Why is there 400v at that j-box ?
From what I can gather, that circuit was an old Aircon circuit for the upstairs part of the building, the upstairs now has a ducted system and the condenser unit is now on the roof.
For some strange reason, the A/C guys never removed the old wiring.
It looks like a school, which makes this kind of shenanigans worse.
Actually, it's a commercial building, upstairs is a law firm and downstairs is a Real Estate agents (what a combination!).
I wouldn't like to be using a garden hose around the j-box in the first picture !
That's not a junction box, it's a conduit tee, you aren't allowed to make joints in them, not that there is a lot of room to do so anyway.
One thing I never noticed when I snapped these pics though and I've gone back since to have a look, is in the second pic, above that metal junction box, you'll see a pipe protruding from the wall, that's a hot water cylinder overflow pipe.
All that wall and they had to put the box there!.