S7-300, CPU 31xC and CPU 31x: Installation 
Operating Instructions, Edition 08/2004, A5E00105492-05 
6-1 
Wiring 
6
6.1  Requirements for wiring the S7-300 
This chapter 
Describes the requirements for wiring the PS, CPU and front connectors. 
Accessories required 
The following accessories are required for wiring the S7-300. 
Table 6-1  Wiring accessories 
Accessories  Description 
Front connectors  for connecting the sensors / actuators of the 
system to the S7-300 
Labeling strips  for labeling the module I/Os 
Shielding contact element, shielding terminals 
(matching the shielding diameter)  
for connecting cable shielding 
Tools and material required 
Tools and materials required for wiring the S7-300. 
Table 6-2  Tools and material for wiring 
To ...  you need ... 
Connect the protective conductor to the rail  Wrench (size 10) 
Protective conductor cable (cross-
section ≥ 10 mm
2
) with M6 cable lug 
M6 nut, washer, spring lock washer 
Adjust the power supply module to mains voltage  Screwdriver with a blade width of 4.5 mm 
Wire the power supply module and the CPU  Screwdriver with a 3.5-mm blade, side-cutters, 
stripping tool 
Flexible cable, for example, sheathed flexible 
cable 3 x 1.5 mm
2
 
Wire end ferrules to DIN 46228