Littelfuse, Inc. SE-325 Series – Neutral-Grounding-Resistor Monitor SE-325N

The SE-325 series is a neutral-grounding-resistor monitor designed for resistance-grounded systems up to 25 kV to detect ground faults and NGR integrity failures. It measures current and voltage at the neutral-to-ground connection and provides a single Form A output contact. The unit operates on 120 Vac or 240 Vac control power, with programmable ground-fault trip levels from 0.5 to 4.0 A and time delays from 0.1 to 2.0 s. It supports selectable fail-safe or non-fail-safe contact modes and includes a standard reset button. The device is CSA certified, UL Listed (E340889), and C-Tick compliant, conformally coated, and measures 150 mm high, 109 mm wide, and 100 mm deep. An ER series sensing resistor and CT200 series current transformer are required for operation.