CTT Solid-Core CT


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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Toroidal solid-core (donut) current transformers are more compact and accurate than traditional split-core CTs. Solid-core CTs are use by electric utilities for billing.  (Note: the low-end accuracy of CCS’ patented Accu-CT split-core technology is better than solid-core CTs)

You must disconnect the measured circuit to install solid core CTs, so they are better suited for new wiring or permanent installation.

  • Safe, low-voltage 0.333 Vac output at rated current for indoor use only in 50 or 60 Hz electrical services
  • Accuracy ±1% from 10% to 130% of rated current
  • No exposed metal
  • Phase angle less than 1 degree
  • UL recognized for voltages up to 600 Vac, CE mark, RoHS
  • Twisted-pair, 22 AWG wire leads, 8 feet long
  • Qualified under the Buy American provision in the American Recovery and Reinvestment Act of 2009 (ARRA).
  • Dimensional drawing
  • CTT Solid-Core CT Brochure (PDF 2 page)

Safety Note

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



ModelI.D.Rated Amps (xxx)Max. AmpsMax. Wire GaugeMSRP
CTT-0300-0050.30″54010 AWG, 4* AWG$33.28 each
CTT-0300-0150.30″154010 AWG, 4* AWG$33.28 each
CTT-0300-0200.30″204010 AWG, 4* AWG$33.28 each
CTT-0300-0300.30″304010 AWG, 4* AWG$33.28 each


ModelI.D.Rated Amps (xxx)Max. AmpsMax. Wire GaugeMSRP
CTT-0500-0150.50″15802 AWG, 1/0*$34.32 each
CTT-0500-0200.50″20802 AWG, 1/0*$34.32 each
CTT-0500-0300.50″30802 AWG, 1/0*$34.32 each
CTT-0500-0500.50″50802 AWG, 1/0*$34.32 each
CTT-0500-0600.50″60802 AWG, 1/0*$34.32 each


ModelI.D.Rated Amps (xxx)Max. AmpsMax. Wire GaugeMSRP
CTT-0750-0300.75″301303/0, 300* kcmil$38.48 each
CTT-0750-0500.75″501303/0, 300* kcmil$38.48 each
CTT-0750-0700.75″701303/0, 300* kcmil$38.48 each
CTT-0750-1000.75″1001303/0, 300* kcmil$38.48 each


ModelI.D.Rated Amps (xxx)Max. AmpsMax. Wire GaugeMSRP
CTT-1000-0501.00″50260300 kcmil, 500* kcmil$40.56 each
CTT-1000-0701.00″70260300 kcmil, 500* kcmil$40.56 each
CTT-1000-1001.00″100260300 kcmil, 500* kcmil$40.56 each
CTT-1000-1501.00″150260300 kcmil, 500* kcmil$40.56 each
CTT-1000-2001.00″200260300 kcmil, 500* kcmil$40.56 each


ModelI.D.Rated Amps (xxx)Max. AmpsMax. Wire GaugeMSRP
CTT-1250-0701.25″70520500 kcmil, 750* kcmil$47.84 each
CTT-1250-1501.25″150520500 kcmil, 750* kcmil$47.84 each
CTT-1250-2001.25″200520500 kcmil, 750* kcmil$47.84 each
CTT-1250-2501.25″250520500 kcmil, 750* kcmil$47.84 each
CTT-1250-3001.25″300520500 kcmil, 750* kcmil$47.84 each
CTT-1250-4001.25″400520500 kcmil, 750* kcmil$47.84 each

The “Max. Amps” is the highest continuous current that the CT can handle.
The “Max Wire Gauge” is the largest wire gauge that should fit through this size of CT.
* These sizes may or may not fit, depending on the insulation thickness.
List prices for 1-30 piece quantities. Call for pricing on larger quantities.