Soxfan963,
You can place ferrite suppressors on all cables that way you get the best results they are very cheap from Ebay.
The Ethernet cable should be OK they have twists to prevent noise, but a shielded version is the best.
All cables should be shielded (motor, home and spindle).
All cables should be twisted (i.e.) cables to Motors, home and spindle, cable inside the controller.
Regards,
Mauri.