Advice needed for controller box layout

[JAZZCNC]

Really that case is little on the small side. You also need to think about heat and removing it with some fans.

Regards layout then first I wouldn't worry about trying to fit it all within in the confines of the plate because the reality is after it's wired you won't ever lift it out.

So I would put 2 drives up one side with one across top. The PSU like you have on it's side on the other side.
Then have the BOB Lower down because most of your wires connections will be coming in thru the bottom ie: Limits, E-stop, probes, etc
All Power and higher voltage wires or devices need to be kept far away from signal wires as possible and idealy run thru separate trunking crossing at a minimum. (See pic to get the idea of layout I mean)

You will need fuses for each drive and the main Psu. Regards Safety Relay then while you don't exactly need a Proper Safety relay with protected and monitored contacts you do need a Hardware driven safety system, which is what Clive S is refering too.

Relying just on Software E-stop is dangerous and shoudn't be used even on DIY router. Don't for one minute think this machine won't snap your arm like a carrot if get in the way, equaly neither will it think twice about ploughing it's cutter thru your hand just like it would a piece of Oak.!!

For this reason you need an E-stop safety system that uses a Relay to kill power to every thing that can hurt you. Then only after it's safe will it allow the system to Reset and Only with a Dedicated Momentery Reset button not just by releasing the E-stop button.

The extra cost is minimal so it's stupid to not do it.