Boosting low campground voltage

Correct campground voltage

Correct campground voltage is very important. If you operate your RV on low campground voltage you will damage your RV. You can fix low campground voltage. For my RV I have decided to install a Hughes Autoformer to make the correct campground voltage every time I plug in the RV.

It took nearly two years to write the article about correct campground voltage. Here is a quick timeline.

It all started when we got our new to us 2008 Tiffin Bus. Unlike our previous RV, this one is power-hungry mostly because it has a residential refrigerator. Here is a link to the story. Our New RV

Our air conditioner failed

About three weeks later our air conditioner failed and we had to replace it. During the conversation with the technician, he mentioned that they fail due to prolonged operation and getting too hot. I thought it was somewhat amusing because you don’t run the air conditioner when it is cold outside. This was the first time I heard of low voltage operation creating more heat. At the time I didn’t know you could correct the campground voltage.

Power-hungry RV

During the first year of owning our power-hungry RV, I started occasionally hearing our air conditioners slow down and they were not putting out as much cold air. This was because of low campground voltage but I didn’t know it at the time.

I became suspicious when I installed a full-time voltmeter to monitor the problem and could occasionally see the brownout voltages. When this happened, the air conditioner would slow down. The low voltage slowdown never happened when we were operating our RV either from our generator or from solar but only when we were plugged in at the campground. Although you can’t call it correct campground voltage both my inverter and generator put out the correct voltage.

Hughes Autoformer

So I got a Hughes Autoformer to correct the campground voltage back to voltage within ideal limits (this is the grey box in the picture above). I didn’t want to replace air conditioners due to premature failure. They are expensive and because of Covid-related supply chain issues, they are hard to get.

About six months ago (about six months after I installed the Hughes Autoformer) I wrote the article below about correct campground voltage and offered it to FMCA to publish.

So this article was picked up in its original form by the Family Motor Coach Association Family RVing magazine and published in the May 2022 edition.

The difference between this post and the FMCA published article is that I am able to include a few more words and some more pictures. Extra information in this post can be identified by the stars. (***) The other difference is that not all readers of this blog are members of FMCA. Typically articles like this only appear in the FMCA magazine, but since I wrote it, I can share it here.

We were not compensated by FMCA, Hughes, or anyone else for our article.

About FMCA

FMCA is a wonderful RV club. We are proud to be members. Family RVing is their first-class RV print magazine. A couple of years ago we were lucky to be chosen for the very first non-professional cover photo. Here is a link to our article about the cover photo. We made the cover photo

If you are an RVer, I endorse membership in the FMCA RV club. Here is a link to the FMCA website. FMCA

Boosting low campground voltage

Article by Scott Fox FMCA Family RVing Magazine, May 2022

Voltage spikes receive considerable attention, but low voltage also can cause damage. The Hughes Autoformer is designed to combat that issue.

Campground voltage can be very low – Why is this a problem?

What is the ideal campground voltage? If the campground voltage is low, can you boost your voltage? Why would you want to boost your voltage? What is an RV Hughes Autoformer? Do I need one? How does it work?

We have installed a Hughes Autoformer voltage booster on our RV, and after researching and using the product, I’d like to answer the above questions and explain why you might consider adding one to your RV as well. 

*** Picture of my full-time voltmeter showing low voltage. ***
 Low Voltage shown on our Hughes voltmeter.
***This voltmeter, also from Hughes is at the front inside our RV… We keep it installed all the time. When the voltage is in the acceptable range the meter is green but turns red when the voltage is low. This picture showed low campground voltage in North Carolina before I had our Autoformer installed. Low voltage can damage your RV installing this voltmeter inspired us to install the Autoformer since then we have been boosting our RV voltage every time we plug in the RV. ***

A Hughes Autoformer plugs into the electrical pedestal at the campground, and then the RV power cord plugs into the Autoformer. Because I wanted to keep the Autoformer inside the RV, I mounted it in one of our storage compartments between the power cord and RV – rather than between the electrical pedestal and the cord. To do this, I cut the power cord inside the RV and hardwired the Autoformer into the cord before the automatic transfer switch. 

In the unlikely event that you never plan to plug into a campground electrical system, you do not need an automatic transfer switch or a Hughes Autoformer voltage booster. But if you use campground electricity, this device can be a valuable addition to your RV.

What is the ideal campground voltage? 

*** What is the correct campground voltage? Is it 110-volts or 120-volts? ***

The voltage delivered to your house (or RV) is ideally 120-volts.  (In the U.S. we use a split system of two 120-volt wires to create the possibility of 240-volts.)  Acceptable voltage is a range between 110-volts and 120-volts.  Some appliances can function at voltages down to 108-volts. Voltages up to 132v typically will not cause damage. Most appliances require a minimum of 110-volts and ideally will be 120-volts.

*** Picture of the inside of my 50-amp electrical plug. ***
Installing the autoformer required making some new short 50 amp power cords.
*** To install our Autoformer and EMS I had to make two short 50-amp “extension cords”. This is because our Autoformer is meant to be plugged into the campground pedestal. To eliminate the possibility of water entry and possible theft I installed our Autoformer inside the electrical compartment of our RV. ***

A low voltage situation exists below 110-volts and is considered a “brownout” situation. All lower voltages cause higher amperage draws for motors. The amount of effort (load) required by the motor doesn’t change.

Think of the load (the device you want to operate electrically) as a weight on the end of a lever. If the lever is long (higher correct voltage) then the weight will be easy to lift with a given force (current). If however, the lever is short (low voltage) then the load will require more force to lift (higher current). 

Loads do not change when the voltage changes. Assuming the voltage remains low, the current required to operate the load increases. The problem is that increased current causes increased heat associated with the increased current.

Voltage, amperage, and watts

The relationship between voltage, current, and watts is simple. The one thing to remember when discussing electricity use is that loads (watts required) don’t change. A 1500-watt load requires 1500 watts (of energy) to run. The two variables are voltage (potential energy) and amperage (current). If one goes up, the other can go down and still operate the same load.  To run a 1500-watt load at 120-volts you need 12.5 amps of current.  To run a 1500-watt load at 110-volts you need 13.63 amps of current. The issue associated with using extra current is that extra current creates extra heat. Extra heat leads to accelerated wear.

Current and resistance

As current increases, resistance to the flow of the current increases. As current increases in a river, resistance creates erosion on the banks of the river.  In terms of electricity, resistance creates heat both in the wires and in the devices that the current is powering. In motors increased heat leads to decreased efficiency and decreased lifespan. Increased voltage decreases current and decreases heat due to the decreased resistance.

*** Picture of the inside of my transfer switch. ***
Inside the transfer switch. Article correct campground voltage
*** After making the short 50-amp power cords I had to remove the long power cord connections from the transfer switch so that I could replace them with one of my new short cords from my Autoformer to the transfer switch. The standard long power cord plugs into the Autoformer and the output of the Autoformer plugs into the transfer switch. This involved the four large wires (green, black, red, white) in the upper left of the picture. As a side note, you should open your transfer switch at least once a year and make sure that every screw holding the wires is properly tightened. ***

***Can you correct low campground voltage? yes, you can ***

More than a transformer

The primary component of a Hughes Autoformer voltage booster is a transformer. Almost all transformers are used either to step up voltages or step down voltages. The power company uses transformers to change the voltage before it enters your house. Without transformers, we would not have an effective electrical system anywhere in the world.

The Hughes Autoformer voltage booster is a special type of smart step-up transformer. The voltage booster takes a lower voltage and increases it, sacrificing a little of the available current that is used to power the device.  This potential current loss is not significant. The greater efficiency associated with operating at the correct voltage makes up for most of the current loss.

Not an autotransformer

The Autoformer is not an autotransformer. It has multiple windings, whereas an autotransformer has a single winding with multiple taps that allow for different voltages.  Without multiple windings, any electrical failure in an autotransformer can be a significant safety issue.

*** A transformer will provide electrical isolation between its windings. An Autoformer does the same thing the same way. An autotransformer does not provide electrical isolation. The names are almost the same. It is important not to confuse the two words or think that the devices are the same thing. An autotransformer is not an acceptable way to correct campground voltage. ***

An autotransformer, with its single winding, does not provide for isolation between source and output. Thus, a failure in an autotransformer can result in full input voltage being delivered to the output when not needed, resulting in undesired high voltages.

*** Picture of my electrical compartment. The transfer switch is at the top left. ***
Autoformer and power Watchdog EMS installed inside my electrical compartment. Articlecorrect campground voltage
*** Autoformer and Power Watchdog EMS were installed inside my electrical compartment. The correct order for installation is power pedestal followed by Hughes Autoformer then Power Watchdog EMS then transfer switch. Of course, all RVs are different and if you are not comfortable or don’t have room to put the Autoformer and Power Watchdog inside the RV then Hughes includes a small cable lock with the Autoformer. ***

As a multiple-winding, computer-controlled, smart transformer, the Hughes Autoformer is designed to provide additional levels of protection.

The output on the Hughes Autoformer adjusts by load demand and input voltage. When no extra voltage is needed, the voltage is boosted by 2 percent. When a larger boost in voltage is required, the extra windings on the output side of the transformer will engage and step the voltage up to or close to the desired 120-volt output (10 percent).

Why do I need it?

As the number of RVs in a campground increases, the additional occupancy increases the amount of electricity required from the campground electrical system. Each additional RV in the campground adds to the load. And since most campgrounds were not designed for the new, more power-hungry RVs, their electrical systems may not be sufficient to accommodate the increased number of users. When this happens, voltages drop and can endanger every RV in the campground.

*** If the campground voltage is low, appliances will run at the lower voltages by drawing more current. This is because the load required to run the appliance doesn’t change. When this happens the extra current will create undesired extra heat in the circuit. Extra heat leads to extra wear on components and will lead to failure.***

When the electrical grid at the campground is perfect, you don’t need a Hughes Autoformer voltage booster. The problem is that in RV parks the electrical grid is undersized (for the number of RVs at the park) and not perfect. When an RV park is busy, let us say on a Saturday afternoon in the summer, there will be a large number of RVs all drawing power from the RV park electrical system, running air conditioners, and other electrical appliances.

*** Picture of the Autoformer installed inside my electrical compartment. ***
My Hughes Autoformer installed inside my electrical compartment Article correct campground voltage
*** Autoformer installed inside my electrical compartment. The LED lights on the front identify any fault conditions that may exist with the campground electrical system before the electricity enters the RV. ***

When this happens, the voltage at the park decreases, and because the voltage coming into each RV is now lower and the amperage used by each RV increases. As amperage increases, so does heat. As the voltage decreases each RV in the park is more and more at risk from low voltage damage. Each RV will use more current to accomplish the same task and each additional RV will add to the problem. Every inductive load (air conditioner) will get hotter due to the increase in current caused by insufficient voltage.

Each RV that experiences low voltage will suffer electrical damage caused by the extra heat. This is not a club you want to join. Hence, it makes sense to boost your voltage and avoid the issue.

How does it correct for low voltage?

A Hughes Autoformer voltage booster corrects for the lower-than-desired voltage at the campground pedestal and increases the voltage inside the RV to protect it from low-voltage operation. The Hughes Autoformer voltage booster corrects the RV park low voltage back to a more ideal grid voltage inside the RV.

Anytime the Hughes Autoformer voltage booster is plugged in, the voltages is boosted by a minimum of 2%. This will take an ideal input voltage of 120-volts to 122.4 volts making it slightly better. When the voltage drops to less than the acceptable 109-volts an extra 10% boost will correct this voltage back to nearly ideal 119.9-volts.

Even if the voltage drops to a dangerously low voltage of say 96-volts then the Hughes Autoformer voltage booster will correct this by the same 10% back to 105.6-volts. As the voltage drops to these critically low levels, every RV in the campground will start to suffer damage.  RVs equipped with electrical management systems (explained later in this article) will trigger their emergency power off relays and drop from the campground electrical distribution system.

What is the risk of low voltage?

During low-voltage operations, appliances such as air conditioners and refrigerators will run slower, get hotter than they normally would, and ultimately fail. This is because correcting for low voltage results in the electrical current increases, thus increasing the heat. Even if the appliance does not fail right away, the extra heat accelerates wear. This results in less effective operation. The accelerated wear increases the load and causes an even higher amperage draw, thus creating even more heat. All of this can be avoided with the correct voltage. Heat — especially excessive heat — is the enemy of electrical devices such as compressor motors in air conditioners. 

Does it steal electricity from other campers?

Some people believe Hughes Autoformer owners use more than their share of electricity in a campground. They noticed that an RV with a Hughes Autoformer did not trip circuit breakers when their RV did. Thus, they concluded that the Autoformer allowed the RV to use extra electricity. Rather than using more electricity, the RV equipped with an Autoformer uses the electricity correctly, as designed. If you have a 30-amp RV on a 30-amp circuit, your limit is still 30-amps. The question is then, “How do you use the 30-amps?”

Do I need it on a 50-amp RV?

An RV with 50-amp electrical service can experience the same issues as a 30-amp RV. If the input voltage is low, it does not matter whether you have a 30-amp RV or a 50-amp RV. The company produces both 30-amp and 50-amp versions of the Autoformer.

Why is it more critical for a 30-amp RV?

That said, 30-amp RVs have more potential for electrical issues. This is because of the size of the wire in a 30-amp RV power cord. A 30-amp power cord typically has 10-gauge wires. My 50-amp power cord has 6-gauge wires. Each 6-gauge wire carries a maximum of 55 amps. Cord length also plays into this variable. Longer cords, and thinner wire = more resistance.

*** Picture of a 30-amp Autoformer.***
30 amp Autoformer Article correct campground voltage
*** 30-amp Autoformer (picture provided by Hughes Autoformer). ***

Fault Detection and Reporting

The Hughes Autoformer voltage booster will also detect faults in campground electrical systems. The display lights will reveal an open ground connection, an incorrectly wired neutral connection, and a reverse polarity condition. Any of these faults can damage an RV’s electrical system and appliances. The Autoformer includes both a surge protector and some functions — but not all fault detections — of an electrical management system (EMS).

What is an EMS?

An EMS is an electrical device that includes a surge protector and a relay that shuts off power to an RV when a damaging condition exists, such as low voltage. Conversely, the Autoformer corrects for low voltage instead of shutting off the power. Its fault detection feature reports malfunctions. The Hughes Autoformer does not replace an EMS but rather augments it.

Surge Protection

The Hughes Autoformer’s voltage booster includes a built-in surge protector with indicator lights that identify if the unit has been hit by too many surges and can no longer provide protection. Not all surge protectors have an emergency power-off feature. Typically, this feature is part of an EMS that includes a surge protector.

Why not just use an EMS for voltage drops?

This is a fine idea for a temporary voltage drop. But do you really want to live without your air conditioner when what you really need is a boost in voltage to correct for an inadequate RV park electrical system?

Is an EMS still necessary?

I still have an EMS installed between the Autoformer and the automatic transfer switch on my RV. When a voltage boost is necessary, the Autoformer will perform this task before the EMS shuts down the power. If the Autoformer is unable to boost the voltage sufficiently, the EMS will protect my RV from issues not corrected by the Autoformer.


In my opinion, the Hughes Autoformer provides the highest level of correction and protection for my RV electrical system. I am glad I installed it.

About the author — Scott Fox is a retired Navy pilot and flight instructor who has been traveling full-time in his RV for almost four years and camping for more than 50 years. Scott’s blog,, shares stories and explains some of the more technical aspects of RVing. 

That is it, the entire article about correcting campground voltage.

I want to thank the professional editors at FMCA for improving and helping me with the re-writes. Correct campground voltage is going to be a bigger problem as campground stays are being more popular. I suggest that at a minimum every RV have a robust EMS and that you test the electrical system before you plug in your RV.

Please subscribe and join us on our journey

We will add you to our email list and send you updates about once a week. Here is a link. Subscribe

This link is to the 50-amp Autoformer that we are using to get the correct campground voltage.

Hughes Autoformer

We also use the Hughes 50-amp Power Watchdog Smart Surge Protector EMS and are very happy with its performance but this article was about the Autoformer.

50 amp Power Watchdog Smart Surge Protector

This is the Hughes voltmeter we have installed in our RV. Really on a 50 amp RV, you should have two of these voltmeters installed one on each 50-amp circuit.

Dual Color Digital Voltmeter

The links above are freely provided. We do not get income or commissions. No, we don’t make paid endorsements.  We don’t make recommendations but instead, we will tell you what we like (or dislike).

Just like the rest of the stuff on our blog, we hope that it helps you. We are so happy you find these articles worth your time.

36 thoughts on “Correct campground voltage”

  1. I have observed my air conditioner slow down in RV campgrounds but I didn’t know why it was slowing down. Now I know. Thanks

  2. Just read the article on Autoformers, in the May, FMCA magazine … been considering buying one … Would like to hardwire the unit in my coach and use it all of the time. Is there a model that has a terminal strip inside the unit that I could hardwire into the coach replacing the current surge protector since space is limited in the electrical bay?

    1. The Autoformer is designed to be plugged in. The receptacle for the plug is built into the unit on the side. This plug and receptacle would take up very little room. The cord then plugs into the end of the power cord.

      The only reason to open the box would be to replace the surge protector module after it was hit with surges and did its job and has protected your coach.

    1. Yes. If you put the EMS before the Autoformer then the EMS low voltage feature could shut the power off before the Autoformer could correct the voltage.

      If you put the Autoformer before the EMS the EMS will see the higher voltage and keep the power on.

  3. This is an awesome setup for limiting spikes and surges. Also thanks for pointing out that Surge Protectors don’t last forever. They get “consumed” when they absorb surges to the point that they then no longer work. It is great that you can replace the surge protector inside the unit.

  4. Some RV Parks specifically ban the Hughes Autoformer because it does drain more power from the system. The extra volts do not come from the air, they have to be taken from the line.

    1. I have heard that as a rumor but have not been able to identify any park that has done this. My guess is that these parks also have a marginal over-allocated electrical system.

    2. Hello, Paul, (Message from Brett at Hughes Autoformer)

      If you turn on an appliance, volts will be taken from the line to do the work the appliance is supposed to do, with or without a Hughes Autoformer voltage booster in use.

      The ‘Autoformer’ is there to protect your inductive loads (AC unit, microwave, refrigerator, fans, pumps, compressors, motors, jacks, etc) that will be damaged if you use them consistently with low voltage as it causes an increased amp draw.

      In both circumstances, you are still limited by the breaker at the pedestal to either 30A or 50A. So you cannot “get more” than what the breaker will allow.

      The Autoformer is not 100% efficient, but the power consumed is negligible.

      The NFPA ‘regulation’ has been removed, yes, parks can make up their own rules if they choose to.

      The problem is inadequate voltage from many different causes – older parks with insufficient infrastructure, bigger more power-hungry RVs, or more RVers due to COVID or working remotely, etc.

      The ‘stop gap’ solution for your own personal RV and equipment is a Hughes Autoformer voltage booster.

      Otherwise, it would be to have a generator running, unfortunately, solar/battery is not quite there yet.

      1. Thanks for sending me Brett’s response. I hadn’t thought about the limiting factor of the pedestal breaker. There is one thing I don’t know about the Autoformer and it could be important. What protects the Autoformer from the situation that burned up my Xantex, a bad plug that caused the two lines to energize before the neutral? Resistive loads like my home water heater don’t need the neutral, but my Xantrex sure did!

        1. Brett at Hughes Autoformer

          The Autoformers are mainly a voltage booster with surge/spike protection. They cannot alter the wiring NOR can they shut off the power.

          So if the wiring is bad (faulty, burnt, wired wrong, etc) whatever is going into the Autoformers, will go out of the Autoformers.

          Only surge protectors with EPO (emergency power off) like the Watchdog, or EMS (electrical management system) like other brands can shut off the power into the RV if a wiring issue is detected (reversed polarity, open neutral, etc.)

  5. It’s true some parks don’t allow them but they are wrong in their thinking and so are you.

    The extra volts don’t come from the air is funny though.

    It’s about total power used. They do not pull extra power. If you are plugged into your site power panel you have a 30 or 50-amp breaker. Which you are allowed to use.

    You can not pull more than your pedals breaker limit so the input side of your Autoformer can only pull the max of 30 or 50. At whatever voltage is supplied. It then bumps up your voltage by using more amps but once again below your breaker at the park’s set point. So if the park has low voltage say 108 volts @ 50 amps = 5400 watts before the breaker pops and let’s say you are at a park with 120 volts @ 50 amps = 6000 watts before the breaker pops.

    So you are using less total watts with Autoformer. It’s ohms law volts x amps = watts

    1. Thanks for your comment. I have seen the Autoformer bump the voltage in real-time correcting for the sag that occasionally happens at a campground. I glance over to my voltmeter and see it quickly change from red to green. I am really happy I have one when I see that happen because I know the effect of low voltage on my air conditioner.

  6. The braided shield shown in the male plug wiring picture should not be done this way. There should never be any stray uninsulated wires in any electrical box or plug. Doing so is an invitation for disaster.

    Here, the shield was cut off and remnants literally touched the white wire terminal. This is bad.

    1. I agree, this is what you get when you take the picture before the job was finished.

      Really the worst part about it is this was the way it looked when I first pulled the cover off the plug. This is factory work. 

      The fibers you see in the picture are twine from the inside of the power cord, not wires. I took this picture to make sure that when I rewired the new extension cord I got the wires back to the original location.

      I assure you that the fibers were all removed from the inside of the plug before I buttoned it back up.

      1. The fibers looked copper in color on my laptop and that is why I reacted as I did.

        I’ve found similar issues in other purchased products, much worse than shown in that image. I’ve found issues like wires not connected at all, screws not tightened, wired incorrectly, on and on.

        Keep looking up!

  7. I have an EMS with a surge protector built in my RV.

    My issue is that in several RV parks the voltage often spikes up to 133 volts or higher for a time and then drops. My surge protector limit is 132 volts, and it cuts power at 133 or higher.

    Power comes back on when the voltage drops, only to cut the power again when it gets to 133. In some campgrounds with a fluctuating voltage, I have had to use the bypass switch in order to have continuous power. Is there a device that will keep the voltage below 133 volts so I don’t have to bypass the surge protector?

    1. I don’t have a quick answer to this question. Also, I have never seen this problem.

      Perhaps someone in the “brain trust” will see it and comment. Sounds like the opposite problem that I have been seeing.

      1. Thanks for responding. You would be surprised at how many RV Parks have fluctuating voltage, and it’s common here in the West. It may depend on how many other RV’s are using power, but reducing the spikes or high levels would be helpful to avoid the surge shutdowns.

        I will watch for other comments to resolve this problem.

    2. Brett at Hughes Autoformer

      High voltage in RV parks is very uncommon. I have only heard of a couple of customers asking about this. Unfortunately, the Autoformer is only a voltage booster. It does not ‘buck’ the voltage down, nor is it a universal power supply that gives you a constant power output despite your input varying.

      In the future, we hope to have a unit that can buck and boost voltage. But for now, using power will bring down the voltage, keeping an eye on it, going to the generator, etc are your options unless you see a buck transformer or universal power supply out there.

      132 volts is technically the upper limit to what is ‘acceptable’. I forget the organization, but it was listed as 10% +/- nominal voltage which is 120. So that gives you 108 to 132.

  8. I’m a bit confused about the picture of your electrical compartment. I understand your installation process. (The correct order for installation is [campground] power pedestal followed by Hughes Autoformer; then Power Watchdog EMS; then transfer switch.)

    I see the male plug, which, I assume, is coming from the campground pedestal, plugged into the Autoformer going straight up. Is that actually coming from the box above it?

    I then see the cable coming out of the Autoformer into the EMS. What is the open female outlet from the Power Watchdog EMS used for?

    I guess what is confusing me is I don’t see is your cable from the power pedestal.

    1. Had I designed it, you would have seen the electrical cord reel in the electrical compartment. But you would haven’t seen anything else because there wouldn’t be any room for the camera.

      Alas, the electrical cord reel is forward in the middle of the coach two compartments forward, near my inverter/converter.

      The cord runs from this compartment back to the transfer switch and then back to the inverter converter. It takes the same path as does the wire from the generator to the transfer switch.

  9. Rick said that the Autoformer is “not allowed by the National Electrical Code” but didn’t leave a valid email address. Please give quotations from the code and I will publish them.

  10. You did not cover HIGH VOLTAGE … My EMS protected my camper several times last weekend when the voltage at the KOA went above 130 volts … When I went to look at the voltage most times the voltage was above 127 and most times 130 volts… I am not sure when it shuts off but it did… My neighbor has the same EMS unit .. his shut off also protecting his camper

    1. To protect yourself from high voltage you need an EMS with an Emergency Power Off (EPO) feature. The ideal location for this device is between the Autoformer and the coach. The Autoformer corrects for low voltage and the EMS with EPO will protect you from high voltage.

  11. The article is excellent. However, THIS certainly is for only intermittent use AND not for a permanent installation if someone were thinking of such!

    This unit is fine for intermittent use as needed for unintentional voltage drop, however when parked at some old RV Parks, and I do mean old, if one were to depend on one of these for constant use it would not last more than six months.

    1. I have asked Louis which components in the Autoformer he expected to fail and am awaiting his response.



      I do not understand your thought behind this. The Hughes Autoformer voltage booster, is simply a transformer (two if 50A) with multiple windings and taps. Just as a step down transformer operates 24/7/365 on a power pole outside your home, our autoformers can operate continuously as well. The transformers do not degrade over time by being used, again, it is an iron core with copper wire, it does not ‘get used up’. The relay has a service life of many thousands of cycles, the surge/spike module can get used up if it absorbs surges/spikes but that is precisely what it is designed to do, and if it does get used up, you can replace it to have surge/spike protection again. The LED lights on the front do not really burn out, they are LED lights. The Lexan sticker on the front may fade or become brittle with years of constant UV exposure, but that is about it, just keep them out of rain/standing water and you should have many years of service.
      Power pole transformers step down the voltage into your home for what you need, the autoformer just steps up the voltage into your RV, they are essentially the same thing.

  12. I thought this type of power conditioner – like the Hughes Autoformer was being effectively banned by the new Electrical Code?


      First, the NEC is done by the NFPA (which is a .org, not a .gov). Anything the NFPA/NEC comes out with is not code or law automatically. It must be codified by the authorities having jurisdiction (cites, towns, counties, etc). They have the ability to modify, reject or accept recommendations into code (law). So they never were ‘banned’ legally unless the cities or towns codified it specifically. Secondly (and more importantly), they have reversed this ‘ban’ because the NFPA does not have authority to ‘ban’ what connected device you plug into an outlet as long as the plugs/connectors, etc are the correct types. It would be like the NFPA banning which stereo or hairdryer you can plugin. As long as you are not making it unsafe by fudging the connectors, etc, they do not have authority to regulate that. This was just done in December 2021. So rightfully so, the Hughes Autoformer voltage booster is not “banned”. You can go onto the NFPA site, create a free account, and find the verbiage there. I believe it is under section 551.72E

  13. Great write-up. I have both the Hughes Autoformer RV220-50-SP and the Hughes Bulldog PWD50-EPO and plan to hardwire them just as you have done. I am wondering if it could be installed on the output side of the transfer switch so as to provide the same protections and conditioning features for power coming from the generator as well as shore power.

    1. Russell, I have seen that done before with an EMS but I don’t think it is necessary. It is completely unnecessary to boost your generator voltage with an Autoformer. The reason that campgrounds do not always put out enough voltage is that they are underdesigned and overused. This never happens to your generator power because you are the only user.

      Generators almost always put out perfect power.

  14. I’ve been lucky in not losing power due to the low voltage but we would stay an average 107v all day and night. Every once and a while I’d see the voltage up to 110 but that was very rare.

    All my fans and ac units seem to struggle during the day but now (with my Autoformer installed) even at the peak of the day this unit is holding my voltage to 118v with 3ac(~2.5kilowatts) and even when two units start at once I don’t see any fluctuations.

    I wish I would have known about this Hughes Autoformer 30 amp sooner. I will be telling everyone at our RV park about this and definitely will be buying another if this one ever breaks. I am kind of leery about the weather resistance of the unit as I can’t put it under any cover being in an RV park.

  15. I run a camping website and have a few articles on the amperages and voltages of RVs. This article you provided has given a lot of insights. Keep it up.

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