Product Overview
The LA2-10 / LAJ-10 (LFZBJ-10GY) current transformer is an indoor wall-through epoxy cast-resin current transformer for medium-voltage switchgear. It is designed for current measurement, energy metering, feeder monitoring and relay protection in AC systems with rated frequency of 50Hz. For Southeast Asia and other international markets, this product should be positioned for 11kV and 12kV class indoor switchgear applications, with insulation coordination and test requirements aligned with IEC instrument transformer standards.
The product adopts a cast-resin insulated wall-through structure. The primary conductor passes through or connects across the transformer body, while the secondary winding provides a standardized 5A or 1A output for meters, protection relays and monitoring devices. Compared with hollow window-type CTs, the LA2-10 / LAJ-10 structure is more suitable for switchgear layouts requiring a molded wall-through body, extended primary terminals, and a fixed mounting plate through the cabinet partition.
For international projects, the model can be described as a 12kV-class indoor epoxy cast-resin wall-through current transformer. The catalogue shows a rated insulation level of 12/42/75kV, which is commonly used for 12kV equipment class applications. Accuracy and protection classes can be configured according to project requirements, including metering classes such as 0.2, 0.5 and protection class 10P10.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Wall-Through Epoxy Cast-Resin Current Transformer |
| Model series | LA2-10 / LAJ-10 (LFZBJ-10GY) |
| Structure | Wall-through type, epoxy resin cast insulation, indoor installation |
| Voltage class | 11kV and 12kV class indoor medium-voltage systems |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz |
| Rated secondary current | 5A or 1A |
| Rated primary current | 50A, 75A, 100A, 150A, 200A, 300A, 400A, 500A, 600A, 630A |
| Typical use | Current measurement, energy metering, relay protection, feeder monitoring |
Product Display
The LA2-10 / LAJ-10 (LFZBJ-10GY) has a compact cast-resin body with primary terminals extending from both sides and a central mounting plate for wall-through installation. The secondary terminal block is arranged on the resin body for convenient connection to measuring instruments and protection relays. The outline drawing shows an overall length reference of about 480mm, with a wall-opening reference suitable for cabinet partition installation.
Applications
- 11kV and 12kV class indoor medium-voltage switchgear
- Fixed metal-enclosed switchgear, metering panels and feeder cabinets
- Current measurement and electric energy metering circuits
- Relay protection circuits using 10P10 protection class
- Wall-through installation in switchgear partitions or cabinet mounting plates
- Southeast Asia distribution projects using IEC-oriented 12kV equipment class specifications
Features
- Wall-through cast-resin structure: The CT is designed for installation through a cabinet panel or switchgear partition, with primary terminals on both sides of the molded body.
- IEC-oriented voltage class: The product is suitable for 11kV and 12kV class systems when the rated insulation level and project requirements are confirmed.
- Epoxy resin insulation: The cast body provides insulation strength, mechanical protection and moisture resistance for indoor service.
- Metering and protection use: Accuracy classes can include 0.2, 0.5 and 10P10, supporting both measurement and relay protection circuits.
- 5A or 1A secondary output: 5A is suitable for conventional metering and relay systems; 1A can be selected for lower secondary burden or longer wiring.
- Southeast Asia project suitability: The product can be specified for 50Hz systems, 12kV class switchgear and IEC-based technical documents commonly used in export projects.
Principle
The LA2-10 / LAJ-10 (LFZBJ-10GY) current transformer works by electromagnetic induction. When primary current flows through the primary conductor path, magnetic flux is generated in the core. The secondary winding then induces a proportional current signal, normally 5A or 1A, for meters, energy meters, protection relays or monitoring devices.
For metering circuits, the CT should maintain ratio accuracy and phase accuracy within the specified burden. For relay protection circuits, the protection core must maintain dependable output during fault-current conditions. Therefore, current ratio, secondary current, rated burden, accuracy class, short-time thermal current and dynamic current must be selected together with the switchgear and relay protection design.
Model Designation
| Code | Meaning |
|---|---|
| LA2-10 | Indoor wall-through epoxy cast-resin current transformer model reference |
| LAJ-10 | Related wall-through current transformer designation used for similar cabinet applications |
| LFZBJ-10GY | Related cast-resin wall-through designation with protection / reinforced structure reference |
| 10 | Catalogue voltage class reference; used for 11kV / 12kV class projects by insulation confirmation |
| GY | Manufacturer structural suffix; final meaning should follow factory drawing and nameplate |
Technical Data
| Item | Specification |
|---|---|
| Rated voltage class | 11kV and 12kV class indoor systems |
| Rated insulation level | 12/42/75kV |
| Rated frequency | 50Hz |
| Rated secondary current | 5A or 1A |
| Rated primary current | 50A to 630A reference range |
| Accuracy classes | 0.2, 0.5, 10P10 |
| Rated output | 0.2 class: 10VA; 0.5 class: 15VA; 10P10 class: 10VA reference |
| Rated short-time thermal current | 7.5kA to 40kA reference range depending on primary current |
| Rated dynamic current | 19kA to 100kA reference range depending on primary current |
| Ambient temperature | -5°C to +55°C |
| Applicable standards | IEC 61869-2 current transformer requirements; GB20840.2-2014 / GB1208-2006 references by project agreement |
Selection Table
The selection table below is adapted from the catalogue data and expressed in a website-friendly IEC-style format. Long headers are wrapped into multiple lines to avoid layout overflow.
| Rated
Primary Current (A) |
Accuracy
Class Combination |
Rated
Output (VA) |
Short-Time
Thermal CurrentIth (kA) |
Dynamic
CurrentIdyn (kA) |
|---|---|---|---|---|
| 50 | 0.2 0.5 10P10 |
0.2: 10 0.5: 15 10P10: 10 |
7.5 | 19 |
| 75 | 11.25 | 28 | ||
| 100 | 15 | 37.5 | ||
| 150 | ||||
| 200 | 22.5 | 56 | ||
| 300 | 30 | 75 | ||
| 400 | 40 | 100 | ||
| 500 | ||||
| 600 | ||||
| 630 |
Note: Final current ratio, rated output, accuracy class, thermal current and dynamic current shall be confirmed according to the approved drawing, nameplate and technical agreement.
Dimensions
| Item | Reference Dimension | Engineering Note |
|---|---|---|
| Overall length | Approx. 480mm reference | Overall length includes primary terminal extension and cast-resin body. |
| Body length | Approx. 370mm reference | Used for cabinet depth and wall-through installation check. |
| Mounting plate width | Approx. 200mm reference | Confirm with cabinet opening and mounting plate layout. |
| Opening size | Approx. 160mm × 220mm reference | Wall opening must be confirmed before switchgear production. |
| Mounting holes | 4-Ø14 reference | Hole position and plate thickness should follow the approved drawing. |
| Weight | Approx. 19.2kg reference | Actual value depends on final ratio and configuration. |
Terminals
The primary terminals are arranged on both sides of the current transformer and marked according to polarity. The secondary terminal block is located on the cast-resin body and should be wired strictly according to the approved schematic. Typical terminal references include P1 / P2 for the primary side and 1S1 / 1S2 or other secondary markings for metering and protection outputs.
| Terminal | Function | Application Note |
|---|---|---|
| P1 / P2 | Primary terminals | Used for busbar or primary conductor connection and polarity reference. |
| 1S1 / 1S2 | Secondary winding | Used for meter, relay or monitoring-device connection according to the specified core. |
| Grounding point | Protective grounding | Grounding shall follow local electrical safety rules and project wiring practice. |
Service Conditions
- Installation location: indoor medium-voltage switchgear
- Rated voltage: 11kV and 12kV class systems by project confirmation
- Rated frequency: 50Hz
- Ambient temperature: -5°C to +55°C
- Indoor environment should be free from explosive gas, corrosive vapor, conductive dust, heavy pollution and abnormal condensation.
- For Southeast Asia projects with high humidity, coastal conditions or elevated ambient temperature, anti-condensation and creepage/clearance confirmation is recommended.
Standards and Compliance
For international and Southeast Asia projects, the LA2-10 / LAJ-10 (LFZBJ-10GY) current transformer should be specified using IEC-oriented language. The recommended standard reference is IEC 61869-2 for current transformers, with legacy or local references such as IEC 60044-1, GB1208-2006 or GB20840.2-2014 used only when required by the project. Routine tests may include ratio test, polarity check, accuracy verification, insulation test and power-frequency withstand test.
Installation and Dimensions
The LA2-10 / LAJ-10 (LFZBJ-10GY) is designed for wall-through installation in indoor switchgear. Before cabinet production, the wall opening, mounting plate, primary terminal clearance, busbar path, secondary terminal direction, grounding point and maintenance space should be confirmed with the approved outline drawing. Because this model has primary terminals extending from both sides, the installation space on both sides of the switchgear partition must be checked carefully.
Safety Notes
- Confirm voltage class, insulation level, current ratio, secondary current, accuracy class and rated output before production.
- Check the wall-through opening, primary terminal clearance and mounting holes before cabinet assembly.
- Connect primary and secondary terminals according to polarity marks and the approved wiring diagram.
- The CT secondary circuit must not be open-circuited while primary current is flowing.
- Before disconnecting meters or relays, short-circuit the secondary circuit with an approved shorting device.
- One point of the secondary circuit should be grounded according to project electrical safety requirements.
- Installation and commissioning shall be performed by qualified medium-voltage electrical personnel.
Ordering Info
- Product model: LA2-10 / LAJ-10 (LFZBJ-10GY)
- Voltage class: 11kV or 12kV class
- Rated primary current and rated secondary current: 5A or 1A
- Accuracy class: 0.2, 0.5 or 10P10
- Rated output for each secondary core
- Rated short-time thermal current and rated dynamic current
- Wall opening, primary terminal direction and switchgear layout
- IEC standard requirement, routine test report and certificate requirements
- Quantity, label language, packaging and project documentation requirements
Selection Guide
- Confirm system voltage: Use 11kV and 12kV class wording for Southeast Asia projects, then confirm 12/42/75kV insulation level.
- Select current ratio: Choose 50A to 630A according to feeder load current, metering range and protection setting.
- Select secondary current: Use 5A for conventional systems or 1A where lower secondary burden is preferred.
- Choose accuracy class: Use 0.2 or 0.5 for metering and 10P10 for relay protection circuits.
- Verify short-circuit ratings: Match Ith and Idyn with the switchgear fault level and relay protection requirement.
- Check cabinet fit: Confirm the wall opening, primary terminals, body depth and maintenance clearance before production.
- Approve drawings: Final product selection should follow the approved outline drawing, nameplate and technical agreement.