When I moved into this house it was far more than just tingle voltage between the EGCs and the floor. The first thing I did on day one was connected the cooktop to a cold water pipe and that fixed the problem temporarily. Later I figured out the "ground" I was using was actually the cast iron drain pipe from the stainless kitchen sink, connected continuously by metal to the earth under the slab. (Chrome over brass tailpiece and trap, copper drain pipe)
Shortly after that I drove new rods and connected new copper from the panel to them. As time went on my GES was improved. Now I think I may be the ground for the neighbors too. I have a couple of amps on the PoCo neutral with my main breaker off. There is so much stray current going around it is hard to figure out what is going on. All of the grounding leads coming down the poles carry current, all the way up my street. The worst is almost 3 amps.

[Linked Image from gfretwell.com]

I suspect that will be true anywhere that has wye distribution tho. (a whole street, ~20 transformers, fed from a single phase) All of that unbalanced current is going wherever there is a path and a 2ga neutral on the poles is not carrying all of it. I really do not think there has been nearly enough analysis of where stray current comes from and where it goes. It has been blamed for pin holing pipes here and a number of other less noticeable issues.


Greg Fretwell