Aluminum Building Wire vs. Copper Building Wire: Why do we use copper in our homes?
As you know, aluminum and copper are the top conductors of electricity used in most electrical cables. While aluminum is a leader in power cables, copper is a popular conductor for home wiring. Care to know why? Read this blog to find out.
History of Copper and Aluminum Wiring
Both aluminum and copper have been used in wiring as early as the beginning of the 19th century, being the excellent conductors of electricity. Back then, building wire as we know it did not exist on the current scale. Electricity was almost exclusively tied to power grids operated by utility companies, and aluminum was by far the most popular cables in the utility poles because of its low price and lightweight. When it comes to power grids, nothing really ever changed in the 21st century- aluminum is still by far the most popular cable in overhead power lines, again, because of its low weight and low price.
However, when it comes to building wire, it is copper that rules modernity. Home wiring as we know it was first introduced in the United States in the late 19th century, but it was still seen as a privilege and, frankly, an experiment at that time. Wiring in American homes became mainstream as we know it today in the 1920s-1930s. The mainstream technology was so-called knob-and-tube wiring, in which a copper wire was run through porcelain insulation. Even then, copper was already a leader in home wiring because of its superior safety and electrical conductivity.
The 1960s to 1970s: Brief Reign of Aluminum in House Wiring
In the 1960s, copper prices skyrocketed for the first time in modern history, causing manufacturers and homeowners to switch to aluminum wiring. The era lasted until 1980. However, there were issues related to safety. Despite the existing stereotypes, safety was not a result of the fact that aluminum is unsafe for homes. The factors that were involved were more complex and related to the era.
While people turned to aluminum wiring, the outlets and other elements of circuits were not made to fit aluminum cables, compromising safety. As a result, electrical fires skyrocketed during these decades. Aluminum's natural property is to expand when heated. Aluminum used until the 1970s in-home wiring was not the same as the modern aluminum alloys; it did not adhere to the modern safety standards and had a profound tendency to overheat. Combined with unfit electrical lines, it created risks. Some houses from the 60s and 70s still have old aluminum wiring. It is recommended to replace this type of wiring with new copper or aluminum one.
Why is Copper Better For Homes?
Copper has better conductivity than aluminum. In fact, copper is used as a standard for measuring conductivity because it conducts the electrical current better than any other metal, except for silver.
Copper also has tensile strength that is about 40% higher than aluminum. Because of this, it is less prone to breakage than aluminum.
Copper also has lower thermal expansion properties than aluminum, which means that it does better when exposed to extreme temperatures and is likely to last longer.
Copper is also way easier to install, as aluminum can be damaged in the process of installation, and copper is very flexible. Since home wiring is very often installed in a DIY way, you wouldn't want to risk aluminum cables breaking in the process of installation. The melting point of copper is higher, so the risk of the electrical cable is lower even if you manage to do something wrong.
Service entrance cables and utility wires installed are most often installed by professionals who are much more equipped to prevent the damage from happening; that is why these cables are fine with an aluminum conductor.
Copper is strong and reliable, and while it is more expensive when you buy it, it may be cheaper if you consider service life. All popular cables used in the home, including NM-B, THHN, and UF-B, are made with copper conductors.
