Siemens SIMATIC RF166C Operating Instructions Manual page 33

Circuit breaker
According to IEC 60364, line protection is required, i.e. the supply lines must always be
protected externally.
All supply voltages must be protected with a UL/IEC approved fuse 24 V DC / 16 A (tripping
characteristic type B or C). At ambient temperatures of 40 °C to 55 °C, the power supplies
must be protected with a UL/IEC approved fuse 24 V DC / 12 A.
Power supply of the assembly
Two voltage groups are available for the communications module, 1L+ (supply voltage) and
2L+ (load voltage).
Another power supply may be required in order to supply all communications modules of an
assembly with the required voltage. Another voltage supply of 1L+ and 2L+ may be needed
to form different potential groups, or because the voltage is insufficient for all
communications modules due to the voltage drop. Create a power budget for the selection of
the supply point of the voltage.
Note
Switching 1L+ and 2L+ on and off
Note that the power supply (1L+) supplies the communications module and the readers with
power. Load voltage (2L+) has no direct effect on the RF166C communication module.
The following figure shows a configuration with another voltage supply for the
communications modules. The different potential groups are highlighted in gray.
Figure 5-5
SIMATIC RF166C
Operating Instructions, 12/2019, C79000-G8976-C578-01
Wiring of the power supply
Connecting
5.2 Electrical design of the CM
33