Which thickness CY cable do I need for 1.5kW spindle?

[JoeHarris]

An analogy. If an architect specified a 152x89 RSJ. Would you chose to replace this with a 127x76 RSJ that you had lying around? It might well work, the building would probably stay upright after you've finished it. Hey!, the architect is clearly a fool.

Not wishing to fuel the fire, but what cross section cy are people generally using between driver and stepper?! (genuine question!)
Signed foolish architect

ps. This video is quite useful for those with less experience when it comes to connecting steppers to the cable itself, I would be interested to hear comments on his methodology from those who have done this many times before... - https://www.youtube.com/watch?v=Xbiipb6nnZg