Connecting a 3mm electrical wire in a non air environment?
Short answer: Your question doesn't even remotely indicate that you know what you need to know about electrical safety.

When I went to school, I did a 14 day internship at a small company that builds control/switch cabinets. If I had delivered a work of craftmanship of the quality of that picture, my boss would have said very ugly things to me. From the third day on. So, this isn't even acceptable in any other installation. Hope you didn't take that photo yourself, but got it from somewhere else¹.

So, no, under no circumstances is it OK to, with your level of knowledge, install electrical stuff in an explosion-safe environment. Only certified electricians should do that.


¹ things that are wrong:


stranded wire must have a crimped-on strand sleeve when screwed fast
wires on the left change diameter – that isn't per se impossible, but I'd very much expect a fuse there.
is that freaking unisolated copper wire freedangling between contacts? What if any friction breaks loose a few strands, which then end up in contacts!?!??
screw terminals aren't properly secured to the rail, and although these cables look far from mechanically rigid, are rotated by the cable forces.
my boss would have felt his aesthetic feelings hurt by the non-alignment of the wires. But that's just personal taste.