Siemens SCALANCE X-300EEC, Compact Operating Instructions

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6.7.2.2 Connecting the external 24 VDC power supply
24 V safety extra-low voltage (SELV)
WARNING
● The IE Switch X-300 is designed for operation with safety extra-low voltage (SELV). This
means that only SELV complying with IEC 60950-1 / EN 60950-1 / VDE0805 can be
connected to the power supply terminals.
● The power supply unit for the IE Switch X-300 power supply must meet NEC Class 2, as
described by the National Electrical Code(r) (ANSI/NFPA 70).
● The power of all connected power supply units must total the equivalent of an LPS (limited
power source).
● If the device is connected to a redundant power supply (two separate power supplies), both
power supplies must meet these requirements.
● The signaling contact can be subjected to a maximum load of
100 mA (safety extra-low voltage (SELV) 24 V DC).
● Never operate the device with AC voltage or DC voltage higher than 58 V DC.
Connecting to the power supply (SELV)
● The power supply is connected using a 4-pin plug-in terminal block.
● The power supply can be connected redundantly. Both inputs are isolated. There is no
distribution of load. When a redundant power supply is used, the power supply unit with the
higher output voltage supplies the IE Switch X-300 alone.
● The power supply is connected over a high resistance with the enclosure to allow an
ungrounded set up. The two power inputs are non-floating.
Terminal block assignment (4-pin)
Table 6-4 Pinout of the 24 to 48 V safety extra-low voltage (SELV)
Pin number Assignment
Pin 1 L1+ (24 to 48 V DC)
Pin 2 M1
Pin 3 M2
Pin 4 L2+ (24 to 48 V DC)
To wire up the power connector, use a copper cable of category 18-12 AWG or cable with a
cross-section of 0.75 to 2.5 mm².
Connecting
6.7 Power supply
SCALANCE X-300EEC
Compact Operating Instructions, 11/2019, A5E02630809-14
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