Awhile back, I had an airline pilot and his family as clients. They had been in an historic St. Paul house on the edge of the high limestone bluff of the Mississippi River for a year or so and were fixing up the place. I was called in when they couldn't figure out how to turn off some of the circuits.
The circuit breaker panel had a lot of green TW conductors indiscriminatly used for 15 and 20 amp branch circuit hot and neutral, but they didn't show up at the j-boxes out on the circuit. I finally found the panelled over original fuse center 6" to the side of the CB panel, all the fuse blocks removed and the green TW soldered onto the ends of the old branch circuit homeruns. But this still didn't account for the three circuits that stayed hot even when the service disconnect was open.
Then I found the well house (well house? in inner city St. Paul?!!). There was a rusted solid 5 HP 3Ø motor in it! The starter had voltage in it. I then located a second underground service, behind batt insulation on the basement wall, entering the building's opposite side from the 100 A 120/ 240 1Ø. 30A 240V 3Ø 3 wire. This underground 3Ø service came from a little open delta bank half way down the bluff and over a ¼ mile from the xformer feeding the 1Ø.
Some yahoo had picked up the neutral off the 1Ø service and put the two legs of the 3Ø that kinda measured 120V back into duty!
