Split-Core Low-Voltage Current Transformers (Rectangular Window-Type)

Low-Voltage Current Transformers (0.72 kV max.)


About the Product

Intended for switchgear-panel manufacturers and other users, these rectangular, resin-insulated, low-voltage window-type current transformers are self-extinguishing and highly water-resistant. Each of these current transformers can be mounted on a busbar (the busbar can be either horizontally or vertically installed in the switchgear panel). Alternatively, the current transformer can be fixed directly to the switchgear panel; in this case, wiring can be done with a busbar or with insulated copper wires. The product comes with one type of mounting accessories, to be chosen by the customer from available options.

Features of the ES-1S-C Series

  • Single-core
  • Split-core window-type
  • For use with protective relays, or with measuring or monitoring instruments
  • Can be installed onto an existing system without cutting (or removing) the primary busbar or insulated wires


  • Standard: IEC or IEEE
  • For indoor use
  • Rated voltage: ≦ 0.72 kV
  • Frequency: 50/60 Hz
  • AC/BIL: 3/- kV
  • Ith = 40 In/1S
  • Included: a choice of mounting accessories
  • Other specifications and standards available upon request

Selection Table

Other standards and specifications available.

Current (A)
Secondary Current (A)Burden/Accuracy
Core 1Core 2
ES-1S-AES-1S-60A400~8005 – 30VA/1.0 or 15VA/0.52.1Single-Core
ES-1S-80A *600~12005 – 30VA/1.0 or 15VA/0.52.1Single-Core
ES-1S-100A *1000~20005 – 30VA/1.0 or 15VA/0.52.2Single-Core
ES-1S-120A *2500~40005 – 40 VA/1.0 or 30VA/0.53.7Single-Core
ES-1S-165A *4000~70005 – 40 VA/1.0 or 30VA/0.54.3Single-Core
ES-1S-BES-1S-100B *1000~20005515VA/5P20+30VA/0.510Two-Core
ES-1S-120B *2500~40005515VA/5P20+30VA/0.59.5Two-Core
ES-1S-CES-1S-165C800~10005 – 7.5VA/5P106Split-Core
1250~16005 – 10VA/5P106Split-Core


* Models marked with an asterisk require caution when mounted on a busbar. Care must be taken, when the switchgear panels are being moved or when during an earthquake, to prevent the current transformer from sliding due to its weight.



Rectangular Current Transformers ES-1S-A/B/C Series

Easy-to-print document, containing product description, specifications, and a comparison table.

CT & PT Selection Guide: How to Choose a Current Transformer or Potential Transformer

How to select, based on application and power system attributes, the primary and secondary currents, burden, accuracy, rated frequency, type (indoor vs. outdoor), insulation material, etc.