SR-2 Soil Resistivity Meter

The instrument may be used with either two (2) or four (4) pins, which are set into soil in a straight line, at equal distances. The Pins are named C1, P1, P2 and C2. Voltages are driven between C1 and C2, while resistance drop is measured between P1 and P2 (4 pin method).

In the two pin method, the resistance drop is measured between C1 and C2 only. The distance between the pins is equal to the depth of the soil resistance.

The four (4) pin method has been standardized by ASTM as Standard G 57-95(a) and this method is also described in NACE Internationals, Peabody’s Control of Pipeline Corrosion, Second Edition, pg.