I use keystone cat5e jacks and gigabit ethernet cables. As easily available as 3/4 conduits - just a couple aisles away. Some attachments later and it looks just as good. Gigabit being 23AWG means it can carry stepper currents too, and I have 4 extra wires for endstops and stuff. Finally, I can unplug the cables and use them for my PCs when I’m not milling.
I suspect both our methods won’t work too well if we completely enclose our machines.