Klein Tools GFCI RT250 LCD Outlet Tester - Awesome Tools Under $30

Brendan Lamothe

Key Takeaways

  • The Klein Tools LCD display tester is a versatile and standalone tool.
  • It includes a hold feature, beneficial for quick and accurate readings.
  • The tester excels in detecting and diagnosing outlet issues precisely.

Overview of the Klein Tools LCD Display Tester

The Klein Tools LCD Display Tester operates with two AAA batteries, making it fully independent from the outlet for power. When powered on, it accurately diagnoses various electrical issues by displaying specific codes on its LCD screen.

The LCD display provides real-time updates such as 122 volts AC, wiring status (e.g., CORRECT), and specific fault codes like OPEN GRD and HOT/NEU REV.

One notable feature is the 10-second hold function that allows you to view results even after removing the tester from the outlet. This is particularly useful during home inspections or when quick testing of multiple outlets is required.

Moreover, the tester excels in scenarios where traditional LED testers fall short. For example, it can detect and display issues like OPEN GRD NEU where LED testers may show no response despite voltage presence.

When testing GFCI outlets, the device accurately measures the trip time, providing precise readings like .01 seconds for efficient and detailed inspections. The accuracy of the Klein Tools LCD Display Tester is notable, delivering consistent results close to those of standard outlet testers.

Priced at $20, this tester offers remarkable value for anyone needing to verify electrical outlets, from DIY enthusiasts to professional inspectors.

Diagnosing Outlet Issues with the Tester

Demonstration of OPEN GRD Error

When diagnosing outlet issues, you might encounter an OPEN GRD error. This indicates that the ground connection is missing. You can see this error while still having a 123 volts AC reading on the display.

Identifying OPEN NEU >30 VAC Fault

An OPEN NEU >30 VAC fault occurs when the neutral wire is disconnected, but voltage still flows through the power to ground. This might result in approximately 60 volts AC on the neutral leg.

Issues with Reversed HOT/NEU

If the HOT and NEU wires are reversed, the tester will display HOT/NEU REV. Despite the fault, the display continues to show 123 volts AC. This error is crucial to identify as it can cause safety hazards.

The Hold Feature and Its Advantages

One of the key highlights of the Klein Tools LCD display tester is the hold feature. This function allows you to keep the reading on the screen for 10 seconds after removing the tester from the outlet.

This feature is particularly useful during home inspections. You can plug it into an outlet, get your voltage reading, and then look at the display without needing to stay in an awkward position. Simply plug it in, get your reading, and you have 10 seconds to view the result comfortably.

Here’s how it benefits you:

  • Ease of Use: No need to stay crouched or bent over an outlet.
  • Quick Transitions: Move from one outlet to another efficiently by using the hold feature.
  • Enhanced Accuracy: Verify readings without straining your neck or back.

For electricians, DIY enthusiasts, or property inspectors, this feature ensures your workflow remains smooth and efficient. If your outlets are not easily accessible, you can trust the hold feature to save time and provide accurate readings.

Comparing With Basic LED Testers

Features and Benefits:

When you compare the Klein Tools LCD display tester to Basic LED Testers, you're looking at a significant difference in functionality and efficiency.

  1. Standalone Operation:

    • Klein Tools LCD Display Tester: Operates with two AAA batteries, meaning it doesn't require power from the outlet.
    • Basic LED Testers: Require power from the outlet to function.
  2. Fault Indication:

    • Klein Tools LCD Display Tester: Displays specific faults such as OPEN HOT, OPEN GRD, OPEN NEU >30 VAC, and HOT/NEU REV.
    • Basic LED Testers: Limited to simple LED indications without detailed fault descriptions.
  3. Voltage Display:

    • Klein Tools LCD Display Tester: Shows accurate voltage readings such as 122 volts AC.
    • Basic LED Testers: No detailed voltage display.
  4. Hold Feature:

    • Klein Tools LCD Display Tester: Holds the reading for 10 seconds. Useful in awkward positions where you can't see the screen directly.
    • Basic LED Testers: No hold feature, requiring constant viewing during the test.

Practical Examples:

Imagine testing an outlet where the ground and neutral are both severed.

  • Basic LED Tester: No LEDs light up, leaving you uncertain if the tester is actually working.
  • Klein Tools LCD Display Tester: Accurately shows OPEN GRD NEU, letting you know exactly where the fault is.

GFCI Testing:

  • Klein Tools LCD Display Tester: It can test GFCI outlets and display the exact trip time, such as .01 seconds.
  • Basic LED Testers: Typically do not provide trip time, only indicating if the GFCI is functioning or not.

Reset Functionality:

  • Klein Tools LCD Display Tester: The power button resets the device for testing multiple outlets quickly.
  • Basic LED Testers: No reset functionality, which can slow down inspection workflows.


  • Klein Tools LCD Display Tester: Offers precise voltage readings. For example, it reads 122.7 when the outlet is 122.
  • Basic LED Testers: Generally lack precise voltage accuracy, providing limited data.

Using the Klein Tester on GFCI Outlets

First, plug the Klein tester into the GFCI outlet in question. Once connected, press the test button on the tester.

  • Test Result Display: The device will display the exact time it took to trip the GFCI, such as 0.01 seconds. This helps in assessing the responsiveness of the GFCI outlet.
  • Hold Feature: If the GFCI outlet is in a difficult-to-read position, the Klein tester’s hold feature maintains the reading for 10 seconds. You can unplug it and view the result conveniently.

The tool enhances your efficiency, especially during inspections. Its precise timing of the trip response can give you a clear indication of the GFCI outlet's performance.

Testing the Accuracy of the Klein Tester

Testing the accuracy of the Klein Tester is straightforward and efficient. Start by inserting the tester into an outlet. You should see a reading of the voltage displayed immediately. For instance, it might show 122.7 volts. Compare this reading with another reliable outlet tester. If the other tester reads 122 volts, the Klein Tester is giving a very accurate measurement.

Accuracy Check

Using the Klein Tester is beneficial for prosumers and DIY enthusiasts. Here’s a quick rundown:

  • If the Klein Tester shows 122.7 volts
  • Another tester shows 122 volts
  • The difference is minimal and acceptable

For general use, like in home inspections, this level of accuracy is more than sufficient. The Klein Tester provides reliable and consistent readings, making it a great tool for everyday tasks. If your needs exceed basic outlet testing, investing in a multimeter might be advisable.

Conclusion and Product Recommendation

This Klein Tools LCD display tester is a highly efficient and reliable tool that is indispensable for both prosumer and DIY enthusiasts. Priced at $20, it is affordable and offers impressive features, including:

  • Standalone Operation: Requires only two AAA batteries.
  • Accurate Readings: Provides precise voltage measurements such as 122 volts AC.
  • Fault Detection: Identifies common issues like OPEN HOT, OPEN GRD, OPEN NEU, and HOT/NEU REV.
  • Convenient Hold Feature: Holds readings for 10 seconds, making it easy to read data even in inconvenient positions.
  • GFCI Testing: Measures trip time accurately, useful for inspections.

This tester is highly recommended for anyone needing a dependable outlet tester. Its comprehensive fault diagnostics and user-friendly features make it a standout tool in any toolkit. Don't miss the chance to add this versatile and effective tester to your collection.