Coil Element for a Current Sensing Device

A coil element includes a winding body and a length of wire wound around the outer surface of the winding body. A cross section of the outer surface perpendicular to the axis of the winding body has a substantially rectangular shape. A first axis of the cross section is equally spaced from the two first sides and has a dimension, a, and a second axis of the cross section perpendicular to the first axis of the cross section is equally spaced from the two second sides and has a dimension, b. The cross section has a first radius rc, a second radius ra, a third radius rb, and a fourth radius rao; wherein a≥b; rc