Siemens SINAMICS PERFECT HARMONY GH180 Operating Instructions Manual page 62

Electrical Connections
7.3 Grounding, Cabling, and Shielding Recommendations
VFD Output Cables
The following recommendations apply when the VFD is grounded to the facility ground though
a single connection at either the input cabinet or at the output cabinet:
● Ground output cable shield connections only on the VFD end using short lead lengths,
preferably shorter than 61 cm (24 in). Multiple ground connections on output cables can
cause circulating currents that may elevate the potential on the ground bus in the VFD
cabinet. The elevated potential could introduce noise into the control section of the VFD.
● It is not necessary to ground the cable shields at the motor end, unless a customer
specific safety requirement exists.
● When multiple cable sections are used in series, each cable section should have its VFD
end of the shield grounded. Refer to the figure
sections (or splices) are used.
Note
Long Length Cable Application
For long length cable application, the length of cable cannot be longer than 2 km using 21-
cell system. If the cable length exceeds 2 km, the 24-cell system must be used.
Figure 7-1
When the VFD is solidly grounded to the facility ground structure at multiple points, the following
recommendations apply:
● Shield connections of the output cables may be grounded at both ends using short lead
lengths, preferably shorter than 61 cm (24 in).
● The cable shields at the motor end may be grounded.
● When multiple cable sections are uses in series, then each cable section may have the
shield connections grounded at both ends.
VFD Input Cables
The input cable shields may be grounded at either end. Consult the local codes and regulations
for guidance.
60
Grounding of cable shields when multiple sections (or splices) are used.
Grounding of cable shields when multiple
Operating Instructions, 07/2018, A5E42736645A_AB
Air Cooled 6SR5