The mature aluminum alloy cables from the United States have been promoted and applied in China for nearly eight years, and are now basically accepted by all parties in the cable application field. The aluminum alloy cable industry and market have now become a booming sector, with various types of aluminum alloy cable products constantly flooding the market. However, the connection technology and supporting products—the most critical issues related to the safety of aluminum alloy cable applications—have been deliberately avoided for the past eight years and have consistently failed to attract the genuine attention of the industry and users. It is well known that most safety hazards in cable applications stem from the connections.
In 1968, the United States invented aluminum alloy cable technology, sparking a revolution in conductor materials. For the application of aluminum alloy conductor cables, manufacturers, led by Southern Cable, actively collaborated with organizations such as UL to research suitable connection technologies and related connectors for aluminum alloy conductors and cables, achieving technological breakthroughs and establishing corresponding standards. Aluminum alloy cables, coupled with supporting connection technologies and products, have contributed to the nearly 50-year successful application of aluminum alloy cables in North America and other countries without a single safety incident.
In 2006 and 2007, two American companies introduced mature American aluminum alloy cable technology and products to China, pioneering and promoting the development of China's aluminum alloy cable industry. However, due to different national conditions, cable connections vary in installation, connection methods, and manufacturing standards, making foreign connection technologies and connectors unsuitable for domestic use. The current situation in China is that, previously, there was no aluminum alloy cable technology or products, and consequently, no corresponding connection technologies or supporting products. Furthermore, due to various factors, aluminum alloy cable manufacturers themselves lacked the capacity to conduct research on connection technologies and connectors compatible with aluminum alloy cables. Consequently, in the early stages of the promotion and application of aluminum alloy cables in China, due to the lack of other solutions, and knowing it was impossible, they reluctantly adopted the copper-aluminum transition terminals originally used for aluminum cables as connectors for aluminum alloy cable connections—an erroneous connection solution. Since then, the application of aluminum alloy cables in China has continued to use this unscientific and incorrect connection solution, creating safety hazards in the application of aluminum alloy cables.
Why are the use of copper-aluminum transitions and other so-called alloy connectors with performance incompatible with aluminum alloy cables unscientific, erroneous, and potentially dangerous? A simple example will illustrate this: As we all know, aluminum alloy conductors fundamentally improved upon the physical and mechanical defects of aluminum as a conductor. They completely solved the serious safety problems caused by the poor mechanical and compressive creep resistance of aluminum in low- and medium-voltage power transmission connections. However, in current aluminum alloy cable connections, the presence of aluminum in copper-aluminum terminals still results in the same defects. What is the difference between this connection method and directly using aluminum cables? What are the advantages and value of using aluminum alloy cables? Furthermore, there's the issue of using so-called alloy connectors with performance incompatible with aluminum alloy cables. The alloys of these connectors are incompatible with the aluminum alloy cables in terms of chemical, electrical, mechanical, and especially compressive creep resistance. What are the consequences of this connection method? These will not be elaborated upon here.
Regarding the copper-aluminum transition terminals currently used in aluminum alloy cable applications, these terminals are originally designed for aluminum cable connections. However, the connection dimensions of these terminals cannot be safely matched with the dimensions of the terminal equipment. This often leads to the harsh situation where the terminal contact surface is directly ground down during construction to reduce its size and accommodate the connection requirements. Grinding down the terminal contact surface directly damages its mechanical properties and causes insufficient electrical performance and current-carrying capacity, resulting in overload and overheating at the connection point, directly creating a fatal safety hazard. Furthermore, due to the different manufacturing processes of aluminum cables and aluminum alloy cables, the inner diameter of the copper-aluminum transition terminals used for aluminum cables does not match the outer diameter of the aluminum alloy cable conductor, requiring specialized crimping tools and strict standardized construction procedures. However, in China, it is difficult to guarantee standardized construction procedures for aluminum alloy cable and terminal connections during installation, resulting in significant quality risks associated with these connections.
A safe, trouble-free, and correct connection method is:
Firstly, when using aluminum alloy cables, a dedicated aluminum alloy copper connector with the same chemical, electrical, mechanical properties, and resistance to pressure and creep should be used for connection. Only when the performance of the aluminum alloy cable and the connector are consistent can a perfect connection be achieved, truly realizing the advantages and value of using aluminum alloy cables.
Secondly, the dedicated aluminum alloy copper connectors used for connecting terminal equipment must be perfectly matched to the size and performance of the terminal equipment in terms of connection dimensions and electrical performance. This eliminates the need for multiple adapters or other methods, ensuring a secure connection with the terminal. This completely eliminates and avoids safety hazards caused by rough construction practices such as abrasion of the terminal connection surface due to incompatible terminals.
Furthermore, the inner diameter of the aluminum alloy end connecting the aluminum alloy cable and other accessories must be matched with the outer diameter of the cable conductor with zero tolerance, reducing the pressure required by crimping tools. The outer diameter of the terminal is compatible with traditional tools for crimping copper cables, eliminating the need for specialized aluminum alloy cable crimping tools during construction. Copper cable crimping tools can be used directly, offering the same convenience and reliability as copper cable crimping, facilitating standardized construction, and effectively improving the quality of cable connection construction.
The development of aluminum alloy cable technology and products is an inevitable trend. How to correctly select connection solutions in aluminum alloy cable applications is a crucial issue concerning the safety and security of aluminum alloy cable applications, and is also necessary for the healthy development of the aluminum alloy cable industry. This relates to the long-term interests of users and the industry. Research and advancement in aluminum alloy cable application technology is a reality that the aluminum alloy cable industry can no longer avoid. Whether domestic aluminum alloy cable applications can achieve a successful application history of ten, twenty, or even longer without a single safety incident, as in North America, requires researching and using correct connection technologies and scientific connection solutions. This is a paramount issue that cannot be delayed.
