RV Electricity – Surge protector types and what they each do


By Mike Sokol

Hey Mike,
I’m looking at purchasing a surge protector for my RV and there seems to be a big difference in price. Many of them are in the $75 to $100 range, while others cost more than $300 or so. Does the extra money buy you more protection, or is that a bunch of advertising malarkey? —Steve S. 

Dear Steve,
That’s a great question.  Here’s a quick review of what surge protectors actually do.

#1  Absorb voltage spikes (surges) that result from nearby lightning strikes, power company line switching, and big electric motors in the area starting and stopping

#2  Provide visual indicators of pedestal outlet miswiring conditions including open-ground and reversed hot-neutral polarity

#3  Monitor over-voltage conditions and open-neutrals, and will shut down the power going to your RV to prevent damage to your appliances and electronics

#4  Monitor under-voltage conditions and shut down the power to protect your air conditioner and refrigerator compressors from over-current damage

#5  Display current usage on each leg of power from the pedestal

#6  Provide a restart delay in case of power interruption to prevent your air conditioner compressor from attempting a hot-start under head pressure

#7  Detect open-ground conditions which can allow hot-skin/contact-voltage conditions to occur that can be deadly to humans

All of these are good things, but not all surge protectors do all of them. So if you purchase a basic $100 surge protector (like the one on the left), then you get #1 and #2 above. It will protect your RV from voltage spikes (surges) and give you indicator lights that show basic polarity and ground connections. But it can’t disconnect your RV from power if something goes wrong in the middle of the night, and it can’t measure voltage or current usage.

On the other hand, the $300+ Advanced/EMS surge protectors (like the one on the right) can do #1 thru #7 listed above, so they not only protect your RV from voltage spikes (surges) due to nearby lightning strikes and power company switching, they also monitor the pedestal power for under and over-voltage conditions as well as test the ground connection.

And if something goes wrong with the power at any time, they include a big internal relay (called a contactor) which will go “clunk” and disconnect your RV from shore power. This function can save you many thousands of dollars especially if the 30-amp cordset from your RV is plugged into a TT-30 outlet that was accidentally miswired with 240-volts (I get emails about this happening every week). Read about it HERE.

So is a $100 basic surge protector a good investment? Yes it is, but it can’t protect your RV (and you) from 90% of the bad stuff out there. A $300 to $400 Intelligent/EMS surge protector is a much better investment because it can not only save your RV’s electrical system from damage, it can also detect open ground conditions and disconnect power to your RV in a fraction of a second. And that can save lives.

What do I recommend? While Progressive Industries and Surge Guard both make great products, I’ve got to give the edge to Surge Guard. I believe they have superior engineering in their advanced units, especially the 50-amp versions which can detect open neutral conditions inside of your RV. That’s right… It can find an open neutral on a 50-amp shore power connection downstream of itself even using a portable pole-mounted unit.

I can’t really recommend the Camco surge protectors since their design seems to be at least a few generations back. And there are a few other units being offered in both flavors from companies such as Hughes, but I’ve not had a chance to open one up yet and put it on the bench for testing so I can’t make a judgment one way or another. But as soon as they’ll send me one for testing I’ll have a go at deconstructing it.

Also, most manufacturers make install versions of their surge protectors, so you can mount them in your electrical compartment and run a wire to a remote display inside of your RV. That’s really handy and does eliminate one thing that can be stolen. But I like the portable units for testing campground pedestals before accepting the campsite.

Just remember that if you have electrical damage to your RV on a trip, you’ll not only lose the cost of replacing things like your air conditioner, microwave and refrigerator, you can also lose your entire vacation time. And you just can’t put a monetary price on lost time with your family.

Hope that explains the differences.

See you next week. In the meantime, let’s play safe out there….


Mike Sokol is an electrical and professional sound expert with 40+ 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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I unfortunately bought the Camco PD50 about 4 years ago. It was doing fine until last winter which was very rainy in Palm Springs where we spent February. When I went to use it again, it started going crazy making a loud buzzing sound when as soon as it tried to latch in. It wouldn’t work after that. When I got home, I laid a towel under it as I opened the case. Out poured about 1/2 cup of water. It claimed to be “water resistant” and was never submerged. It did hang out in the rain though. The water… Read more »


https://rvpower.southwire.com/products/surge-protection/50a-portable-model-34850-with-lcd-display/ Surge Guard Warranty: Limited Lifetime Warranty Information Any properly installed device that proves defective in normal use will be repaired or replaced at Southwire’s option provided the procedure as stated below is followed: 1. Contact Southwire Customer Support at 1-800-780-4324 to obtain a Return Materials Number. 2. Properly package returned unit. 3. Display Return Materials Number on outside of box. 4. Include Proof of Purchase, including date of purchase. 5. Supply full written description of the problem. 6. Specify your name, address, and daytime phone number. 7. Ship unit postage prepaid directly to: Return Materials Department Southwire Company, LLC… Read more »

S Greene

We have a Progressive that was 3 years old and failed this year. Progressive sent us a replacement immediately and didn’t even want the old one sent to them. Our Progressive has a metal ring that we run a cable lock through and around the pedestal. If we have to use our 50/30 converter, we run the same cable through the handle of that too. A lot, but not all, pedestals have the ability to lock with a small padlock. We know that any enterprising thief can break the padlock and/or cut the cable, but hopefully we are at least… Read more »


I think it nice that the Surge Guard 50A, can detect floating neutral inside the RV. However I am not finding a permanently mounted Surge Guard with a remote you can mount inside the RV. If this option is not available, this means if you elect goes off you must go outside and see if your Surge Guard is seeing an error or if the shore power is simply off. Also I am reluctant to hang a $300-$400 device on the RV Park power post when it can be easily and very quickly stolen. I had a 50A RV in… Read more »


Did research before purchasing our new 2017 travel trailer and bought a Hughes 30 amp Autoformer the same day. Expensive but gives us peace of mind. Has already been helpful once at a very old RV park. The best feature is watching the unit boost power to compensate low voltage from heavy power usage at the parks. It surprises me when walking around RV parks I see so many units with their power cords plugged directly into the pedestal. I’ve even been asked a few times what my Hughes unit was for. After a brief explanation they admit lack of… Read more »

Don Creamer

Remarkably timely article! While I admit that I’m the village idiot when it comes to electronics, there was enough in here to help with our purchase of out FIRST surge protector. Yes, we were at (I’ll say this quietly) Camping World today looking at what they have (not much) and purchased one that won’t plug into our Aliner. Taking it back and starting over, and your article will help. Thank you!


I must be tired… for a moment I panicked that I didn’t test the pedestal after I parked last night. Just remembered I’m not plugged in. *Face palm*

Phil Atterbery

Hello Mike. I am Ft in a 2004 Diesel Bounder 38N. It has an Intellitec 50A EMS 900 load shed system installed from the factory. From your experience, how reliable is this EMS? Mine has failed and I’m not real sure of the cause. I believe severe weather in the area may have caused the problem. My trusted local RV mobile tech trouble shot the problem to a failed EMS control board. The mode display panel has also gone nuts. Now it shows that I’m using my genset & the 50A park power at the same time. I now have… Read more »

Mike Sokol

Phil, from my discussions with several design engineers of EMS units, any of them can fail from too many lightning induced surges in the area. But you can add a second surge cheap protector at the pedestal to help protect your expensive surge protector in your EMS or Transfer Switch. So a $75 basic surge protector on the pole/pedestal can help save your $500 to $1,000 built in EMS/Protector. I have confirmed this with the product engineers, so no, the surge protectors in-line will not interfere with each other. This should be a full article, I think.

Phil Atterbery

TY for the response Mike. Chapter 2 of this story goes like this.
The new EMS board & display panel arrived from the vendor. Our tech installed them with no issues. Now we have a new problem. The display panel has become erratic. The 6 second video is on our FB page. It appears to be possessed. And, the original problem still exists. BTW, I’ve been using a Surge Guard 50a for several years and it was in use during this episode. Now we’re waiting on the engineer at H&H (the vendor) in FL to figure it out.


Progressive Industries offers free replacement of a blown unit. Surge Guard does not. So if ur Progressive unit “sacrifices” it self, u don’t have to spend another $350+ to replace it. That is the kind of company I like to work with.

Mike Sokol

I think that Surge Guard has extended their warranty to match Progressive. But I’ll ask them to be sure.


What’s cheaper a good quality EMS or replacing circuit boards in AC units,refrigerators ,water heats and furnaces? After using a Progressive 50 amp EMS for several years I have had numerous times at older RV parks where the pedestal was miswired or a ground was missing.CYA and invest in a good EMS.And NEVER plug any cord into a campground or RV park pedestal without turning off the pedestal breakers first.