Sunday, December 3, 2023


RVelectricity – Quick 30-amp outlet tester for cheap

By Mike Sokol

Dear Readers,
You may have noticed that I launched my RVelectricity Webcasts this week, and have been creating all sorts of YouTube videos while I’m stuck inside. Here’s a really short one [below] for you about a simple yet effective test for 30-amp RV outlets that will cost you about $25 even if you have to buy everything. If you have some of these devices laying around, so much the better.

While metering a pedestal can be very accurate in determining its basic wiring, many campers are not practiced with a meter and make mistakes. So here’s how to do it without a digital meter that has probes. And I’ve included a short video to show you.

Step 1: Get a plug-in digital meter like this one for about $10 on Amazon. I have three of them and they’re all within a volt of my rather expensive Fluke meter.

Step 2: Get a 3-light outlet tester from anyone you like for less than $6. You don’t need one with a GFCI test since you’re not testing an GFCI protected outlet. Here’s one on Amazon.

Step 3: Get a 30-amp to 15-amp outlet adapter like this one from any source you like. I believe I got mine from Tractor Supply, believe it or not, but any RV store will have them as well. As a last resort, it’s Amazon to the rescue.

Now put them together as I show in the video. Just click on the screen shot to watch how it works.

If the 3-light tester shows that the polarity of the outlet is reversed or the ground is open, then don’t proceed. And if the meter voltage is less than 105 volts or more than 128 volts, don’t plug your RV into it.

Of course the gold standard test is to use a Total Electrical Protection (TEP) Surge Protector like one from Surge Guard. But my little test rig will tell you a lot about the general wiring of the outlet without having to resort to poking meter probes into the contacts.

While you’re at it, sign up for my YouTube RVelectricity channel. Lots of new stuff on there, and I’m making more every day.

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 For more info on Mike’s qualifications as an electrical expert, click here.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.





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RhythmMachine (@guest_126870)
2 years ago

So, we just picked up a trailer and I’m trying to get prepared before heading out. I’ve seen several people mention surge protectors and power testers. A surge protector makes sense to me, but I can’t help but wonder… if I’m plugging into the same box that hundreds if others have used, how often will I find that there is a significant enough problem to prevent me from using jt? And what do you do if you do discover a problem – ask to be moved to another spot? Go without power?

Steve S. (@guest_72412)
3 years ago

Mike, you surprise me.
In a previous post you show a 3 light circuit tester that has a built-in voltmeter.
One device, 2 functions.

I went and bought 2 of them.
One for the camper, one for the toolbox.
Now I have a simple plug-in where I don’t have to change out devices.

Martin A (@guest_72349)
3 years ago

Mike I have been using similar plug and 3 light for some time, wasn’t aware of the meter. In your training can you mention people should look in the pedestal before plugging in to test or connect. A few years back during summer I reached in a low pedestal to retrieve my 3 light tester, and I thought I got shocked, turns out I was stung by a hornet/wasp that had a nest in the box. I checked several nearby empty spaces, all had them.

Drew (@guest_72256)
3 years ago

But wait! If you act right now we’ll send you both of these incredible test units for $12.99 AND a case to keep them in! But that’s not all….you’ll also receive a second set of testers at no additional charge except for a small processing fee.

Sorry Mike, I couldn’t resist!

Chris (@guest_72206)
3 years ago

Mike, great tip. I combined the AC voltmeter and tester light with a small (six inch cord) three-outlet power strip I got at Harbor Freight so I just plug that into the 20-amp then 30-amp pedestal outlets.

Wolfe (@guest_72268)
3 years ago
Reply to  Chris

There’s a 3-light tester that has a voltmeter built in, which Mike is usually advertising on here. About $7 most sources. That still doesn’t save you from needing a non-contact tester for the energized ground (chassis) / “hot skin” condition.

impavid (@guest_72149)
3 years ago

Good video and clearly explained. I do however disagree with “You don’t need one with a GFCI test …”. Every RV I’ve owned, and I suspect every RV out there, has a GFCI outlet, so if you’re buying a three light tester you might as well buy one that you can test all your circuits.

DAVE TELENKO (@guest_72145)
3 years ago

Mike thats sooooo Kool, wow & sooooo simple to make & use!
Thanks for figuring it out.

Gary Swope (@guest_72030)
3 years ago

Thanks, Mike. Good info.

wanderso (@guest_71894)
3 years ago

But this does not check hot skin?
I use a two-ended combined hot skin sensor (& 15A {bleeped} light/GFCI tester), then plug in my EMS which has a delay for monitoring before supplying power and displaying voltage.
More expensive for sure, but who would connect to shore power without an EMS? So I have only two devices and I’m covered for all contingencies.
Thanks for your tutorials!

Mike Sokol (@guest_71926)
3 years ago
Reply to  wanderso

Lots of folks won’t pay for an advanced surge protector. And yes, adding a NCVT to check for hot-skin voltage would be the safest thing to do. Thanks for watching…

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