RV Electricity – Low Voltage Report

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Dear Readers,
Since the Stray Voltage Patrol is already generating some interesting reports, I’m going to use one of them to discuss the problem of low voltage in campgrounds, especially state owned and operated parks. Here’s what part of an SVP report looks like: 


What did you discover? Pedestal voltage measured too low (below 104 volts)

Describe what you discovered:  Voltage 117 with about 10% of sites filled, but got down to 93 Volts with 85% of sites filled. Very time-of-day dependent as campers turned on AC or cooking loads, but voltage in the 90s is terrible sag!

Number of campsites tested: 4

Name of campground: Willow Bay Recreation Area

Campground owner name: PA State Park


What are the basics? Well, it’s simple. The electrical distribution grid powering this campground wasn’t designed with enough capacity to provide a full campground with stable electrical power. There’s a variety of specific design flaws that could be suspect, but I’m guessing it might be the main power company line transformers being of insufficient size to power the entire campground when everyone is running their air conditioners at the same time. While the power company can, in fact, change the taps on the incoming transformers to boost the voltage a bit, that 117 volts is actually very close to the NEC (National Electrical Code) design specs. In fact, I’ll bet that if you turned off EVERYTHING in the park, the voltage would bump up to 120 volts. 

So is this bad? In a word, yes. Now, it’s not likely to cause a hot-skin/stray-voltage, nor is it likely to start a fire in your RV. However, it’s very likely to cause many RV air conditioners to either not start or even burn out. Residential refrigerators in the RVs will also have the same sort of issues. Compressor motors tend to be very amperage hungry during startup, and rely on a stable 120-volt power source to get up to speed quickly. I’ve often said that anything below 100 volts can be damaging, and here we have an example of 93 volts. So, use at your own risk since I don’t think the state park is going to pay for your new air conditioner or refrigerator. 

Is there a quick fix? Now the inevitable questions about Hughes AutoFormers will start coming in. And while an auto-boost transformer could increase the voltage at a single campsite, it will be stealing even more voltage from the campsites around it. Don’t believe the marketing hype on the Hughes website. A booster transformer can’t restore full wattage (power) to a campsite. It can only restore full voltage by essentially stealing it from other campsite pedestals in the area. That’s why the 2020 version of the National Electrical Code will likely prohibit booster transformers in campgrounds. 

Why does this happen? It’s also possible that the branch circuits in the park weren’t designed with heavy enough electric wiring for the length of run between campsites. For example, if you run a 10-gauge/30-amp extension cord 25 feet you might experience 2 volts of drop under full load. But run a 10-gauge branch circuit 200 feet (8 times as far), and the voltage drop under full load will be increased to perhaps 8 x 2 volts = 16 volts. Starting with 120 volts at the distribution point, we can subtract that 16-volt drop and end up with only 104 volts at the pedestal. And that’s just for ONE campsite that’s running their air conditioner. Multiply that by dozens or even hundreds of RV air conditioners at a campground, and you’ll see just how and why 93 volts is possible. Yikes!

Is this an expensive fix? Well, it sounds like either the incoming power company transformers are out of capacity, so the power company will need to upgrade to larger KVA units, or the underground wiring is too small for the lengths of run they have to do, so the old wiring will need to be dug up and rerun with heavier gauge copper wire. Both options are expensive, which will have to be passed on to the consumer, either by taxes and increased registration fees for the state-run parks, or increased day rates for privately owned campgrounds. Running new electrical distribution isn’t cheap, but it’s probably the only way many parks like this can get their power up to acceptable levels.   

Please answer in the comment section below about any state parks or private campgrounds you’ve found that have low voltage. It appears to be a major problem in many campgrounds. 

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.

##RVT862

 

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George Daunis
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George Daunis

Mike, I was at a park in Mass this Fourth of July during a heat wave in the high 90’s. Power was typically running from high 90 volts to 105 volts during the days with all the AC’s running full blast. The campground owner passed out a flyer instructing people to switch their refers and water heaters to propane if possible. Also to raise the thermostat a couple of degrees higher. All good ideas, but my question is why could you not just start your generator and run off the gen until power recovers as night approaches. If I did… Read more »

Dennis Foley
Guest
Dennis Foley

Soo Locks Campground in Sault St Marie, the voltage went low enough at night to have my EMS shut off the power quite a few times, then turn it right back on. The voltage hovered around 104. It’s cold there so I assume a lot of people were running heaters, but the park was not full. Nice spot and people by the way!

Frank
Guest
Frank

Mitchell RV Resort, Perrin Texas. Site 63, reversed polarity on 30 amp plug detected by our Progressive Industries EMS. Had been previously reported according to park management but had not been corrected as of 9/6/18.

Mike Sokol
Editor

That’s one of the easiest fixes to make, since you just have to swap two wires in the pedestal. It appears they’re not concerned about mis-wiring issues, or possibly they don’t believe you. I would tend to believe your EMS.

Cynthia Steiner
Guest
Cynthia Steiner

We had to leave our 4 night stay at Yosemite after only one night due to the fire this summer. It forced us to find another campground for 3 nights before we got to the next reserved campground spot. We were on 7 week trip from Indiana to California and back. We got a spot at Club Royal Oak in Kingsburg, CA. Our inside volt meter showed we were only pulling in 94 volts, but the campground maintenance man insisted he checked the electric hook up and it was fine. Our air shut off and temps were in low 100’s.… Read more »

Mike Sokol
Editor

“Our inside volt meter showed we were only pulling in 94 volts, but the campground maintenance man insisted he checked the electric hook up and it was fine.” They all say the power is fine, even when your voltmeter says it’s just north of 90 volts. What he really should say is there’s nothing he can do about it. At least that would be the truth. As I’ve noted earlier, what’s required for a fix is an upgrade of the entire power distribution infrastructure. Kind of like when a new highway has to be built to accommodate a growing city.… Read more »

William Maginot
Guest
William Maginot

We have been on the road since July 6th and have stayed at 7 different campgrounds (including the FMCA rally in Gillette) and all but one had good power and no faults. The campground in Ruidoso, NM (Riverside RV Park) had low voltage. I tried to work with them, but nothing got accomplished. The L1 voltage varied from 118v to 102v. The L2 voltage remained fairly constant, 120v to 118v. The row we were on had a mixture of 30a & 50a. I had the opportunity to look at the breaker boxes when one of the sites lost power. I… Read more »

Mike Sokol
Guest
Mike Sokol

I’ve seen a number of campgrounds that didn’t alternate the 30-amp outlet between the two legs on each pedestal. What that does is allows a bunch of 30-amp RVs to pull down one side of the 50-amp outlets, just as you experienced. The fix is pretty simple, alternate the 30-amp connection in each pedestal on that branch circuit between L1 and L2. That will balance the current load from 30-amp RVs between the two hot legs. Better for everyone that way. Unfortunately, not a lot of casual campground technicians or even licensed electricians understand this simple load balancing trick.

Mike Sokol
Guest
Mike Sokol

“He professed he knew something about electricity, but did not even know how to read my meter.” Yeah, I don’t think so. Just like a DJ always carries their own headphones, any electrical maintenance tech should carry their own meter, and be able to figure most any other meter in a pinch. Before you can understand or work on anything electrical, you have to understand how to meter it. I’m currently slammed with getting all my other RVelectricity articles and videos done and published, but very soon I’ll begin shooting videos on multi-meter operation. I think it’s a very important… Read more »

Al
Guest
Al

I’ve had my EMS shut down our camper on a couple of visits to the Kentucky Horse Park, Lexington KY. 30 amp circuit was experiencing problems. First time, I visited the office and attendant was selling a dog bone to person ahead of me, saying they could return it when they left the park. Said the 50 amp circuit was OK. I went back and put in my 50-30 dog bone. No further issues.

Mike Sokol
Editor

That’s likely because the 50-amp outlet on the pedestal wasn’t as badly worn, so stepping down from 50-amps to 30-amps is a reasonable solution. Now, you still can’t pull any more than 30-amps from your RV since your RV’s internal circuit breaker panel should have a 30-amp master breaker. But if there’s a better plug connection, then that normally translates into less voltage drop at the plug and more stable power.

David
Guest
David

Had similar problem there on site 174 two yrs ago. Smoke and sparks flew when I plugged in 50 amp and flipped the breaker on. Immediately turned off and called the office. Maintenance worked on and declared OK. Turned on air and went to nearby Georgetown for supplies. Returned two hrs later and no air. Maintenance came again and replaced a breaker. Declared OK. Fired up air again but wouldn’t seem to cool down. Found rear air blowing warm. Mobile tech diagnosed a\c unit shot. Did not know enough about electrical issues to question what may have been the cause.… Read more »

Mike Sokol
Editor

I would say that if smoke and sparks fly from any pedestal, you DO NOT want to accept a quick fix from the campground maintenance staff. While there are likely exceptions, I’ve found that most campground repair crews really don’t have any idea how to troubleshoot electrical problems or test a pedestal for proper operation after any repair. I’ve offered my training services to a number or campground franchise operations, but they’re not interested. However, if enough of you ask the campground associations to provide training for their associate members, maybe that will get the ball rolling. Chuck and I… Read more »

Nancy Michaels
Guest
Nancy Michaels

Mike, back in July we parked in an otherwise unoccupied hook up area in Thedford, NE at the Arrowhead Motel. Was just going to be a short overnight stay. After plugging into a 50 amp set up, our air conditioner did not work (95 degrees out) and then smoke rolled out of the open compartment where our DVR and dish receiver stay. We pulled the TV component out immediately and unplugged from the main hook up. We later found that this mis-wiring had fried our electronic components – dish receiver, convection microwave and central vac. Expensive and time consuming repairs… Read more »

Mike Sokol
Editor

Sounds like an open neutral allowed the 120/120-volt split from the 240-volt service to divide unevenly. So one of the incoming poles could have dipped to maybe 40 volts, and the other pole would rise to 200 volts or so. As you found out, most appliances won’t survive that level of voltage overload and will quickly burn out. Yes, EVERYONE needs an intelligent/ems surge protector that will disconnect your RV from dangerous voltages and open grounds.

Terry O'Keefe
Guest
Terry O'Keefe

Just a comment about wire size loading and the age of a given campground,or even house. As an electric co. troubleman,I have seen all kinds of voltage problems. What people have to remember,is that in the no so distant past,there were homes with 15 or 20 amp services! Then they went to 30,60,100,150,now 200 amp services! Used to be that if you had a tv in your camper you were the odd one in the group,now my class A has 4,and electric hot water,microwave residential refrigerator and such.Campgrounds are updating as they can afford to, but are under no obligation… Read more »

Mike Sokol
Guest
Mike Sokol

It will likely cost even a small, older campground a few hundred thousand dollars to upgrade the wiring to accommodate modern, power hungry RVs. And as you and I both noted, SOMEBODY’s got to pay for it. The campground owners won’t do it themselves unless they can charge an increased rate. And unless this is a state park there’s no tax dollars to supplement the upgrade. If it IS a state park, then the limited government funds are spread out over other infrastructure needs such as roads. There’s just no simple solutions, so the best we can do is figure… Read more »

Jeremy
Guest
Jeremy

We had the opposite happen on labor day weekend. We stayed at Newberry Campground in the U.P. of Michigan and our Progressive EMS shut off 3 times during a 2 night stay due to HIGH voltage.

Curtis King
Guest
Curtis King

For Jeremy…….was that the old KOA in Newberry or Kritters? I have reservations for Kritters end of September. Thanks
Curtis

Jeremy
Guest
Jeremy

Curtis, it was the old KOA.

Mike Sokol
Guest
Mike Sokol

I’ve seen this voltage rise caused by an undersized neutral on the incoming feed from the power company. One of the reasons for this is that 3-phase power distribution often plans for a certain amount of balanced current between the 3 phases. And many 3-phase systems for factories primarily fed 3-phase electric motors which don’t need a neutral at all. So the designers of many 3-phase power distribution systems could get away with smaller neutrals, thus saving some money on the wiring. However, RVs are hooked up single-phase, so if there’s a huge power load on one or two of… Read more »

Wolfe
Guest
Wolfe

“Inevitable” is right… I was going to ask about line conditioners as a solution (in general; I haven’t used an Autoformer specifically). I wonder about the “stealing” characterization and NEC advisory, though, because I would think you’re still limited by the pedestal’s breaker amperage, no? If line conditioning works like a variable tap transformer, you could turn 80V@30A input into 120V@20A out, but the breaker would pop if you tried to draw more wattage out at 120V (?). With Ohm’s Law, you’re using your (now) 2400W “share” at 120V without burning out your equipment, but you still can’t pull “extra”… Read more »

Mike Sokol
Guest
Mike Sokol

To clarify my point about booster transformers stealing voltage from other campsites, what happens is the transformer will trade volts for amperes. That is, if the voltage at the pedestal is 20% down, it will draw additional amperage from the pedestal to make up that voltage. And since that amperage draw is downstream of the pedestal circuit breaker, you will never get full wattage. So instead of 30 amps available at 120 volts (3,600 watts) from a properly sized distribution system, you might only have 24 amps at 120 volts (2,880 watts) available. Since 30 amp shore power is often… Read more »

Mike Sokol
Guest
Mike Sokol

How did this pass inspection? Of course, there could not have been any kind of electrical inspection to allow this to occur. It would be interesting to find out who the AHJ (Authority Having Jurisdiction) is for the county. I’ll make a few calls next week and see if I can find out who’s in charge of this.

Doug
Guest
Doug

Colorado River Thousand Trails, Columbus TX along the river sites.

Old undersized aluminum wiring. After a flood they put in new 50 amp pedestals to replace the previous 30 amp pedestals- without upgrading the wiring run.

Even when sites are less than 50 percent occupied, voltage sags below 104 volts many times per day and night.