Look at the section; it is easy to see because the thicker wires use copper-clad aluminum. Therefore, the general copper clad aluminum is a soft wire, and there are many small filaments and multiple strands. But as long as you cut the cross section and see the whitish (aluminum color) you can identify what material it is.
Fire method; only need to use a lighter to burn, look at the burning phenomenon and the result after combustion, copper-clad aluminum and copper-clad aluminum-magnesium wire, when the flame contacts the wire, the conductor will hang down straight, not easy to blow, burn After that, the conductor color is gray or darker; since the melting point of aluminum is lower than the melting point of copper.
The difference: the conductor after the Copper Clad Aluminum Winding Wire will be broken with a finger, which is brittle and will break into multiple sections. If the oxygen-free bare copper wire is burned to form a bead, it is a copper wire. The thickness of the copper wire is not the same after burning. The filament is melted and the thick wire is as it is.
Third, scrape with a tool; tinned copper wire after scratching appears yellow, is copper. After the anaerobic bare copper wire is scratched, the primary color is also copper. Copper-clad aluminum wire and copper-clad aluminum-magnesium aluminum have white snow. Or the wire can be rubbed on the concrete floor to get the same effect. Copper clad steel wire can also be identified by this method or with a magnet. These three methods are used together before and after. It is believed that the identification of copper wire will not be difficult, and the purchase of cheap and good cables is also very simple.