Product Overview
The YOJOCK Outlet Tester is a versatile electrical tool designed for standard 3-wire and GFCI-protected 90-250 Volt AC outlets. It provides quick and accurate detection of socket wiring failures, displaying results on an LCD screen and indicator lights. This device is an essential tool for maintenance personnel, inspectors, and homeowners to ensure electrical safety.
Key Features
- Electrical Problem Checker: Detects socket wiring failures in 3-wire and GFCI-protected 90-250V AC outlets.
- Clear Color LCD Screen: Provides at-a-glance indication of correct wiring (Green) or problems (Orange), and displays actual voltage.
- Easy to Use: Simple plug-in operation with clear LED indicators for identifying six common wiring issues.
- One-Click GFCI Tester: Checks if the trip breaker is functioning correctly in GFCI receptacles.
- Safety Certified: Conforms to CAT.II 300V and CE certification standards, ensuring safety and reliability.
Safety Information
This device is designed for safety and reliability, conforming to CAT.II 300V and CE certification standards. Always exercise caution when working with electricity.
- GFCI Test Caution: Ensure the GFCI test is performed correctly under proper wiring conditions with a current greater than 5mA. Be aware that using the GFCI test function on regular receptacles may cause the household wiring system to trip.
- Professional Assistance: If any wiring issues are detected, it is recommended to consult a qualified electrician for inspection and repair.
- Operating Environment: Use the tester within the specified operating temperature (0°C-40°C) and humidity (20%-75%RH) ranges.
Setup and Operation
Getting Started
The YOJOCK Outlet Tester is ready for use directly out of the box. No batteries are required as it draws power from the outlet. Simply plug the tester into the 3-wire AC outlet you wish to test.
Reading the Display and Indicators
The device features a vibrant color LCD display and LED indicator lights to show the wiring status. The LCD screen will display the actual voltage and indicate correct wiring with a green screen, or wiring problems with an orange screen.

This image illustrates the tester's LCD screen in both correct (green) and error (orange) states, along with a comprehensive chart explaining various wiring fault indications using LED patterns.
Wiring Indication Chart
| Condition | LED Indicators |
|---|---|
| Correct | Two orange lights on the right |
| Open Ground | Middle orange light on, right orange light off |
| Open Neutral | Left orange light on, middle and right orange lights off |
| Live/Ground Reverse | Left orange light on, middle orange light off, right orange light on |
| Live/Neutral Reverse | Left orange light off, middle orange light on, right orange light on |
| Live/Ground Reverse, Missing Ground | Left orange light on, middle orange light on, right orange light off |
GFCI Test Function
To test a Ground Fault Circuit Interrupter (GFCI) protected outlet, plug the tester into the outlet.
Press and hold the GFCI button on the tester for approximately two seconds.

This image demonstrates how to perform the one-click GFCI test by pressing the dedicated button on the device. A successful test will trip the GFCI circuit.
If the GFCI receptacle trips (power is cut off), it indicates that the power leakage protection is working correctly. If it does not trip, the GFCI may be faulty and should be inspected by a qualified electrician.
Caution: When using this function on regular receptacles, it may cause the household wiring system to trip. Ensure the GFCI test is performed correctly under proper wiring conditions with a current greater than 5mA.
Product Specifications
| Specification | Value |
|---|---|
| Operating Voltage | 90-250V/45-65Hz |
| Phase Voltage Accuracy | ±(2.0%+2) |
| Leakage Voltage Accuracy | ±(2.0%+2) |
| Operating Temperature | 0°C-40°C |
| Operating Humidity | 20%-75%RH |
| Storage Temperature | -10°C-50°C |
| Storage Humidity | 20%-80%RH |
| Altitude | ≤2000m |
| RCD Test Current | >30mA |
| RCD Working Voltage | 220V±20V |
| GFCI Test Current | >5mA |
| GFCI Working Voltage | 110V±20V |
| Safety Standards | CE, CAT.II 300V |
| Item Weight | 100 g |
| Dimensions | 8.31 x 7.7 x 7.49 cm |
| Model Number | YOJOCK-TPGFCI-LCD |
| Power Source | Corded Electric |
| Batteries | Not Required |
Maintenance and Troubleshooting
Maintenance
The YOJOCK Outlet Tester requires minimal maintenance. Keep the device clean and dry. Avoid exposing it to extreme temperatures or humidity. Store it in a safe place when not in use to prevent damage.
Troubleshooting
If the tester does not light up or display readings when plugged into a live outlet, ensure the outlet is receiving power. If the issue persists, the device may be faulty. If the GFCI test does not trip a GFCI outlet, the GFCI outlet itself may be defective and require professional inspection.
Warranty and Support
This YOJOCK Outlet Tester comes with a one-year guarantee. For support or warranty claims, please refer to the contact information provided with your purchase or visit the manufacturer's website.
Additional Resources
Product Images

The YOJOCK Outlet Tester in use, demonstrating its compact size and clear LCD display when plugged into a standard wall socket.

A detailed view of the tester's LCD screen, highlighting the voltage readings and the LED indicators for various wiring conditions.

An X-ray view of the YOJOCK Outlet Tester, showcasing its internal circuitry and emphasizing its CAT II 300V safety rating and high-definition screen for clear readings.

This image depicts the versatility of the YOJOCK Outlet Tester, showing its application in different settings such as testing electrical systems, checking new house circuits, and conducting office security inspections.

A user holding the YOJOCK Outlet Tester, with callouts indicating the voltage display, the wiring check instructions chart, and the GFCI test button, emphasizing its portability and ease of use.

The YOJOCK Outlet Tester shown with its retail packaging and the accompanying user manual, indicating a complete product package.
Instructional Videos
This video illustrates the basic operation of a grounding outlet tester, showing how to plug it into an outlet and interpret the indicator lights for correct wiring.
A detailed video showcasing the various functions of a circuit breaker finder, including non-contact AC detection, polarity checks, loop resistance measurement, and GFCI testing, similar to the YOJOCK tester.
This video provides a demonstration of an outlet tester plug, highlighting its ease of use for checking electrical outlets for proper wiring and safety.





