Connection 
  5.2 Power supply 
SCALANCE W774-1/W734-1 
Operating Instructions, 09/2015, C79000-G8976-C325-06 
25 
 
 
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.
 
For the power supply, there are two options with the SCALANCE W774/W734: 
●  Direct feed in via the four-pin socket (position 
①) 
●  Power over Ethernet via the RJ-45 Ethernet interface P2 (position 
②). The other 
Ethernet interface P1 is not capable of PoE. 
 
The four-pin connecting socket has the following pin assignment: