Neutral Earthing Resistors

Inserting a resistor between the neutral star point of a transformer and earth limits fault current to a safe level still remaining at sufficient intensity to allow a selective and fast fault detection by means of simple over-current relays.

Neutral Earthing Resistors are widely used in industrial distribution systems to provide added safety by limiting phase-to-earth fault currents to reasonable predetermined values. In directly earthed systems high earth-fault currents can cause excessive damage to transformers, generators and associated equipment.