sacrificial anode(An anode attached to a metal object, such as a boat or underground tank, to inhibit the object's corrosion. The anode is electrolytically decomposed while the object remains free of damage. AHD Alexander Demidov)
anodic protection(Anodic protection (AP) is a technique to control the corrosion of a metal surface by making it the anode of an electrochemical cell and controlling the electrode potential in a zone where the metal is passive. AP is used to protect metals that exhibit passivation in environments whereby the current density in the freely corroding state is significantly higher than the current density in the passive state over a wide range of potentials. Anodic protection is used for carbon steel storage tanks containing extreme pH environments including concentrated sulfuric acid and 50 percent caustic soda where cathodic protection is not suitable due to very high current requirements. An anodic protection system includes an external power supply connected to auxiliary cathodes and controlled by a feedback signal from one or more reference electrodes. WK Alexander Demidov)
functional earthing(Combined protective and functional earthing is required when :- Some equipment in particular electronic communication eqpt use filter circuits to reduce electromagnetic interference. They do this often by shielding the electronics with metal screening and diverting the induced current into the protective conductor. In other words the equipment will not function correctly if not connected to earth. when the same conductor is used to provide earth protection and functional earth small currents typically milliamps will be present in the earth wire when the equipment is working. Alexander Demidov)
