High-impedance grounded neutral systems are permitted for which type of system?

High-impedance grounded neutral systems are specifically designed to limit the fault current that can flow in the event of a ground fault. This is particularly important in three-phase alternating current (AC) systems, where the potential for large ground fault currents can cause significant damage and pose safety risks.

In three-phase systems with voltage ratings between 480 volts to 1,000 volts, high-impedance grounding provides a reliable method to maintain system stability and operational continuity during ground faults. This method allows for the detection of ground faults without allowing large fault currents that can lead to equipment damage or electrical hazards.

Using high-impedance grounding in lower voltage systems or in single-phase systems does not typically provide the same level of protection or benefits as it does in the specified three-phase systems. Hence, high-impedance grounding is most effectively applied to the designated range of three-phase systems to manage fault currents appropriately.