Klein Tools RT390 Circuit Analyzer with Large LCD, Identifies Wiring Faults, GFCI and AFCI Tester, Voltage Drop, Displays Trip Time

Every homeowner should have one of these! It takes the guesswork out od troubleshooting an outlet and saves time!

I needed a arc fault tester and I decided to pay the extra for the voltage drop version. After testing a few different outlets. I am very happy with this.

I have used Klien tools for years and the name stands alone as the best in the industry for many tools... However, I have never been a huge fan of their test meters and such. They seem to be a little bulky next to the other brands. The size of this one is ok, but I have discovered that it does not do everything it should do. I purchased it to test Arch Fault circuits in a new home. It DID NOT trip all circuits. I do mostly commercial work, so not real familiar with the residential Arch Fault breaker. When we got our inspection, I mentioned to the inspector that the tester did not trip all the Arch Fault breakers. In short, he told me that the Klien Arch Fault tester would NOT trip all circuits. He couldnt explain why, but told us that he could not use the Klien version of the tester for this reason. It will trip some breakers, in our case where we had some combo Arch Fault / GFI breakers it worked fine, but wouldnt trip others... adding up to about 50% that it would trip to 50% that it would not trip. It does seem to be a good polarity tester and a decent GFI tester, for that reason I decided to keep it since I dont do a large amount of residential work anyway and shouldnt have much need for the Arch Fault tester in the near future. Since it is listed as a AFCI Arch Fault tester, I would NOT recommend this product and that is what this review is based on. IF you are using as a GFCI tester, then it would be fine.

Dont let the inspector know you have it. Let them stick with their tester.

GFCI only testers are pretty cheap: just get the plug on kind with plain incandescent bulbs that show you bad wiring combos and have a GFCI test button. Those do fine. I got this for the AFCI testing ability, and I am impressed with it. I assumed that the tester cheats by synthesizing some kind of voltage signal on the wire that tricks the breaker into tripping, but this device has a component inside that generates an actual electrical arc. (There is a teardown video on YouTube that is great). If the breaker doesnt trip (e.g. you use it on an unprotected circuit) the arc will go on for a bit and heat up the component. The device has a temperature safety built in that will show you the arc generator is too hot and wont let you trigger it. This is a quality tool. Now, I did say for wiring state and GFCI the cheapo passive plug in ones are sufficient, but this tool also has a more comprehensive readout for the outlet state. For example, on one of my outlets, after the breaker tripped with the AFCI test, I got a read out saying something was wrong with the off state of the outlet. I have to now check to see what happened.

It has worked in the past on GFCI protected circuits and AFCI-only breakers. However, when I was testing a working outlet (it showed correct wiring) on a dual-function breaker and pressed the AFCI button, the lights on the same circuit flickered for a second, and the breaker never tripped. The breakers test button trips it properly. A few minutes later (after the tester was unplugged), I could feel the sides of the tester getting extremely warm to the touch, so I dont know if something inside was damaged. I was able to test the same outlets using a different GFCI-only tester and they tripped the breaker properly. I read another review here that said an older version of this device cant test dual-function breakers but it may have been updated since then. But when I contacted Klein, they confirmed the RT310 is not designed for dual function breakers, and they also said they dont currently have a tester that will work for that purpose.

I have dual spec breakers in my shop and need to periodically confirm they are functioning correctly for both arc detect and GFI. GFI is easy to emulate, no so easy to create an arc within the breaker specification this test device is designed for that purpose.

Easy to use

great tester esp. for AFCI

I purchased a older home which had GFI and AFCI s in the breaker panel. I wanted to test them, this did the trick. I actually bought the other Kline tool for recpticals to test wiring and GFI functions. I like the other better for GFIs as it tells you trip time. Amazon sells both, get them both. Test everything, be safe Sparky.