A method for manufacturing a conductor bar of a rotating electrical machine includes providing a conductor defining a longitudinal direction and having a rectangular cross section, and building up an insulation to a thickness d around the conductor by progressively winding an insulating tape around the conductor a plurality of times in the form of a spiral in the longitudinal direction. The building up of the insulation includes winding the insulation tape around the conductor using parallel winding up to a first partial thickness, and winding the insulating tape around the conductor using non-parallel winding from the first partial thickness.