Continental Control Systems sells several different families 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 ratio outputs) 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 family 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.

Family	Rectangular Window	Amp Range	Accuracy(1)	Phase Angle(1)	MSRP
CTM-0360	0.30 in.	5-70 A	1.0%	< 2.0°	$29.00
ACT-0750	0.78 in.	5-250 A	0.75%	< 0.5°	$43.50
ACT-0750 C0.6	0.78 in.	15-250 A	0.5%	< 0.25°	$57.00
CTS-0750	0.75 in.	5-200 A	1.0%	< 2.0° (2)	$47.00
CTS-1250	1.25 in.	70-600 A	1.0%	< 2.0° (3)	$55.00
CTS-2000	2.00 in.	400-1500 A	1.0%	< 2.0°	$68.00
CTB	Up to 8 x 24 in.	150-6000 A	1.5% (4)	< 1.5°	Varies

(1) The accuracy and phase angle specifications are generally from 10% to 100% of rated current. ACT-0750 models are specified from 1% to 100% of rated current.

(2) The phase angle is not specified for models CTS-0750-005, CTS-0750-015, CTS-0750-030, and CTS-0750-050

(3) The phase angle is not specified for models CTS-1250-070 and CTS-1250-100

(4) The 0.6% accuracy option is available for custom CTB Series orders

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	Round Window	Amp Range	Accuracy(1)	Phase Angle(1)	MSRP
CTT-0300	0.30 in.	5-30 A	1.0%	< 1.0°	$32.00
CTT-0500	0.50 in.	15-60 A	1.0%	< 1.0°	$33.00
CTT-0750	0.75 in.	30-100 A	1.0%	< 1.0°	$37.00
CTT-1000	1.00 in.	50-200 A	1.0%	< 1.0°	$39.00
CTT-1250	1.25 in.	70-400 A	1.0%	< 1.0°	$46.00

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

Descriptions

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.

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.

Accu-CT® ACT 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.

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.

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.

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.

Safety Note

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