Wiring diagram for 4x4 cnc router

[Danielroyal25]

Hi guys!

I am a complete novice to electronics as you may tell by the diagram i am about to post. Could you please make any comments on the diagram good or bad and point me in the right direction if there is something obvious and is likely to go bang!
I think all the details are there as to steppers / drivers used and key components. Im not to worried about the wiring of the steppers to the drivers, its mainly the safety system.
The questions i have are:
What fuses do i need?
What cable sizes do i need?
Should the spindle be earthed to the spindle mount / frame or should i take it back into the main point in the control box?
Linking the charge pump to cut the safety circuit how is this done - via a relay or software driven?
Am i ok linking the power supply connections at the terminal block with small linking wires - one to the other etc?

A massive thanks to Dean for getting me this far, just wanted to clear the last few questions up as hopefully the diagram will be easier to follow than me typing it out.

I will be splitting the power supply and control side up by having to cabinets / boxes.

Thanks!!