COVERED ELECTRIC WIRE

PROBLEM TO BE SOLVED: To improve stress corrosion cracking resistance of a conductor, and lengthen its service life by setting the impurity content of the conductor totaling a specific quantity or less except for the silver content. SOLUTION: The impurity quantity of a conductor is set totaling 60 ppm or less except for silver. It is desirably set no more than 40 ppm, and is particularly set not more than 20 ppm. Purity of the conductor is desirably set not less than 99.995%, and since the conductor is constituted of copper on which the total content of Ni, S and H as an impurity is 5 ppm or less, stress corrosion cracking resistance can be improved further. Heat treatment is desirably performed on the conductor under a condition of not causing recrystallization. When heat treatment is performed on an impurity quantity-limited conductor under a conduction of not causing complete recrystallization such as to maintain strength equal to a hard copper wire, the stress corrosion cracking resistance can be improved further. The conductor of a covered conductor has an insulating covering on an outer periphery. The conductor may be either of a single track and a stranded wire by interwisting plural strands.