Fault Current Calculation

British Standard 7671.

Vide IS 3043, the maximum permissible current density at the surface of an earth elctrode is :

{(7.57 x 10power3) / (Root [Rho x t])}

where, Rho is the earth resistivity where the earth electrode is buried and t is the duration of fault.

Now, can you please calculate the electrode surface area required for your application - yourself?

Amplitude of fault current plays any part along with duration of fault current?

I-squared-t.

Fault current divided by the permissible current density will give the required cross section of the electrode surface.

For better calculation of the fault current,we need to know the contact voltage and the loop resistance.If=Ue/Rsch, where If is fault current,Ue is contact voltage and Rsch is loop resistance.

Patrick whowha