What's wrong with the copper wire blackening in the wire?
This is the copper wire oxidation, it will seriously affect the resistance, resulting in a decrease in ampacityCopper is generally the quality of clearance, impurities more.
The line opened fire one line stranded wire, copper wire really burn red will not bend, the black oxide layer is not easy to fall off, the bending is not crisp. The copper aluminum wire burns to the red, naturally bends or breaks down, and black, the oxidation layer is easy to erase, the bending is crisp, easy to break.
Black wire is generally had been struck by lightning or large current caused by the first to confirm this line is the copper wire or copper wire, now there are a lot of copper as copper wire, this line can not withstand the power load, and easy plating blackening, if it is the best for copper and aluminum wire, because plated the copper has been completely oxidized and lose the function. If it's a copper wire and the skin is not bad, you don't have to change it.
