Escapees Park bands Autoformers?

[Smitty77_7]

We're visiting in an Escapees Park, and reading the rules, they band the usage of Autoformers?

 

It was my understanding, that Autoformers do not use more power? They basically (And for sure, could be wrong...) act like what you see when trying to stream 'Buffering...'. They can't draw more power from the pedestal then is delivered to the pedestal. (That was my understanding.). They should help the RV with the Autoformer, while not impacting anyone else around them. (Again, my understanding.)

 

So, what am I missing? Why would any park band the usage of Autoformers?

 

Just trying to understand, best to all, and TIA,

Smitty

[docj]

Hi Smitty:

 

The thing to remember when trying to analyze what an autotransformer does is that it is located AFTER the breaker at your pedestal. Therefore, it can't affect what comes out of the pedestal to your RV.

 

So, if you're at a 30A site the breaker on your pedestal will limit current flow to 30A regardless of anything you and your autoformer do. If the park is having a "brownout" and is delivering power to you at 105V the pedestal still limits your current to 30A. So the amount of power you are drawing is 30A x 105V = 3.15kW

 

Most models of the Hughes autoformer would boost the voltage on the output side by 10V if it sensed a voltage as low as 105V. But doing that will reduce the current flow to your RV. So instead of 30A at 105V your RV will see 27.4A at 115V. That's the same 3.15kW (I'm ignoring any losses in the autoformer.)

 

Where people get confused about this is that they see that you are now using only 27.4A and they think "now he can rob another 2.6A out of the pedestal thereby depriving other people of needed power." But, in fact, you really are still using 30A at the pedestal, nothing has changed there. You can't increase your power usage or you will trip the pedestal breaker.

 

People who ban autoformers could use a course in electrical engineering, but most are usually too convinced of their own righteousness to bother to listen to anything you can say. All the more reason to do some rewiring in your RV to allow the autoformer to be placed inside, out of sight.

 

Joel

[Kirk W]

So, what am I missing? Why would any park band the usage of Autoformers?

The short answer is, the management doesn't understand what they actually do or how they work and they believe the popular mythology. That used to be a fairly common thing to run into in parks but seems to be fading away very slowly.

[Dutch_12078]

People who ban autoformers could use a course in electrical engineering, but most are usually too convinced of their own righteousness to bother to listen to anything you can say. All the more reason to do some rewiring in your RV to allow the autoformer to be placed inside, out of sight.

 

Joel

 

The folks that ban autoformers (autotransformers) or their insurance companies might also be aware of NEC Article (551) that apparently prohibits their use for RV's.

 

NFPA 70, Article 551 "Recreational Vehicles and Recreational Vehicle Parks"

 

Part II, 551.20 "Combination Electrical Systems"

 

(E) "Autotransformers. Autotransformers shall not be used."

[Barbaraok]

Bet in most cases it is the insurance company who, for some reason, has had to pay out a claim that some how involved someone using an autotransformers. Would be interesting to know what the reasoning for the NEC rule.

 

We also need to remember that, as a whole, we have a woefully scientifically illiterate society.

 

Barb

[Ray,IN]

Dutch, that clears this topic up, never knew that. Just for curiosity sake, this week I'll drive over the the fire station and see if the 2016 NFPA code book reads the same.

I believe what docj wrote is true. Can't remember much of my electrical theory class in college though.

[Dutch_12078]

Dutch, that clears this topic up, never knew that. Just for curiosity sake, this week I'll drive over the the fire station and see if the 2016 NFPA code book reads the same.

I believe what docj wrote is true. Can't remember much of my electrical theory class in college though.

 

Ok, but there is no 2016 edition of NFPA 70, the NEC. The current version is the recently released 2017 edition, and the previous edition was 2014. Both editions, as well as quite a few before them, all contain the same wording. I haven't checked every edition going back, but I can say that the 1993 NEC has exactly the same entry, so it's probably a fair assumption that it's there in all the intervening editions as well.

[Yarome]

It's not hard to believe there might not be insurance issues involved, but there is "some" truth that they "steal" available power from other campers. Not in the sense that they will draw more current than is allowed on a 30 or 50 amp hookup, but they are not lossless devices. Think about what an autotransformer does and when it does it. The park's electrical system is not able to handle the current demands being placed on it. So what does your autoformer do? It increases the demand on an already taxed system... exasperating the low power situation.

 

Ie., You have a constant load of 1000watts. Your autotransformer burns 45watts 24/7 so your actually pulling 1045watts to get your 1000watts of needed power.. even when it's not actively stepping up the voltage. A low power situation occurs. As the voltage drops your autoformer starts pulling even more power in order to maintain your 1000watt load. Multiple that by everyone in the CG using an autoformer "taking" more power from the system than they are actually "using".

 

At least that's their argument. It's just semantics really... easily argued either direction.

[skp51443]

This makes a good case for getting your autoformer discreetly installed inside your RV where it is out of sight.

 

Choices come down to damage your stuff with low voltages, add an autoformer, turn your stuff off or move to another site/park with good power.

 

You have to make your own call, but for me suffering low voltage damage was not an option.

[Kirk W]

Think about what an autotransformer does and when it does it. The park's electrical system is not able to handle the current demands being placed on it. So what does your autoformer do? It increases the demand on an already taxed system... exasperating the low power situation.

While all of that is actually true, the RV park customer arrives and he pays for either 30a or 50a and frequently pays a premium for the higher rated plug. So long as he uses no more than the pedestal he is paying for is rated to supply, he isn't stealing anything but only changing how he chooses to use the power he is paying for. So long as the park's circuit breakers work as the limiting device, the user of an auto-transformer device is only reallocating the manner in which he uses that 30a or the 50a of power that he is paying for.

 

It is interesting to me that I have never seen such rules in RV parks that were recently wired to be able to supply the power which they offer to their customers. Of course, such parks also are never impacted by any of the voltage boost devices because they have a solid power supply.

[DavidMc]

We might also consider the 'default' wiring standard being used for the design of an RV park electrical system.

 

I think it compares to how a house is wired -- for a house example:

Input =

. . Main breaker pair provides 200 amps total.

Consumers =

. . one or more pairs of 50 amp breakers (220 volt electric stove/oven, electric heat system, etc)

. . some 30 amp breakers (220 volt electric clothes dryers, water heater, etc)

. . a large pile of 20 amp breakers for room outlets and lighting.

And then you see that the Input is often "over-subscribed" if all the Consumers use their full permitted -by-the-breakers current.

 

In a house, usually not everything is running up against its permitted limit at the same time. Sort of depending upon random usage through the house.

This is reflected in the "utilization percentage factor" for each circuit - - that factor used in the design spec for a house.

 

RVs consolidate the usage - producing a higher utilization percentage than an individual room of a house.

[oldjohnt]

Okay here's the deal as I best recall from my electrical engineering education and practice working for years with a fine group of electricians and electrical technicians, although its been years since I retired, so NO WARRANTY LOL but I don't think the laws of physics changed since I retired !!

 

1) An autotransformer is a passive electrical device and the laws of physics and principles of "Conservation of Energy" dictate that since its NOT 100% efficient, you get LESS ""electrical"" energy OUT then the Pedestal delivers IN, due to heat losses. Energy in must still = Energy out, but its just that some of the energy out is converted and lost as heat versus I x R to the RV. IE the transformer uses some energy ALL the time its plugged in as its is still drawing current (albeit far less then if a load is applied). It does NOT create or destroy energy, ONLY changes its form (E x I versus Heat). Even if just setting there plugged in but your RV is drawing nothing, its still consuming some energy fed from the Pedestal.

 

2) A transformer is basically an inductive load and inductors, unlike capacitors, oppose a change in current. One result of that is when devices like motors or transformers (Inductors) are shut down there can be a resultant voltage spike. If you ever watch a knife switch when a motor load is removed see the resultant arcing.

 

3) OF COURSE someone is still paying for ALLLL the power the pedestal delivers (be it used as I x R or Heat) and you're NOT stealing anything its just that someone is paying some for heat and some for I x R to the RV.

 

4) HERES THE RUB if your service is metered, its YOU not the park that's paying, so they have no worry if your transformer is setting up there using energy in the form of heat or not. HOWEVER if the park is paying (non metered at site) all those transformers are setting there all the time drawing power and sort of wasting it as heat. If I'm paying the bill I don't want a bunch of "heaters" siting there as that's in part what a transformer is doing. IT PRODUCES SOME HEAT EVEN IF NO LOAD IS APPLIED AND THAT COSTS MONEY

 

5) An autotransformer is indeed an advantage to the RV because it can raise its output voltage if needed to better serve and protect RV appliances,,,,,,,,,,,,REGARDLESS it's still a passive not 100% efficient device and if it must deliver more power to the RV more power has to be supplied from the pedestal SO WHO IS PAYING FOR THAT ???????? The RV if its metered at site, but the park if not.

 

6) On the side of the park owner, even with all the above, when an inductive load goes off line there can be resultant voltage spikes which can in theory at least affect other users.

 

BOTTOM LINE Sure an autotransformer can protect an RV,,,,,,,,,,,,,,,,Sure no one is stealing anything as regardless if its used to produce I x R for the RV or heat, its paid for by someone BUT that's the question, is it the user or the park???????????

 

MORAL OF THE STORY

 

a) Sure a private park owner has every right to not allow autotransformers (regardless if he understands transformers or not, that's irrelevant) REGARDLESS IF ITS ELECTRICALLY CORRECT OR NOT, if you don't like the rules go elsewhere!!!

 

I bet there are sound engineering reasons why a park might choose to NOT allow autotransformers, see above OR see what the NEC has to say, NOT me !!!!

 

c) I did NOT look up the NEC regulation, but over like nearly 50 years of and having studied and used the NEC and attending several NEC courses, ITS MY PROFESSIONAL OPINION if they don't allow an autotransformer, there are sound engineering reasons why and that remains so even if a lay person doesn't understand why. They know much more about this topic then most of us who aren't experts including myself for darn sure lol

 

d) Even if the "management" doesn't understand autotransformers (They are likely businessmen and not techs or engineers or electricians, I would NOT expect them to understand them), the engineers and technicians and electricians who designed the system and/or insurance companies and lawyers might BUT REGARDLESS its their right and their call to ban or not to ban even if it were NOT electrically sound. WE all have the right to NOT stay there.

 

NOTE if you don't like or understand the NEC or want to flame on engineers, don't take my word for it, its NOT me talking, its the NEC experts, SO IF YOU'RE RIGHT AND THEY'RE WRONG TAKE UP YOUR ARGUMENTS WITH THEM NOT ME I'm not here to argue ONLY to help if I can. DO WHATEVER YALL LIKE IS FINE BY ME I'm sure not here to stop you. Go tell the RV park owner he's all wet lol and because you say so he has to allow them and the NEC is simply wrong and you're right !!!!!!!!!!!!!

 

If I were a gambling man and had to bet on if the NEC was right or other persons, especially non technicians and non electricians and non engineers, I would bet on the NEC but that's still no warranty, they make changes and correct mistakes when its proven they are wrong, but many of their rules are there to save lives or property and are based on accident investigations SO MAYBE THEY ARE WRONG IN NOT ALLOWING AUTOTRANSFORMERS ??? If so and anyone can establish such take it to them NOT me, they are willing to listen and make improvements in my experience when I attended courses taught by ones on their board.

 

The park owner still has every right to ban or not ban autotransformers regardless if he's right or wrong or understands them, and if the NEC bans them there's a darn good chance they have sound engineering reasons why even if lay people don't understand it. Just because you or I don't understand something, that don't mean its wrong or right !!!!!!!!!!!!

 

Nuff (too much) said, take or leave the NEC rules at your own risk, do as you please, if the NEC is wrong go flame on them not me.

 

IMPORTANT PS: In addition all the energy discussion above, there's the whole LIFE SAFETY consideration having to do with issues like Single Point Grounding and Neutral Ground Bonding concerning the safety of "certain" transformers !!!!!!!!!!!!!!!!! Remember, the RV panel, unlike your home panel, does NOT have Neutral bonded to Ground. The safety issues can be more important then energy, but I'm NOT going to describe and explain all that here. I can't explain in a paragraph what can take whole books to cover lol

 

John T BSEE, JD, Longgggggggg retired electrical power distribution design engineer and rusty so consult or correct the NEC if you're right and they're wrong NOTTTTTTTTTT me, or tell the park owner he has to change his rules, good luck with that one lol.

[Zulu]

The folks that ban autoformers (autotransformers) or their insurance companies might also be aware of NEC Article (551) that apparently prohibits their use for RV's.

 

NFPA 70, Article 551 "Recreational Vehicles and Recreational Vehicle Parks"

 

Part II, 551.20 "Combination Electrical Systems"

 

(E) "Autotransformers. Autotransformers shall not be used."

 

Whew! Glad I bought a voltage regulator instead.

[Bill Joyce]

I wonder if an "Autotransformer" is referring to a park's own transformer. Many years ago we were in a campground in Arizona where the park voltages were jumping around, sometimes into the 130+ voltages. The owner said they were using a new fancy transformer that was not tuned yet and he was ready to go back to the simpler type. I wonder if that fancy transformer is the reason for the prohibition, not the units we use in RVs.

[Smitty77_7]

Great reading in this thread, many thanks to all that shared their knowledge.

 

The no autoformer comment, was in the same area about when temperatures are of 95, to restrict AC usage to one unit at a time. So the parks overall electrical system must not be able deliver full 50A power to the sites at the same time.

 

I'm on my second Hughes. The first one was toasted on our trip to Alaska, from spike of power out of a smaller parks generator system. (I had the Hughes inline first, then the EMS second. We had a long thread about the pro's and con's on the pecking order of EMS and Autoformers about 5 years ago:)! I elected to keep my Hughes inline first.) The first unit was on board and installed in the same cabinet that the EMS is in.

 

Bought my second used Hughes (1st was from a Country Coach owner that was coming off the road. The replacement second unit was from an Escapees member.), but due to cabinet modifications, have not installed it alongside of the EMS. I keep in in a basement, and the few times we've needed it, I place it next to he power pedestal. So, would be pretty obvious in it's usage. (We're going to do one more shuffle of the cabinet equipment, when we shift over to Lithium in a few years, will move both he EMS and then install the Hughes inline next to it again at that time.)

 

I have no problem with a park having rules against Autoformers. Just did not understand why, as I had thought they did not 'consume' any more power then was being delivered to the pole. (Even if say that 50A service, was only seeing 45A, due to overall park power consumption.)

 

So again, appreciated all the info sharing... And will now post a separate question this 'sparks'.

Best to all,

Smitty

[oldjohnt]

Smitty, thanks for the feedback and added info. To your statements:

 

"So the parks overall electrical system must not be able deliver full 50A power to the sites at the same time"

 

That's the whole "Diversity" and "Duty Cycle" computation which can be a bit tricky especially applied to an RV park. Its one thing to the bean counters and who's paying the bill versus how a conservative engineer may design something. It costs big bucks to install more expensive copper that's required to design for a full 30 or 50 amps at each and every site versus averages or how diversity or duty cycle type charts might indicate, plus much of the NEC is concerned with certain MINIMUM ONLY requirements although an engineer like myself might design for above and beyond, BUT THE CUSTOMER MAY NOT WANT TO PAY FOR ALL THAT and be satisfied with minimum yet still NEC approved methods.

 

"as I had thought they did not 'consume' any more power then was being delivered to the pole"

 

They (plus their loads) cant consume any more power then the pedestals overcurrent protection device allows HOWEVER they can consume some degree of power (heat) even if the RV isn't consuming anything whatsoever. Energy IN = Energy OUT its just that some of the OUT is heat and rest is I x R to the RV.

 

John T

[Yarome]

This makes a good case for getting your autoformer discreetly installed inside your RV where it is out of sight.

 

Choices come down to damage your stuff with low voltages, add an autoformer, turn your stuff off or move to another site/park with good power.

 

You have to make your own call, but for me suffering low voltage damage was not an option.

 

Exactly!

 

So long as he uses no more than the pedestal he is paying for is rated to supply, he isn't stealing anything but only changing how he chooses to use the power he is paying for.

 

Exactly!

 

Which is why it can be successfully argued from either perspective (CG owner vs patron).

 

It's a no win argument.. and as John pointed out.. there are also potential cost considerations depending on metered or non that might be driving a CG owner to either allow or ban autotransformers.

 

I think Stan has the right approach. If you got it.. use it.. but don't flaunt it.

[Barbaraok]

Smitty,

 

Did I miss something, or did you forget to say which Escapees park you are at?

[Smitty77_7]

Hi Barb - No, I did not post it. But since it's in their rules that they handout, doubt they'd mind. And if the overall power to the park is not robust enough to handle max usage of the 50A at each site, understand they're request to minimize AC usage to one unit at a time, during peak demands. Better to have everyone have some power and AC, then to damage the system and no one gets any power or AC:)!

 

This is Timber Valley, which is a COOP. We've been comparing COOP's this year, as we need up returning out site at Park of The Sierras in Coarsegold, as part of our Domicile shift from California. (Trying to make as many clean breaks as possible, while retaining what is now our 'vacation home' and a 'rental'. We're being very legal, and keeping detail records of our travels, for the first 3-5 years after out change to SD Domicile.)

 

Have enjoyed both Evergreen in Washington, and now that the storm blowing thru the Pacific Northwest is almost gone - getting gout to enjoy the Sutherlin and Roseberg areas of Oregon:)!

 

Best to you, and all,

Smitty

[Barbaraok]

We stay in Timber Valley every year, usually twice. I don't remember seeing the autotransformer rule, but do remember the rule on run only 1 A/C. After 10 yrs, you'd think they would realize they need to upgrade if they want people in the future to buy in. Did see the person across from us have to move this fall because the power to her site went out. It was 106 when we arrived - extremely hot and everyone had A/Cs running - naturally! In fact, one of the reasons we decided not to buy into that location was the power problem 10 years ago.

 

This is sort of similar to the problems they had at Evergreen. How do these parks expect to stay viable, they know that eventually those that are there will move on/die and new people need to be welcomed, but the refusal to maintain/upgrade systems turns people off. Seems that the 'cut off my nose to spite my face' attitude is alive and well. Really sad when you think about it.

 

If you like wine - go visit Misty Oaks, outside of Sutherlin. We love their wines and always stock up on our way south to Arizona every fall.

[skp51443]

COOPs are independent organizations and so pretty much set their own rules so the club can't do much aside from education and suggestions in situations like this.

[Dutch_12078]

I wonder if an "Autotransformer" is referring to a park's own transformer. Many years ago we were in a campground in Arizona where the park voltages were jumping around, sometimes into the 130+ voltages. The owner said they were using a new fancy transformer that was not tuned yet and he was ready to go back to the simpler type. I wonder if that fancy transformer is the reason for the prohibition, not the units we use in RVs.

 

Bill, the NEC section I quoted is entirely about the wiring standards for the dual high/low voltage systems used in RV's. There are other sections devoted to park wiring standards.

[oldjohnt]

Bill Joyce,

 

Some years back (may have different now) a transformer might be equipped with automatic tap changers so if voltage dropped the tap point would change to correct and the switching could possibly cause some issues with certain types of sensitive equipment. That's probably NOT what the NEC is talking about above.

 

If the NEC prohibition has to do with issues such as Single Point Grounding and Neutral Ground Bonding and other life safety issues dealing with a proper safety equipment grounding conductor Id sure be hesitant to ignore their rules myself, but if it has more to do with the energy considerations I discussed above, Id be somewhat less concerned. When they talk about alternate energy sources and separate derived sources having to do with a prohibition of any sort, my engineers ears perk up and I pay close attention. Alternative sources and whether or not they are configured as separately derived or not HAS A LOT TO DO WITH GROUNDING AND BONDING, TRANSFER METHODS AND LIFE SAFETY!!!!!!!!!!!! There's a difference in transformers and isolation transformers and auto transformers when it has to do with safety and wiring methods.

 

Best wishes n God Bless, yall keep safe now

 

John T

[Smitty77_7]

So, Misty Oaks (Thanks Barb), and quite a bit of great info on autoformers - really a win/win for me on this thread:)!

 

Smitty

[Lou Schneider]

One factor that hasn't been addressed is the series resistance of the electrical supply.

 

When an air conditioner compressor starts, it's starting surge puts an extremely low impedance load across the incoming power feed. How much the voltage sags during this surge is directly related to the total circuit resistance between the park outlet and the voltage source (transformer or generator).

 

If you're right next to the park's distribution transformer, chances are you have very low wire resistance between you and that source. You'll get lots and lots of current to start the compressor motor and will also see little voltage sag during the starting surge.

 

But if you're further away the longer wire run places more resistance between you and the source, limiting how much current you can pull during the surge while also introducing more voltage loss.

 

The transformer windings in an autotransformer add additional series resistance to the circuit, further limiting the peak current you can pull. The steady state voltage may look fine since it's being boosted back to normal by the autoformer, but you'll still have less surge current available to start the compressor.

 

This is probably the real reason autotransformers aren't allowed by the NEC. From a psychological standpoint, I know if I'm in a low voltage situation I'll load manage to reduce my electrical demand - make sure the refrigerator and water heater are switched to gas, not try to start the a/c while the microwave is in use, etc. If you're using an Autoformer, it will hide the brownout as it boosts the incoming voltage so there's less incentive to reduce demand.