An NGR consists of a resistor, a contactor, and a control unit. The resistor is connected between the generator neutral and the ground. The contactor is a switch that can open or close the resistor circuit.

NGR Sensing Resistors are attached in parallel to the Neutral Grounding Resistor. The sensing resistor allows a protective relay which detects resistor failure in a continuous manner. Sensing Resistors are used in combination with neutral grounding resistor monitor relays.