So can the copper wire and aluminum wire can be connected directly? the answer is: Certainly you can’t.

Why can’t you connect directly? 

First, the electrical resistivity of the aluminum wire and the copper wire is different. 

Second, this is the most critical, that is, the aluminum wire is very easy to oxidize, forming a layer of oxide on its surface, plus aluminum is smaller than the hardness of copper, which will greatly increase the aluminum wire and copper wire connections. The contact resistance, when using the current through this connection place, the contact resistance will heat, if it is a large current, the heat is very serious, and the connection will be burned. 

Third, according to the safety operation specification, the aluminum wire cannot be connected to the copper wire. 

Direct connection:

1. When copper, aluminum conductor is directly connected, the contact surface of the two metals is extremely easily formed by moisture, carbon dioxide and other impurities, thereby forming a primary battery in which aluminum is a negative electrode, copper is a positive electrode. To generate electrochemical corrosion, the contact resistance of copper and aluminum joint is increased.

 2. in addition, due to the difference between the elastic modulus and the thermal expansion coefficient of copper, aluminum, after the operation is multi-thermal cycle (energized and power-off), the contact point will cause a large gap to affect the contact. Contact resistors are also increased. The increase in contact resistance can cause an increase in temperature. Corrosion oxidation at high temperatures will exacerbate, resulting in a vicious circle, making the connection quality deteriorate, and finally leading the contact point temperature and even smoke, burning and other accidents. 

Connection methods 

1.Use Aluminium-Copper Bimetallic Cable Lugs  to connect the copper cable and aluminum cable.First we can connect the aluminum conductor to the aluminum tube of the Aluminium-Copper Bimetallic cable lugs,then connect the copper conductor.Copper aluminum of CROP bimetallic lugs  is tightly welded, and electro chemical corrosion can be completely eliminated. Also can be use copper tinned copper lugs to connect the copper cable and aluminum cable.