It’s really a question of what you feel comfortable with doing, this is a personal judgement on whether you’re happy that you can earth things properly and not zap yourself or anyone else who touches it. I know that I am but I’ve got a long history of wiring things up and some literal scars to show which mistakes I learned from.
As for legality, Switzerland may be quite strict, if you’re still going to plug the whole thing into an outlet rather than hard-wire it into a breaker in your consumer unit that can mean you don’t need a licensed electrician in some territories but check your local laws.
Yes, this is the DC voltage that the sine wave AC is rectified to, multiply the AC RMS voltage (220) by sqrt(2) to get the DC and the AC peak.
The most common symptom is that your machine becomes unreliable and disconnects from the USB during jobs. The input noise filter to the VFD is there to stop it messing with all your other appliances and should work fine.
Yep, looks like a decent box.
There seems to be a remote operator cable and kit to put a remote keypad on the VFD so you could keep it hidden in the box where it’s safe and chip / dust free.
Well, a DIN rail and a few DIN blocks for connecting up the wiring inside the box along with a nice earthing block might make things easier.