Amprobe GP-2 Geo-Test - Manual (Page 40)

GP-2 GeoTest
EN - 40
parallel, especially if those elements are close and therefore interactive. For this
reason, in case of a linked system the following formula is quicker and more effective
than the calculation of the single horizontal and vertical elements:
Rd =
ρ
/ 4r
r= radius of the circle which circumscribes the link.