7251.1-201 Low-voltage complete switchgear and control equipment Part 1 General

A company lays cables and uses 4 cable branch boxes. The branch boxes are produced by a domestic famous brand manufacturer. About a week after the cable was put into operation, the branch box #2 of the first circuit failed. In order to further clarify the reasons why the equipment cannot produce normally, the client hopes to conduct a quality analysis on whether there are quality problems in the "cable branch box" involved that caused the failure.
quality analysis results: The
quality analysis expert group discussed and conducted a comprehensive quality technical analysis on the relevant information and on-site investigation and inspection of the "cable branch box" involved, and made the following suggestions and conclusions:
The involved "cable branch box" itself did not have quality problems, and the failure was caused by construction quality issues. This failure was mainly caused by a discharge site in the double-pass casing and insufficient insulation thickness.