1.5 kw Chinese spindle cable

[JAZZCNC]

No you don't need anything that heavy 1.5mm/2 or even 1mm/2 CY cable will work fine. Also while there will be 4 pins on the connector only 3 or them are actually used so you only need 3 core.
Often poeple use 4 core because it's the same cable they would use for the steppers. Or they want to add there own a Ground for the spindle, personaly I don't find a need.

I can suggest a supplier that will sell by the meter but they will want more for carriage than the cable so probably not worth it really. You'll be better going to Maplins or local electrical supplier and asking for CY cable.
http://www.csecables.com/acatalog/CY-Cable-p1.html