16mm2 solid core?!
That's about 4.5mm in diameter of solid copper. Those Germans must be out of their minds!
In Australia our multi-core fixed cables have full-size earths up to 2.5mm2, then 4mm2 cables have a 2.5mm2 earth, 6mm2 through 16mm2 have earths two sizes smaller (2.5mm2 through 6mm2), 25mm2 through 70mm2 have earths three sizes smaller (6mm2 through 25mm2), and 95mm2 and up have earths four sizes smaller. (Given that the size steps get relatively smaller as the absolute size goes up, it's actually 25mm2 that gets the proportionally smallest earth there.) All modern versions have insulated earths, though bare earths can be found in older buildings.
We also get the options of flat or
circular cables, the latter having tougher sheathing (usually coloured orange) and available in either 450/750V or 0.6/1kV ratings (up to 6mm2, above which it's 0.6/1kV exclusively). The flat cables are rated 450/750V (older versions were 0.6/1kV) and go up to 16mm2. Also worthy of mention are "twin active" flat cables (with red and white cores) commonly used for switch drops, and "SDI" (s
nsulated) which contains just a single insulated and sheathed core (most often with red inner insulation, but occasionally also black or white). SDI is usually rated 450/750V up to 16mm2, and 0.6/1kV for 25mm2 and up. (Are cables similar to SDI used in other countries?)