Some small rural Communities in Germany, especially close to France still have a 133/230V system w/o neutral. Some guy recently started complaining at another board... "At my aunt's I tried installing a new light and my phase tester glowed on both wires! And then I measured 127V frome each wire to ground, what's wrong there???" Kinda liked that post...
There's one important thing about working on such a system: If it's fused and the circuits aren't labeled, unscrew both phase fuses and not only one!!! Many DIYers will work "if the light's off when i unscrew the fuse it's gotta be safe!" and that's a real abd idea with such a system... you'll still have 127V to ground on one wire.
According to a German expert you'd use the blue wire as a phase in such a system. If I wired in conduit I'd probably prefer black and brown as well as the other accepted phase colors (orange, purple, white, grey, though i'd avoid grey since it used to be neutral).
