Copper vs Aluminum Wires: Cost & Electrical Applications

[Crazyhorse2882]

If electrons flow on the surface of a wire, why isn't copper coated aluminum wire used in electrical applications instead of solid copper wire? It would be more cost effective

 

[phinds]

Electrons only flow near the surface at very high frequencies and high frequency waveguides are hollow for that very reason.

 

[nsaspook]

If electrons flow on the surface of a wire, why isn't copper coated aluminum wire used in electrical applications instead of solid copper wire? It would be more cost effective

It is used but the required gauge is two sizes larger (possibly increasing the needed conduit size) than solid copper for the same utility power (60hz skin depth is about 9 mm so for most commercial and residential wiring it's unimportant) application. Fires in houses build in the 70's with Al wiring has made many people reluctant to save maybe 20% on wire when wire is a small percentage of cost on most projects. (a 10 million dollar machine in a multi-billion dollar factory with 20K wire costs is a typical example)
http://www.commscope.com/docs/cca_solutions_br.pdf

 

[meBigGuy]

I think *waveguides* are hollow because they are conducting electromagnetic radation within the internal area in TM or TE mode.

 

[alphy]

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I can provide some insights into the differences between copper and aluminum wires in terms of cost and electrical applications. While it may seem logical to use copper coated aluminum wire due to its cost effectiveness, there are several factors that need to be considered before making this switch.

Firstly, the surface of a wire is not the only factor that determines its conductivity. The material and its physical properties also play a significant role. Copper has a higher conductivity compared to aluminum, meaning it can carry more electrical current with less resistance. This is particularly important in high power applications where any resistance can result in energy loss and potential hazards.

Additionally, the conductivity of copper is less affected by temperature changes compared to aluminum. As the temperature increases, the resistance of aluminum also increases, resulting in a decrease in its conductivity. This means that aluminum wires are not suitable for high-temperature environments and may require larger wire sizes to compensate for the decrease in conductivity.

Moreover, copper is also more durable and has a longer lifespan than aluminum. This is due to its higher melting point, corrosion resistance, and ability to withstand mechanical stress. As a result, copper wires require less maintenance and have a lower risk of failure, making them a more reliable choice for electrical applications.

In terms of cost, it is true that aluminum is a cheaper material compared to copper. However, when taking into account the factors mentioned above, the overall cost of using aluminum wires may be higher due to the need for larger wire sizes, increased maintenance, and potential risks of failure.

In conclusion, while copper coated aluminum wire may seem like a more cost-effective option, the differences in conductivity, durability, and temperature resistance make solid copper wire a more suitable choice for most electrical applications. As scientists, it is important to consider all factors and make informed decisions based on empirical evidence rather than solely on cost.