Protective Angle and Protective Zone of ground Wires
The protective angle of a ground wire is defined as the “angle between a vertical plane through a ground wire and a slanting plane connecting the ground wire with the other most conductor.
Experience with various line indicates that an angle of (20°) gives satisfactory protection. Some line with shielding angle as high as (45°) is in use. The performance of the lines is rather poor. However, some utilities have adopted (30°) to be the angle of shielding with good results.