Littelfuse, Inc. Protection Relays & Systems SE-330-03-11

The SE-330 is a neutral-grounding-resistor monitor designed to detect ground faults and resistor failures in resistance-grounded electrical systems. It features a panel-mount or surface-mount enclosure with specified physical dimensions, dual Ethernet ports, USB and microSD interfaces for datalogging and firmware updates, and programmable trip levels for ground-fault and resistor-fault conditions. The unit includes three configurable relay outputs (K1, K2, K3), a real-time clock with rechargeable battery, and support for Modbus TCP/IP, IEC 61850, and Ethernet/IP protocols. Diagnostic LEDs, an analog output, and NGR short detection are included. Trip times range from 12 to 60 seconds, and resistor-fault trip levels are adjustable. The firmware supports geo-magnetic filtering, UTC offset for SNTP, and logging limited to the two most recent months of data.