Connecting up
5.1 Power supply
SCALANCE MUM856-1
44
Operating Instructions, 08/2021, C79000-G8976-C628-02
5.1
Power supply
Note
Galvanic isolation of the power supply unit
To ensure dielectric strength according to IEEE 802.3, the supplying 24 V power supply unit
must be galvanically isolated with a dielectric strength of 1500 VAC. The galvanic isolation
must also not be bridged by other devices connected to the same power supply unit.
Note
All power supplies (24 V power supply unit or PoE) must not be connected to a mains supply
higher than 300 V and the overvoltage category II.
Information on the power supply
There are two options for the power supply:
•
Power over Ethernet via the 8-pin M12 Ethernet interface P1 (position
①
).
The power supply cannot be connected redundantly.
•
Direct infeed via the 4-pin M12 socket (position
②
)
The power supply can be connected redundantly. The inputs L1/L2 are decoupled There is
no distribution of load. The power supply unit with the higher output voltage supplies the
device alone.
For the direct feed-in of the power supply use copper cables with the following properties:
•
Round cable cross-section with 6 to 8 mm diameter.
•
Two-wire cable with 0.5 (AWG20) to 1.5 mm
2
(AWG20) cross-section per wire. The
temperature stability must be at least 105 °C.
•
With redundant power supply: Four-wire cable with 0.5 (AWG20) to 1.5 mm
2
(AWG20)
cross-section per wire. The temperature stability must be at least 105 °C.
•
Permitted tensile load at least 100 N.
•
Listing of the cables according to the national installation regulations. In areas where NEC
or CEC applies: Type PTLC or ITC
To connect the functional ground, use a copper cable of category 20 AWG or a cable with a
cross-section
≥
0.75 mm².
