Siemens SINAMICS S120 Equipment Manual page 389

Functional equipotential bonding
For EMC reasons, the shield of the motor cable should be connected through a large surface
area both at the Power Module as well as at the motor.
The drive line-up must be arranged on a common bright mounting plate in order to comply
with the EMC limit values. The mounting plate must be connected to the protective conductor
connection of the control cabinet through a low impedance. It simultaneously serves as a
functional equipotential bonding surface. This means that no additional functional
equipotential bonding is required within the drive line-up.
If a single, bare metal mounting plate is not available, then equally good functional
equipotential bonding must be established using cable cross-sections as listed in the table
above or, as a minimum, with the same conductivity.
When mounting components on standard mounting rails, the data listed in the table apply. If
only smaller connection cross-sections are permissible at the components, then the largest
possible cross-section should be used, e.g. 6 mm
to distributed components located outside the control cabinet.
Copper cables with appropriate cross-sections (> 2.5 mm²) must be used for the functional
equipotential bonding of PROFIBUS nodes.
NOTICE
Component destruction as a result of high leakage currents
The Control Unit or other PROFIBUS and/or PROFINET nodes can be destroyed, if
significant leakage currents flow via the PROFIBUS or PROFINET cable.
• Use a functional equipotential bonding conductor with a cross section of at least 10 mm²
No functional equipotential bonding conductors are required for PROFIBUS inside a control
cabinet. For PROFIBUS connections between different buildings or parts of buildings, a
functional equipotential bonding must be routed in parallel to the PROFIBUS cable. The
following cross-sections must be observed in accordance with IEC 60364-5-54:
● Copper 6 mm²
● Aluminum 16 mm²
● Steel 50 mm²
Additional information about equipotential bonding for PROFIBUS can be found at:
http://www.profibus.com/fileadmin/media/wbt/WBT_Assembly_V10_Dec06/index.html
Note
Non-observance of the above guidelines on functional equipotential bonding can lead to
faults on the fieldbus interfaces or to malfunction of the devices.
AC Drive
Manual, 06/2019, 6SL3097-5AL00-0BP1
between components of an installation that are located at a distance from each other.
Cabinet design and EMC for components, Blocksize format
11.7 Protective connection and equipotential bonding
for SMC. These requirements also apply
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