EN – R6…R9 Quick installation guide   17
Check the insulation of the power cables and the motor
Check the insulation of the input cable according to local regulations before connecting 
it to the drive. 
See figure B on page 157.
1. Check the insulation of the motor cable and motor before connecting it to the 
drive. Measure the insulation resistance between each phase conductor and then 
between each phase conductor and the Protective Earth conductor using a 
measuring voltage of 1000 V DC. The insulation resistance of an ABB motor must 
exceed 100 Mohm (reference value at 25 °C or 77 °F). For the insulation 
resistance of other motors, see the manufacturer’s instructions. 
Note: Moisture inside the motor casing will reduce the insulation resistance. If 
moisture is suspected, dry the motor and repeat the measurement.
Check the compatibility with IT (ungrounded) and corner-
grounded TN systems
 EMC filter 
The internal EMC filter is not suitable for use on an IT (ungrounded) system or on a 
corner-grounded TN system. Disconnect the EMC filter before connecting the drive to 
the supply network. Check the table on page 18.
WARNING! Do not install the drive with the internal EMC filter connected on an 
IT system (an ungrounded power system or a high-resistance-grounded [over 
30 ohms] power system), otherwise the system will be connected to ground potential 
through the EMC filter capacitors of the drive. This can cause danger, or damage the 
drive.
Do not install the drive with the internal EMC filter connected on a corner-grounded 
TN system, otherwise the drive will be damaged.
Note: When the internal EMC filter is disconnected, the drive EMC compatibility is 
considerably reduced.
 Ground-to-phase varistor
The ground-to-phase varistor is not suitable for use on an IT (ungrounded) system. 
Disconnect the ground-to-phase varistor before connecting the drive to the supply 
network. Check the table on page 18.