Why can not copper wire and aluminum wire be connected together?

- Mar 25, 2019 -

1. Since the chemical and physical properties of copper and aluminum are very large, copper and aluminum should not be directly connected. Of course, the connection between copper and aluminum is inevitable. When the demand is connected, the copper-aluminum transition clamp, the copper-aluminum transition joint, the copper wire or the aluminum wire and the tin wire are directly connected.

 

2. Again, the electrochemical properties of the two metals, copper and aluminum, are different. If they are directly connected, once they encounter water, carbon dioxide and other impurities constitute an electrolyte battery, which is because aluminum is easy to lose electrons into a negative electrode, copper is difficult to lose electrons into a positive electrode, so in positive The negative electrode constitutes an electromotive force of 1.69V, and a small current flows through it, eroding the aluminum wire, so-called galvanic erosion. This will result in poor touch between copper and aluminum, and the touch resistance will increase. When there is current, it will increase the temperature of the joint part, and the temperature will increase and the joint erosion will be accelerated, and the touch resistance will be increased to form a vicious cycle until it is burned.

 

3. Since copper and aluminum are two different metals, a brief electrical connection will cause an electrochemical reaction (erosion). The time is a little longer, the touch resistance at the joint will increase, the fever will be generated, the circuit will be turned on and off, the voltage will be high and low, and even cause a fire.