What is the difference between copper wire and aluminum wire?

2023.1.4 Articles GOTREND Technology Co.,Ltd

GOTREND Article-What is the difference between copper wire and aluminum wire?

Enameled wire is a very important part of inductor transformer components and the main material that determines key properties. All enameled wires used in all GOTREND inductor are enameled copper wires. 
But there are also two kinds of wire on the market, copper wire and aluminum wire, so let's understand what is the difference between copper wire and aluminum wire?
What are the advantages and disadvantages of each?  What are the respective uses in use?

1、Copper Wire
1.1 Properties and applications.
GOTREND inductors use copper wire because of their good electrical and thermal conductivity. 
In the same life, practical copper wire is used as a wire. Good electrical conductivity, a large number of manufacturing wires, cables, brushes, etc.; Good thermal conductivity, commonly used to manufacture magnetic instruments and meters that must be anti-magnetic interference, such as compasses, aviation instruments, transformer components, etc.; Excellent plasticity, easy to hot and cold pressure processing, can be made of pipes, rods, wires, strips, strips, plates, foils and other copper materials.
There are two kinds of pure copper products: smelting products and processed products.

1.2 Advantages of copper wire: 
(1) Low resistivity :
The resistivity of aluminum cable is about 1.68 times higher than that of copper cable. 

(2) Good ductility :
The ductility of copper alloy is 20 to 40%, the ductility of copper for electrical engineering is more than 30%, while the aluminum alloy is only 18%. 

(3) High strength :
The allowable stress at room temperature, copper is 7 to 28% higher than aluminum, respectively. Especially the stress at high temperatures, the difference between the two is even more distant.

(4) Anti-fatigue :
Aluminum is prone to repeated bending and breaking, while copper is not easy. In terms of elasticity indicators, copper is also about 1.7 to 1.8 times higher than aluminum. 

(5) Good stability :
Corrosion resistance, copper wire is resistant to oxidation and corrosion, while aluminum wire is susceptible to oxidation and corrosion. 

(6) Large ampacity :
Due to the low resistivity, the copper cable with the same cross-section is about 30%-50% higher than the allowable ampacity of the aluminum cable (the maximum current that can pass), especially more and more household appliances, and the basic use of copper for home improvement.

(7) Low voltage loss :
Due to the low resistivity of the copper cable, the same current flows through the same section. The voltage drop of the copper cable is small. Therefore, the same transmission distance can ensure a high voltage quality; In other words, under the allowable voltage drop conditions, the copper cable transmission can reach a long distance, that is, the power supply coverage area is large, which is conducive to the planning of the network and reduces the number of power supply points.

(8) Low heat generation :
Under the same current, the heat generation of the copper wire cable with the same cross-section is much smaller than that of the aluminum wire cable, making the operation safer. 

(9) Low electrical loss :
Due to the low resistivity of copper, the electrical energy loss of copper cable is low compared to aluminum cable, which is obvious. This is conducive to improving the utilization rate of power generation and protecting the environment.

(10) Oxidation resistance, corrosion resistance : 
The connection head of the copper wire cable has stable performance and will not cause accidents due to oxidation. 
The instability of the connector of the aluminum cable often causes accidents due to oxidation that increases the contact resistance and heats up. Therefore, the accident rate is much greater than that of copper wire cables. Especially in some places where the copper wire and the aluminum wire are docked, there is a problem if it is not connected for a long time. Therefore, the docking of copper wire and aluminum wire must be strictly required to be connected.

(11) Convenient construction :
① The copper wire has good flexibility and the allowable radius of bending is small, so it is convenient to bend and easy to pass through the pipe.
② The copper wire is resistant to fatigue, repeated bending is not easy to break, so the wiring is convenient.
③ The mechanical strength of the copper wire is high, and it can withstand a large mechanical pull, which brings great convenience to the construction laying and also creates conditions for mechanized construction.

1.3 Disadvantages of copper wire: 
The high price of copper wire and the large ratio of copper wire determine the high cost of copper wire. As a cable with many performance advantages, is the high cost! So our common overhead line basically doesn't use copper wire, it is good or too heavy, so the overhead line is often used more aluminum wire, and the ground wire usually uses copper wire.

2、Aluminum wire 
2.1 Properties and Applications 
Aluminum wire is used very rarely in inductance transformers, but more industries in order to save copper scarce resources, developed a new material "copper-clad aluminum wire", refers to the aluminum wire wrapped in a layer of copper, and and make the copper and aluminum interface on the atomic bond to produce metallurgical combination, it not only plays the excellent conductivity of copper and the quality of aluminum light characteristics, but also customer service aluminum easy oxidation, large contact resistance, joints are difficult to weld the drawbacks.

Aluminum wire refers to its longitudinal full length, and the uniform cross-sectional real refers to the metal linear material made of pure aluminum or aluminum alloy. Products are processed along the heart pressure and delivered in rolls. Cross-sectional shapes include circles, ellipses, squares, rectangles, equilateral triangles, and regular polygons. According to the material, it is divided into pure aluminum wire and alloy aluminum wire. According to the use, it is divided into industrial aluminum wire and process aluminum wire.

2.2 Advantages of aluminum wire 
(1) Cheap price :
Copper rod is 3.5 times the price of aluminum rod, and the proportion of copper is 3.3 times that of aluminum, so aluminum cable is much cheaper than copper cable, suitable for low-cost projects or temporary electricity. 

(2) The cable is very light :
the weight of the aluminum cable is 40% of the copper cable, and the construction and transportation costs are low.

(3) Oxidation resistance, corrosion resistance :
aluminum in the air and oxygen reaction quickly generates an oxide film, can prevent further oxidation, so aluminum wire is a high voltage, large cross-section, large span overhead transmission materials, but as a low-voltage line These advantages no longer exist.

2.3 Disadvantages of aluminum wire 
(1) Aluminum wire conductivity is low, electrical loss is large, tensile strength is poor, corrosion resistance is low, the joint part is particularly easy to oxidize, if connected with the copper wire, the joint part is more prone to corrosion due to the potential difference, and it is easy to cause road breaks. 
These are relative to the use of low-voltage lines, but the advantages of aluminum lines on high-voltage lines are also quite obvious, which we must clarify and cannot be asserted in one fell swoop.

(2) Copper wire and aluminum wire cannot be connected together. 

(3) The difference between the chemical and physical properties of copper and aluminum is very large, so copper and aluminum should not be directly connected. Of course, copper-aluminum connection is inevitable, when the connection is needed, generally use copper-aluminum transition clip, copper-aluminum transition joint, copper wire tin or aluminum wire after direct connection.

(4) Copper and aluminum two metals of the electrochemical properties are different, if they are directly connected, once encountered with water, carbon dioxide and other impurities formed by the electrolyte, a chemical battery is formed, which is due to the fact that aluminum is easy to lose electrons to become negative electrodes, copper is difficult to lose electrons to become positive electrodes, so between the positive and negative electrodes formed a 1.69V electromotive force, and there is a small current through, corrosion of aluminum wire, that is, the so-called electrochemical corrosion.

This will cause poor contact between copper and aluminum, and the contact resistance will increase. When there is a current passing through, it will increase the temperature of the joint part, and the temperature will increase and accelerate the corrosion of the joint, increasing the contact resistance, creating a vicious circle until it burns out.

(5) Copper and aluminum are two different metals, and simply joining them together will cause an electrochemical reaction (corrosion). Over a little longer time, the contact resistance at the connection will increase and heat up, causing the circuit to be on and off, the voltage to rise and fall, and even cause a fire.


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