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Product Discontinued
Information is for legacy purposes

CTL-1250 Series

Split-Core Current Transformer

Revenue Grade Accuracy

—Excellent Linearity

—Low Phase Angle Error


Window Opening 1.25 Inch, 250 and 400 Rated Amps

The CTL-1250 series CTs with option C0.6 are revenue grade, split-core current transformers with excellent linearity and phase angle accuracy.

  • Safe: burden resistor built-in, 333 mVac voltage output at rated full scale current, no shorting blocks needed
  • IEEE C57.13 and IEC 60044-1 accuracy: over full temperature range
  • Very low phase angle error: essential for accurate power and energy measurements
  • Glove-friendly: easy to open and install while wearing safety gloves
  • Approvals: UL Listed, CE Mark, RoHS
  • Patent Pending
  • Download: CTL-1250-Datasheet.pdf


Model Rated
CTL-1250-250 Opt C0.6 250 350 call
CTL-1250-400 Opt C0.6 400 600 call
  • Note: The CTL-1250 CTs are only available with option C0.6, indicating IEEE C57.13 class 0.6 accuracy.
  • List prices for quantity 1 to 30 pieces. Call for pricing on larger quantities.
  • Max Amps is the recommended maximum continuous current. For best accuracy with the WattNode® meter, we recommend operating no higher than the rated amps.

Performance Graphs



  • Graphs show typical performance at 23°C, 60 Hz
  • Graph shows a positive phase angle when the output leads the primary current.



All CTL-1250 model specifications are for operation at 60 Hz. The accuracy specifications apply over the full operating temperature range (-30°C to 55°C) unless otherwise noted.

Option C0.6 Accuracy

With Option C0.6, the Accu-CT is calibrated and verified to meet IEEE/ANSI C57.13-2008 class 0.6 accuracy and IEC 60044-1 class 0.5 S accuracy and each CT is shipped with a certificate of calibration.

  • Accuracy:
    • ±0.50% from 15% to 100% of rated primary current
    • ±0.75% from 1% to 15% of rated primary current
  • Phase angle:
    • ±0.25 degrees (15 minutes) from 50% to 100% of rated current
    • ±0.50 degrees (30 minutes) from 5% to 50% of rated current
    • ±0.75 degrees (45 minutes) from 1% to 5% of rated current
  • IEEE C57.13 accuracy: class 0.6 from 10% to 100% of rated current
  • IEC 60044-1 accuracy: class 0.5 and 0.5 S from 1% to 120% of rated current


  • Primary rating: 250 and 400 amps nominal, 600 Vac, 60 Hz nominal
  • Measurement category/ CAT III
  • Maximum continuous primary amps: see Models table above
  • Maximum primary conductor gauge: 750 kcmil (see Wire Gauges)
    • Note, the largest size may not fit in all cases, depending on insulation thickness.
  • Output: 333.33 mVac
  • Internal burden resistance: less than 10 ohms
  • Output lead wires:
    • Standard length: 8 ft (2.4 m)
    • Gauge: #18 AWG
    • Type: MTW, UL 1015
    • Voltage: 600 Vac
    • Style: Two conductor: white and black, twisted



  • Width: 3.27 inches nominal (83.0 mm)
  • Height: 3.17 inches (80.5 mm)
  • Thickness: 1.38 inches (35.0 mm)
  • Window: 1.25 x 1.30 inches (31.7 x 33.0 mm)
  • Weight: 11.3 oz (320 grams)


  • Operating temperature: -30°C to 55°C
  • UL listed: file number E359088 (FTRZ), standard UL 916
  • cUL listed (Canada): file number E359088 (FTRZ7), standard CAN/CSA-C22.2 No. 1010.1 (1992)
  • CE mark: IEC 60044-1; Declaration of Conformity
  • RoHS
  • Assembled in USA, qualified under the Buy American provision in the American Recovery and Reinvestment Act of 2009 (ARRA).
  • Label barcode: QR Code, “Model ; SerialNum”


Opt C0.6

All CTL-1250 models come with Option C0.6 indicating that they meet IEEE/ANSI C57.13-2008 class 0.6 accuracy and IEC 60044-1 class 0.5 and class 0.5 S accuracy from -30°C to 55°C (see CT Accuracy Standards).

  • Accuracy improves to ±0.5% from 1% to 120% of rated primary current from -30°C to 55°C.
  • Phase angle improves to ±0.25 degrees from 1% to 120% of rated primary current from -30°C to 55°C.
  • Includes a certificate of calibration
    • Order option C0.6,N if you need the C0.6 accuracy, but do not need a certificate of calibration.

See Also


Safety Note

Warning: Hazardous Voltages – Only qualified personnel or licensed electricians should install the WattNode meter and current transformers.