To be sure, there are all different types of electrical conductors used in electrical wire and cable. Silver, gold, and bundled conductors are used as electrical conductors, but the most commonly used materials, by far, are aluminum and copper.

But why are copper and aluminum wire the most prevalent, and what are the relative advantages and disadvantages of each, with respect to each other? This post will break all of that and more down.

Copper Wire’s Advantages

Copper is likely the most commonly used material for the manufacture of electrical conductors. There are many good reasons for this that engender the widespread use of copper wire and cable.

For one, copper offers excellent electrical conductivity. This means that copper is more effective at handling a load of current under voltage without overheating or discharging. This makes it an efficient, safe conductor that produces a lower fire risk (assuming the proper gauge is utilized for the application).

Copper is also a stronger metal, specifically with respect to tensile strength. Copper’s tensile strength is roughly 40% higher than aluminum. This makes copper electrical wire and cable more durable, but it also means it is easier to work with.

Specifically, because copper is stronger, it is easier and more practical to draw it through conduit. Thinner, lighter gauge wires can stretch and snap when drawn; this makes copper preferable to aluminum in these applications.

In addition, copper exhibits a lower coefficient of thermal expansion, which means it doesn’t grow and shrink very much in response to changes in temperature.

Copper also offers a high degree of malleability and versatility. Because it is malleable and strong, it can be used to form very thin conductors, more efficiently than could be done with aluminum. 

Where Copper Wire Falls Short

With all of these advantages stated, you’d think copper would have the market for electrical conductors cornered, but be that as it may, there are still some areas in which it falls short.

The main one is price. Copper is significantly more expensive than aluminum, in some cases three to four times as much. This makes electrical wiring with copper extremely cost prohibitive when compared to aluminum.

Because of the high price, copper wiring is often targeted by thieves. Copper wire stocks are more likely to be targeted in high-crime areas than those of aluminum, adding to the risk.

Despite its strengths, copper is also very heavy, and in fact weighs several times more than aluminum per unit volume. This makes it more expensive to transport and more difficult to install. It also means that installations of copper wire will require greater support than aluminum wire because of the weight.

On top of that, copper wire is highly subject to corrosive damage. This is one of the reasons that marine battery wire is made from individually tinned conductors; in a marine environment, copper wouldn’t stand a chance. Exposed copper wire quickly corrodes in humid environments, which can cripple the electrical system that uses it, and result in a higher risk of fire.

Where Aluminum Wire Wins

Aluminum wire, like copper, has several inherent advantages. Probably the most significant advantage aluminum has over copper is cost. As stated, it is several times more affordable, making it more practical in a wider range of applications.

Since aluminum is lighter, it can also be more effectively used in aerial installations. For instance, aluminum triplex wire is often used for power distribution to homes and businesses because it is lighter and more affordable than copper.

Aluminum is also generally fairly resistant to corrosion. This means it requires low maintenance over time, particularly in environments that offer harsh conditions.

Even though copper technically offers better conductivity, aluminum’s conductivity-to-weight ratio is actually better. This means that less mass in aluminum needs to be used to confer the same conductive abilities as copper, and adds to aluminum’s economy.

Because of the reasons mentioned here, this is the preferred material for triplex and quadruplex wire. Aluminum triplex wire and quadruplex wire are commonly used for power delivery to homes and businesses as a cost-effective alternative to copper.

Aluminum Wire: Disadvantages

While aluminum wire definitely has some advantages over copper, it is not without its drawbacks.

One is that aluminum wire has a higher coefficient of thermal expansion than copper. This means it expands more in response to higher and lower temperatures. As stated, aluminum is also not as strong as copper, which can make it more difficult to work with.

As a result, it can be more difficult to form aluminum wire, or to draw it through conduit, as repeated stresses can cause the wire to snap. Copper is more forgiving of multiple stress cycles than aluminum wire is.

This lower tensile strength is the reason for a little known fact regarding aluminum triplex wire. The bare neutral wire included in the triplex configuration has a steel member running through the middle of it. This is to reinforce the aluminum wire and add tensile strength. Without the steel member, the wire would stretch to the point that it could sag all the way to the ground, especially in the presence of high winds, or with ice or snow loading.

Aluminum can also be potentially difficult to solder, especially since exposed aluminum is prone to developing a thin layer of oxidation that hampers soldering efforts. Also, aluminum connections can be more difficult to make, requiring the use of an anti-oxidation compound.

Aluminum can also be more susceptible to damage in the presence of constant vibration, causing cracks to form and the wire to become brittle.

Need More Information on Electrical Wire and Cable Before Purchasing?

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