@carlsbad if you think all an amplifier needs is the power to drive the average wattage on the spec sheet, then you can power most amps with a lamp cord.
I am totally not sure about this advice as lamp cords supply lights which these days are just a few watts, with much variability. Probably 18 AWG or thereabouts?
Amp spec sheets that I have seen specify maximum watts and it is this peak that is informative for conservative decision making (should there be a choice), not average watts - class A/B, for example, vary with volume. So no, I don’t think that all an amp needs is the average wattage.
Many amps require much more than a lamp light (my class A amp is about 350 watts, and some are much more), so it’d be prudent to consider a heavier gauge, such as the generic ones which also have regulatory approved connections.
Without checking, in my country I think they are generally rated for about 2,400 watts - one size fits all, kinda thing. Plenty. Easy.
No need for consideration to be given to a choice between 8 or 10 or 12 AWG etc etc. Blah. Seen this, true.