Rockwell Automation 1336T Wiring and Grounding Guide, (PWM) AC Drives - Manual (Page 50)

50 Rockwell Automation Publication DRIVES-IN001M-EN-P - March 2014
Chapter 3 Grounding
Grounding PE or Ground
The drive safety ground, PE, must be connected to scheme or earth ground. This
is the safety ground for the drive 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 or electrical codes. Some codes require redundant
ground paths and periodic examination of connection integrity. Global drive
systems requires the PE ground to be connected to the transformer ground
feeding the drive system.
RFI Filter Grounding
The use of an optional radio frequency interference (RFI) filter can result in
relatively high ground leakage currents. Therefore, use an RFI filter only in
installations with grounded AC supply systems and RFI filters that are
permanently installed and solidly grounded to the building power distribution
ground. Make sure the incoming supply neutral is solidly connected to the same
building power distribution ground. Some codes require redundant ground
connections and periodic examination of connection integrity. Refer to the
instructions supplied with the filter.
Grounding Motors
The motor frame or stator core must be connected directly to the drive PE
connection with a separate ground conductor. We recommended that each motor
frame be grounded to building steel at the motor. Refer to
Cable Trays on page 68
for more information.
Grounding and TN-S Five-wire Systems
TN-S Five-wire distribution systems are common throughout Europe, with the
exception of the United Kingdom and Germany. Leg-to-leg voltage (commonly
at 400V) powers three-phase loads. Leg-to-neutral voltage (commonly at 230V)
powers single-phase loads.
IMPORTANT Do not use flexible cables or any plug or socket that can be accidentally
disconnected.
IMPORTANT Do not connect ground to neutral within a system cabinet if you use a TN-S
Five-wire distribution system. The neutral wire is a current conducting wire.
There is a single connection between ground and neutral, typically in the
distribution system.