@moonbase: Well, it depends upon whether it is a real problem or not ...........
eg I fitted an 8.5Kw Electric Shower last year: I sized the cable using BS7671 (IEE Wiring Regs) tables governing not just the maximum current, but also the duty cycle (how much and how often it would be passing that current) and the nature of any insulating materials (walls, timber, rockwool) etc. that it might pass through or be covered by.
The cable gets vaguely warm to the touch (Outer insulation!) after 5 minutes use.
That is not a problem.
And that's after following closely worked and well-understood guidance - in your case, the voltage and the risks are rather less and the consequence of occasionally warm cables (not hot!) is not likely to be significant and the selection of cable size can be less scientific - BUT following the Motor Manufacturer's advice is a good idea. What does that say?
@wod: Yes, a lightweight "mains" cable would be fine, subject to environmental conditions.