Asking for a friend who's not too big on the internet... ;-)
- On a farm. 1000' underground three wire power run to a well. Buried about 3 feet down.
- There is about 200' of three black cables from the barn to a fence post. There there they come above ground and a switch from three black wires to two black and one yellow which run underground from there to the well. (I'll call them B1, B2 and Y for now with Y assumed to be ground/common. (an assumption of intent, not fact!))
- At the barn's circuit breaker panel... 240 volts measured across the wires at a double breaker. 120 volts from each of those wires to ground. These are presumed to be B1 and B2.
- At the "fence post" joint, and at the well... B1 to Y is 120 volts, B1 to B2 is 120 volts and B2 to Y is 0. (i.e. no combination is 240 volts.)
I'm confused by the 120 volts between B1 and B2 an the zero between B2 and Y.
- Y an B1 are good.
- B2 is broken and in contact with wet soil. (I.e. grounded)
He bought an underground wire locator (a TX to attach to one end and an RX you walk with to find the break). So far it has not been too useful in finding where the break is, most likely due to very wet and saturated ground, but when testing the end of the lines, it seems to indicate that B2 is the problem.