Tuesday, October 4, 2022


RV Electricity – No~Shock~Zone by Mike Sokol – Issue 20

Issue 20 • June 30, 2019

Brought to you as a public service by RVtravel.com. Support comes from our sponsors, advertisers and the contributions of readers, who believe that an educated RVer is a safe, happy RVer.

Subscribe to one of our many online newsletters (including this one) about RVing.

Read back issues of this newsletter and many other articles by Mike Sokol on RVtravel.com. Warning: There is a lot to learn here.

Welcome …

By Mike Sokol   

This week I’m featuring an interview I just did with Todd Mullane from Proteng, where we discuss fire protection systems for RVs. I’ve asked both my Facebook and RVtravel.com readers to send in questions, and they sent a lot of great ones. We’ll have to whittle down the list to the Top-10 Questions, but we’ll all learn a lot about how fires occur in RVs, ways to protect our families from an RV fire, and how to stop fires from burning your big investment to the ground.

Also, I just turned 65 last month (yikes!), so you’ll want to read my Road Signs essay where I look back at all the strange jobs I’ve had since I was a preteen, along with my plans for the next 30 years or so. Optimistic about the future? You bet I am.

I’ll also list my previous 2019 RV Electricity seminars, post my upcoming seminars, and ask for your help finding new places to present RV Electricity education around the country. So thanks for visiting and please read on.

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.

If you haven’t yet, be sure to join
my new Facebook group, RV Electricity.
(More than 2,800 members and counting.)

RV Road Safety

How can we protect our RVs from a fire?

Fewer things are more frightening or devastating than a fire in your RV. While I’m not a firefighter by any stretch of the imagination, many of my high school buddies and even guys who played in my rock bands were either volunteer or paid firemen. The stories they told about fires they worked were fascinating and frightening at the same time. For these heroes (and I classify anyone who runs INTO a burning structure to save your bacon a hero), some of the worst fires they worked involved mobile homes and RVs.

Think about it … You have a confined space stuffed full of combustible material, wrapped in thin metal, and limited egress points. Plus, there are typically propane tanks, plastic jugs of gasoline, and an unknown number of adults, children and pets. Once a fire starts in an RV you have literally seconds to get you and your family out safely, so don’t think you’re going to actually fight that fire with the little 2 1/2 lb. extinguisher hanging in the kitchen cabinet. Its real job is to give you and your family a few more precious seconds to get out safely.

So what can you do to stop a fire once it starts in your RV? Well, there’s a new firefighting system called THIA from a company named Proteng. I interviewed Todd Mullane from Proteng on Friday night. Todd is a retired veteran Fire Chief having served in the United States Air Force, Air National Guard over 30 years, with training from the Air Force Fire Academy, Texas A&M Fire Academy and University of Maryland Fire Academy.

Here are a few highlights from my interview with him. Because it’s an hour-long video, I’m going to edit it into bite-sized 10-minute portions in the next several days and post them one at a time on YouTube over the next few weeks. But here’s what I’ve learned so far based on some the excellent questions you posted. And yes, I’m JMS if you don’t know that already.

Read more.

Email me at mike (at) rvtravel.com with your questions.

Amazon Deals of the Day!
Here are more than 1,000 special deals, just for today. And the items just keep on changing. If you can’t find a great deal here on something you want, then, well, you must not need anything. If nothing else, it sure is fun to poke around here to see the incredible array of cool stuff that’s available today at bargain prices! Click here for today’s deals!

Watch Mike’s one-hour recorded webcasts
(in case you missed them)
All about portable generators. Recorded May 19, 2019
RV power pedestals: what you should know. Recorded May 10, 2019

Industry Updates

Cummins to acquire fuel cell supplier Hydrogenics

Story by RVBusiness

Cummins Inc. announced that it has entered into a definitive agreement to acquire, through a wholly-owned subsidiary, all the issued and outstanding shares of fuel cell systems provider Hydrogenics Corp. for an enterprise value of approximately $290 million.

“We are excited that Cummins has reached an agreement with Hydrogenics to welcome the employees and innovations of one of the world’s leading fuel cell and hydrogen generation equipment providers to our company,” said Tom Linebarger, Cummins chairman and CEO. “We look forward to partnering closely with Hydrogenics’ team in the coming weeks as we work toward closing the transaction. Upon closing, we will share more details about the acquisition and our strategy to offer a broad portfolio of power solutions to meet our customers’ needs.”

“It takes vision and an innovative spirit to take on next generation technologies and provide the environment for them to grow,” said Daryl Wilson, president and CEO, Hydrogenics. “Hydrogenics has worked for 24 years to emerge as a global leader in fuel cell and hydrogen solutions in the power industry. We are deeply honored to now join with Cummins on the transformative journey of next generation clean power solutions.”

As a part of the transaction, The Hydrogen Co., a wholly-owned subsidiary of L’Air Liquide, S.A., and Hydrogenics’ current largest equity shareholder, will maintain its ownership in Hydrogenics.

Survey Question

Do you have a digital clamp meter?

In addition to a digital multimeter, another great troubleshooting tool is called a digital clamp ammeter (or clamp meter). This is a little more advanced than using a voltmeter to measure pedestal voltage. It’s all about measuring amperage in various electrical systems. With that in mind, please answer the following survey:

Tesla vs. Edison: The Life-Long Feud that Electrified the World
Nikola Tesla is largely overlooked among the great scientists of our modern era. While Thomas Edison gets the glory for discovering the light bulb, it was his one-time assistant and life-long arch nemesis, Tesla, who made the breakthrough in alternating current electricity. Today all homes and electrical appliances run on Tesla’s AC current. This book is fascinating!

Last month’s survey results:

(Click on image to enlarge.)

Do you carry a digital multimeter with you?

I’m impressed. Looks like 90% of you carry some sort of digital meter, and only 10% don’t use one because you don’t know how. Pretty great numbers, really.

Be aware that I’ve begun republishing my original 12-part No~Shock~Zone series on RV Electricity, and will be including extra articles on digital meter usage in the near future. I’ve already published a recent article on using a digital meter to measure 120-volt outlets HERE, and I reran Part 3 of NSZ on metering 50-amp outlets correctly HERE. So keep reading and studying, and please pass any of my articles on to anyone who has an RV. If you have any questions relating to digital meter usage, please email mike@rvtravel.com with the subject line “meters” and I’ll see it right away.

—Mike “The Meter Man” Sokol

Tools and Other Devices

Get yourself a good tool kit

As a road dog, I’ve spent many an hour putting my Sprinter Van back together at a rest stop or hotel parking lot. How did I do it? Well, besides being a pretty decent mechanic, I downloaded and printed out every repair manual I could find on this thing.

Plus, I brought along a good selection of mechanics tools. In some cases, having the right tools (and the knowledge to use them) saved me DAYS of waiting for someone to tow me to a shop and fix something simple, like a serpentine engine belt or fuel filter clogged by a gas station with crappy diesel.

I’ve been looking for a nice portable tool kit for my next RVing adventures, and I think this one from Crescent is a good contender. I just need to add a few digital meters and tape (electrical and gaff) plus a hammer and pry bar to persuade things that need persuading. For less than $100 you can add a nice tool kit to carry on your next RV trip, which can save you a lot of heartache with a quick roadside repair. Get it on Amazon.com, or find something similar at your local big box store (Sears, Home Depot, ACE, etc.).

Last Month’s RVtravel.com Posts

These articles are rated Moderate to understand for most RVers.

Electrical safety for RVers – Part 2: How to use a digital meter.
What causes transfer switch burnt neutrals?
Back to the beginning. Plus: Electrical safety for RVers – Part 1.
Surge protector types and what they each do.

Last Month’s JAM (Just Ask Mike) Session posts:

These articles are rated Easy to understand for beginners.

What are AC and DC power?
GFCIs are different in an RV than a house.
Is there a cheap and quiet generator?
Is it OK to use a 90-degree power cord adapter?

Mike’s Featured Tips in last month’s RV Daily Tips Newsletters:

(These are not necessarily electricity related.)
Keep your cool out there
Bye bye petroleum!
Knuckle busters … Save yourself from (bigger) shocks.
Organization is the key to happiness.

Stop rust and corrosion
Of the many gremlins that attack your RV —like mold, mildew, leaks and black streaks — rust will attack your hand tools, spare parts, door hinges & other vulnerable metal surfaces & moving parts over time. STA-BIL® Rust Stopper prevents rust & corrosion by protecting metal surfaces with a long-lasting barrier while lubricating parts & tools to stop squeaks & sticking. Learn more.

Q&A’s from my Facebook group:

I’m getting a lot of interesting questions on my RV Electricity Facebook Group. Here’s one about hooking up a battery disconnect switch. 

Q:  I want to install a battery cut off (disconnect) switch. I have two six-volt golf cart batteries. Do I install the switch on the positive or negative side? —John Swauger

A: Wow, there were a ton of answers from readers for this one, with many heated posts about this way or that way being the right or wrong way. So let me boil this down into a few definitive answers.

You can find tons of examples (NASCAR, for example) that have them on the positive terminal. And, alternately, there are a lot of examples (and emotional support) for the disconnect switch being placed on the negative terminal.

If you think about it, this isn’t about accidentally making contact with the frame from a tool on the positive terminal of the battery. It’s about having a disconnect switch on the  battery terminal which would completely isolate the battery from the wiring, and would that wiring then be rendered safe from accidentally shorting it to the frame.

That being said, I think there’s a lot of confusion about the word “disconnect” in this context. As a verb, if we “disconnect” the battery using a wrench on the terminals, we certainly want to remove the negative battery terminal clamp first. That avoids the problem of having a wrench on the positive battery terminal making contact with the frame, creating a high-amperage short circuit.

I know all about this since when I was a teenage pump jockey in the ’70s I witnessed one of the mechanics getting his wedding ring trapped between a wrench on the positive battery terminal and the frame of the car. The result was several hundred amperes of current flowing through his wedding band (yes, it was still on his finger at the time), and heating it up to cherry red in a just a few seconds as he was screaming and trying to get loose. Yes, it had welded his ring and wrench to the frame. Once he yanked it loose he ran to the sink and submerged underwater in a cloud of steam. So I know NOT to do that.

But if we use the word “disconnect” as a noun, then it’s a disconnect switch already on the battery. So when you throw the “disconnect” switch, you’re actually disconnecting your RV’s entire 12-volt DC electrical wiring from the positive (or negative) terminal of the battery. In either case it’s impossible for any voltage differential to exist on the wiring due to the house battery, and it should be 100% safe.

I’ll do an extended article on this in a few weeks, but the main point is that if you “disconnect” the battery with a wrench, you need to remove the negative terminal first (and replace it last). But if you use a “disconnect” switch, it’s perfectly fine for it to be on the positive or negative battery terminal depending on which one is more accessible. So you can install it wherever it makes the most sense physically, and the electrons won’t care.

And kudos to whoever mentioned electron/hole theory. But of course, it’s not relevant to this battery disconnect discussion – only a cool piece of obfuscation. I used this Jedi mind trick as a student in school all the time whenever I wanted to “tweak” the teacher and disguise the fact that I hadn’t completed some assignment, and they hated it(!). And now I’m a professor who has my students try to do the same thing to me. I guess what goes around, comes around, eh?


Email me at mike (at) rvtravel.com with your questions.

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 

Mike’s RV Electricity Seminars

Knowledge is power, and I’m delighted to offer my educational RV Electricity seminars to RV Shows and Rallies around the country, both large and small. If you know of an RV show or rally that could use this educational content, please contact mike@rvtravel.com with the subject line Seminars.

Advanced 3-hour Training Class in Hershey confirmed, Sept. 14. More information and preregistration HERE. The actual registration page will be online in a few days, so check back soon.

Upcoming Seminars

Enumclaw Expo RV Show near Seattle, WA: Aug. 1-5, seminar dates and times TBA.

Hershey RV Show in Hershey, PA: Sept. 11-15, 9 a.m. to 10 a.m. Understanding RV Power & Surge Protection (free seminars).

Holiday Inn Harrisburg/Grantville, PA: Sept. 14, 1 p.m. to 4 p.m./5 p.m. Advanced RV Electrical Troubleshooting. 3-hour class plus 1-hour Q&A ($125 per seat). More information and preregistration HERE

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.

Road Signs

By Mike Sokol

Looking back on 65 years …

Golly, I can’t believe I actually made it to 65 last month! Of course, my twin brother, Joe, is 20 minutes older than me, so I was sure to remind him of the fact that he turned 65 before I did.

In any case, 65 is a great time to reflect on things I’ve done in the past, and things I want to do in the future. I’m hoping for another 30 years, and that’s not just wishful thinking. My grandmother was 87 years old when she died and didn’t have a gray hair on her head (Thanks, Grandma). And my dad is still kicking at 90 years old and doesn’t have a gray hair on his head either (Thanks, Dad). I’m noticing a few “highlights” in my hair, which my wife is apt to point out.

But no matter what the state of your hair is, or even if you have no hair left, I think that life should be about what you’ve done before and what you plan to do next. So without further ado , here are some of the highlights of what I’ve done over the last 65 years and a few possibilities for what I would like to do in the next 30 years, if the good Lord’s willing and the creek don’t rise.

Special linguistics note: Yes ado (as in further ado) is the correct spelling, not the french word adieu (goodby or farewell) which I incorrectly wrote and our fearless copy editor Diane was quick to correct. If you want to know why I was wrong click HERE for a lesson on eggcorns, but your head is going to spin. See, you’re never too old to learn something….

Read more.


Editor: Mike Sokol. RVtravel.com publisher: Chuck Woodbury. Managing editor: Diane McGovern.

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..

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This newsletter is copyright 2019 by RVtravel.com.


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3 years ago

I have a friend that uses an adapter with 2 30 amp male plugs on 1 end and a 50 amp female on the other side. He uses this set up when 50 amp is not available and 2 30 amp plugs are present. He says it produces 50 amp service. Is this safe and will it harm any appliances in the coach?

Bill Forbes
3 years ago

Didn’t see a good answer to today’s question – I have an analog clamp meter which I rarely use.

Bruce Anderson
3 years ago

The shore power works fine. The generator power doesn’t work at all. It use to. Someone said the transfer switch needs to be replaced. Someone else said the transfer switch contact screws are loose. Is there a test to positively prove what the problem is? The breaker panel and transfer switch appear to be one unit in a sheet metal box. I have a 30amp system would any new transfer switch be compatible if replacement is required? Can the switch be tested or repaired. 1994 Damon Frontier Flyer 29′. Generac Generator NP-52G, 92050.

3 years ago

While on Army duty, one of our radio mech’s managed to short his wedding ring to an extremely high voltage transmitter power supply. Bye bye finger and ring.
As a result, I wear no metal anywhere.

Bob Godfrey
3 years ago

RE: buying a tool kit. Don’t fall for the cheap flea market type kits for when you need that tool to work it will more than likely fail on you. In one of my past lives I sold brand named tools and I had a mechanic’s “helper” buy a 3/8″ adapter for his sockets from me. A few days later he was banging on the side of my truck telling me I sold him garbage. Upon further investigation I asked him to bring me the extension he was trying to use my adapter on and when I looked at it it was not even square. He had purchased the entire kit at a flea market for about what he paid me for the adapter and thought I was ripping him off but he soon realized he had wasted his money. Those flea market tools are actually dangerous because the sockets will shatter and pieces will wind up everywhere, maybe even in your eye.

Mike Sokol
3 years ago
Reply to  Bob Godfrey

As we like to say, good tools are expensive, but cheap tools are “darn” expensive!

3 years ago
Reply to  Mike Sokol

Years and years ago, when the Dead Sea was only sick, I was using a good brand of 3/8″ inch ratchet and 3 foot snipe to take off lug nuts. Finally realized on the Dodge Power Wagon the left side lug nuts were reverse threads as many Chrysler products were then. When the lug nut came loose it blew the guts out of my ratchet. I took it back to the store, new guts were inserted (no damage at all to the housing) and all was well. No questions were asked on the lifetime warranty which saved a bit of embarrassment.

3 years ago

I have a Clamp Amp, but it is the old fashion analog type.

Mike Sokol
3 years ago
Reply to  Ed

I had a Triplett analog clamp meter 40 years ago that I used all the time for troubleshooting industrial machines. In some ways it was more useful than a digital meter because it showed bumping amperage levels better than a digital display.