RV Electricity – Can I add a second surge protector?

Dear Mike,
Thanks for your No Shock Zone articles! I am a big fan. I have a technical question based on an issue raised by a fellow camper. I have a Progressive Industries Surge Protector (EMS-HW50C Portable Electrical Management System) on my 50A diesel pusher, and I also use a Camco Dogbone RV Circuit Analyzer with integrated surge protection and fault indication (125/250V 50M/50F Amp) for use at the pedestals.

I got the Camco circuit analyzer primarily as a way to monitor the quality and safety of the power of the pedestal, but the unit also provides surge protection. I’ve had a fellow camper suggest that putting a second surge protector on the pedestal is a bad idea, since I already have a surge protector on the rig. Is putting a second surge protector at the pedestal okay, or a bad idea? —Michael C.
Dear Michael,
Actually, it’s a very GOOD idea. You’re adding additional joules of surge protection at the pedestal, which will also help keep lightning spikes out of the inside of your RV. Plus you can use the portable surge protector to do a preliminary check of the campground power BEFORE you accept the campsite….
However, for any of you who don’t have an intelligent/EMS surge protector like your EMS-HW50C which checks for high and low voltage as well as open grounds, let me suggest that instead of something like a basic Camco circuit analyzer, you get an intelligent surge protector for the pedestal such as the Surge Guard 34950 (50-amp) or 34930 (30-amp) unit. This will not only increase the joules of spike protection due to the extra MOV devices, it will add downstream open-neutral testing and shutdown on the 50-amp version. 
As a power precheck before-making-camp procedure (before you pull in your RV, level it and connect up the water, etc.), I’m recommending that everyone first use a NCVT (Non Contact Voltage Tester) such as  the Southwire 40116N to check the campsite pedestal to make sure the box itself doesn’t have a stray voltage. (Yes, I’ve had several emails in the last month with this really dangerous condition.)
If the pedestal does have a stray voltage, DO NOT accept the campsite and move on. If it’s OK (shows no voltage on the outside of the pedestal box), then plug in your intelligent surge protector and check the outlet for open ground, reversed polarity and reasonable voltages (102 to 132 is considered acceptable, but I think a range of 105 to 128 is safer). If the voltage is a little low you might be OK using this pedestal as long as you don’t run hot plates and air conditioners. And if the polarity is reversed you’re still probably safe, but the campground should be notified and repair the problem quickly.
However, if the outlet ground is open, then DO NOT accept the campsite and ask to move to another one after notifying the campground of the problem. Bypassing your surge protector on a pedestal that has an open or hot ground is putting your life and the lives of anyone else touching your RV in danger, so please take this seriously. 
Next week I’m going to post a cleaning procedure for any campground pedestals that were in the flood path of Hurricane Florence. No, you can’t just wait for the outlet to dry out and plug in. Any pedestal that’s been underwater needs to be properly cleaned and tested before being put back into service. 

Let’s play safe out there….


Mike Sokol is an electrical and professional sound expert with 40 years in the industry. Visit NoShockZone.org for more electrical safety tips. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.



8 Thoughts to “RV Electricity – Can I add a second surge protector?”

  1. Ernie Russell

    Mike, your recent article on adding a second surge protector made me think of my trip a few weeks ago. We pulled into rural Maine late one evening. As an aside, we started RV ing in 2011 with a 30 amp trailer. For this I bought thought was a state of the art SurgeGuard 34830. In 2015 we moved to a 50 amp trailer for which I bought what I thought was a state of the art SurgeGuard 34850.

    Back to Maine. After the usual mix ups at the CG, we ended up in a 30A site so I plugged in my 34830 plugged the trailer in and powered up the pole, knowing that Surge Guard had my back. Nothing! Upon inspection I had a red light and the message “Reverse Polarity”. No problem. I told the manager and he came out and reversed the polarity at 9:30pm, while I watched. Plugged the Surge Guard in again and once again no power. This time low voltage. We changed sites and had power.

    The next day we drove to Lubec for a week. This redefines rural. 4 1/2 days later our 12V dies. With No help available I called my mobile service guy in GA and after my description he thinks my batteries are dead. I carry a charger and he was right. Now to find out why. No blown fuses or circuit breakers, so I call WFCO for help. They advised there are 2 fuses on the converter that protect against Reverse Polarity. Where have I heard that before?

    Problem solved, but why? I then re-read my info sheets from the Surge Guards. Turns out it is the same sheet for both products. And there it says that the 50 amp unit blocks reverse polarity and the 30 amp passes it, but with a red light. Thanks a bunch!
    On the way home I stopped at Hershey and talked to Surge Guard. Typically, they had a bunch of new hires who didn’t know any history but assured me that the new ones don’t do that. And I can’t solve my concerns for a 2nd $800 investment in 2 new units.

    So, all this to say that in your article you mention that we are probably safe with reverse polarity. Of course you are right, but your readers need to plug their protection into the pole and let it go through the countdown before plugging their rig into the protection.

    Thanks for all your work and writing on our behalf.

  2. steve roland

    I asked you a while back about having more than one ground rod at a residence and you were going to address it. I think I missed your assessment. Could you direct me to your response? I can give more details of my specific setup if it helps.

    1. I’m going to move these specific electrical questions over to the forum. Are you signed up for it already? If not, it only takes a minute and the signup/login process seems to be working well.

  3. J anne

    I have had damage to electronic equipment from reverse polarity so I don’t think the probably be okay statement is wise in your article.yes fine for many trailers etc but not for all! I learned the hard way!

    1. Any PROPERLY wired RV electrical system won’t care about reversed polarity on the incoming AC power. Of course, reverse polarity of the 12 volt DC power will result in catastrophic failure of nearly every 12 volt system and connection. So I’m curious about what happened to your electronic equipment. Can you elaborate with more information on the failure? Email me at mike@rvtravel.com with more information, please.

  4. John Snell

    The youtube videos regarding checking pedestals doesn’t use a non touch stray voltage checker, which I have. Do you check the outside of the pedestal before you plug in as you would the outside of your rv after you plug in.?

    1. Yes, check the outside of the pedestal first. I’ve had several reports lately of the pedestal box itself not being properly “grounded” and they have 120 volts on them. So touching the pedestal box while standing on wet ground could be deadly. Just turn on your NCVT and make sure its battery is good with the indicator light blinking (or whatever). Then bring the NCVT up to the outside of the box until you make contact with it. If the box itself has a stray voltage your NCVT should light up from inches or even a foot away.

  5. Kirk Locus, Canandaigua, NY

    Another great article Mike. Thank you for all of these!

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