Hey Charles,
a router power cables does not emit the same type of EMI than a VFD-to-spindle cable, but the recommendations in my VFD manual could be considered as generally valid:
- Use shielded wiring for the motor cable and all analog and digital control lines.
- Allow the effective shield area of these lines to remain as large as possi ble; i.e., do not strip away the shield (screen) further away from the cable end than absolutely necessary.
- Avoid parallel arrangement of low-level signal wiring and power-carrying or noise-prone conductors.
On the Original Series, all stepper motors cables are unshielded 
, I don’t know for Elite Series.
I agree to what Tom and Derek say. A closed-loop stepper driver reads the encoder and tries to correct it by itself for smaller deviation, but it’s only if there is a major difference between step commands and read steps, that it triggers an error condition that stops the CNC controller program.
Also Tom is right, if the stepper driver does not receive a STEP command due to cable fault or EMI, it will not expect to read it on the encoder.