Deciphering the "fake problem" of aluminum alloy cable connection terminals

Aluminum alloy cable connection terminal is an important problem of aluminum alloy cable, and the controversy about the solution to this problem has been endless
.
Many companies often express their opinions
around aluminum alloy cable connection terminals.
What is the truth of the aluminum alloy cable connection terminal problem?

There is a general consensus in the cable industry that the manufacturing standards for terminals and cable conductors are different, and their respective chemical composition requirements are also different
.
The current manufacturing standard for terminal blocks is GB/T 14315-2008 "Crimp type copper, aluminum terminal blocks and connecting pipes for power cable conductors", of which 4.
1.
2 clarifies the naming of copper-aluminum transition products, and in item 5.
1, it stipulates that "aluminum is not lower than GB/T 3190 No.
2 industrial pure aluminum (L2)"
.
The current national standard for the chemical composition of aluminum alloy cable conductors is GB/T 30552-2014 "Aluminum alloy wire for cable conductors", which stipulates that 6 grades of aluminum alloys can be used as cable
conductors.

It can be clearly found that the above two products are manufactured according to different national standards, and their material selection is also different, so there is no superiority or disadvantage
.
And this also shows again that the so-called connection terminal problem is actually "layman's jargon", because the so-called technical differences themselves do not exist
.

At this point, on the other hand, companies that have been grasping the "connection terminal problem" for a long time inevitably make people doubt their cognitive level and rigor in the professional field
.
China's aluminum alloy cable market is still in its infancy, and many unknown companies can still play a role, but there is no doubt that with the gradual maturity of the industry, truly scientific connection terminal solutions will be widely used
.

Some companies that question the copper-aluminum transition terminal are too simple and direct in thinking about the problem of connecting terminals: one of the main reasons why aluminum alloy cables can be safely applied is because the joint safety performance is good, and the strong guarantee of good joint performance is the creep performance of aluminum alloy conductors
.
Since the joint is composed of an aluminum alloy conductor and a copper-aluminum transition terminal, only the conductor has better creep performance, and the aluminum part of the copper-aluminum transition terminal does not have, and the joint is also unreliable, so the aluminum part of the copper-aluminum transition terminal should also use materials
with the same creep performance as the conductor.

Such concerns do need to be taken into account
in practical applications, especially when using bolt-on mechanical connections (e.
g.
T-terminals for cables).
As everyone knows, they only consider the problem on the one hand, but ignore one point, the copper-aluminum transition terminal is usually crimped by confining pressure or pit pressure, this crimping has two characteristics: one is that the crimping force is large, far greater than the yield strength of the conductor, and creep happens to occur near the yield strength; Second, compared with creep deformation, the deformation of terminal crimping is huge
.
Combining the above two points, after crimping treatment, the effect of creep deformation has been completely weak to a negligible extent
.
Therefore, the so-called "unstable copper-aluminum connection terminals" statement is simply untenable
.

In the industrial sector, the application time of the equipment is proof
of the practical effect.
Taking the North American market, which is currently the most mature aluminum alloy cable application in the world, Thomas Betts and Tyco terminal blocks widely used in aluminum alloy cable application projects, its material has 1000 series aluminum alloy, but also 6000 series aluminum alloy, creep performance is very excellent, perfect solution to the copper aluminum transition terminal aluminum part lack creep performance concerns
。 Aluminum alloy cable and terminal block connection system has a safe operation history of more than 40 years in North America, has been successfully applied in a number of world-class major projects, so far there has been no problem, with practical results to show the scientific and rational solution it provides
.

If there is a real problem with the copper-aluminum transition terminal, why have multiple projects and many customers in the US market never questioned it? Has no one discovered or considered a similar problem in forty years?