Why is Copper a Good Conductor of Electricity?

Have you noticed that electrical wires mainly consist of copper? This is because copper has excellent conductivity. It allows electricity to pass through it. Therefore, copper wires are used on both small and large scales. However, the question is: why is copper a good conductor of electricity?

 

What makes copper conduct electricity, making it a superior option? We have other options for making wires, such as brass and aluminum. However, copper is always preferred in all cases. Why is it so? In this article, I will explain the logic behind copper electrical conductivity. You’ll learn why copper is preferred over others. So, let’s get started!

 

Why is Copper a Good Conductor of Electricity?

 

The logic behind the high electrical conductivity of copper lies in its free electrons. Copper has a single valence shell electron. Moreover, forces of attraction between the nucleus of copper and valence shell electrons are very low. So, this electron is weakly bound and can move freely. As a result, it moves and allows electricity to flow.

 

Every atom consists of a different number of electrons. These electrons are present in their shells.  Each of these shells has its specific limit.  The copper has 29 of the total electrons. The distribution of these elections in the shells is as follows:

 

1st shell (K-shell) = 2 electrons

2nd shell (L-shell) =  8 electrons

3rd shell (M-shell) =  18 electrons

4th shell (N-shell) =  1 electron

 

If you see, the 4th shell has only one electron. This electron present in the outermost shell is called a valence electron. The 1st shell is close to the nucleus. The shell will keep going far from the nucleus as we go up. The 4th shell is most distant from the nucleus in the case of copper atoms. Generally, the nucleus attracts the electrons. 

 

However, due to the distance between the nucleus and the 4th shell, it cannot attract the valence electron strongly. It results in a single valence electron moving freely without any hindrance. When the electric field is applied, this valence electron moves, allowing the electricity to pass through copper. Moreover, the copper has low resistance, which is another plus. 

 

Quick Highlight: One electron, upon movement, collides with another. This collision induced movement in the second electron. This happens in a chain when the electric field or voltage is applied. As a result, the electricity can easily flow from one end to another. The movement of valence electrons causes this chain of moving electrons.

 

Factors that Affect the Electrical Conductivity of Copper

Copper generally shows very low resistance to electricity, right? This results in the smooth flow of current in these materials. However, some factors increase the resistance, affecting copper’s electrical conductivity. Let’s discuss each of those factors and how they impact copper’s electrical conductivity.

 

1- Temperature

 

The increase in temperature reduces the electrical conductivity of copper. How? Because an increase in temperature increases the vibration between the electrons. This vibration causes a collision between the electrons. As a result, they move in random directions. This random movement of electrons increases the resistance against the flow of electricity. 

 

On the flip side, a decrease in temperature keeps the electrons stable. There is no random movement of electrons that could increase resistance. So, the electricity can easily pass through. You might say collisions of electrons also happen when we apply an electron field. That is right, but that collision is more organized, not random. 

 

Quick Highlight: When a valence electron moves due to the applied voltage, it hits another electron one after the other. This chain is more organized instead of uncontrolled collision. Supercooled copper wires (-273.15°C or 0 K) generally offer zero resistance and have ideal electrical conductivity. 

 

2- Impurity & Alloy Elements

 

The impurities present in copper can have a harmful impact on electrical conductivity. Moreover, copper can also be mixed with some alloy elements. Those elements can also reduce the conductivity. Copper, in its pure form, has low resistance. However, impurities increase this resistance. 

 

It means that electricity can still pass but lose energy to overcome the resistance. This results in less smooth or efficient electrical conductivity. For example, impurities such as nickel or arsenic will reduce the electric conductivity of copper. Moreover, alloy element properties also matter. If the alloy element conducts electricity, it won’t lower the copper’s conductivity and vice versa.

 

3- Mechanical Stress & Deformation

 

If copper undergoes stress, its electric conductivity will be altered and reduced. The reason is that stress disrupts the atomic structure of atoms. For example, you have copper material, and you hammer it forcefully. As a result of hammering, copper will deform. 

 

Its atomic structure will be disrupted, affecting the orientation of electrons. So, when an electric field is applied, valence electrons will move. But it won’t be able to induce other electrons’ movement effectively. As a result, the electricity won’t be able to flow smoothly. 

 

Electrical Conductivity of Copper as Compared to Silver and Aluminum

Generally, silver, copper, and aluminum are used for electrical appliances. But which ones of these offer ideal conductivity to be used in wires? Let’s figure it out.

 

Among these three, silver stands at the top. It offers exceptional conductivity as the electricity flows smoothly without facing any hindrance. It has a resistivity of 1.59 × 10⁻⁸ Ω·m, making it ideal for wires. However, silver is not used in making wires. Why? Because it is a premium material and very expensive. Its higher cost makes it impractical to be used in cables.

 

The copper stands at the second position. It has a resistivity of 1.68 × 10⁻⁸ Ω·m. This material is extensively used in making wires and other electrical appliances. Why? Because it comes in affordable pricing. Wires made of copper are both cost-effective and offer ideal conductivity. The aluminum is at the third position with a higher resistivity of 1.68 × 10⁻⁸ Ω·m.

 

Interestingly, both copper and aluminum have one valence electron. Buying aluminum’s electrical conductivity is compromised as compared to copper. The reason is that aluminum has a total of 13 electrons. Their valence shell is relatively closer to the nucleus. On the flip side, copper has 29 electrons and uses four shells. Three valence electrons are far away from the nucleus. 

 

In the case of aluminum, the nucleus attracts the valence strongly due to the lesser distance. As a result, the electron cannot move freely, unlike copper’s valence electron. Due to this, copper is more electrically conductive and actively used in wires. Aluminum wires are also available in the market. But their electrical performance is less efficient than copper wires.

 

How Does the High Electrical Conductivity of Copper Influence its CNC Machining?

Copper’s higher electrical conductivity does not directly impact its CNC machining. However, it indirectly offers some perks during machining. 

 

The copper has freely moving electrons. It helps with both electrical and thermal conductivity. This material can quickly dissipate heat due to better thermal conductivity. During the CNC machine, the cutting tools produce heat during cutting. The copper material efficiently dissipates that heating and avoids overheating issues. 

 

If copper doesn’t dissipate heating, its CNC machining would be time-consuming.  You will have to cut it slowly and give the heat time to dissipate. However, the electrical conductivity directly has no impact on how copper undergoes CNC machining. 

 

Frequently Asked Questions

 

Is copper the best conductor of electricity?

Silver has more electrical conductivity than copper. However, it is costly and is not used in electrical appliances. After silver, copper is the most electrical conductivity and practical option for wires. It is affordable, and readability is available everywhere.

 

How does aluminum wiring compare to copper?

Copper wiring is considered superior to aluminum. Aluminum has fewer electrical conductors as compared to copper. Moreover, it offers more resistance to the flow of electricity. Aluminum wires are still used but are always large in size to effectively carry electricity.

 

Why is copper wire good for electricity?

Copper has freely moving electrons in its valence shell. This electron can easily pass the electricity, making copper electrical conductive. Copper material also offers very low resistance. Due to this, copper wires are preferred for electricity.

 

Conclusion

 

Copper is a very popular material used in various industries. Manufacturers use CNC machines to cut and shape it to make multiple products. One of the most popular uses of copper is to create wires and electrical components. As this is used to make wires, it is electrically conductive. However, many don’t know why or how copper conducts electricity. 

 

In this article, I discussed the logic behind the electrical conductivity of copper. You will also learn how it compares to other materials, such as aluminum and silver. In short, copper has free valence electrons weakly bound to the nucleus. The free movement of electrons allows electricity to pass. I hope this article helps you understand the logic behind the electrical conductivity of copper material.