RT250 GFCI Outlet Tester

Professional-Grade GFCI Tester with Backlit LCD and Trip Time Measurement

Full manufacturer title

Klein Tools RT250 GFCI Outlet Tester with LCD Display, Electric Voltage Tester for Standard 3-Wire 120V Electrical Receptacles Receptacle Tester

Member of The 90+ Clubscored 90+ out of 100

Typical price

$16

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Klein Tools RT250 GFCI Outlet Tester with LCD Display, Electric Voltage Tester for Standard 3-Wire 120V Electrical Receptacles Receptacle Tester image 1

Ravvy verdict

95.6 / 100

Buy this if you want a foolproof way to verify GFCI safety and line voltage, accepting that it is slightly bulkier than basic neon bulb testers.

Best for: DIY homeowners and professional inspectors seeking precise safety data
Buy it if: You want large backlit LCD is easy to read in dark spaces.
Skip it if: You are industrial electricians working with high voltage three phase systems.
Best alternative: Klein Tools 32500HD Multi-Bit Screwdriver/Nut Driver, Impact Rated 11-in-1 Tool with Phillips, Slotted, Square and Torx Tips (HVAC technicians, electricians, and serious DIYers who use impact drivers)

How it scores on what matters

Legibility99.0
Accuracy97.0
Safety Features96.0
Battery Life90.0
Portability88.0

Ravvy factor scores, 0 to 100, derived from specs, owner reviews and category norms.

What it is

The Klein Tools RT250 elevates the standard outlet tester by replacing cryptic LED patterns with a clear, backlit LCD screen. Designed for both professional electricians and cautious homeowners, this tool provides real time voltage readings and specific fault messages. Its standout feature is the integrated GFCI trip timer, which measures exactly how many milliseconds it takes for a safety breaker to engage, ensuring your home meets modern safety codes. Beyond basic continuity, the RT250 utilizes patent pending technology to identify dangerous open neutral and open ground conditions that simpler testers might miss. The inclusion of an Auto-Hold function is particularly useful for outlets tucked behind furniture or in dark corners, as it freezes the data on the display for later viewing. It is a rugged, compact diagnostic tool that takes the guesswork out of residential electrical maintenance.

Ravvy AI insight

While most testers only tell you if a GFCI works, the RT250 tells you how fast it works. This is critical because a slow-tripping GFCI can be just as dangerous as a dead one in wet locations like kitchens or bathrooms. The digital voltage readout also helps identify brownout conditions or overloaded circuits that a simple light-based tester would ignore.

Generated from owner feedback, product specs, pricing, and retailer data. Last updated Aug 20, 2026.

What owners praise

Large backlit LCD is easy to read in dark spaces
Measures GFCI trip time in milliseconds
Digital voltage display identifies low voltage issues
Auto-Hold feature saves readings from hidden outlets
Sturdy construction survives toolbox abuse
Clear text fault descriptions instead of codes

What to know first

Larger footprint than traditional non-LCD testers
Requires batteries unlike passive testers
Limited to standard 120V 3-wire outlets

Specifications

UPC: 092644693212
GTIN: 092644693212
Brand: KLEIN TOOLS
Color: Multi
Model: RT250
Style: Receptacle Tester
Brand Name: KLEIN TOOLS
Style Name: Receptacle Tester
Unit Count: 1 Count
Item Weight: 4.16 ounces
Part Number: RT250
Manufacturer: Klein Tools
Power Source: Corded Electric
Item Type Name: Klein Tools RT250 GFCI Receptacle Tester with LCD Display, for Standard 3-Wire 120V Electrical Outlets
Item Dimensions: 4.53 x 1.16 x 2 inches
Number of Items: 1
Measurement Type: Voltmeter
Specification Met: CSA
Included Components: 2 x 1.5V AAA Alkaline Batteries and Manual
Warranty Description: See Manufacturer Website
Maximum Operating Voltage: 120 volts
Minimum Operating Voltage: 120 volts_of_alternating_current
Global Trade Identification Number: 00092644693212

How to get the most out of it

Testing GFCI Speed

Plug the device into a GFCI outlet and press the test button. The screen will display the trip time in milliseconds. Anything over 25ms should be investigated, as modern codes require fast interruption to prevent injury.

Ownership tips

tip

Using the Auto-Hold

When testing an outlet behind a heavy appliance, plug the RT250 in and wait a second. The Auto-Hold feature will capture the voltage and wiring status, allowing you to pull the tool out and read it in a comfortable position.

care

Battery Maintenance

Since this tester uses two AAA batteries to power the LCD, check for corrosion once a year if you keep it in a humid garage. The tool will still indicate some faults without batteries, but you lose the digital display benefits.

Frequently asked questions

Does this tester work on 220V outlets?

No, this specific model is designed strictly for standard North American 120V 3-wire electrical receptacles. Using it on higher voltage circuits may damage the internal electronics.

Can it detect an open ground?

Yes, it features patent pending technology specifically designed to identify open neutral and open ground conditions. These are displayed as clear text on the LCD rather than flashing lights.

Why does the screen show voltage but no wiring status?

If the screen is powered but shows an unusual reading, ensure the tester is fully seated in the outlet. If the outlet is working but the display is blank, check that the AAA batteries are correctly installed.

Is the LCD screen backlit?

Yes, the RT250 features a bright green backlight that activates when a voltage is detected. This makes it significantly easier to use in crawlspaces or during power outages than standard non-lit testers.

Where can you buy the RT250 GFCI Outlet Tester?

RT250 GFCI Outlet Tester is sold through Amazon, and KLEIN TOOLS also lists it through its own site and major retail partners. The buy link on this page goes straight to the current Amazon listing, which is where stock and pricing update most often.

How much does the RT250 GFCI Outlet Tester cost?

The last price Ravvy recorded was $16. Retail pricing on tools & home improvement moves with promotions and stock, so treat that figure as a reference point and check the live listing before you buy.

How do you get the RT250 GFCI Outlet Tester for a cheaper price?

Three tactics work best: watch for holiday and seasonal sale events when tools & home improvement discounts run deepest, compare the open box or renewed listing against new stock, and check whether KLEIN TOOLS is running a coupon or bundle. Adding the product to your Ravvy wishlist keeps it handy so you can revisit the listing when prices drop.

Is the RT250 GFCI Outlet Tester in stock right now?

It was in stock at our last check. Availability on popular tools & home improvement can change within hours, so the live listing is the source of truth.

Is the RT250 GFCI Outlet Tester worth it?

Ravvy scores it 95.6 out of 100. The strongest argument for it is large backlit LCD is easy to read in dark spaces. The trade off to weigh is larger footprint than traditional non-LCD testers.

Who should buy the RT250 GFCI Outlet Tester?

It fits dIY homeowners and professional inspectors seeking precise safety data If that does not describe your situation, compare it with the other options in Tools & Home Improvement before committing.

What are the key specs of the RT250 GFCI Outlet Tester?

UPC: 092644693212. ASIN: B08QW7K1JJ. GTIN: 092644693212. Brand: KLEIN TOOLS.

What are good alternatives to the RT250 GFCI Outlet Tester?

Compare it against the other scored picks in Tools & Home Improvement on Ravvy. We rank every option in that group by the same criteria, so you can see which model wins on value, quality, and owner sentiment before you decide.

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