Siemens SIMATIC S7-1500 System Manual page 136

Connecting
8.9 Protective conductor and potential equalization, functional ground
Note
The ground potential and enclosure (PE) for the SIMATIC Drive Controller are connected over
a low-impedance internal connection.
Electric shock without grounding
If there is no protective conductor connection or the connection is incorrectly implemented
for devices with protection class I, high voltages can be present at open, exposed parts,
which can result in death or serious injury if the parts are touched.
• Ground the device in compliance with the applicable regulations.
Communication connections
Equipotential-bonding cables are not required for fieldbus components within a control
cabinet if they are configured as detailed above.
For communication connections between separate parts of a plant (for example devices in
different control cabinets) and between buildings or parts of buildings, you must ensure
potential equalization.
If data lines (PROFINET, PROFIBUS or DRIVE-CLiQ), for example, run through more than one
control cabinet, potential equalization with a potential equalization conductor is required. Lay
the equipotential bonding conductor together with the data line.
The following minimum cross-sections are required pursuant to IEC 60364-5-54:
• At least 6 mm² for copper
• At least 16 mm² for aluminum
• At least 50 mm² for steel
NOTICE
Disruption to data connection or device defect in the absence of equipotential bonding
Considerable leakage current can flow over the data line if no potential equalization is set
up. Disruption to data connection or device defects are possible.
Lay an equipotential bonding conductor together with the data line.
Due to the maximum length of 100 m for PROFIBUS copper cables at 12 Mbps or for
PROFINET copper cables, and aspects of electrical isolation, EMC protection and equipotential
bonding, we recommend using fiber-optic cables for connections between buildings.
134
WARNING
SIMATIC Drive Controller
System Manual, 11/2023, A5E46600094-AD