Substation Rock Resistivity

[RSChinn]

We are empirically testing substation rock spalls for resistivity and come up with around 10,000 ohm-meters of resistivity. The IEEE80 uses a typical example of 2500 to 3000 ohm-meters for substation rock resistivity. Are we way off base? Our samples are 1-1/2" drain rock.

 

[cuky2000]

The resistivity values of 2000 to 3000 Ohm.m referred in your post is for crushed rocks in wet conditions.

For dry conditions, the resistivity value is much higher in the order on million (10^6) Ohm.m.