update - appeared to be a bad ballast. one in the whole string was affecting all nearby lights. it doesnt explain how it could affect those on an emergency ckt, but it could have just been an illusion.
we have an elevator nearby, but these are the only affected lights. the closer ones arent.
VFDs yes, but again, not nearby or off the same panel.
lighting consists of two types: 277V electronic ballast, direct/indirect fixture; and recessed pendant type, i dont know this info offhand but will...
baffling issue - We have a bank of lights in a new space just built out. There is one circuit feeding an area of a floor. half of the lights on this circuit randomly dim and brighten, from 350 to 500 lux. the odd part is that there are a handful of emergency lights scattered through this area...
