Harmonic filters and the like seem to be the cure all. Went on a svc. call to a resturant today, it's served by 2 200a single phase services.Seems they had problems with light flicker and dimming/brightening. owner said one of the larger ec's in the area told him he needed a harmonic filter among other things. A few thousand dollars worth of "improvements". Did a little snooping and discovered a loose neutral connection at line side of service disco. Problem solved. Instant Hero! (and a free meal to boot). [Linked Image]