Statement: Which one of the following is used in earth pit:
- Aluminum and Iron
- Graphite and Silver
- Graphite and magnesium
- Salt and charcoal
Correct answer: 4. Salt and charcoal
Explanation: For improving the conductivity of poor soil the salt and charcoal are added in the earth pit.
The earthing resistance actually depends on the soil resistivity of the particular area. The higher soil resistance means the fault current will not be able to find a low resistance path and will not dissipate in soil.
Salt and charcoal are added in the earth pit for improving conductivity.