Siemens 3UG4 User Manual page 229

Application examples
The figure below shows monitoring for ground fault/insulation fault in the case of an
ungrounded 2-wire IT AC system. The voltage source is the secondary side of an isolating
transformer that galvanically isolates the system and the downstream circuit.
①
Image 9-2
Note
The maximum cable length of the control cables is 50 m or 100 pF/m.
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
Loads
Monitoring for ground fault/insulation fault in the case of an ungrounded 2-wire IT AC
system
3UG458. insulation monitoring relay
9.3 3UG4581 insulation monitoring relay
229