EF2 is the Ground Fault.
if the motor cable is longer than that specified for the drive size, it will increase the magnitude of the earth leakage current, due to stray capacitance and trip the drive.
The possible solutions are:

1. Check the motor and motor cables for ground faults.
2. The use of motor choke to reduce the level of dv/dt.
3. If it's the installation is in industrial and the cable is shielded find out if you can remove the earthing for the cable.
4. Try to reduce the switching frequency and note the difference.
5. Also good choice is to disconnect grounding capacitors by pulling out disconnecting switch. Refer attached document.

Released for:Schneider Electric India