What is the likely voltage rating for equipment that employs resistance grounding?

Resistance grounding is employed primarily in medium voltage systems, typically in the range of 1kV to 25kV. In practice, a common application for resistance grounding occurs in the 5kV to 15kV range to provide a degree of fault protection while limiting ground fault currents.

The selection of 6.6kV as a voltage rating is significant because it falls within this typical medium voltage range where resistance grounding is advantageous. This method is used to balance the need for safety (by limiting the ground fault current to a manageable level) with the operational needs of industrial and utility systems. Hence, equipment operating at 6.6kV often employs resistance grounding to enhance system reliability and protect equipment while facilitating maintenance and operational procedures.

Equipment rated lower, such as below 5kV, usually employs different grounding methods, including solid grounding, to manage fault currents more effectively. Therefore, the context of resistance grounding supporting systems within the 6.6kV range clearly aligns with industry practices.