Bill,

I agree with your points. The new house, #2, wouldn't notice the missing neutral at its service. . .that is until the plumber (that you mentioned in the post before) breaks the continuity of the pipe heading out of the old house, #1, towards the new house.

Your point about current flowing in the pipe under regular conditions is dead on, and, I think, agrees with Don(resqcapt19). The equivalent circuit of the water pipe between house #1 & #2 is a low series resistance between the neutral bars of the respective services. Each neutral bar will have three parallel resistances to ground (theoretical "zero ohms" ground), (1)one resistance being the supplemental ground rod to earth resistance, (2)another resistance being the pipe's own contact with earth, and (3)the resistance of the service entrance neutral + service lateral neutral + transformer ground wire + earth resistance at the transformer ground. This equivalent circuit is created, also, if the houses are connected by their own private water line, or by connection through the water utility. Each service, with unbalanced load, will have unbalance current that will return, divided through the three parallel resistances. This causes the reverse of a voltage drop. . .that is, each service neutral will rise above zero by the I x R where R is single resistance gotten by adding the three parallel resistances. The voltage on the neutral of one house, when different than the neutral voltage of the other house results in a current in the water pipe resistance.

This is just for two houses. The description gets absurdly complex when more houses are included, houses connected to a common metal water distribution system, and more than one transformer supplies the houses. [Linked Image]

(I woke up still thinking about this one. . .I should draw a diagram. A.)

[This message has been edited by ElectricAL (edited 11-09-2001).]

Al Hildenbrand