Where is the receptical that you would use this for, do you come across them often and could you replace the receptical with a new style grounded type? I must admit to having never seen a dryer receptical without a ground pin.
Code has, for some years now, required outlets intended for use for dryers to be four pin, with a proper ground and neutral. That wasn't always the case, however, a few years back a single neutral/ground pin was permitted. Yes, that was dumb. The problem with simply replacing a three pin outlet with a four is that the necessary conductors almost certainly aren't present behind the outlet.
