Wiring
4.3 Requirements for the protective conductor
SINAMICS G115D distributed drive
Operating Instructions, 12/2020, FW V4.7 SP13, A5E48681219B-002
53
4.3
Requirements for the protective conductor
A high leakage current flows through the protective conductor in converter operation. The
protective conductor of the converter must not be interrupted for safe touch protection in
converter operation.
This primarily results in requirements for the minimum conductor cross-section of the
protective conductor.
No restriction applies to the length of the protective conductor for touch protection.
However, short protective conductors are advantageous for EMC-compliant installation.
WARNING
Electric shock due to interrupted protective conductor
The drive components conduct a high leakage current via the protective conductor.
Touching conductive parts when the protective conductor is interrupted can result in death
or serious injury.
•
Comply with the requirements for the protective conductor.
Dimensioning the protective conductor
The figure below takes the SINAMICS G115D Wall Mounted drive as an example.
①
Protective conductor for mains supply cables
②
Protective conductor for converter line supply cables
③
Protective conductor between PE and the control cabinet
④
Protective conductor for motor cables
The minimum cross-section of the protective conductor
①
…
③
depends on the cross-section
of the mains supply cable and the minimum cross-section of the protective conductor
④
depends on the cross-section of the motor cable:
•
Mains supply or motor cable ≤ 16
mm
2
⇒ Minimum cross
-section of the protective conductor = cross-section of the mains supply
or motor cable