Siemens X-400 User Manual

Operating Instructions for SCALANCE X-400 Industrial Ethernet Switches 
C79000-G8976-C186-03 

67

 

 

 

 

Warning 
SCALANCE X-400 is designed for operation with safety extra-low voltage (SELV). 
This means that only safety extra-low voltages (SELV) complying with 
IEC950/EN60950/ VDE0805 can be connected to the power supply terminals. 
The power supply unit for the 24 V DC supply must comply with NEC Class 2 
(voltage range 20.4 - 28.8 V DC, current requirement max. 2 A). If the device is 
supplied with power redundantly, both power supply units together must comply 
with NEC Class 2. 
Exceptions: 

●  Power supply with PELV (according to VDE 0100-410) is also possible if the 

generated rated voltage does not exceed the voltage limits 25 V AC or 60 V 
DC. 

●  Power supply by a SELV power source (according to IEC 60950) or PELV 

power source (according to VDE 0100-410) without limited power is also per-
mitted if suitable fire protection measures are taken by: 
-  Installation in a cabinet or suitable enclosure 
-  Installation in a suitably equipped, closed room 

 

 

Caution 
The subject unit must be located in a Restricted Access Location where access 
can only be gained by SERVICE PERSONNEL or by USERS who have been in-
structed about the reasons for the restrictions applied to the location and about any 
precautions that shall be taken when operated in an air ambient of 50°C - 60°C