Paul, thanks. That's really only single 3 phases load connected to the tarnsformer.
Winnie, thanks. I absolutely agree with your comment regarding grounded & ungrounded term.
We are aware with the disadvantage, derating cable/ insulation system. The disadvantage related to cost $$ may be ignored, as system continuity will overide that. I just need to makesure the safety concern. Someone ask me (with a reference/book) which mention ungrounded system is not safe. What kind of safety issue? We will try to eliminate.
Thanks all
