User Manual

3UG458. insulation monitoring relay.
10.3 3UG4581 insulation monitoring relay
3UG4 / 3RR2 monitoring relays
218 Manual, 02/2013, NEB927043002000/RS-AA/002
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.
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1
3(
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$
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① Loads
Figure 10-3 Monitoring for ground fault/insulation fault in the case of an ungrounded 2-wire IT AC
system
Note
The maximum cable length of the control cables is 50 m or 100 pF/m.