This manual covers the operation, installation, settings, and technical specifications for the Littelfuse SE-330 microprocessor-based…
The Littelfuse SE-330 is a microprocessor-based device designed to detect Neutral-Grounding Resistor (NGR) failures and ground faults in resistance-grounded systems. It measures NGR resistance, NGR current, and neutral-to-ground voltage to ensure system stability and safety. The device is compliant with the 2018 Canadian Electrical Code and includes features for remote operation and datalogging.
| Trip Level Range | 2 to 100% of CT rating |
|---|---|
| Trip Time Range | 0.1 to 10.0 seconds |
| NGR Resistance Measurement | Continuous |
| Ground Fault Current Sensing | 1- or 5-A secondary, or 50-mA secondary |
The SE-330 is compliant with the 2018 CE Code.
An SE-330, a 20- or 100-kΩ ER-series sensing resistor, and a current transformer (CT) are required.
It trips if the NGR resistance varies from its calibrated value or if neutral voltage exceeds the trip level while NGR current is low.