For the proper functioning of the electrical system and the safety of the operating persons, it is essential to provide effective earthing. The complete earthing of a system includes proper design and installation. After completing the installation of earth electrodes in a site, it is always recommended to measure resistance between the electrode and the true earth.
The earthing resistance of an electrode depends on
1. Resistance of the electrode
2. Contact resistance between the electrode and the soil
3. Resistivity of the soil
The electrolytic resistance mainly depends on the electrolytic medium that is resistivity of the soil. In all practical purposes the resistance of electrode (ohmic resistance) and contact resistance between the electrode and soil can be negligible since it has very small fractions of an ohm.
There are two types of resistance.
1. Ohmic resistance
2. Electrolytic resistance
The characteristics of a material which opposes the flow of current is known as resistance. The value of resistance changes from one material to another. The resistance offered by the material to the current flow from one end to another end is termed as ohmic resistance.
Resistance to current flow from one electrode to another electrode in any conductive
medium is called as Electrolytic Resistance.
In our testing method we measure resistance of the electrode and the medium between the electrodes, Hence it comes under electrolytic resistance.