For reliable protection of overhead transmission lines from direct lightning strokes using ground wires, the protection angle ‘a’ between the vertical line through the ground wire axis and the line passing from the ground wire axis to the outer most line conductor should be _______.

For reliable protection of overhead transmission lines from direct lig

1.	For reliable protection of overhead transmission lines from direct lightning strokes using ground wires, the protection angle ‘a’ between the vertical line through the ground wire axis and the line passing from the ground wire axis to the outer most line conductor should be _______.
A.	10° - 15°
B.	50° - 60°
C.	20° - 30°
D.	40° - 50°
Answer» D. 40° - 50°