Thanks guys, it seems to make a bit more sense.
In my research, I've just watched a video of a guy wiring his steppers with
Cy cable. He used a 4 core plus earth and didn't use the earth. He did however expose the wires in his control box and connected them to the side of the metal box to earth them. I'm planning on building a Perspex box, so do I still need to earth the cable or can I just use the 3core and earth as my 4 wires?
Thanks
Mick