Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual page 221

Reference for ambient conditions
For information on ambient conditions, refer to the
Reference Manual.
Please note
• When mounting on varnished or anodized metal parts, use special contact washers or
• Provide a large-surface and low-impedance metal-to-metal connection for fastening the
• Always touch-protect live mains conductors.
The figure below shows an example of EMC compatible wall-mounting of an S7.
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
remove the insulating layers.
shielding/protective protective ground bar.
P S
A.2 Protection against electromagnetic interference
S7-300 Automation System, Module data
C P U
Appendix
A-11