How to check pedestal power when hooking up

EDITOR’S NOTE: Please pass this article along to the owners of RV parks where you stay or park owners you know

By Mike Sokol
I believe that every campground operator should get the proper test gear to check each pedestal for correct AC power BEFORE you pull your RV in and hook up. It’s a simple two-step process that should only take a minute or two to verify the power is okay. Then you can pull your rig into the spot, plug in and feel secure that you are safe from a potentially dangerous RV hot skin condition (watch video to learn what this is).

I still recommend you get your own advanced surge protector in case something happens to the power AFTER you hook up. But the PPC (Pedestal Power Check) should catch 99-plus percent of all electrical problems.

Southwire 40130N

STEP 1
Use an NCVT (Non Contact Voltage Tester) to confirm the pedestal box itself isn’t electrically hot. The Southwire 40130N is a great unit for this. Turn on the NCVT and verify the battery isn’t dead by looking for the indicator light in the tip, then touch the tip of the tester to the pedestal box itself. If it beeps near the metal box, then turn around and walk away from the pedestal, and immediately call the electrician. The pedestal box has lost its ground and is now electrified with up to 120 volts. If the NCVT doesn’t beep, the box passes this initial test. 

Now turn on the pedestal circuit breakers and test the hot slots on the 30- or 50-amp outlets just to confirm that your NCVT is still working. On a 30-amp outlet with the ground at the top this will be the left contact. On a 50-amp outlet it will be both the right and left sides. If the NCVT beeps on the hot side of the outlet but still doesn’t beep on the ground hole in the outlet and the outside of the metal box, then basic grounding is okay and proceed to Step #2.

Surge Guard 50 amp

STEP 2
Use a 30- or 50-amp advanced surge protector such as the Surge Guard 34930 (30 amp) or 34950 (50 amp) to test the appropriate pedestal outlet for proper voltage and polarity. While you could possibly use a series of dog-bone adapters and only a single surge protector for both outlets, it’s really the best to use a 30-amp surge protector on the 30-amp outlet, and a 50-amp surge protector on the 50-amp outlet. Yes, I know this is a lot more expensive than a regular meter, but some of the COE campgrounds won’t allow anyone to plug meter probes in a pedestal, and I’ve heard that this may also be happening at state run campgrounds. But an advanced surge protector is OK for this use and much quicker especially with non-technical personnel.

The best and safest procedure is to turn off the pedestal circuit breaker(s) and plug in the advanced surge protector. Then turn on the circuit breaker and watch the 10-second countdown on the Surge Guard. It should then give you appropriate lights that tell you the pedestal outlet is okay, as well as indicate the measured voltage. If it’s less than 102 volts or more than 132 volts, or the lights indicate a wiring problem such as a lost ground, then something isn’t right with the power going to the pedestal, and you should mark it “out of service” until an electrician can find and correct the problem. If it passes this test, then all is well and you can proceed to pull into the campsite and plug your RV into shore power.

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23 Thoughts to “How to check pedestal power when hooking up”

  1. Robb

    Hi Mike. I’ve been using Progressive Industries EMS units since I started RVing 5 yrs ago. Since that time they have found 3 “bad” pedestals. On one occasion when I brought this to the attention of the campground electrician, he commented, “ I hate those things” and then correctly rewired the box. Can’t say enough about these units.

    Robb
    Stuart, Fl

  2. Stephen Wickland

    Hi!
    You guys ARE saving lives by educating us RVers about possible electrical issues at campground hookups! And you potentially saved my bacon last week! I plugged into a 30amp pedestal at the Munising, Mi KOA. Everything seemed fine…but was I mistaken. After I was all plugged in and having the RV all leveled and such, it dawned on me to get out my voltage tester. As I placed it on my RV’s door it lit up like a Christmas Tree! Out of the 10 different times I had been connected at various campgrounds, this was the first time I had ever gotten a “hot skin” reading. So, I proceed to check the metal steps and metal frame around the door and as you might have guessed…it was “hot” as well. I then went to the pedestal and everywhere I place my reader it indicated that the entire pedestal was hot. I immediately notified the campground management and they discovered some kind of short/defect in the pedestals wiring. Potential disaster averted. And I looked super-smart in my wife and kids eyes. A rare occurrence indeed! Thank you for this great service you provide weekly to all of us RVers. I will be supporting you monetarily from this point on. I feel kind of sheepish (cheap!) about not doing so sooner.
    All the best ! And keep up the EXCELLENT work!

    1. Mike Sokol

      Stephen,

      Thank you very much and I’m glad you and your family are safe. A Non Contact Voltage Tester (NCVT) is very safe to use as a quick check for an RV hot-skin. And it’s pretty terrifying to realize that your entire RV and tow vehicle (if it’s still connected) is indeed at a dangerous voltage.

      While many of my readers might never encounter a hot-skin on their RV, it only takes a few seconds to test for this dangerous condition. Note that Chuck Woodbury encountered a similarly miswired pedestal with a potential RV hot-skin hardly a month ago, and I have received dozens of similar emails from readers all over the country who have had the same experience.

      So, those of you who don’t have one, please get an NCVT and use it to test for a hot-skin voltage as part of your normal RV hookup routine. It could save your life.

  3. Booneyrat

    Mike is correct about a good quality EMS type protector.What do people think when they spend thousands for an RV then skimp on electrical protection?

  4. Colleen

    I noticed that you are using the term “advanced surge protector” rather than EMS. New RVers are often confused and think that buying a $100 surge protector protects them adequately when what they really need is an EMS. Calling two very different products by the same name confuses them further.

    1. Mike Sokol

      EMS is a trademark of Progressive Industries, so you can’t buy a Surge Guard EMS or a Camco EMS. In fact I could be taken to court for trademark infringement if I called them EMS units. So I’m describing the two different levels of protection by function rather than trademarks. Basic surge protectors do just that, only clamp the surges. But advanced surge protectors also monitor voltage and polarity and have a relay to shut off the power. And to get picky I really don’t like calling ANY of them “surge protectors” since they’re really transient spike protectors. Or at least that’s how engineers refer to what they do. If you have any better way to differentiate the different levels of surge protectors that’s not a trademark violation, than I’m willing to consider it.

  5. Shipp

    I am totally unclear why any RV outlet would need to allow for 220 volt service to be at the outlets, regardless of whether it is a 30 amp service or a fifty amp Service. I have always wired my outlets for two separate 120 volt services with either 12 ga ( I prefer 10 ga for the neutral.) or 8 to 6 ga wire depending on the plug configuration. If a 220 PLUG were to be inserted, it would show zero voltage, NOT 220. Checking with a volt meter on both hot wires shows Zero, not 220. However, checking each hot to ground or neutral shows 120 v. An RV runs just fine off of the two separate 120 volt sides. All trailer parks have two separate 120 phase circuits coming from the power company. It is a simple solution to use one phase for one part of the park and the other phase for the rest. There is NO reason that I know of, to have two phase circuits going to an RV. It requires only a little more thought to wire this configuration and a lost common simply means no voltage, instead of burning every thing out.

    1. Mike Sokol

      It’s all about the cost of the copper. By wiring the two hot legs out of phase and sharing the neutral between them, you can get by with 4 wires instead of 5 wires. That’s a significant cost reduction. This get better when you distribute 3-phase power, which is what the power plants make and send on all the high-tension wires. In 3-phase wye distribution, just 4 wires can carry 3 times the power of a single phase pair using the same size copper wire. And in delta distribution you only need 3 wires to carry 3 times the power of a single phase pair. Thank you Nicola Tesla for inventing 3-phase power.

      Copper is expensive, so even the short runs in your home or campground would be prohibitively expensive if you did separate 120-volt runs. Now in England they run 240-volts hot-to-neutral on everything so there’s no need for a 120/240-volt split of a single phase like we do in the US. This is how we’ve done it in the US since we built the first power plant in Niagra Falls in the 1890’s, so we’re not changing anytime soon.

      1. Shipp

        Thank you for that explanation but I still don’t totally agree. As I suggested in my post, you simply have to increase the size of the neutral, not all the wires so it is still two hots a neutral and a ground. If you tie the ground wires to the neutral, AND add a ground rod at each end of a run, your neutral will be not that more expensive. AND there is no danger of 220 in the RV.

        1. Mike Sokol

          A larger neutral wire will still cost more, which is why it isn’t done. Plus you not only have to increase the size of the conductor, you would also have to use a larger plug with a 100-amp neutral contact. As I noted, the safest way to distribute power to RVs is how they do it in the UK with a Cee-Form connector running 240 volts. But it ain’t happening here…

  6. Tom C

    Have you discussed the problems if the neutral is loose or dropped…that is also another potential danger. Including burning out your appliances…

    1. Mike Sokol

      Yes, I’ve discussed the open neutral problem many times on this forum. In fact, I’m working on a demonstration that shows how an open neutral will burn out appliances on the high-leg of a 50-amp shore power feed when the neutral opens up and the 240-volts divides unevenly. But I have a LOT to do, so it’s not on the top of my list yet.

  7. Sherry Dawson

    Mike Sokol, thanks for another good set of directions for staying safe. I copy everything you write into a document that I can study as often as I need to.

    I have two questions. Should we start the voltage test with the circuit breaker off? I’m assuming there could be a dangerous condition even with it off. Then we should test again with the breakers on. Is that right?

    You rarely mention the 20-volt outlet, which many owners of small campers must use for their main power. Most RVers also use it occasionally for an extension cord to run outdoor lights, cooking equipment, entertainment systems, fans, etc. Also, many of us who boondock might ask permission to plug into household current at a day park or a business for an emergency charge to a wheelchair or mobility scooter battery, or phone or computer battery, etc. Could you give us a quick safety tip for those two situations.

    I would hope you would include testing the campground 20 volt outlet in your future electrical safety articles.

    I really appreciate all you do to help us stay safe. I’ve learned a lot from you and feel lucky that I didn’t experience problems when I owned an RV decades ago! Now I know how ignorant I was. . .

    1. Mike Sokol

      The idea of starting the test without touching the breaker (which should be off already) is because it’s possible that the pedestal box itself could be electrically energized. And yes, I’ll work on a test procedure for 20-amp outlets.

  8. Bill Fisher

    Last year, on our way to Alaska, we spent one night in Great Falls, MT at a well known campground. Pulled into the site and after checking the power pedestal I hooked up our 30 amp cord. Our hard-wired Progressive Industries EMS faulted with a ground problem. Since I had only installed the PI EMS not long before we left on the trip, I wanted to make sure it was, in fact, the power pedestal and not our new EMS, so I dug out my multimeter (I was in the electronics service industry for forty years) and sure enough, proved the EMS was correct. I called the campground office and explained the problem. They came down and guided us to another site and our EMS said the power was okay. They actually thanked me for troubleshooting their power problem and said they would get someone to check it out and fix it. Now whether they did or not is anyones guess.

    1. Mike Sokol

      Believe it or not I’ve talked to “electricians” who’ve wired up campground pedestals incorrectly, and never used a meter to test anything.

  9. Larry

    I’ve had this happen to me a number of times and the campground host’s response was always nobody’s complained before. I use a progressive surge guard and it wouldn’t let the power through. One time the power box was new and had come wired incorrectly from the factory.

    1. Gary D Bogart

      Many campgrounds use a handyman for all their maintenance, and are not qualified to work on electrical situations. I have over the years run into hot skin or reversed polarity many many times.

      1. Mike Sokol

        In my day job of pro-audio, only the most experienced crew are put in charge of connecting up the generator, distributing power to the stage, and testing for hot-skin voltage on the guitar amps, etc… In fact if I’m on site I’m automatically assigned that duty since it’s so important to the health of the gear and safety of the crew and performers. But that’s not the case with campgrounds, it seems.

  10. John M

    I just had this happen to me. I plugged my 30 amp Surge Guard in and it showed all was good. Later that night my power went out. I checked the pedestal and it showed 132 volts. I notified the park and they had to have the city come out and adjust the voltage back down. I was glad to have the surge guard in place. .

    1. Mike Sokol

      This is exactly why you need an advanced surge protector. While the power might test correctly when you hook up, it can change at any time.

  11. Tom

    If you did not attend the great RVillage rally in Elkhart, you missed two very important seminars on RVs and electricity. Mike is an excellent and gifted speaker.
    As a result , I now have both a non-contact tester and a surge guard.

    1. Mike Sokol

      Tom, thanks for your kind words and attending my seminar in Elkhart. I really do like being in front of a crowd asking me all kinds of technical questions. Some of you may not know that I’m also an adjunct professor at a major conservatory teaching highly technical classes. And I’ve found that I learn a lot from my students, sometimes just by the questions they ask.

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