[SOLVED] Safety grounding of isolated dc circuit in metal enclosure?

How can you include a safety feature to an isolated DC circuit placed on nylon separators in a metal box, parts of which are painted, other parts are bare metal? The circuit uses as much of a single-sided copper-clad board as possible for an unbroken ground plane. There is a simple ADC (part digital device) and everything else is analogue.

The power supply is an smps adapter(/any old dc adapter) that connects to the circuit via a mostly metal dc barrel adapter, which is fastened to the box, and as far as I would think the dc adapter is completely isolated from the box, so that shouldn't be important, maybe?

I was wondering what you're supposed to do to protect the user (me) from electric shock if any of the positive cables came loose for whatever multitude of feasible reasons and touched the bare metal parts of the box? Would the safety fuse blow if this happened so my question is unnecessary?

Is it common practice to connect the chassis to 0V? Makes sense but also throws up questions about being a solution which brings other problems and may be a worse solution than the original problem itself. I imagine that it creates other problems, perhaps, like an unwanted ground loop or radiating things I do not understand well like emi/rfi, etc.

...Is it bad practice, and possibly more dangerous than not connecting the chassis to anything, to connect any "isolated" DC circuit chassis/enclosure to the ground plane/star connection point because: you do not know how the DC adapter is wired regarding earth ground and neutral, you can never really know how the wiring has been done in a building in the same way?

Safety regulations require grounding of a metal enclosure if there's any risk that it could get in touch with a hazardous contact voltage. Reinforced insulation of the circuit against the enclosure can be implemented alternatively.

The protective ground connection must have suffcient cross section to carry the maximum short circuit current.

It is quite appealing to betake the metal surface of the case as an efficient ground plane for the GND power bus, but doing that you will put the circuit in direct contact with Earth, which is not a good idea in terms of safety.

You could alternatively place an intermediate plate(GND) between the chassis(Earth) and the board itself, so that this one would act as a safe shield for the analog signals.