Tripp Lite
1111 W. 35th Street
Chicago, IL 60609
+1 (773) 869-1776
+1 (773) 869-1329

Instant-Read AC Outlet Circuit Tester with Diagnostic LEDs

  • Simple to use plug-in tester
  • Instantly displays several common wiring fault

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Tripp Lite's instant-read CT120 circuit tester detects wiring stability in standard 120 volt AC wall sockets. Simply plug the circuit tester into a receptacle and view the lighted 3 lamp status display for verification of correct wiring, open ground, open neutral, open hot, hot-ground reversal and hot-neutral reversal fault conditions. Sticker on the tester offers lighting combinations for each wiring condition. Ultra-portable design and easy to read lighted display makes the CT120 an excellent addition to any laptop carrying case, tool belt or workbench. Low cost design saves the expense of hiring an electrician to determine wiring stability.


Offers instant-read notification of correct wiring status of any 120VAC wall socket with a standard NEMA5-15R receptacle (not for use with Ground Fault Interrupt -GFI outlets).

Diagnoses several common wiring faults, including open ground, open neutral, hot-ground reversal and hot-neutral reversal fault conditions (detects most common wiring problems, but not all fault conditions)

Lighted, easy to read 3 lamp status display allows non-technical users to quickly determine the presence of wiring problems and schedule electrical repairs without damage to sensitive electronic devices

Ultra-portable design makes the CT120 and ideal addition to any laptop carrying case, tool belt or workbench

Prevents equipment damage and unsafe wiring by easily identifying common electrical fault conditions so that they can be repaired by a qualified electrician

Low cost design saves the expense of hiring a professional electrician to determine wiring stability

Package Includes

NEMA 5-15PCT120 circuit tester

Operating instructions

RoHS compliant


UPC Code037332116345
Product TypeCircuit Tester
Accessories TypeCircuit Tester
Nominal Input Voltage(s) Supported120V AC
Voltage Compatibility (VAC)120
Input Plug TypeNEMA 5-15P
Diagnostic LED Details3 indicator lights (2 yellow / 1 red)
Housing ColorBlack
Shipping Dimensions (hwd / in.)4.80 x 1.80 x 4.00
Shipping Weight (lbs.)0.20
Unit Dimensions (hwd / in.)3 x 1.5 x 0.5
Unit Weight (lbs.)0.08
Product Warranty Period (Worldwide)Lifetime limited warranty

Questions & Answers

More Q&As may be available on the CT120 model support page.

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Mon - Fri 8 AM - 5:30 PM CST
+1 (773) 869-1776

Mon - Fri: 8 AM - 5:30 PM CST
+1 (773) 869-1234

Tripp Lite
1111 West 35th Street
Chicago, Illinois 60609
United States

+1 (773) 869-1111 Main
1 773.869.1329 Fax

Business Hours
8 AM - 5:30 PM CST

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Need help with your purchase?
We're always available to help with questions, including product selection, sizing, installation and product customization. Call us at +1 (773) 869-1776 or email