Grounding resistivity is the most important parameters in the lightning protection construction. It is suggested that the parameters be measured directly to avoid error. If conditions restrict, the data can be estimated according to the following data which is a common basic data in different environments. In dry areas they should be multiplied by 1.5-2.

I. The following is the data of resistivity (Ω.m) in different environment.

Places                                        Resistivity  (Ω/m)

Cities in plain                                  100

Cities in mountains and plateaus                   150-300

Farms                                        100

Old soil fields                                  100-200

Soil with sand (fields)                            300-500

Soil with stones(fields)                           400-800

Stones with sand                                1000

Broken rocks                                   5000

Complete rocks                                 20000

II. The following is the quantity of the product suitable for different environments.

Resistivity  (Ω/m)       Horizontal style(amount)          Vertical style(amount)            

ρ≤500                 10-15 kg/m                  12-16 kg/m

500＜ρ≤1000           15-20 kg/m                  16-22 kg/m

500＜ρ≤1000           20-30 kg/m                  22-32 kg/m

ρ＞2000                30-35 kg/m                  32-40 kg/m