Right – so that probably clears things up.
If I have a distribution panel that has, say:
4x 3W LED lamps
1x 1Amp 12v USB charger (Cigarette socket)
1x 20W incandescent bulb
2x 55W halogen lamps
4x 55W halogen lamps
and 2x 20W speakers driven by a nominal 500W mini amp
means that the peak draw from the panel if everything is on is 12+12+20+110+220+40W = 418W
Which in theory could require 34A of current if they were all on at the same time.
So if I were to wire 2x 20A cables to each pole to the panel and then single 3A, 10A or 20A cable as needed to each circuit that would be OK?
Chances of having all on at once are zero, but best to plan….