A method of mapping voltage potential along a metal structural member
extending underground through a range of depths comprises the steps of
providing a voltage meter having positive and negative terminals, a
reference electrode connected to the positive terminal, and a half-cell
connected to the negative terminal; forming at least one hole in the
ground alongside the structural member; contacting the reference electrode
with the structural member at an aboveground location; and positioning the
half-cell at a series of test points in the hole(s) and taking a series of
voltage potential measurements respectively corresponding to the series of
test points, wherein the test points are located at different depths.
Preferably, the method further comprises the step of plotting test point
depth versus voltage potential. A novel drill bit for drilling the hole
through earth comprises a common wood-boring auger shank and a flat
masonry-style drill bit tip.
