Siemens SIMOCODE pro C System Manual page 215

Ground-fault module connection example
Figure 12-22 Ground-fault module connection example
The output signal of the transformers 3UL22/3UL23 is connected to terminals C1 and C2 of
the corresponding ground-fault module.
Information on installing the residual current transformer 3UL23: See Manual 3UG4/3RR2
Monitoring Relay (https://support.industry.siemens.com/cs/ww/en/view/54397927),
Chapter 13.2.5.
NOTICE
Routing the connecting cables / using shielded cables
To avoid interference injection, which could result in incorrect measurements, route these
connecting lines parallel and twisted, if possible, or use shielded cables.
SIMOCODE pro
System Manual, 05/2019, A5E40507475002A/RS-AD/004
Mounting, wiring, connecting, system interfaces, configuration guidelines
12.2 Wiring, connecting
215