Resistance-earthed neutral

 A resistance earth system is used for mining in India as per Central Electricity Authority Regulations. Instead of a solid connection of neutral to earth, a neutral grounding resistor (NGR) is used to limit the current to ground to less than 750 mA. Due to the fault current restriction, it is safer for gassy mines. Since the earth leakage is restricted, leakage protection devices can be set to less than 750 mA. By comparison, in a solidly earthed system, the earth fault current can be as much as the available short-circuit current. The neutral earthing resistor is monitored to detect an interrupted ground connection and to shut off power if a fault is detected.