Correct me if I'm wrong in my thinking, please. I have a customer that currently has 3 seperate runs of 4/0 URD triplex. Each run is in its own Sch 40 PVC pipe. They travel 175 feet underground from the main service to a control building. One of the triplex runs are feeding a 200 amp(120/240)single phase panel. The other two are paralleled into a 400 amp disconnect feeding a phase converter.
My dilemma is, I am removing phase converter and installing true 3 phase service (120/240). Can this be done(rightfully) with the 3 runs. My thinking is to use all 3 runs to feed 400 amp switch. Can I parallel these 3 runs in the following manner?
Run #1: A,B,N
Run #2: B,C,N
Run #3: C,A,N
I would then run a new service to the single phase panel. Or should I just bite the bullet and start over with quadraplex?