I was reading this thread and some of you stated that there is no real edvidence of problems with harmonics. And it's just a economic theory to sell products and service. I can tell you right now that it is a very real problem, that has infected an entire high school district I work for. After upgrading all the lighting (from T12 to T8 electronic ballast) and computer labs (switch mode power supplies).The electrical system has caused major problems on equiptment. And I personally discovered the building steel has been acting as the neutral.If I disconnected the ground (green) wire in a box while a load was in use,I would get shocked.As if you were to disconnect a neutral under load, the return end will shock you. To cure problem: All sensitive electronic equipt. on it's on system (K20 rated XFRMR, 200% neutral panels,dedicated circuits-one neutral for one phase conductor). Some have even gone further and run a extra green wire (w/yellow stripe) for isolated ground.
