Earth Fault Current = Rated Current / Impedence
where Rated Current = Rated KVA / (Rated KV x 1.732)
Example : 1600KVA TX , 11/0.433KV, Impedence : 6
--> Earth Fault Current = [1600KVA / (0.433 x 1.732] / 6
= 355.57A
Note :
To refer to catalogue to choose which size of cable that can carry 355.57A
