ABB DCS 400, Manual, Page: 105 / 192

II K 5-5
Installation
Definitions
Earth, earthing for safety
Ground, grounding for EMC, connection with chassis or
housing with low inductance
Important instructions for plants with line fil-
ters
Filter in an earthed line (TN or TT Network)
The filters are suitable for earthed lines only, for example in public
European 400 V lines. According to EN 61800-3, filters are not
compatible in insulated industrial lines with own supply transformers
due to their safety risks in such floating lines (IT networks).
Earth fault detection
Filters (with internal discharging resistors), cables, the converter
and the motor have together a considerable capacitance to ground,
which can cause an increased capacitive earth current. The tripping
threshold of an earth fault detector that measures this current must
be adapted to this higher value.
High voltage test
Because of the capacitors of the line filter the high voltage test has
to be done with dc voltage to protect the components.
Warning
Line filters contain capacitors, which can keep dangerous voltages
at the terminals after the switch off of the mains voltage. The dis-
charge by internal resistors takes some seconds. Therefore a wait-
ing time of
at least 10 s and a voltage check are obligatory before
you begin your work at the equipment.