Klein Tools Circuit Analyzer RT390

Announced this week is a new Klein Tools circuit analyzer RT390. Think of it as a circuit tester but far more advanced. Let’s check it out below.

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Klein Tools Circuit Analyzer RT390 – Features

Klein Circuit Analyzer RT390

If this seems familiar, that’s because it is similar in form factor to their RT310 GFCI/AFCI outlet tester. The RT310 was more advanced than your basic outlet tester. Not just because it could test AFCI and GFCI outlets but because it had an easy to read “display” and more could provide more data that just isn’t available on basic outlet testers. However the “display” was really just lights to indicate the wiring state of the outlet. It was not an actual display such as the LCD’s found on many gadgets today.

That’s where the RT390 circuit analyzer comes in. It features a similar form factor to the RT310 and brings along its features. However it adds an actual backlit LCD display and some extra features.

Klein Circuit Analyzer RT390 in action

The cord used to plug into an outlet is detachable for easy storage. This also makes it easy to replace in case it gets damaged. It using a cable also has the advantage over regular outlet tester. This is because it will be able to easily fit all types of outlets including recessed outlets. The cord also allows you to hold and and face the display in your direction. No matter the outlet is located low on the ground or above you.

Klein Tools Circuit Analyzer RT390 – Detection

This model will allow you to detect all sorts of wiring faults in standard, AFCI, and GFCI outlets. Including faults a basic outlet test can’t such as double open neutral and ground with hot connected. The display will simply tell you the status of the wiring and you wont have to hassle with comparing lights against a code system. Such as those found on basic outlet testers.

It can also inspect AFCI and GFCI outlets including trip time and trip current. It will also perform percentage voltage drop tests at 12A, 15A, and 20A. The display will also tell you the AC line voltage.

It’s designed for us in North American 120V AC 3 wire electrical outlets and features a safety rating of CAT III 135V.

Klein Circuit Analyzer RT390 contents

It runs on 3x included AAA batteries and powers off automatically after 5 minutes of inactivity. It comes with a soft case included.

Klein Tools Circuit Analyzer RT390 – Pricing & Availability

It is priced at $149.99 and showing available in certain retailers. Showing as pre-order in others.

  • Identify common wiring faults in standard, AFCI and GFCI outlets
  • Inspect AFCI and GFCI devices, includes trip time and trip current
  • Perform percentage voltage drop tests at 12A, 15A and 20A
  • Display AC line voltage
  • Easy to understand results displayed on a large LCD screen
  • Powers off automatically after 5 minutes of inactivity to conserve battery life
  • For use with North American 120V AC 3-wire electrical outlets
  • Safety Rating: CAT III 135V
  • Detachable cord for easy storage

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Check out these other articles on the Tool Craze website:

Klein Tools AFCI / GFCI Outlet Tester RT310 Honest Review

Klein Tools GFCI Receptacle Tester with LCD RT250

Klein Tools Non Contact Voltage Tester with Laser Distance Meter NCVT-6 Honest Review

Klein Tools 40′ Glow in the Dark Fish Tape 50660

Klein Tools Rolling Tool Backpack 55604


  • DrewBHAM says:

    The detachable cord looks to be a standard cord used for a lot of electronics so it would also allow you to add a longer cord if you were using the tester in a confined area or you just wanted to have a long cord. I have even seen 25 foot cables.

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