Support Center

Welcome to the Continental Control Systems’ support pages. This section contains articles to assist with installing, configuring, troubleshooting, and using our WattNode meter and current transformer products. Information on other products, accessories, and services that are sold by other companies that work with WattNode products are also list here.
This product line is no longer being stocked, 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.

in Legacy Products