Dear All,

 

I’d like to share an experience with the fall of potential method: if I call E the electrode under measurement (in a square arrangement of approx. 20m), P the inner Potential electrode and C the outer current electrode, I could get a flat curve of the E resistance whilst C was away from E by a distance corresponding roughly to the side of E. I was quite surprised since I thought this distance was too short and I expected a  non flat resistance curve since E and C were supposed to couple with each other. Hence a question: can you theoretically get a flat curve when E and C voltage gradients still significantly overlap and, if so, does it necessarily mean that the resistance corresponding to the middle of this curve correspond to the real resistance of E to earth ?

 

Thanks for your lights.

A sketch of the arrangement would be helpful.

Are you looking at two earth grounds?

Gents,

Thanks for your contributions. By fall of potential method, I meant this using 3 électrodes:

- E, which is the electrode to be measured

- P, which is the potential electrode

- C, the current electrode

The testing current is impressed in E and returns through C. See attached for illustration.

Regards.

 

fall of potential.pdf