Rockwell Automation 20G PowerFlex SCR Bus Supply - Manual (Page 19)

Installation/Wiring 1-5
PowerFlex SCR Bus Supply User Manual
Publication 20S-UM001G-EN-P
General Grounding
Requirements The Safety Ground terminal (PE) must be connected to the building
grounding scheme. Ground impedance must conform to the requirements
of national and local industrial safety regulations and/or electrical codes.
The integrity of all ground connections should be periodically checked.
For installations within a cabinet, a single safety ground point or ground bus
bar connected directly to building steel should be used. All circuits
including the AC input ground conductor should be grounded
independently and directly to this point/bar.
Figure 1.3 Typical Grounding
Safety Ground Terminal - PE
The Bus Supply safety ground (PE) must be connected to the customer
grounding scheme or earth ground. This is the safety ground for the Bus
Supply that is required by code. This point must be connected to adjacent
building steel (girder, joist), a floor ground rod, bus bar or building ground
grid. Grounding points must comply with national and local industrial
safety regulations and/or electrical codes.
RFI Filter Grounding
Using an external RFI filter may result in relatively high ground leakage
currents. Therefore, the filter must only be used in installations with
grounded AC supply systems and be permanently installed and solidly
grounded (bonded) to the building power distribution ground. Ensure that
the incoming supply neutral is solidly connected (bonded) to the same
building power distribution ground. Grounding must not rely on flexible
cables and should not include any form of plug or socket that would permit
inadvertent disconnection. Some local codes may require redundant ground
connections. The integrity of all connections should be periodically
checked. Refer to the instructions supplied with the filter.
+DC
SCR
Bus Supply
- DC
R (L1)
S (L2)
T (L3)
PE
Ground Grid, Girder or Ground
Rod (Building Ground Potential)