3.3.4.4 Probabilities of damage in case of indirect lightning strikes into supply lines

Now, the supply line is no longer directly struck, but the lightning strike point is close to the line. In this case, the high energy coupling of a partial lightning current to the supply line can be ruled out; however, the possibility of magnetically induced voltages on the line remains. 

The probability values P_Z that a lightning strike next to a supply line leading into a structure will cause internal systems to fail depend on the shielding properties of the supply line and the isolating interfaces or SPDs provided in accordance with IEC 62305-4 (Equation 3.3.4.4.1):