The earth pit's dirt is more conductive thanks to salt and charcoal. The fault current thus has an easier time traveling through machinery to the earth. Low resistance for earth fault currents is maintained by the alternate layers of salt and charcoal.

Solution
1. Low resistance to earth fault currents is maintained by the layer of salt and charcoal.
2. They will keep moisture in due to the ionic behavior of salt and charcoal.
3. Because it is an adsorbent, charcoal is used to retain moisture for a long time, and salt is added to boost conductivity. Both of these items aid in passing leakage current through    earth wire as soon as possible to reduce the risk of shock.