Cable lugs are connectors that are used to connect/terminate cables together, and they form an important part of an electrical system. Cable lugs are normally made from one of two metals – copper or aluminium or their respective alloys.
As far as functionality goes, they both serve similar purposes, but the differences are more to do with their specific characteristics and applications. Let’s take a look at why aluminium cable lugs used to be popular as well as why copper is now the preferred choice for cable lugs.
The history of aluminium cable lugs goes back to the early days of the 1960s, when a substantial amount of engineering innovation was happening, and aluminium was part of that innovation. Back then in India, aluminium wires were being used in almost every home wiring system. Since the electrical wires were made of aluminium, electricians used aluminium cable lugs for jointing in order to avoid a galvanic reaction and ultimately a failed joint.
However sound this practice may be they still ran into a lot of termination failures. Connections being lost at these junctions had aluminium cable lugs being used, and as a result of this, electrical fires started occurring frequently. Electricians did not know why this was happening, because aluminium is a very good conductor of electricity and they had been using it for a while.
When the fires became too wide, research finally revealed that aluminium cable lugs were the source of the problem. One of the problems was the formation of aluminium oxide which led to a large percentage of fires, and the problem persisted even after trying a variety of combinations.
Eventually, it was decided that aluminium simply isn’t the right metal for electrical wiring, and that’s when copper came into the picture as a more effective replacement.
The great thing about using copper for cable lugs is that it overcomes all the problems that are found in aluminium cable lugs. The key to improved safety with copper lugs has something to do with the “co-efficient of thermal expansion”. Without going into the technical details of the term, what you need to know is that a higher co-efficient indicates greater risk of fire, and copper has an extremely low co-efficient of thermal expansion.
Thanks to this, it does not create fire safety hazards, and copper-based wiring systems are now used around the world. There is of course a catch. Aluminium happens to be a much cheaper metal than copper, so copper cable lugs and wiring can cost quite a bit more than aluminium cable lugs. That is probably one of the main reasons why, back in the 1960s, manufacturers went with aluminium wiring before shifting to copper, and why aluminium cable lugs are sometimes used in wiring even today.
At this point, we know about the main difference between aluminium and copper, as well as the main advantage and disadvantage of each. Aluminium is cheaper but causes problems, while copper is good but comparatively very expensive. The big question is – should you go with aluminium or copper cable lugs?
Unfortunately, the answer isn’t clear cut. The lure of the low cost of aluminium continues to drive electrical manufacturers to use aluminium wiring. Factor that along with aluminium-related innovations making them just as safe as copper lugs. It is now possible to find aluminium cable lugs that are coated with copper and then with a subsequent layer of tin. This impedes the rusting as well as formation of oxide on the surface.
It is true that in the early days, aluminium simply wasn’t the right choice for cable lugs, and since then, copper became the preferred choice for cable lugs. All things considered, however, it’s now much safer to use aluminium cable lugs as compared to the earlier days. Despite these improvements in aluminium wiring and electrical components, somehow the impression that copper cable lugs are better than aluminium hasn’t really gone away.