CNC newbie electronics query II

[irving2008]

Oh dear, you have a lot to learn. Current is like water flowing in a pipe. If the pipe's too small it'll burst (get hot), but it doesn't matter if the pipe's too big. Voltage is like pressure making the water flow. A smaller pipe won't burst but the pressure is reduced (voltage drop) so indeed the bigger the better within reason, as the voltage drop is less. So 0.5mm wire rated at 11A is OK. For BOB to driver you need, ideally, 3 core screened (STEP/DIR/GND+Screen), but you can use the same 4-core CY cable as the driver to stepper, just don't use one of the cores.

A 5A fuse should be sufficient but its not critical, a 13A is OK.