Overview
The BH-0.66 IV vertical square-hole current transformer, also known as the BH(SDH)-0.66 IV, is an indoor plastic-case low-voltage current transformer designed for accurate current measurement, metering, and monitoring in AC distribution systems up to 0.66kV. It features a vertical rectangular window structure optimized for upright busbar installations and space-constrained switchgear cabinets.
This through-core CT converts primary current flowing through its aperture into a standardized 5A secondary signal, compatible with common meters, protective relays, and monitoring equipment. Typical applications include low-voltage switchgear, distribution panels, energy metering circuits, and industrial power systems operating at 380V or 660V with 50Hz frequency.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Rated voltage | 0.66kV |
| Rated frequency | 50Hz |
| Rated secondary current | 5A |
| Installation type | Indoor |
| Window orientation | Vertical square-hole |
| Available aperture sizes | 60×30, 80×30, 100×30, 120×50 mm |
| Accuracy classes | 0.2, 0.2S, 0.5, 0.5S |
| Application class | Metering and monitoring |
Model Designation
BH / SDH – Indoor enclosed current transformer series for low-voltage cabinet applications
0.66 – Rated voltage class: 0.66kV
IV – Vertical square-hole (upright window) design series
60×30, 80×30, 100×30, 120×50 – Window aperture dimensions in millimeters for busbar or cable routing
Construction
The BH-0.66 IV current transformer features a robust indoor plastic case with a through-core, vertical window-type structure. The housing is made of flame-retardant, high-insulation thermoplastic material that provides mechanical protection and electrical isolation for the internal cast-resin insulated core and secondary winding. The design ensures safe operation in standard low-voltage switchgear environments while supporting reliable performance under continuous load conditions.
Technical Parameters
Service Conditions
- Installation location: indoor
- Ambient temperature: -5°C to +40°C
- Rated frequency: 50Hz
- Environmental requirements: The installation environment should be free from severe vibration, conductive dust, corrosive gas, explosive medium, and heavy pollution.
- Special conditions: For special altitude, humidity, or environmental requirements, technical confirmation is recommended before ordering.
Technical Parameters
The BH-0.66 IV vertical square-hole current transformer is designed for low-voltage applications with primary currents ranging from 600A to 3000A. Key electrical characteristics include a rated secondary current of 5A, accuracy classes of 0.2, 0.2S, 0.5, or 0.5S, and rated outputs of 5VA or 10VA depending on the selected ratio.
| Rated Current Ratio | Accuracy Class |
|---|---|
| 600/5, 800/5 | 0.2 5 |
| 1000/5, 1500/5 | 0.2S 5 |
| 2000/5, 3000/5 | 0.5 / 0.5S 10 |
Installation & Wiring
Wiring Diagram
Connect the secondary terminals according to the polarity marks (typically marked with “*” or “P1”/“S1”) and in accordance with the project wiring diagram. Ensure that the secondary circuit is never left open when the primary conductor is energized, as this can result in dangerous overvoltages and equipment damage.
Selection & FAQs
Selection Guide
- Select the 600A–3000A ratio from the maximum busbar current and required metering range.
- Choose a 60×30mm, 80×30mm, 100×30mm, or 120×50mm vertical window with safe clearance.
- Specify the available 0.2, 0.2S, 0.5, or 0.5S accuracy class for the selected ratio.
- Calculate the meter and cable-loop burden and confirm the 5VA or 10VA output is sufficient.
- Verify upright orientation, busbar alignment, mounting space, polarity, grounding, and terminal access.
Frequently Asked Questions
Q1: Can this BH-0.66 current transformer be installed outdoors?
No, this model is strictly rated for indoor installation. It requires an environment free from severe vibration, conductive dust, and corrosive gases. Contact us for outdoor-rated alternatives.
Q2: Which accuracy class is available for the 2000/5A ratio?
The 2000/5A and 3000/5A ratios offer 0.5 and 0.5S accuracy classes. They feature a rated output of 10VA. Confirm specific metering requirements with our engineering team.
Q3: What is the primary current range for this vertical square-hole CT?
The BH-0.66 IV series supports primary currents from 600A to 3000A. All models provide a standard 5A secondary current. Ratios outside this range are subject to technical confirmation.
Q4: How do we order for high altitude or high humidity environments?
Special environmental conditions require prior technical confirmation before ordering. Standard models are rated for -5°C to +40°C at normal altitudes. Please contact our sales team with your specific site parameters.
Q5: Are custom technical parameters available outside the standard reference range?
Yes, custom parameters are available subject to a technical agreement. Standard outputs are 5VA or 10VA depending on the selected ratio. Contact the manufacturer to finalize custom specifications.
Q6: Where is the BH-0.66 IV low-voltage transformer typically applied?
This current transformer is designed for low-voltage power distribution and metering applications. It operates at a rated frequency of 50Hz. Verify system compatibility with our technical department.