Neutral-To-Earth Connection
The resistor connects between the system neutral and the earthing grid to limit current during a single-phase earth fault.
GreenPower
GP-NER-3.3kVNeutral Earthing Resistor Cabinet
System Rated Voltage3.3 kV
Short-Time Current200 A / 10 s
Nominal Resistance9.5 Ω ±5%
Enclosure ProtectionIP54, outdoor
Product Overview
GP-NER-3.3kV is an outdoor neutral earthing resistor cabinet for 3.3 kV systems. The specified assembly has a 9.5 Ω ±5% resistor with a 200 A, 10 s short-time rating. An LJ-80 protection current transformer provides a 250/5 A current signal. The resistor and CT are housed in an IP54 steel enclosure with front and rear access.
Protection Current Signal
The wiring diagram specifies one LJ-80 CT, with a 250/5 A ratio and 5P20 protection class, for connection to the external protection circuit.
Key Features
Outdoor IP54 Enclosure
The cabinet uses 2 mm cold-rolled steel plate, finished in RAL7035, with a rain canopy for outdoor installation.
Front And Rear Access
Front and rear doors provide access for inspection. The enclosure drawing specifies reinforced panels and ventilation openings lined with dust-proof mesh.
Bottom Cable Entry
Primary, earthing and secondary cables enter from below. The specified entry arrangement includes rubber rings and cable clamps.
Technical Specifications
| Parameter | Data |
|---|---|
| System Rated Voltage | 3.3 kV |
| Short-Time Current | 200 A |
| Duration Of Short-Time Current | 10 s |
| Nominal Resistance | 9.5 Ω |
| Resistance Tolerance | ±5% |
| Current Transformer Model | LJ-80 |
| Current Transformer Ratio | 250/5 A |
| CT Protection Class | 5P20 |
| Installation | Outdoor |
| Enclosure Protection | IP54 |
| Cabinet Dimensions (W × D × H) | 800 × 1000 × 1100 mm |
| Cabinet Material | 2 mm cold-rolled steel plate |
| Cabinet Colour | RAL7035 |
| Base | No. 10 channel steel |
These values apply to the 3.3 kV, 200 A / 10 s configuration shown in the catalog outline and wiring drawings.
Installation And Connections
Foundation And Earthing
The channel-steel base has copper earthing blocks on both sides with M12 threaded holes. Confirm the foundation, anchor positions and cable openings against the cabinet outline drawing.
Neutral And CT Circuits
The primary schematic shows the resistor and CT in the neutral-to-earth circuit. The manual includes the CT secondary and terminal diagrams for the protection connection.
The downloadable manual includes cabinet views, internal arrangements, the base plan and wiring diagrams. Use the supplied drawings and installation instructions for the ordered assembly.
Service Conditions
Altitude
Not exceeding 4000 m above sea level.
Ambient Temperature
-40°C to +60°C.
Relative Humidity
Not exceeding 95% at 25°C.
Power Frequency
48-52 Hz for 50 Hz systems; 58-62 Hz for 60 Hz systems.
The installation site should be free from corrosive gases, steam and explosive dust. State any special operating conditions with the enquiry.
Configuration And Ordering
System And Protection Requirements
Provide the system voltage, neutral arrangement, required earth-fault current, resistance and short-time duration. Include the CT requirements and protection interfaces. Systems without an accessible neutral may require an earthing transformer as part of the earthing scheme.
Additional Equipment
Specify any isolator, earthing-event recording or temperature and humidity control needed for the installation. These are ordering options listed in the manual and should be defined for the supplied cabinet.
Specify Your GP-NER-3.3kV Cabinet
Send your system neutral arrangement and earthing requirements. Include the CT, cable entry, foundation and any monitoring or isolation options needed.