Grounding Rod Resistance

Hi,
I have to design the grounding system of a power plant. Soil resistivity report shows maximum value or 1571 Ohm-cm. I have a query that whether a less than 2 ohm resistance is essentially required for a single rod burried isolated with the system or it is a requirement of total grounding network? Please give the exact reference for this. If single rod resistivity should be less than 2 ohm, then a 9 meter rod is required to fulfill the condition which is impracticable at site. I have gone through IEEE 80 but couldn't found specific value for that. Please clarify.

 

[redtrumpet]

Where did you get the 2 ohm figure? Resistance of the station ground is only one factor to be considered in the design. I advise you to seek professional advice.

 

[busbar]

Pardon me if I have misunderstood your posting, but exact reference with respect to what? IEEE 80 is not meant to be used as a “cookbook.”

It may be necessary to farm out the design to someone more experienced. Be prepared to furnish more detailed information, or authorize the expense of others to iteratively measure and calculate existing geologic features versus the finished product. In my experience for station grounding and safe touch/step values, one cannot key in a few numbers and expect to receive an effortlessly complete design package that matches some performance spec.

No personal offense is meant, but it seems like maybe interpretation of contract specifications and familiarity with standards and fundamentals may be root issues.