Fault localizing and identifying device for electric systems

A device for localizing and identifying faults in an electric system when no power is being supplied by the electric system, comprising a primary unit and a secondary unit, the primary unit comprising a first connection which is connectible to a first conductor or earth conductor in the electric system, and a second connection which is connectible to a second conductor in the electric system, and the secondary unit being connectible to the corresponding conductors at a distance from the primary unit, the primary unit further comprising:

• a coupling unit which has a high impedance state and a low impedance state and which is connected between the connections, and a control unit having a first output which is connected to the coupling unit and adapted to control the coupling unit to shift between said two states, and that the secondary unit is a detector which detects resistance variations between the corresponding conductors due to shifts occurring between said two states under control by the control unit.