 While this test contributes to damage at the cable site, it is practical because the faulted location would have to be re-insulated when found in any case.In a high resistance grounded distribution system, a feeder may develop a fault to ground but the system continues in operation.The faulted, but energized, feeder can be found with a ring-type current transformer collecting all the phase wires of the circuit; only the circuit containing a fault to ground will show a net unbalanced current.