BH-0.66 III Indoor Plastic Case Current Transformer, low voltage distribution

BH-0.66 III Indoor Plastic Case Current Transformer, low voltage distribution

0.66kV indoor window-type current transformers for low-voltage distribution metering and current signal conversion

  • Multiple rectangular window sizes for different busbar and cable installation
  • Rated 5A secondary output with 150A to 5000A primary current range
  • Indoor plastic case construction with insulated flame-retardant housing
  • Accuracy classes 0.5, 0.5S and 0.2 for low-voltage metering & monitoring circuits
  • Designed for 50Hz AC systems, with 3kV/1min power-frequency withstand capability

Product Overview

The BH-0.66 III indoor plastic case current transformer is a window-type low-voltage current transformer designed for current measurement, electrical monitoring, and metering signal conversion in AC distribution systems with rated voltage up to 0.66kV. The primary conductor or busbar passes through the rectangular window, while the secondary winding provides a standard 5A output for meters, instruments, or monitoring devices.

This series is suitable for indoor distribution cabinets, low-voltage switchgear, metering panels, and industrial power distribution equipment. Multiple aperture sizes are available to match different busbar widths and cable installation layouts.

Product Type

Item Specification
Product name Indoor Plastic Case Current Transformer
Model series BH-0.66 III
Product structure Window-type / through-core current transformer
Rated voltage class 0.66kV low-voltage AC system
Installation location Indoor
Typical applications Metering, current monitoring, distribution measurement, low-voltage switchgear

Product Display

BH-0.66 III indoor plastic case current transformer product display

Main Applications

  • Low-voltage power distribution systems rated up to 0.66kV
  • 380V and 660V AC distribution cabinets
  • Energy metering circuits and current measurement circuits
  • Electrical monitoring systems in industrial and commercial buildings
  • Low-voltage switchgear, control panels, and distribution boards
  • Busbar-type current sensing where a rectangular window aperture is required

Key Technical Features

  • Window-type structure: The primary busbar or cable passes directly through the CT window, simplifying installation inside distribution cabinets.
  • Multiple aperture sizes: Window sizes such as 50×50, 60×50, 80×50, 80×80, 100×50, 100×80, 100×80L, 125×60, 130×80, and 165×70 are available for different busbar configurations.
  • Standard 5A secondary output: Suitable for connection to common low-voltage meters, instruments, and monitoring devices.
  • Insulated plastic housing: The enclosed casing supports electrical insulation and helps protect the internal winding and core structure.
  • Low-voltage metering design: Applicable to 50Hz AC systems with rated voltage up to 0.66kV.

Working Principle

The BH-0.66 III current transformer operates according to electromagnetic induction. When the primary conductor carries current through the CT window, magnetic flux is generated in the core. The secondary winding then outputs a proportional current signal, normally rated at 5A, for connected meters or measuring instruments. This allows high primary current to be safely converted into a standardized low-current signal for measurement and monitoring.

Model Designation

BH-0.66 III current transformer model designation

The model code can be interpreted as follows:

Code Meaning
B Enclosed / plastic case structure
H Current transformer
0.66 Rated voltage class: 0.66kV
III Product category / design series
50×50, 60×50, etc. Window aperture size for busbar or cable installation

Technical Data

Item Specification
Rated voltage 0.66kV / 660V
Rated frequency 50Hz
Rated primary current 150A to 5000A, depending on selected model and ratio
Rated secondary current 5A
Accuracy class 0.5, 0.5S, 0.2; other classes according to order requirements
Rated burden 5VA, 10VA, 20VA, 40VA depending on current ratio and specification
Insulation level Secondary winding to ground insulation resistance ≥10MΩ
Power-frequency withstand voltage 3kV, 1 minute
Ambient temperature -5°C to +40°C
Installation altitude ≤1000m under standard service conditions

Rated Burden and Accuracy

Rated Primary Current (A) Rated Burden (VA) Accuracy Class
150–250 5 0.5
300–400 10 0.5
500–800 10 0.5S
1200–1500 20 0.2
2000–5000 40 0.2 / 0.5 / 0.5S depending on specification

Service Conditions

  • Installation location: indoor environment
  • Altitude: not more than 1000m unless otherwise specified
  • Ambient temperature: -5°C to +40°C
  • The installation environment should be free from severe vibration, conductive dust, corrosive gas, explosive medium, and heavy pollution.
  • For special operating conditions, technical confirmation is recommended before ordering.

Standards and Compliance

The product is designed for low-voltage current transformer applications and can be supplied according to relevant GB and IEC requirements, including GB/T 20840.2 and IEC 61869-2. Project-specific requirements can be confirmed according to the final technical agreement.

Installation and Dimensions

BH 0.66 III Current Transformer installation size

The BH-0.66 III series is available in multiple window aperture sizes for different busbar arrangements. Dimensions should be confirmed according to the final model drawing before cabinet design or batch ordering.

Model a b h A B H
BH0.66(III) 50×50 52 52 111.5 87 46 127.5
BH0.66(III) 60×50 62 52 124 100 45 140
BH0.66(III) 80×50 82 52 132 123 45 148
BH0.66(III) 80×80 83 83 156 124 47 172
BH0.66(III) 100×50 102 52 138 148 45 154
BH0.66(III) 100×80 102 85 174 148 47 190
BH0.66(III) 100×80L 102 85 187 148 52 203
BH0.66(III) 125×60 127 62 157 177 55 173
BH0.66(III) 130×80 133 82 181 192 50 197
BH0.66(III) 165×70 165 72 200 215 62 215

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

Installation and Safety Notes

  • Check the CT ratio, accuracy class, burden, and aperture size before installation.
  • Confirm that the busbar or cable size matches the selected window dimension.
  • Connect secondary terminals according to the polarity marks S1 and S2.
  • The secondary circuit of a current transformer must not be left open while the primary circuit is energized.
  • 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 III
  • Window size, such as 50×50, 80×80, 100×80, 125×60, etc.
  • Rated primary current and secondary current
  • Required accuracy class
  • Rated burden in VA
  • System frequency
  • Quantity
  • Special requirements for terminal arrangement, labeling, drawings, certificates, or packaging

Selection Guidelines

  1. Confirm the system voltage: Select the CT for AC systems with rated voltage up to 0.66kV.
  2. Confirm the primary current: Choose the ratio according to the operating current of the circuit.
  3. Confirm the window size: Match the aperture with the busbar or cable size inside the cabinet.
  4. Select the accuracy class: Use higher accuracy classes for metering circuits and standard classes for general monitoring.
  5. Check the rated burden: The connected meter, instrument, and wiring burden should not exceed the rated output of the CT.

FAQs

The BH-0.66 III current transformer is used to convert high primary current into a standard 5A secondary signal for metering, monitoring, and measurement in low-voltage distribution systems.

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

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

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

The primary current ratio should be selected according to the actual operating current of the circuit. The selected ratio should cover the normal load current and allow reasonable margin for load fluctuation without reducing metering accuracy.

The window aperture should be selected according to the busbar width, cable size, and available installation space inside the distribution cabinet. The busbar or cable should pass through the CT window without mechanical interference.

This model is designed for indoor use. Outdoor applications require a current transformer structure suitable 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, which can damage insulation, affect product safety, and create a risk to maintenance personnel.

Please provide the model, current ratio, accuracy class, rated burden, window size, system frequency, quantity, and any special requirements for terminals, drawings, certificates, labeling, or packaging.