(Seriously, it would be a fun project to stuff a USB powersupply in the 400v plug and a add a USB-c cable to mess with people at work... I'd do it but we only have 230v 3-phase outlets and that plug is probably too small.)
I get a strong sense there is a secret tunnel full of antiques behind that wall...?
Useless, you can't charge from USB-a!
(Seriously, it would be a fun project to stuff a USB powersupply in the 400v plug and a add a USB-c cable to mess with people at work... I'd do it but we only have 230v 3-phase outlets and that plug is probably too small.)