Ozfly, From a very simplistic view, we can use the equation P=VI where Power = voltage times current. Using the Denali specs (from their Website) of 400W at idle and 2000W max, at idle I (current) = 3.44Amps and at the extreme, Imax = 17.24Amps. Granted this equation is used to calculate dc power, but it serves to show the worst case constant current draw from the Denalis. 17.24 amps is excessive and not very realisitic, so I would not be concerned with exceeding the 15A rated spec of the standard power cords. I agree with Sean that the bigger the wire gauge the better. I recall seeing a chart that list the wire gauge vs current carrying capability. The trend was the larger the wire size the higher current capability. Just my .02
Ken
Ken