I have a practical problem in E&M which has baffled me and and my electrician. The copper water pipes in my house are carrying a current of small potential (~1V) AC current. Here is my hypothetical circuit diagram:
R1 R2 ~~---o------+--------+ | | | | R3 source ground | | +--------------------+
o is my shower head and ground is actual ground from which the supply pipe enters the house.
R2 represent the assumed (low) resistances of the copper piping. The way I detected the current was while changing a light fixture above the shower head and detecting a flow from my showerhead to the grounded junction box through my forearm. This current produced a mere tingle in my arm and has been confirmed with two different multimeters: my "toy" and the electrician's Fluke.
R3 represents my arm, an intermittent connection to ground.
There is also a 2m copper ground spike embedded in the outside earth connected to nothing which can be used as a reference. The common/neutral line of the breaker box is currently tied at R2 near where the municipal supply line enters the house's basement. The source is unidentified but assumed since there is a measured, felt potential on the copper pipe.
If the circuit is how I have drawn it, I believe the following would be true following Maxwell, Ohm, and/or Volta:
- in the typical case with
R3disconnected all current goes from source to ground via
- while my arm is touching the pipe and the grounded junction box, most of the current goes from source to ground via
R2while a small current goes through
R3is presumed to be of much higher impedance than
Is this a correct interpretation of how the hypothetical circuit would behave?
For the curious, the house is 80-ish years old with some olde-fashioned knob-and-tube (poorly insulated) wiring inside the walls that we guess could be in contact with the plumbing and thus be presumed current source.