Klein Tools Circuit Analyzer 1...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$279.96
$207.83
Klein Tools Circuit Analyzer

Klein Tools Circuit Analyzer 120V AC AFCI GFCI Testing Digital Display Professional Grade

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Model: RT390
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$279.96
$207.83
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Klein Tools Circuit Analyzer 120V AC AFCI GFCI Testing Digital Display Professional Grade

Advanced Electrical Testing Equipment for Professional Diagnostics

The Klein Tools Circuit Analyzer delivers professional-grade electrical testing performance for comprehensive outlet diagnostics and safety device inspection. This ABS plastic construction testing instrument features large color LCD display technology designed for electricians, electrical contractors, and maintenance professionals, providing the reliable performance and industry-leading quality that tradesmen demand from America's most trusted tool manufacturer.

Professional Features & Benefits

Advanced Testing Capabilities

  • AFCI and GFCI Device Testing - Comprehensive inspection with trip time and trip current measurement for complete safety device analysis
  • Wiring Fault Detection - Identifies common wiring faults including dual-open neutral and ground conditions for thorough electrical diagnostics
  • Load Testing Performance - 12A, 15A, and 20A load testing capabilities measure percentage voltage drops for accurate circuit evaluation
  • Large Color LCD Display - Easy-to-understand results display shows wiring faults, device status, voltage readings, and trip timing for professional analysis

Safety and Durability Features

  • CAT III 135V Safety Rating - Professional safety certification ensures reliable operation in electrical environments with Klein Tools quality standards
  • Auto Power-Off Function - Automatically powers off after 5 minutes of inactivity to conserve battery life and extend operational time
  • Drop Protection Design - 6.6-foot drop protection with durable ABS plastic construction withstands jobsite conditions and professional use

Technical Specifications

Dimensions: 7.1 x 2.7 x 1.5 inches, Weight: 0.49 lbs, Voltage Rating: 135V AC, Safety Standard: CAT III 135V, Display: Large Color LCD, Power: 3 x AAA Alkaline Batteries, Drop Protection: 6.6 feet, Construction: ABS Plastic with Electronic Components, Detachable Cord: Yes for Easy Storage

Installation & Usage

  1. Connect circuit analyzer to standard North American 120V AC 3-wire electrical outlet using professional testing procedures
  2. Select appropriate testing mode on large color LCD display for wiring fault detection or safety device inspection
  3. Perform AFCI and GFCI testing with automatic trip time and current measurement for comprehensive device evaluation
  4. Execute load testing at 12A, 15A, or 20A settings to measure voltage drop percentages and circuit performance
  5. Review detailed results on color display showing wiring conditions, device status, and electrical measurements
  6. Store analyzer in included pouch with detachable cord for organized tool management and jobsite portability

Professional Applications

Ideal for:

  • Electrical Installation Testing - New construction outlet verification, wiring fault detection, and safety device commissioning
  • Maintenance and Troubleshooting - Routine electrical system inspection, AFCI/GFCI device testing, and circuit performance evaluation
  • Commercial Electrical Work - Office building electrical testing, retail facility maintenance, and industrial electrical diagnostics
  • Residential Electrical Service - Home electrical inspection, outlet testing, and safety device verification for electrical contractors
  • Code Compliance Verification - AFCI and GFCI testing for electrical code compliance and safety standard requirements
  • Electrical Troubleshooting - Voltage drop analysis, wiring fault identification, and electrical system performance assessment
  • Safety Device Inspection - Professional AFCI and GFCI testing with trip time measurement for comprehensive safety evaluation
  • Circuit Performance Analysis - Load testing and voltage drop measurement for electrical system optimization and diagnostics

Digital Display Technology Advantage

Klein Tools circuit analyzer features advanced color LCD display technology that provides clear, easy-to-understand results for complex electrical testing procedures. The large display shows comprehensive information including wiring fault conditions, AFCI/GFCI device status, trip timing, voltage measurements, and load testing results, enabling electrical professionals to quickly diagnose electrical system conditions and make informed decisions about electrical safety and performance.

Why Choose Klein Tools Quality?

Klein Tools has maintained its legacy of excellence since 1857 as America's premier electrical tool manufacturer, with unwavering commitment to professional safety standards, rigorous testing protocols, and trusted reliability for electrical professionals. This circuit analyzer represents Klein Tools' dedication to innovative electrical testing solutions, precision engineering, and the superior quality that electricians, electrical contractors, and maintenance professionals depend on for accurate electrical diagnostics and safe electrical work practices.



KLN-RT390 - spec sheet

Manufacturer Resources

Product Specs

Afci:
Yes
Application:
Test Wiring Faults, Inspects AFCI and GFCI Devices, Displays Line Voltage, Voltage Drop
Batteries:
3 x AAA Alkaline
Drop Protection:
6.6' (2m)
Gfci:
Yes
Included:
Circuit Analyzer; 3 x AAA Batteries; Instructions; and Pouch
Overall Height:
7.1" (3.9 cm)
Overall Length:
1.5" (17.9 cm)
Overall Width:
2.7" (6.9 cm)
Standard:
CAT III 135V
Product Type:
Circuit Analyzer
Department:
Electrical
Product Group:
Test & Measurement
Product Subgroup:
Electrical Testers
Product Voltage:
135V AC
Product Details:
Circuit Analyzer
Product Height:
1.5080 in
Product Material:
ABS Plastic, Overmold, Electronic Components
Product Category:
Circuit Analyzers
Product Weight:
0.4880 lbs
Product Width:
2.7200 in
Product Depth:
7.0720 in

Klein Tools RT390 – Frequently Asked Questions

1) Will the Klein RT390 circuit analyzer test AFCI and GFCI breakers, or just outlets?
The RT390 tests both AFCI and GFCI devices, and it reports trip time and trip current rather than just a pass/fail light. It plugs into a standard 120V AC three-wire receptacle, so it exercises the protective device from the load side of the circuit it feeds. Alongside that it checks wiring faults, shows line voltage, and measures voltage drop.
2) Can I use a Klein RT390 on 240V circuits or on European outlets?
No. The RT390 is built for standard North American 120V AC three-wire receptacles and is rated 135V AC, CAT III 135V. That rating is the ceiling, not a suggestion, so 208V, 240V, and 230V European outlets are out of scope for it. For a panel or a 240V circuit you need a meter rated for that voltage, not a receptacle-style analyzer.
3) What does the CAT III 135V rating on the Klein RT390 mean for where I can use it?
CAT III covers distribution-level wiring inside a building, which is where receptacle circuits live, and the 135V is the working voltage limit. In practice that means branch-circuit receptacle work in commercial and residential buildings is within the instrument's design envelope. It is not a CAT IV instrument, so service entrance and utility-side work is not what it is rated for.
4) Does a plug-in circuit analyzer like the RT390 replace a plain three-light receptacle tester?
It does the same job and a good deal more. A three-light tester shows a wiring fault pattern and nothing else; the RT390 identifies faults including dual-open neutral and open ground conditions, then adds trip time and trip current on AFCI and GFCI devices, line voltage, and percentage voltage drop under load. If all you ever need is a quick hot/neutral/ground check on an outlet, the cheap tester still does it. If you are commissioning a circuit or proving out a nuisance trip, the three-light tester cannot get you there.
5) How do I find a voltage drop problem on a receptacle circuit with the Klein RT390?
Load testing is the feature for that. The RT390 draws 12A, 15A, or 20A at the receptacle and reports the percentage voltage drop at each step, which is how you separate an undersized or long conductor run from a loose termination. Run the 20A step on a 20A circuit and compare the drop against a known-good outlet on the same panel; a receptacle that sags badly while its neighbours hold up points you at the connection between them.
6) What comes in the box with the Klein RT390, and do I need to buy batteries?
Batteries are included. The RT390 ships with the analyzer, three AAA alkaline cells, instructions, and a pouch, so there is nothing to order alongside it to put it to work. Replacements are ordinary 3 x AAA alkaline. The test cord detaches for storage, and the unit powers itself off after five minutes idle so a tool left in the pouch does not come back flat.
7) I need to document AFCI and GFCI testing for a code inspection. Does the Klein RT390 give me numbers I can record?
Yes, it reads out trip time and trip current for the device under test on a colour LCD, so you are recording a measured value per receptacle rather than writing down that a button worked. It also shows line voltage and flags wiring faults on the same screen. That is the difference between a sheet an inspector can look at and an unsupported checkmark.
8) Will the Klein RT390 survive being dropped on a jobsite?
It is rated for a 6.6 foot (2m) drop, which covers a fall from a ladder step or the top of a step stool onto a hard floor. The housing is ABS plastic with an overmold over the electronics. The supplied pouch and the cord that unplugs from the body are what keep the lead from getting yanked in a bag, which is the more common way these instruments die.
9) Is the Klein RT390 small enough to carry in a pouch on my belt all day?
The analyzer measures 7.1 x 2.7 x 1.5 inches and weighs about half a pound (0.488 lbs) with its three AAA cells, so it rides in a pouch without pulling a belt down. It comes with its own pouch, and the cord detaches so the whole thing packs flat rather than trailing a lead.
10) What model number do I order for the Klein circuit analyzer with the colour display?
Klein Tools RT390 is the part number, and it is a single-configuration tool with no finish or range options to pick. That is the model with the large colour LCD, AFCI and GFCI trip testing, and the 12A/15A/20A load test.
How fast can I get the Klein Tools RT390 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Klein Tools RT390 come with a warranty?
Absolutely. The Klein Tools RT390 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Klein Tools RT390?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Klein Tools RT390 from ZenSupply?
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