Issue 2 • December 31, 2017
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From editor Mike Sokol:
Dear Readers,
Much has happened in the last month. There are now nearly 6,000 readers signed up for this monthly newsletter, and I’ve received hundreds of questions from you about all sorts of electrical issues. While I can’t respond to them all immediately, I’m cataloging and putting them into categories to answer as the seasons and editorial space permit.
For instance, I had many questions last week about wattage requirements of Christmas tree lights. While that’s not specifically an RV power question, it is indeed an important topic to understand for your bricks & sticks home. However, it’s a little late to answer the question in this issue so I’ll save it for next November. Same goes for the questions I’ve received about lightning safety. I’ll answer those questions in May, when it’s actually lightning season.
You all have been great so far and I really appreciate you signing up for this newsletter. Without you I’d be talking to the wall. So please keep reading, and please pass on this newsletter to anyone you know with an RV, or even anyone who wants to learn more about electricity for their home, farm or work. And have them subscribe to this and any other of the great newsletters from RVtravel.com. It’s painless, I promise.
Let’s play safe out there…
P.S. And just a quick note that this newsletter is made possible by the voluntary pledges of the readers of RVtravel.com. We could not bring this to you without their support. If you deem what we provide to you here and at RVtravel.com to be of special value and would like to be a part of our effort, please consider pledging a voluntary subscription. More information is here. We will include you in special emails, articles and videos exclusively for our supporters.
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What’s a Volt?
I’m thinking about rewriting and publishing my entire 12-part Basic Electricity series here that will bring you all up to speed on the basics of electricity including the definition of Volts, Amperes, Current, Resistance, Wattage, etc… That’s because I’ve had a few readers (and students) recently use words like Current and Voltage interchangeably, when they’re totally different things.
Now please don’t think this is required reading, since it will get into some fairly complex concepts at the highest level. However, if you invest some time and brainpower to it, you’ll learn something very useful to your daily lives. Plus, I love to sprinkle in a little historical perspective about the great electrical experimenters of the past, including Ben Franklin, Michael Faraday, Alessandro Volta, and even the Greek philosopher Thales of Miletus, who is credited with discovering static electricity. Stay tuned for Part I of this series in the next newsletter.
Interestingly, I had one particularly vocal student declare that all this electrical talk was simply my opinion. Well guys… I don’t teach or write about my opinion on how electricity works. Everything I write about, put in a video, or say in front of the class comes directly from an engineering handbook or the NFPA 70E National Electrical Code. And if I can’t find it written down in an engineering text, I carefully create a hypothesis, do an experiment, gather empirical data, and have it reviewed by my peers (other electrical engineers). That’s how I came up with the concept I named RPBG wiring (Reverse Polarity Bootleg Grounds).
However, like my actual college students, you are all welcome (and even encouraged) to fact check me. Is it possible that I made a mistake in a formula? Certainly, since all humans are fallible. However, an honest mistake is not an opinion, it’s just a mistake which I’ll quickly correct once pointed out to me. But I do read, re-read, and fact check everything I write numerous times before publishing it. After all, lives are at stake.
How often these electrical problems happen in an RV is only a guess on my part, which I’ll state as such. But you’ll note that I like to take reader polls for your input to quantify the extent of any problems I see. For instance, I ran a reader poll last week about overheated 50-amp shore power cords, which we’ll cover below. I admit to being a little shocked that 10% of those who responded have overheated a shore power plug enough to discolor the plastic, and an additional 10% overheated it enough to melt the plug. Finally, 2% of you responded that it got the plug hot enough to catch on fire. Yikes, that’s really dangerous and unacceptable as an industry. So I’ll create more videos and articles about shore power cord overheating in coming issues. Much to do…
In the meantime, please continue to email your questions to me at mike (at) noshockzone.org . —Mike
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Industry Updates
The latest 2018 edition of the National Electrical Code is here, and there’s a lot of new training and investigation requirements that could affect the RV industry soon. Here’s an important one that I saw at first read. And go here for a more complete reading of the 2018 National Electrical Code’s new mandates.
Electrical Safety Programs Must Now Include Incident Investigation
NFPA 70E (The National Electrical Code) now states that electrical safety programs must include information on how to properly investigate any incidents that may occur in a facility. Guidelines for how this education should occur are brief, as each business will require a unique plan specific to its facilities, but these programs must include primers on root-cause analysis, near-miss reporting, and protocols for follow-up investigations.
What this suggests is that any RV dealership or campground that is aware of or had an incident which resulted in death from an electrical shock, damage to RV appliances from miswiring, or possibly a fire caused by overloaded wiring, must properly investigate the root cause of the accident. That also means that any electrical technician training needs to include incident investigation, diagnostics and reporting. I’m not exactly sure who this needs to be reported to, but that’s certainly part of the incident investigation.
This must be a real need since anytime there’s a death from electrocution I get a number of newspaper reporters calling or emailing me about what actually happened. And in many instances they’ve already called to the local sheriff’s office or power company, and they can’t get any kind of answer of exactly what happened and why it occurred.
On several of the electrocution deaths where I talked to the local sheriff, they didn’t want me to write about what actually happened since they were friends of the family who lost a loved one to electrocution, and the sheriff felt that any additional news coverage would increase their guilt at not having fixed the problem in the first place. But my opinion is that the only way to learn from mistakes is to examine them, so I carefully write about the cause of the accident without laying blame on who actually caused it.
But I do feel that education is the key to reducing deaths and injury from electrical shock. My main point is that “YOU SHOULD NEVER FEEL A SHOCK FROM ANYTHING PLUGGED INTO AN OUTLET.” If you do, then something is terribly wrong and you should have it checked out by an electrician or electrical technician immediately. —Mike
Survey Question
Everyone asks you about pets and spare tires and even power usage on the road, but how about musical instruments? How many of you drag along a keyboard, guitar, harmonica or even an accordion? I would love to jam with any of you in a campground (as long as we don’t do it during quiet hours).
TAKE THE 30-SECOND SURVEY.
Read all of our past surveys here.
Tools and Other Devices
Clamp ammeters are really cool since they can not only measure current (amperage) in a wire without disconnecting it from power, many also include a voltage measurement function with a pair of meter leads you plug in. And most notably, the newest ones often include a NCVT (Non Contact Voltage Test) function that will allow you to test for a hot-skin condition on your RV without actually touching it.
Here’s an affordable clamp ammeter from Southwire that should do the job nicely. Learn more or order at Amazon.
Last Month’s RVtravel.com Posts
How do you know if you have a (dangerous) miswired power pedestal?
Hey Mike,
I didn’t see anything about phase protection in your last article. I realize on a 30-amp service it’s not an issue, but people should know on a 50-amp service it’s a big deal – because without it (phase protection) a miswired shore power pedestal can cause a serious overload on the neutral leg. How do you know when you have an incorrectly wired shore power pedestal? … —Larry McGaugh
Read the rest of the question and Mike’s response. (Reader poll included.)
Surge protector evaluation
Dear Mike,
We purchased a TRC Surge Guard RV Power Protection Model 34730 120-Volt / 30-Amp unit online for our R•pod 177. My question: Is this going to take care of “surge” and electrical management or should we return and get something else? Thank you for your reply. —Linda M.
Is a surge protector enough to protect an RV?
Hey Mike,
I’ve recently purchased the top Progressive EMS 30 Amp surge protector which seems to work great. I now have several extra test gadgets (the Fluke Non-Contact Voltage Detector, as an example) and wonder if I need to hold on to them. Can I now just plug into pedestal power and not worry about extra electrical testing? Thanks. —Martin F.
Overloaded wires – What’s the big deal?
Dear Mike,
You’re always warning us about overloaded wiring, but what can really happen if that occurs? Does the overloaded wiring just get hot, or can it actually catch on fire? —Caleb
Last Month’s Survey
What are your power needs for your RV?
Do you sip electricity or do you want more power? Either way, you need to plan for it in advance. Too many RVers think it’s just like plugging into an electrical outlet in your home. Sad to say, it’s not that simple. You have to plan ahead and adjust your electricity usage to the power that’s available. You can help the industry understand your needs by filling out this short survey and providing your comments. And yes, I know from the phone calls that this column and its surveys are being read by manufacturers who also want to understand your power requirements. Here’s your chance to voice your needs to the industry. So don’t be afraid to speak out and be heard.
Go here for the full survey results and to see the comments that have been posted already.
Don’t come up short!
Sometimes your 50-amp power cord is not quite long enough! That’s when this 15-foot extension cord will come in very handy. Sure, you can use a wimpy orange extension cord with an adapter — and risk burning up the cord, ruining appliances, or maybe even burn up your rig! With this cord along you’ll be all set. Learn more or order.
Q&A’s from Forums
I spend a lot of time on dozens of other RV forums answering questions about electricity. Here are two of them:
From the Jayco Forum:
Q: The campground where I am hosting right now had a problem with several campers in one area with complaints of getting shocked (or tingled) when touching outside metal parts of their rigs. The campground called in an outside electrician and he traced the problem back to one older rig. When it was plugged in to the pedestal the problem existed for all others on that same circuit. He was told not to plug in until his problem was solved. This was just yesterday so I haven’t heard what his internal problem was. The campground circuit was checked completely at each pedestal and found not to be the problem.
A: I’ve talked to a few of my EE buddies about this situation, and we all agree that if you’re seeing this same ground voltage at multiple RVs plugged into different pedestal outlets, then the likeliest cause is a compromised Ground-Neutral bond in the campground’s service panel leg that’s feeding all those pedestals. This can be very dangerous since a ground fault in a single RV can be reflected to everyone else on the campground loop. Also be aware that because UL won’t allow the EGC ground to be disconnected by any safety device, even a Progressive Industries EMS can’t disconnect you from a reflected hot ground (but it will shut down your interior power), nor will any GFCI trip and protect you no matter where it’s located in the circuit.
The best way for the campground to test for a proper impedance EGC ground is to use a ground loop impedance tester such as a SureTest Analyzer or Amprobe INPS-3. These are a little expensive for a casual user since they cost around $300, but certainly any campground or electrician should be able to afford one. I’m advocating that all campgrounds are checked for ground loop impedance every few years, or anytime a pedestal has been damaged and repaired or replaced. But it’s slow going because of the “it’s never happened to me” crowd. However, I get emails about this all the time and have mocked up a demonstration to prove how this works and ways to measure it. —Mike
From the Forest River Forum:
Q: We recently purchased a pop up camper. We set it up in the driveway to check things out. My daughter got a shock when she was standing on the grass and touched the camper door. I checked it out and realized that the extension cord had a missing ground prong on the plug. I hooked up a new extension cord with a good ground wire. Then the camper did not shock me. Exactly what’s happening here?
A: The thing to understand is that anything plugged into a power outlet has at least some leakage current to its chassis. And if there’s not some way to get rid of this current, then it turns into a voltage on the “skin” (actually the chassis) of the appliance or RV. Even the tiny iPhone will develop around 60 volts on its “skin” when plugged into a charger since there’s no ground pin on the plug. But the amount of leakage current in that case is so small (typically less a 1/1000 of an ampere or 1 mA) that you don’t feel it.
However, an RV has a lot of internal connections and appliances, all of which leak a little current to the chassis, and that current is additive. So any RV without a grounded plug can easily leak 1 to 10 mA of current to its chassis, and that would normally be shorted to ground via the ground pin on the shore power cord. If that safety ground connection is eliminated either by a non-grounded extension cord or outlet with a missing ground, then the chassis (skin) of the entire RV can become electrified with voltage.
Sometimes this is a harmless tingle if there’s not a lot of available current or you’re standing on dry ground. But if your feet are wet and there’s significant leakage current (much over 10 mA or 10 milli-amps) then you can be severely shocked or even electrocuted (killed) when touching anything metal on your RV and the wet ground. So every RV needs to be connected (bonded) to a proper safety ground wire in the shore power plug.
If you feel any kind of shock, or measure more than 2 to 3 volts between the RV chassis and a ground rod in the earth, then that safety ground has been interrupted somehow, and the RV can develop a hot skin voltage and turn deadly at any time without you knowing exactly when. So NEVER hook up shore power to an RV without a properly grounded extension cord, and NEVER ignore feeling a shock since that’s a hint that the RV’s safety ground is no longer connected properly. —Mike
Camco Store at Amazon.com
There isn’t much you need for your RV that Camco doesn’t have. If you think we’re kidding, then click through to the Camco store on Amazon where you’ll find some of their best-selling products — all for your RV or for you to make your RVing better. Click here and you’ll feel like a kid in a candy store.
Quick Tips
#3) Using a dog-bone adapter
If you have a 30-amp shore power plug on your RV you can use a dog-bone adapter to plug it into a 50-amp pedestal outlet if that’s the only thing available. However, you won’t get any more power out of it since your RV’s electrical system is limited to 30 amperes of current. And you certainly don’t want to be pulling 50-amps through a shore power cord that’s only rated for 30 amps. Best to eliminate all adapters if possible and plug into the proper 30-amp outlet to begin with.
See Gary Bunzer, The RV Doctor’s, article on this topic here.
#4) Check your test gear batteries annually
Don’t forget to check and possibly change the batteries in your voltmeter and other test gear every year before the RVing season starts. While many of these meters will shut themselves off automatically, batteries still have a shelf life of maybe 5 years at most. A simple battery tester like this one can help keep you from getting stuck without a working meter in the middle of nowhere.
The best book on RV electricity, hands down!
RV Travel contributor Mike Sokol is America’s leading expert on RV electricity. Mike has taken his 40+ years of experience to write this book about RV electricity that nearly anyone can understand. Covers the basics of Voltage, Amperage, Wattage and Grounding, with additional chapters on RV Hot-Skin testing, GFCI operation, portable generator hookups and troubleshooting RV electrical systems. This should be essential reading for all RVers. Learn more or order
Videos by Mike about RV Electricity
• How to use a clamp ammeter.
• How to use a digital multi-meter.
• Don’t use 2-prong ground-lift adapters.
Easy way to level your RV
You have never seen anything like these incredibly innovative RV levelers from Andersen. They provide quick, easy leveling at any increment between 1/2 inch and 4 inches on RVs up to 30,000 pounds. Toss away your blocks! These are far better! Watch the video to see how they work. Learn more or order at Amazon.com.
My Other Life
As many of you know, I’m a pro-sound engineer and technical instructor by day and often find myself in really strange situations. Here’s a picture of an install I worked on last year that may make you a bit queasy if you’re afraid of heights.
Part of my job is installing large sound and lighting systems in schools and churches. And invariably this A-V gear often needs to mount from the ceiling. So how do you get it up there? Well, with a couple of man-lifts and a duct-lift.
That’s not me at the top. I’m on the bottom directing the lift and trying to keep everyone safe. Yes, we had safety harnesses in place and all the OSHA-approved safety gear. But it’s still dangerous work that demands your complete attention. As they say, it’s not the fall that hurts – it’s the sudden stop. —Mike
Road Signs by Mike Sokol
I have learned from a lifetime of misplacing objects, that often the best way to find something is to not look for it directly. Seems counterintuitive, but it’s true for me, at least. I’m the quintessential absent-minded professor who sets down the screwdriver already in his hand while searching for a wrench, only to lose the screwdriver in the process. Then I’ve got to look for the screwdriver without losing the wrench again. So you can see I’ve had a lot of practice looking for lost objects. But knowing how to look for a lost object is important…
STAFF
Editor: Mike Sokol. RVtravel.com publisher: Chuck Woodbury. Managing editor: Diane McGovern. Staff writer: Emily Woodbury. Advertising coordinator: Gail Meyring.
Everything in this newsletter is true to the best of our knowledge. But we may occasionally get something wrong. So always double check with your own technician, electrician or other professional first before undertaking projects that could involve danger if not done properly. Tips and/or comments in this newsletter are those of the authors and may not reflect the views of RVtravel.com..
Mail us at 9792 Edmonds Way, #265, Edmonds, WA 98020.
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This newsletter is copyright 2018 by RVtravel.com.
Just a clarification on the clamp-on amp meter advertised in the newsletter. You cannot get an amp reading by clamping the meter over a whole cord. It must be clamped over a single wire, not a bundle of wires. I have made a pigtail cord that has each wire separated that I keep with my meter. You do have to unplug your device, put the pigtail in and re-plug before you can get an amperage reading.
You are correct. I’m going to do a Mike on Mic video about how this works. So stay tuned…
Mike,
All this info you are putting out there is great-Thanks!
I have a concern and wonder what you think of this.
My Rockwood trailer has one GFI circuit. There is a total of 13 electrical outlets on that one 15 amp circuit. One of them is always used for the fridge, another is used for a fireplace heater, and the rest are for whatever I plug into them.
Somehow putting all the receptacles on one circuit did not seem very smart to me, but maybe it’s not an issue. In general, I have noticed a lot of things electrical on this trailer that just don’t seem like any common sense was involved.
Your thoughts?
Seems like a bad idea to me. Of course, it shouldn’t be dangerous since the 15-amp circuit breaker will limit the current so nothing catches on fire. However, this is likely impractical since it’s way too easy to overload a single 15-amp circuit with even a few appliances turned on at the same time. Plus the additive normal leakage currents probably contribute to random tripping of the GFCI itself. Load balancing across two separate circuit breakers would be a better design, I think. But that would probably cost the manufacturer $20 more in parts.
Mike
Can you please explain ?
RPBG wiring (Reverse Polarity Bootleg Grounds).
Thank you
Mike
Can you please explain ?
RPBG wiring (Reverse Polarity Bootleg Grounds).
Thank you
Here’s the article on RPBG theory that I wrote for EC&M Magazine which goes into great detail. https://www.ecmweb.com/contractor/failures-outlet-testing-exposed
In short, a Reverse Polarity Bootleg Ground condition happens when someone tries to take a shortcut when upgrading a non-grounded outlet from pre-1968 wiring to a grounded outlet. If they don’t run new cable with a ground wire, then some older electricians would simply put a jumper wire between the neutral and ground screws on the outlet. That’s a “bootleg ground” which sort of works, but is a code violation. However, if they accidentally get the hot and neutral wire reversed (polarity) then it becomes a Bootleg Ground that also has Reversed Polarity. Hence it’s a Reverse Polarity Bootleg Ground. I often find them in older churches that have “upgraded” the electrical outlets around the stage to accommodate musicians, and in pre-1968 house garages to accommodate power tools that require a grounded power plug. What’s really dangerous of RPBG miswiring is that it will fully electrify the chassis of anything with a grounded power cord plugged into it, but the appliance will appear to operate normally. And there is no Smart Surge protector on the market that can detect or disconnect you from an RPBG. Nor can you find one with any standard voltmeter test. However, a basic Non Contact Voltage Tester can easily discover an RPBG. How often these happen is anyone’s guess, but they generally happen when a DIY guy, workcampers, or church volunteers offers to hook up grounded outlets for cheap. That’s when the trouble begins.
Good morning Mike,
This issue is making my head hurt. I have a 2001 Newmar Dutch Star 3852. Hooked up to shore power, from time to time, while watching TV the AC power shuts off. It will come back on in a while but sometimes takes a long time. I went to the electrical panel in the bedroom, determined which breaker controlled the TV and lights. It is a 30/20 amp breaker but it was not tripped. I turned it off (30A) and back on and and when in the off position, the TV came on. Turned it back to on and the TV shut off. I then turned the breaker off and the TV and the power stayed on. If I turn it off, wait a few seconds, turn it back on, it will stay working until the next time. Yikes! Thank you, Greg.
I’ve got to think on that a bit.
Mike
That is the ultimate in anti knowledge and experts that has become pervasive in our society. Since it’s only your opinion you should have told him to test it by grabbing the terminals of an auto or RV battery one hand per pole . Or possibly test Newton’s law of gravity and jump from a high location to see if he would fall..
I am sorry if I sound cruel but that kind of stupidity is endangering us all.
Some students seem to want to argue for the sake of argument and seem proud of their ignorance. Of course if they don’t write down the proper answers on a test and show their work, then they flunk my class. It’s as simple as that, and the university has always backed me up 100%.
And some of them just don’t understand that I don’t make up the electrical “laws”. We call it Ohm’s Law, not Ohm’s Suggestions for good reasons. The math works for as many decimal places as you care to use. Of course when I first learned Ohm’s law we used slide rules, so it should be super easy nowadays on a calculator.
Me too
I have a 2005 Fleetwood providence, while I was attempting to winterize my motorhome I started the generator and tried to turn on the water pump , it did not come on, I then checked the fuses and found that the 10amp fuse to the pump had blown. I replaced the fuse and proceeded to winterize the motorhome. when I finished I turned the generator off and flipped the battery disconnect switch, well everything kept running. flipped the backer switches everything went off except my Xantrex 2500 inverter ,it would not stop running, I had to disconnect the hot battery cable in order to shut the inverter down. Can this be a danger to myself as well to my accessories attached to the inverter.? My AC volt meter was reading 130 in the red.
Hmmmmmm….. Something weird about the Inverter not shutting off PLUS the 10-amp fuse to the water pump being blown. I have to think on this a bit.
Hi Mike,
I’ve got a question….
I was parked in a parking lot with my new (2016) Tiffin Allegro Open Road 32SA . I was not Hooked up to any power, just going into the store for a few items. When I returned to the motor home I opened a cargo door and felt an electrical shock, it felt more like a slight vibration as I ran my finger along the aluminum door. This has happened a few times but as usual with electrical issues, it’s intermittent.
Should I be concerned? What could have caused the issue?
I get a lot of questions about getting shocked from an RV that’s disconnected from shore power. So I’ve answered it in a 2 minute video. https://www.youtube.com/watch?v=MKVvp5b78YQ&feature=youtu.be
For more information on safety around high-voltage power lines, here’s a really great article from Bonneville Power. I’ve talked to the author of this paper about how it relates to RV’s, which is where I got my base information on this topic. https://tinyurl.com/y7zsx4nn
Question me this .
At several illinois statute parks that
have ground fault pedistals. They are tripped by my 50 amp rig.
Why?
If dangerous how do I repair?
I see more and more campgrounds converting to 50-amp GFCI breakers, but unfortunately they’re not really designed to accommodate the normal leakage currents in all of the RV appliances. Those currents are additive and not normally dangerous. On the other hand, if you have any “surge strips” plugged into your RV, then it’s possible that the MOV (Metal Oxide Varistors) are leaky enough to trip the incoming GFCI. If you have any Surge Strips plugged into your RV outlets I would remove them and see how you do. There is a ground-fault leakage test that can be performed on your RV, but I don’t know of any RV technician who knows how to do it since the test requires some specialized equipment and techniques. Let me think about it and maybe I can come up with an easy test.
John,
I’m doing more research on this. What parks were you in and when were you there? Please email any info to me at mike@noshockzone.org.
Hi Mike,
I like your story about the student declaring that all this electrical stuff is just your opinion! The laws of physics are called laws for a good reason. I’m guessing that this student would also claim that most other natural laws are just opinion as well. Perhaps this student would make an exception for something like, oh say – gravity.
The same student said she suspected I was making up all these electrical words. This was from a seminar I was teaching as a guest professor for the Tele-Communications class at a major university, and the host professor seemed embarrassed by his student’s attitude. He told her that “Professor Sokol doesn’t make this stuff up”, and that both he and I taught from engineering, physics and electrical code books. She seemed unconvinced, so maybe she’s also a member of the Flat Earth Society.
Hi Mike. I was trying to read the articles and the adverts were blocking the text. Could not close the adverts. Using a lg g4 phone. Good info in articles. Thanks. Frank
I’ll ask Chuck and Diane to look into it. I don’t do the final ad placement myself, but I do know there’s a lot of automatic advert magic happening in the background sometimes. Maybe there’s something they can do to clear up the problem.
Hi, Mike and Frank,
Chuck is the ad expert, so I’ll bring this to his attention. (Or it might require our I.T. guy working his magic on the formatting, etc.) It apparently slipped by Chuck when your comment first came in. Sorry, Frank. And thanks for catching this, Mike. —Diane at RVtravel.com
I’m considering how to present a 12-part course on basic RV electricity, so I’m looking for a good way to create a little test at the end of each section. Perhaps it needs a self-test section with multiple choice questions. I do more advanced testing at University level right now with an actual set of quizzes and exams for each class, but that’s way too complicated for casual readers. Much more to think about.
As far as complex concepts, plow deep!! I’d much rather have factual science and risk information than sweeping mandates. Best practices are seldom as universal as some claim. I may be strictly safest soldering microchips with welding gloves to keep from burning myself, but couldn’t do the job that way, eh? Once they understand kickback, you’ll find EVERY logger topcuts with their saw against best practices…etc. So, just saying keep up the good work explaining WHY things are done a certain way — wise or not, at least you’ll have warned folks who disagree with advice.
Wolfe,
Will do… In my current seminars I work hard to stratify the teaching levels even in a single classroom situation. That’s because I’ll typically have beginners, intermediate users, and highly skilled technicians, all in the same room. But breaking complex subjects down to the most simple concepts is good for everyone, even the most knowledgeable technicians I teach. That’s also why I like to create simple graphics and demonstrations of complex ideas. It’s really the best way to teach at all levels.
HI MIKE ,,where can I find info on the newer mtr home multiplex wiring systems??? thankes…joe
I don’t think the RV manufacturers will know much about this, so I suggest you talk to tech support of the actual gear manufacturer. Remember, the RV manufacturers are basically component assemblers, and probably don’t understand the inner working of these advanced technologies.
Mike – I’ve read your book, and THOROUGHLY enjoy your newsletter! As a nearly-retired Civil Engineer, I really enjoy your methodical approach and practical explanations. Keep it up and, how do we convince you to make this a weekly newsletter??
Thanks very much. Chuck and I have talked about upping the frequency of my newsletter to maybe twice a month later this year. But that will depend on getting a sufficient number of readers signed up for it. So if each of you who reads this newsletter reaches out to everyone they know with an RV, that will help speed up the process.
Actually, this depends on if the campsite wiring is in daisy-chain or home-run topology. In home-run wiring with a direct feed to each pedestal from the service panel, the campground only needs to provide a 50-amp/240-volt circuit breaker on the main service panel and wiring capable of 50-amps feeding each pedestal. That’s code for home-run wiring since there’s nothing in the NEC that requires each pedestal to be able to power the 50, 30 and 20 amp outlets simultaneously. This is also why it may not be possible to share the 30-amp and 50-amp receptacles at the same time in a home-run pedestal configuration. However, if the pedestals are powered in daisy-chain configuration, then they may run a single 200-amp feed that jumps from pedestal to pedestal. In that case you could run the 50, 30 and 20 amp outlets all at the same time. The latest code is suggesting that home-run wiring is preferred to daisy-chain wiring since there’s less of a chance of a break in the wiring affecting multiple campsite pedestals.
As a review, note that a 50-amp pedestal is actually 100-amps of total power since it’s really 2 legs of 50 amps each. And 50 + 50 = 100 amps.
I think there’s a typo here. In the first sentence of the second paragraph, you meant ‘100’, not ‘1000’, right?
Oops…. Too many zeros. Thanks for the heads up and I’ll go fix it now. Yikes!!!
Great articles as always. As I was just re-reading things something came to me to ask you in your experience of RV campgrounds and such. It seems most pedestals have a 50 amp, 30 amp and 20 amp circuit breakers and plugs. I would hope the build of pedestals are typical but here is my question even if it is a little dumb….I hope pedestals are built to be 100 amp feeds to the pedestal? Wire size and circuit feeds back to a main bank bank breaker. Is this the case? Do you know about the other side of pedestals? Many thanks.