BH-0.66 IV Vertical Square-Hole Current Transformer, low voltage CTs

BH-0.66 IV Vertical Square-Hole Current Transformer, low voltage CTs

0.66kV vertical rectangular-window CTs for low-voltage metering & monitoring

  • Vertical square-hole structure for busbar & cable installation.
  • Four aperture sizes available: 60×30, 80×30, 100×30 and 120×50.
  • 5A secondary output with 600A to 3000A primary current range.
  • Accuracy classes 0.2, 0.2S, 0.5 & 0.5S for metering & monitoring
  • Indoor plastic case construction for 50Hz AC systems up to 0.66kV.

Product Overview

The BH-0.66 IV vertical square-hole current transformer, also referred to as the BH(SDH)-0.66 IV current transformer, is an indoor plastic case current transformer designed for current measurement, metering, and monitoring in low-voltage AC distribution systems with rated voltage up to 0.66kV. The product adopts a vertical rectangular-window structure, making it suitable for upright busbar layouts and compact cabinet installation.

This series converts the primary current passing through the window aperture into a standard 5A secondary current signal for meters, instruments, monitoring devices, or distribution measurement circuits. It is commonly applied in low-voltage switchgear, distribution cabinets, metering panels, and industrial electrical systems.

Product Type

Item Specification
Product name Vertical Square-Hole Current Transformer
Model series BH-0.66 IV / BH(SDH)-0.66 IV
Product structure Indoor plastic case, vertical window-type / through-core structure
Rated voltage class 0.66kV low-voltage AC system
Rated frequency 50Hz
Rated secondary current 5A
Installation location Indoor
Typical applications Metering, current monitoring, distribution measurement, low-voltage switchgear instrumentation

Product Display

BH-0.66 IV vertical square-hole current transformer product display

Main Applications

  • Low-voltage AC distribution systems rated up to 0.66kV
  • 380V and 660V low-voltage distribution cabinets
  • Low-voltage switchgear and complete electrical assemblies
  • Energy metering circuits and current measurement circuits
  • Electrical monitoring systems for industrial and commercial power distribution
  • Vertical busbar layouts requiring an upright rectangular-window current transformer

Key Technical Features

  • Vertical square-hole design: The upright window structure is suitable for vertical busbars and cabinet layouts where installation space is limited in the horizontal direction.
  • Four aperture sizes: Available window sizes include 60×30, 80×30, 100×30, and 120×50 for different busbar or cable arrangements.
  • Standard 5A secondary output: Designed for connection to common meters, instruments, and current monitoring devices.
  • Indoor plastic case structure: The enclosed insulated housing supports mechanical protection and electrical insulation for the internal core and winding.
  • Metering and monitoring accuracy: Accuracy classes 0.2, 0.2S, 0.5, and 0.5S are available according to current ratio and project requirements.

Working Principle

The BH-0.66 IV current transformer works according to electromagnetic induction. When the primary busbar or cable passes through the vertical window and carries current, magnetic flux is generated in the core. The secondary winding outputs a proportional current signal, typically rated at 5A, for connected meters or monitoring devices. This allows high primary current to be converted into a standardized secondary signal for safe measurement and monitoring.

Model Designation

BH-0.66 IV current transformer model designation

The model code can be interpreted as follows:

Code Meaning
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 size for busbar or cable installation

Technical Data

Item Specification
Rated voltage 0.66kV / 660V
Rated frequency 50Hz
Rated primary current 600A to 3000A, depending on selected current ratio and specification
Rated secondary current 5A
Accuracy class 0.2, 0.2S, 0.5, 0.5S; subject to selected ratio and order requirements
Rated output 5VA or 10VA according to current ratio and specification
Ambient temperature -5°C to +40°C
Installation type Indoor cabinet installation, vertical busbar / cable through-window mounting
Applicable standards GB 1208-2006, IEC 60044-1:2003; project-specific requirements can be confirmed by agreement

Rated Current, Accuracy and Output Reference

Rated Primary Current (A) Rated Secondary Current (A) Accuracy Class Rated Output (VA)
600, 800 5 0.2 5
1000, 1500 5 0.2S 5
2000, 3000 5 0.5 / 0.5S 10

Note: Technical parameters outside the above reference range can be confirmed by technical agreement between manufacturer and purchaser.

Service Conditions

  • Installation location: indoor
  • Ambient temperature: -5°C to +40°C
  • Rated frequency: 50Hz
  • The installation environment should be free from severe vibration, conductive dust, corrosive gas, explosive medium, and heavy pollution.
  • For special altitude, humidity, or environmental requirements, technical confirmation is recommended before ordering.

Standards and Compliance

The BH-0.66 IV series is designed for low-voltage current transformer applications and can be supplied according to GB 1208-2006, IEC 60044-1:2003, and project-specific technical requirements. If the project requires updated IEC or GB references, the applicable standard can be confirmed during technical review.

Installation and Dimensions

The BH-0.66 IV series is available in four vertical rectangular-window sizes. The following dimensions are for product selection and cabinet layout reference. Final dimensions should be confirmed with the approved drawing before production or batch ordering.

Available Window Sizes and Overall Dimensions

Model a b h A B H
BH0.66(IV) 60×30 32 62 112 83.5 47 128
BH0.66(IV) 80×30 32 83 134 93.5 48 150
BH0.66(IV) 100×30 32 102 154 99 48 170
BH0.66(IV) 120×50 52 124 203 134 64.5 219

Unit: mm. Final dimensions are subject to confirmed drawing and selected specification.

Installation and Safety Notes

  • Confirm the CT model, ratio, accuracy class, burden, and aperture size before installation.
  • Ensure the busbar or cable passes correctly through the vertical window aperture.
  • Connect secondary terminals according to the polarity marks and project wiring diagram.
  • The secondary circuit of a current transformer must not be left open when the primary circuit is energized.
  • Secondary wiring, grounding, and terminal protection should follow the project specification and local electrical regulations.
  • Installation and maintenance should be performed by qualified electrical personnel.

Ordering Information

Please provide the following information when ordering or requesting a quotation:

  • Product model: BH-0.66 IV / BH(SDH)-0.66 IV
  • Window size: 60×30, 80×30, 100×30, or 120×50
  • Rated primary current and rated secondary current
  • Required accuracy class
  • Rated output / burden in VA
  • System frequency
  • Installation quantity
  • Special requirements for terminal arrangement, labels, drawings, inspection documents, certificates, or packaging

Selection Guidelines

  1. Confirm system voltage: Select this CT for low-voltage AC systems rated up to 0.66kV.
  2. Confirm primary current: Select the CT ratio according to the normal operating current of the circuit.
  3. Confirm aperture size: Match the vertical window size with the busbar or cable layout inside the cabinet.
  4. Select accuracy class: Use 0.2 or 0.2S for higher metering requirements, and 0.5 or 0.5S for general measurement and monitoring circuits.
  5. Check rated burden: The total burden of meters, instruments, relays, and wiring should not exceed the rated output of the CT.
  6. Confirm cabinet space: Check the overall dimensions before switchgear layout, busbar design, or batch installation.

FAQs

It is used to convert primary current into a standard 5A secondary signal for metering, monitoring, and current measurement in low-voltage distribution systems.

The BH-0.66 IV uses a vertical rectangular-window design, making it more suitable for upright busbar layouts or cabinet spaces where the busbar passes vertically through the CT aperture.

It is suitable for low-voltage AC systems with rated voltage up to 0.66kV, including common 380V and 660V distribution applications.

The standard secondary current is 5A, which is suitable for connection to common low-voltage meters, measuring instruments, and monitoring devices.

Available aperture sizes include 60×30, 80×30, 100×30, and 120×50. The final size should be selected according to the vertical busbar or cable layout in the cabinet.

Common accuracy classes include 0.2, 0.2S, 0.5, and 0.5S. The final class should be selected according to the current ratio, rated burden, and project metering requirement.

The CT ratio should be selected according to the normal operating current of the circuit. The selected primary current should cover the expected load current and allow reasonable margin for load fluctuation.

This model is designed for indoor installation. Outdoor applications should use a current transformer structure designed for outdoor environmental conditions, including moisture, UV exposure, pollution, and temperature variation.

When the primary circuit is energized, the CT secondary circuit must not be left open. An open secondary circuit may generate high voltage, damage insulation, and create safety risks for equipment and personnel.

Please provide the model, aperture size, current ratio, accuracy class, rated output or burden, system frequency, quantity, and any special requirements for terminal arrangement, labels, drawings, certificates, inspection documents, or packaging.