Current Transformers Styles

The following sections provide brief descriptions for each series of current transformer. For complete specifications, available current ranges, and datasheet downloads click on the individual headings.

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Accu-CT® ACTL-0750 Split-Core CTs

The Accu-CT family of split-core current transformer offers outstanding linearity and very low phase angle error with easy one-handed opening and closing, even wearing gloves. The ACTL family are UL Listed CTs and meet the safety requirements of UL 2808 (XOBA)

The standard Accu-CT meets the IEEE C57.13 class 1.2. accuracy standard. A revenue grade version meeting the requirements of ANSI C12.1 class 0.6 can be ordered by adding Opt C0.6 to the end of the part number. Each Option C0.6 CT ships with a certificate of calibration.

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Accu-CT® ACT-1250 Split-Core CTs

The Accu-CT revenue grade, split-core current transformer offers outstanding linearity and very low phase angle error with easy one-handed opening and closing, even wearing gloves.

The standard Accu-CT meets IEEE C57.13 class 1.2 and when ordered Option C0.6 it meets class 0.6 accuracy standards. Each Option C0.6 CT ships with a certificate of calibration.

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CTM Split-Core CTs

The CTM series CTs are optimized for branch circuit monitoring. They have a hinged opening mechanism for easy installation. The small size and low cost is ideal for monitoring many circuits in a panel.

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CTS Split-Core CTs

The CTS series CTs are available with windows from 0.75 inch up to 2.0 inch. They have a removable section, so that they can be installed without interrupting the circuit.

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CTB Split-Core CTs

The CTB series CTs are designed for higher currents (up to 6000 amps) and larger conductors, including bus bars. They are available in a wider range of shapes and sizes including five stock models and almost unlimited custom variations. They have a removable section, so that they can be installed without interrupting the circuit.

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CTRC Rogowski Coil CTs

The CTRC Rogowski coil current transformers are accurate, flexible, rope-like current sensors that can be connected around conductors. They greatly simplify AC current measurements of conductors where traditional split-core and solid-core CTs are difficult to use. With its flexible design, the CTRC is perfect for large bus bars and irregular-shaped conductor bundles. In addition, the coil’s small profile allows it to fit into tight spaces where rigid CTs won’t fit.

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CTT Solid-Core CTs

The CTT series toroidal (solid-core) current transformers do not have an opening section, so you must disconnect the measured circuit to install solid core CTs. They are better suited for new wiring or permanent installation.

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Current Transformers with 333 mVac Outputs

Split-Core, Rogowski Coil and Solid-Core Styles

Continental Control Systems sells several different series of current transformers (CTs) in various window sizes, current ranges, and accuracy grades. All of the CTs that we sell feature safe, low-voltage outputs (not current output ratio CTs) for indoor use only in 50 or 60 Hz circuits up to 600 Vac. This type of CT contains a built-in burden resistor and is calibrated to output exactly 333.33 mVac when the CT’s rated full-scale current flows through the conductor in the CT’s window opening.

To select a CT, we recommend first deciding on a style, either an opening (split-core) or a solid-core CT, then select the model you need based on the maximum load current you are measuring and the size of the conductor being monitored.

  • For complete specifications and available current ranges, click on the individual series part number links in the tables below.

Split-Core Current Transformers

Split-core CTs (opening) have an opening section, so that they can be installed without interrupting the circuit. They are available in many current ratings and window sizes to fit one or more conductors.

Standard Models

Family
(click on link)
Window Amp
Ranges
Accuracy(1) Phase
Angle(1)
MSRP
ACT-0750 0.78 in. Up to 250 A 0.75% < 0.5° $47.00
ACT-1250 1.25 in. Up to 600 A 0.75% < 0.5° $56.00
CTS-2000 2.00 in. Up to 1500 A 1.0% < 2.0° $68.00
CTB Up to 8 x 24 in. Up to 6000 A 1.5% < 1.5° Varies
CTRC Up to 12 in. dia. Up to 6000 A 1.0% < 0.5° Varies

(1) The accuracy and phase angle specifications for models ACT-0750 and ACT-1250 are from 1% to 120% of rated current. Other models are generally specified from 10% to 120% of rated current.

Revenue Grade Models

Family
(click on link)
Window Rated Amps Accuracy(1) Phase
Angle(1)
MSRP
ACT-0750 C0.6 0.78 in. Up to 250 A 0.5% < 0.25° $57.00
ACT-1250 C0.6 1.25 in. Up to 600 A 0.5% < 0.25° $67.00

Each revenue grade CT ships with a serialize certificate of calibration.

(1) The accuracy and phase angle specifications for revenue grade models are specified from 1% to 120% of rated current.

Models for Special Applications

CTM-0360 Series CTs are used when standard CTs are too large and accuracy is less important than small size.
CTS-0750 Series CTs are used by some models of Square D Solar Ready Combination Service Entrance Panels

Family
(click on link)
Window Amp
Ranges
Accuracy Phase
Angle
MSRP
CTM-0360 0.30 in. Up to 70 A 1.0%(1) < 2.0° $29.00
CTS-0750 0.75 in. Up to 200 A 1.0%(2) < 2.0° (3) $47.00
CTS-1250 1.25 in. Up to 600 A 1.0% < 2.0° $56.00

(1) The accuracy is specified from 10% to 100% of rated current.
(2) The accuracy is specified from 10% to 130% of rated current.
(3) The phase angle is not specified for models CTS-0750-005, CTS-0750-015, CTS-0750-030, and CTS-0750-050

Solid-Core Current Transformers

Solid-core CTs (toroidal) resemble donuts. To install them, the power must be turned off, the conductor disconnected, and then threaded through the CT window. Solid-core CTs are best suited for new wiring and permanent installation.

Family
(click on link)
Round
Window
Amp
Ranges
Accuracy(1) Phase
Angle(1)
MSRP
CTT-0300 0.30 in. Up to 30 A 1.0% < 1.0° $32.00
CTT-0500 0.50 in. Up to 60 A 1.0% < 1.0° $33.00
CTT-0750 0.75 in. Up to 100 A 1.0% < 1.0° $37.00
CTT-1000 1.00 in. Up to 200 A 1.0% < 1.0° $39.00
CTT-1250 1.25 in. Up to 400 A 1.0% < 1.0° $46.00

(1) The accuracy and phase angle specifications are from 10% to 100% of rated current.

Safety Note

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