As a professional manufacturer of cable branch boxes, DAYA Electric reminds everyone of the necessity to thoroughly understand cable branch boxes. Only with sufficient knowledge can you select the right cable branch box for your needs when purchasing. Here, we will focus on introducing the four key precautions for cable branch box construction to prevent problems and their consequent impacts during the construction process.
The four key precautions for cable branch box construction are as follows:
1、During the construction of the cable branch box, phase separation shall be carried out at a distance greater than 1.2 meters from the cable terminal. Due to the narrow phase-to-phase distance between the installation of the cable branch box and the T-type cable joint, if the length from the outlet bushing of the cable branch box to the phase-separated three-core cable is less than 1.2 meters, the lower part of the stress cone of the T-type joint of the two side-phase cables will often be in the bent part of the cable. This directly affects the contact between the joint stress cone and the cable body, which is the most critical part of the assembly between the T-type cable joint and the cable.
2
、Do not cut off the semi-conductive layer and copper shielding layer of the three-phase cable according to the traditional three-core cable phase separation construction method. Because the semi-conductive layer of the cable must be in contact with the semi-conductive layer of the T-type cable joint; otherwise, an induced potential difference will be generated on the cable surface between the cable semi-conductive layer and the stress cone of the T-type cable joint. This part of the cable may discharge to the ground wire, burning the heat-shrinkable sleeve, damaging the insulation, or even causing burnout.
3
、A cable fixing bracket must be installed in the foundation of the cable branch box. The part of the three-core cable below the phase separation point shall be fixed on the bracket. At the same time, measures shall be taken to ensure that the three-way joint is directly below the terminal post, so as to prevent the cables and accessories in the branch box from being subjected to downward tension. This can effectively avoid air leakage of the outlet bushing of the cable branch box caused by stress.
4、During cable phase separation, align the three-phase cables with the terminal ports of the cable branch box bushings respectively. The middle-phase cable shall be cut short to ensure that the three-phase cables are of appropriate length and flush. This prevents excessive thrust or tension caused by overly long or short phase cables, which may lead to poor contact between the fixed T-type cable joint and the cable or the outlet bushing of the cable branch box, and avoids air leakage of the outlet bushing of the cable branch box due to stress.
It is believed that through the above content, you have gained a certain understanding of how to construct the cable branch box to ensure no problems.
This article is compiled and edited by DAYA Electric Group Co., Ltd. (https://www.hygraphics.com). Reproduction is permitted with proper attribution.