1. Poor workmanship. It mainly refers to the construction process of the cable joint construction personnel before after the conductor is connected.Guangxi cable

(1) Improper handling of the contact surface of the connecting hardware. Whether it is a terminal a connecting tube, there are often impurities, burrs oxide layers on the inner wall of the tube due to the influence of production storage conditions. This is a flaw that people don't notice, but it has a pretty serious impact on the quality of the conductor connection. In particular, a hard insulating aluminum oxide film is easily formed on the surface of aluminum, which makes the connection of aluminum conductors more troublesome than that of copper conductors, the strictness of process technology is much higher. The main cause of thermal connection (crimping, welding mechanical connection), in addition to equipment material performance factors, the key is process technology responsibility. The construction personnel do understand the connection mechanism do operate in strict accordance with the process requirements, which will cause the electrical mechanical strength of the connection to fail to meet the requirements. Operation has proved that when the contact surface between the crimping tool the wire is clean, when the temperature of the joint increases, the oxide film produced is thinner the contact resistance is smaller.Guangxi wire cable

(2) Conductor damage. Strong insulation, easy to peel cut. When making ring cuts, builders use an electric knife to cut left right, sometimes simply use a hacksaw ring to cut deeper marks, which tend to damage the wires due to poor control. Although the peeling is very serious, when the core is bent the crimp creeps, it can lead to increased damage breakage of the conductor at the damaged part. It is easy to find after crimping, the reduction of the cross section will cause serious heat generation. electric wire

(3) When the conductor is connected, the iron core is in place. When connecting conductors, the insulation stripping length requires a 5mm increase in the depth of the crimp joint hole. However, due to the non-standard hole depth of the product, it is easy to cause insufficient stripping length, due to the series position during crimping, a gap will be formed at the end of the wire, which is only due to the wall thickness of the tube. Increased contact resistance heat generation.

2. enough pressure. At present, the relevant information only mentions the number of crimping pits at each end of the cable connection end in the manufacturing process standard drawings, does specify the crimping area crimping depth in detail. The construction crew pressed enough pits as required, but the effect was uncertain. No matter what kind of crimping method is used, the joint resistance is mainly the contact resistance. The size of the contact resistance is related to the size of the contact force the actual contact area, is related to the output tonnage of the crimping tool. The main reasons for insufficient conductor connection pressure are as follows.

(1) The pressure of the crimping machine is insufficient. In recent years, there have been many crimping machine manufacturers, the management is chaotic, there is no unified standard. Especially the mechanical crimping pliers produced in recent years, only the crimping hole is narrow, but also the upper lower molds do match after crimping; some manufacturers buy produce foreign models of crimping tools, due to the implementation of foreign standards, the nominal cut of domestic conductors. The area is compatible, the quality of crimping is difficult to guarantee.

(2) The gap between the connectors is large. At present, the connection accessories used by most cable joint units are terminals crimping tubes produced by oil-paper cables as sector-shaped conductors. Theoretically speaking, the effective section of the round core the sector core is the same, but the actual operation comparison, the crimping effect of the two is quite different. Since the cable conductor is a tightly stranded round core, the inner diameter of the commonly used fittings has a large gap cannot achieve the pressing force. The contact resistance is inversely proportional to the applied pressure therefore causes an increase.Guangxi cable manufacturer

(3) The quality of fake inferior products is poor. Fake shoddy accessories are only of impure material, rough appearance, prone to cracks after pressing, but also inaccurate in specifications, the effective cross-section varies greatly, which does meet the quality requirements of crimping. Under normal conditions, it generates serious heat fluctuates slightly under load. A failure must occur.

The above content comes the Internet. If there is any infringement, please contact us to delete it, thank you.