I am rewiring my Prusa I3 Rework and was looking at the number of wires needed for the hot end assembly. My setup has the following wires going to the carriage:
stepper - 4 wires
24v 40W heater - +24V, GND
E3Dv6 fan - +24V, GND
part cooling fan - +24V, GND
thermistor - 2 wires
BLTouch - SERVO SIGNAL, SERVO +5V, SERVO GND,
I was thinking at the very least I could combine the ground wires of the heater and fans and maybe the BLTouch if the +5V ground isn't isolated from the +24V ground.
The heater GND is not actually ground, it is switched via the mosfet.
Same with the part cooling fan via a different mosfet.
Cant see any reason why you cant use one +24v wire tho.