Got a call over the weekend. After lots of tribulation about how convience outlets on a 400A three phase AC distro was wired, it was determined that 190 Amps on phases X & Y were fine when balanced with 175 Amps on Z. Close enough. Real question was in detecting 70v between neutral and ground. Given the load is fairly balanced, what would be the next choice for something that would cause this voltage? Note this is a question for students. Pro's should hold back until the answer is given by the students or contact me off line to debate or discuss what to check first as the most possible cause.