Why are we looking for depth when installing an earth terminal ?
The main point of going deep is to get an homogeneous soil and not subjected to climate changes. The resistivity of the ground surface changes with the seasons, phenomenon which disappears in depth. The soil is also wetter. The more the ground is humid the more it conducts electricity and so will be effective at running off default currents.
The earth rod makes it possible to find a stability which guarantees the earth system’s efficiency. Normally its length is comprised between 1 and 2 meters but the rod can be lengthened by means of junction sleeves. We use threaded sleeves for rods with threads and conical nozzle couplings for rods unthreaded.