PURPOSE: To reduce sag at the time of 100% electrification as well as improve strength by forming the title line with the invar line, composed of a Ni-Fe alloy wire having a small linear expansion coefficient, as the center wire and with the wire material, in which an Al material for the electrification purpose is coated on the center wire, twisted.

CONSTITUTION: In the title line used for an electrification object, the Al coated invar line A to which the Al coating 2, composed of an Al material having an electrification purpose, is applied is twisted to the invar line 1 composed of a Ni-Fe alloy wire having a small linear expansion coefficient, the coating 2 has a conductivity of 23-40%, and the maximum allowable temperature is 300-400°C. This constitution enables strength to be improved with the degree to thicken an electric wire outer diameter minimized and sag at the time of high temperatures (when 100% electrification) to be reduced.