Siemens SIMATIC S7-1500 System Manual page 135

Dimension the protective conductor as follows:
Table 8- 3
Cross-section of mains supply
conductor
≤ 16 mm²
> 16 mm² to ≤ 35 mm²
> 35 mm²
For other materials, the cross-section of the protective conductor is to be increased so that it
has at least the same conductance as copper.
Potential equalization
If there is no common bare metal mounting plate, you need different potential equalization
that comes as close as possible to a cross-section in accordance with the "Cable cross-section
for copper protective conductors" table, or at least with the same conductance.
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪
⑫
SIMATIC Drive Controller
System Manual, 11/2023, A5E46600094-AD
8.9 Protective conductor and potential equalization, functional ground
Cable cross-section for copper protective conductor
SIMATIC Drive Controller
SINAMICS S120 Line Module
SINAMICS S120 Double Motor Module
SINAMICS S120 Single Motor Module
SINAMICS Sensor Module Cabinet-Mounted (SMC)
SINAMICS Terminal Module (TM)
Power supply, for example, SITOP
HMI device
Control cabinet
Functional ground bar
Flexible protective conductor
Control cabinet door
Cross-section of protective conductor
As mains supply conductor cross-section
16 mm²
0.5 × mains supply conductor cross-section
Connecting
133