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

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Single-Core Low-Voltage Current Transformers (Rectangular Window-Type) - CIC

CIC | CHALLENGE INDUSTRIAL CO., LTD., since 1974, is a global supplier of Single-Core Low-Voltage Current Transformers (Rectangular Window-Type). CIC specializes in the manufacture of instrument transformers, distribution transformers, detuned reactors, epoxy insulators, electronic energy meters, etc. Also provided or distributed are a wide range of other electrical or electronic apparatus.

Certified to ISO 9001, CIC ensures superior quality of its goods through such advanced technologies and materials as Swiss-manufactured equipment (for the production of resin insulators), Araldite® epoxy resin, and technology transferred from Messwandler-Bau (MWB) of Germany.

Backed by 44 years of experience, CIC offers custom-made products, OEM/ODM services, and technical support tailored to the needs of its discerning clientele.

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

ES-1S-A Series

1 core. Rectangular, low-voltage, resin-insulated current transformers for switchgear-panel makers et al. For use with measuring or monitoring instruments. This current transformer can be mounted on a busbar or fixed directly to the switchgear panel.

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-A Series

  • Single-core
  • Window-type
  • Designed to be used with measuring or monitoring instruments


  • 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.

Series Model Primary
Current (A)
Secondary Current (A) Burden/Accuracy
Core 1 Core 2
ES-1S-A ES-1S-60A 400~800 5  -  30VA/1.0 or 15VA/0.5 2.1 Single-Core
ES-1S-80A * 600~1200 5  -  30VA/1.0 or 15VA/0.5 2.1 Single-Core
ES-1S-100A * 1000~2000 5  -  30VA/1.0 or 15VA/0.5 2.2 Single-Core
ES-1S-120A * 2500~4000 5  -  40 VA/1.0 or 30VA/0.5 3.7 Single-Core
ES-1S-165A * 4000~7000 5  -  40 VA/1.0 or 30VA/0.5 4.3 Single-Core
ES-1S-B ES-1S-100B * 1000~2000 5 5 15VA/5P20+30VA/0.5 10 Two-Core
ES-1S-120B * 2500~4000 5 5 15VA/5P20+30VA/0.5 9.5 Two-Core
ES-1S-C ES-1S-165C 800~1000 5  -  7.5VA/5P10 6 Split-Core
1250~1600 5  -  10VA/5P10 6 Split-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.

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