Yep that’s a 230V socket and yep that’s a tiny wire shorting it. But don’t worry it wasn’t energized. We needed to short phase and neutral for continuity checks at the panels, we had to identify all the terminal blocks, they weren’t labeled for the practice. Our teacher told us that last week an apprentice did this to a powered socket he thought would be deenergized, luckily it was just a loud bang and he didn’t got injured.

Here are two panels without any labels as a practice, we had four of them in a small simulated room interconnected between each other with lamps, sockets and switches wired to them, a fun game with our multimeters.