KLEIN TOOLS RT250 GFCI Outlet Tester with LCD — 120V Receptacle Voltage & GFCI Trip Time

The Klein Tools RT250 is a plug-in receptacle tester with a backlit LCD that reads outlet voltage, identifies common wiring faults, and displays GFCI trip time for standard 3-wire 120V electrical outlets.

When troubleshooting North American residential and commercial outlets, you want clear answers fast. The RT250 combines a bright, easy-to-read LCD with patent-pending detection logic to flag open neutral and open ground conditions, indicate incorrect wiring, and show how long a GFCI takes to trip. Built by Klein Tools, the unit is compact, rugged, and designed for electricians and building professionals who need accurate diagnostics at the receptacle.

How does the RT250 show outlet voltage and wiring faults?

The RT250 uses a large backlit LCD to present measured line voltage and a labeled wiring-status readout. Instead of relying solely on indicator lights, the display gives direct numeric voltage plus a simple description of detected wiring conditions, reducing interpretation errors on-site.

• Backlit LCD shows measured AC line voltage clearly in volts.
• Text readout identifies common wiring faults like open neutral, open ground, reversed hot/neutral.
• Auto-Hold freezes readings for outlets in awkward positions.
• Compact plug-in design makes tests quick without extra leads.

Can it test GFCI function and how is trip time reported?

The RT250 can actuate and evaluate GFCI devices and reports the time it takes for the device to trip. You get a numeric trip-time readout on the LCD so you can verify that GFCI protection responds within expected intervals for safety and code checks.

• Built-in GFCI test initiates a trip and measures the response time.
• LCD displays the elapsed milliseconds or seconds for the trip event.
• Useful for commissioning, maintenance, and troubleshooting GFCI-protected circuits.
• No separate test leads required—works directly at the receptacle.

What wiring faults will the RT250 detect and how reliable is it?

The RT250 detects the most common and safety-related wiring faults encountered at 3-wire 120V receptacles. Klein's patent-pending open neutral and open ground detection improves fault identification compared with simple LED-only testers, helping reduce false diagnoses.

• Detects open neutral, open ground, hot/neutral reverse, and other standard wiring faults.
• Patent-pending logic reduces ambiguous readings, improving confidence in the result.
• Displays clear text and numeric values rather than relying on pattern decoding.
• Sturdy design and reputable manufacturing from Klein Tools for professional use.

Who is this for? The Klein Tools RT250 is intended for electricians, maintenance technicians, home inspectors, and facility managers who need accurate, fast verification of 120V receptacle wiring and GFCI performance. It’s compact enough for service vans and job-site tool belts, provides clear readouts that reduce guesswork, and offers the durability professionals expect from Klein Tools. If you frequently troubleshoot outlets, commission GFCIs, or perform safety inspections, the RT250 gives measurable, documented results without extra test leads or complicated interpretation.