RV Electricity – Just Ask Mike (J.A.M.): Combination voltage and 3-light tester


By Mike Sokol

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM.

Dear Mike,
I have one of the voltage testers you’ve previously recommended and it works great plugged into an outlet inside of my RV as a quick reminder of the voltage, as well as being a pretty nifty night light. But I also carry around a 3-light tester for basic outlet checking. Is there anything small and economical you can recommend that does both? —Doug

Dear Doug,
Yes, I do have a new test product that I like that functions both as a 3-light tester, as well as being a plug-in digital voltage tester. And since this one was originally designed for testing European power (240 volts), it should be just fine if it accidentally tangles with a miswired 30-amp outlet (while using an appropriate dog-bone adapter, of course).

I found this nifty tester online a few months ago and have been using it in a variety of voltage checking situations – and it looks really solid so far. Named the HT106B Socket Tester Pro from Kaiweets, it performs all of the 3-light tests for outlet polarity, open ground, open neutral, etc., as well as being a 3-digit digital voltage indicator.

In addition, it performs a standard 5 mA GFCI safety test – which you should be performing on all of your GFCI outlets once a month (or at least once a camping season). I’m showing it plugged in next to a standard 3-light outlet tester on my bench for size comparison. While it’s not something you’ll want to carry around in your pocket, this gadget is certainly a reasonable size when compared to a traditional digital meter.

Its only real drawback that I can find is that the ground pin is designed for an outlet oriented in traditional “ground-down” configuration. And as we all know, receptacles (outlets) on campground pedestals are required to be mounted with a “ground-up” configuration. So you may need to stand on your head to read the voltage numbers, or just use a short (1 ft.) extension cord which allows you to reorient the display.

Also, for quick voltage and polarity testing of the 30-amp outlet on a campsite pedestal I use one of these 30-amp to 15-amp dog-bone adapters in my RVelectricity seminars and it works great.

Where to get one? Well, as usual you can purchase it HERE on Amazon for around $14 including Prime shipping, and possibly from a few more places if you look around. However, I’ve not seen it in any of the standard big-box stores we all know and love (Big Blue and Big Orange). If you know of other places to get it locally please let me know in the comments below and I’ll update the post.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there….



Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

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Joel L

I have a progressive industries EMS-PT30 surge protector. It seems to test for all the things this Kaiweets tester does except the GFCI. Do I really need this tester also?

Bob Bullock

Mike, I bought the Kaiweets tester you recommended, and found it to be off by 10 volts (read 115V vs. 125V actual, as measured by a Klein and a Fluke meter). I wasn’t expecting much, and I realize products aren’t always perfect, but just thought you might want to gather some more data on this model.

Steve S.

TTU (Two Thumbs UP) on this combo unit Mike!
Years ago when we started camping we bought a 3 light tester and plug-in voltmeter. Because . . . that’s what was available and cheap. Every time we go camping, the first thing we do before plugging the rig into the pedestal is plug the dogbone (like the one pictured above), and a 3 light tester to verify proper wiring. We then unplug the 3 light tester and plug in the voltmeter to confirm proper voltage. In all these years, I never thought to check for new gadgets. How nice to have a single device that does both jobs! I know its a minor inconvenience, but they all add up. One less item in the electrical toy box, and one less thing to have to remember to do when hooking up. It all adds up.

Roy Beals

HI, I am Roy at flagman@wi.rr.com . I have a Surge Guard model 34951 portable surge guard. I lost power in my 2011 Monaco Cayman , but only for a short time . I checked the surge protector and it read 119V on one leg and 120v on the other it read 60 amp .But it read only 3a on the 119v leg and no amps on the other. I read a message “NO BLE” and under, it read “peers”. Do I need to worry about anything ? Please reply by email or by phone at 2622208024 .I would be grateful for any help, Roy…


Mike, Thanks for the tip on this tester. After your extremely fine talks at RVillage Rally in Florida, I ordered one when I got home. What a great idea!

Steve Barnes, Kamloops, BC

Mike, I just replaced my 4 6 volt Interstates. I got 10 years x 5 months/year service out of them.
I want to monitor my new ones. I want a meter for permanent mounting in my 5th showing percentage charge, not just voltage. My objective is to never use them if falling below 50%. Does this exist?


If you want to see a very NOT pocket size but true all in one tester, check out my gonzo prototype… 😀


Determination is the mother of really ugly engineering!

Eddie Harris

Hello Mike, is there a gadget like this for 50amp receptacles? We have the volt tester but this would help.

Karin S.

Hello Mike,

Since you did not mention the reverse polarity neutral gruond issue, may I assume this gadget does NOT test for it either? And that we will still need our non contact voltage testers to make sure our RV’s are not “charged?”