Since forums have somewhat different audiences, I'm posting this question in a few different places. I'm looking for advice and experienced comments.
I have a major 'heavy industry' faciiltiy that has all manner of power quality issues. It is my belief that these issues are the result of combining frequency drives, induction heating equipment, and HID lighting with an ungrounded 480 delta service.
For example: one lamp ballast with a high-impedence fault to ground caused weeks of poor welds on the line ... until the problem was 'solved,' mainly by accident.
I'd like to completely separate the lighting from the plant power. I'm thinking of installing 480 delta- 480/277 Wye transformers, grounding to the building steel.
The place has approximately 700 fixtures, of the 400w metal halide type.
Naturally, there are other plans afoot .... changing to T5's, moving/ adding lights, even the change to 277 will make less expensive ballasts available.