I guess I've never tried out a 120v outlet wrongly wired up to 277v lighting, but, I know some of these 120v outlets are putting out 277v and that's the only explanation as to why. This is former commercial property (480 having 277 to balance) that is now residential. As per code 210.9 exact quote: "Branch circuits shall not be derived from autotransformers unless the circuit supplied has a grounded conductor that is electrically connected to a grounded conductor of the system supplying the autotransformer". So I guess it's all legal if there's a $100 dollar or so autotransformer between the two.