Ragnar: I'm sorry to say but I think your theory is wrong: If you could plug in 4.8 mm pins into the US socket, a grounded socket would accept Schuko plugs but without ground. Furthermore: It's harder to get the larger pins in than the smaller as you start interfering on the Nema socket. I have a adapter that accepts both the Schukos and Nema plugs (made by Kopp). It takes some effort to insert a Schuko plug.