Siemens SIMATIC S7-1500 System Manual page 53

4. Connect the opposite end of the grounding cable to the central grounding point/protective
conductor busbar (PE).
Figure 4-3
Not e
A lt ernative grounding of the mounting rail
If it is ensured that the mounting rail is permanently connected to the protective conductor
system using an equivalent installation that complies with standards, for example, by
permanent attachment to a grounded control cabinet wall, grounding via the grounding screw
can be omitted.
Reference
Additional information on the precise dimensions of the mounting rails can be found in the
Dimension drawings of the mounting rails (Page 246) section.
Automation system
System Manual, 09/2016, A5E03461182-AD
Attaching the protective conductor
Installation
4.2 Installing the mounting rail
53