S7-300, CPU 31xC and CPU 31x: Installation 
Operating Instructions, Edition 08/2004, A5E00105492-05 
5-1 
Installing 
5
5.1  Installing an S7-300 
 
Here we will explain the steps required for the mechanical assembly of an S7-300. 
 
 
Note 
Note the installation guidelines and notes on safety in this manual when mounting, 
commissioning and operating S7-300 systems. 
 
Open components 
S7-300 modules are "Open Components" according to IEC 61131-2 and EC directive 
73/23/EEC (Low-Voltage directive), and to UL/CSA Approval an "open type". 
In order to conform with specifications on safe operation relating to mechanical strength, 
inflammability, stability and touch-protection, the following alternative installation modes are 
prescribed: 
•  Installation in a suitable cubicle 
•  Installation in a suitable cabinet 
•  Installation in an appropriately equipped and closed operating area 
Access to these areas must only be possible with a key or tool. Only trained or authorized 
personnel is allowed access to these cubicles, cabinets or electrical operating rooms.