A friend of mine just had a look at a newly (or at least within the last 10 years) renovated attic apartment (finished attic, a big thing in the cities here to get more expensive living space without building new houses, even heavily subsidized by the cities). Rather new panel, quality breakers (Made in Austria), GFI, everything. The test button on the GFI didn't do anything. Took off the cover and, for some reason, started tracing the main ground wire. Flex conduit in drywall cavity. Pulled on the wire... 10 cm came out... 20... 50... and after one metre of wire the ground was over... the original installer just didn't hook it up to anything...
