RV Electricity – Just Ask Mike (J.A.M.): Should I turn off circuit breakers?

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By Mike Sokol

Everyone: Welcome to my J.A.M. Session

This is an experiment to see if you like this Just Ask Mike (J.A.M.) format for a secondary weekly column. I’ll change out the jam for blueberry occasionally, and possibly peach, but no grape jelly is allowed (ugh). Also, no whole wheat toast, only white bread or a toasted English muffin. Please comment if you like this type of article format or not. Thanks…


Welcome to J.A.M. (Just Ask Mike), a weekly column where Mike Sokol answers your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM.

J.A.M.

Dear Mike (aka J.A.M.),

We just returned from our initial Spring Wake-Up Trip. The RV Park we stayed at was exceptionally nice. At any rate, when I went to hook up to the pedestal, all the breakers were in the ON POSITION! Why do RVers leave the breakers on when they leave the campground?

Thought you should maybe mention someplace down the road for RVers to make sure they turn the breakers OFF before they disconnect their power cords.

Thanks. —Jeff


Dear Jeff,

That’s a great suggestion, so here it is. I’m not going to get into the psychology of “why” RVers do certain things, except to say that perhaps ignorance is bliss. So thanks for helping me to educate everyone.

The problem with plugging and unplugging your shore power cord while the pedestal circuit breaker is on is actually twofold. First, the American- (NEMA-) designed plugs we use in our houses and RVs are not totally safe for plugging into a live outlet. As you can see from the picture, it’s possible for your fingers to slip into the gap and touch the live contacts before the plug is totally seated. That can result in a painful shock (or even electrocution – death from shock) if you’re standing in a puddle of water and make contact with a live wire. This suggests that it’s doubly important to turn off the pedestal circuit breaker before plugging or unplugging your shore power cord-set from a pedestal outlet in the rain. And we’ve all had to hookup or disconnect shore power in the rain, haven’t we?

Secondly (and just as important), plugging and unplugging your shore power cord while the pedestal breaker is on will induce arcing from the current trying to jump the gap in the contacts. This usually creates a bunch of pretty sparks which are actually tiny bits of your metal contacts being super-heated and burning up like tiny meteorites zipping through the atmosphere.

Doing it once or twice is no big deal, but doing it hundreds of times will cause a reduction in the contact area of your plug and receptacle. And that reduced contact real estate will force all the current through a smaller surface area, resulting in plug heating. Plus this constant bombardment of tiny hot spots in the contacts will result in oxidation (rust) which will increase the electrical resistance and contribute to even more heating of the plug. Eventually you’ll need to replace your RV’s shore power cord-set, which ain’t cheap! You want to inspect your shore power plug regularly to make sure it’s shiny and bright like the one in the picture above.

I’ve had a few suggestions from readers that pulling out the plug rapidly will stop it from arcing, but that’s simply not the case. And all circuit breakers should be rated for switching under normal loads. In industrial settings we use SWD (Switch Rated) breakers for high inrush circuits like banks of florescent light fixtures. And if campgrounds wanted their circuit breakers to last for decades, then SWD rated breakers would be a good option. However, few of them think that far ahead. But I would guess that even consumer rated breakers would be rated for 10’s of thousands of cycles under load, which suggests perhaps a decade or more of proper operation.

I have a hypothesis that constantly plugging and unplugging shore power connectors with the circuit breakers on (and under load) contributes to the number of obviously overheated and visibly burned shore power plugs, especially the 30-amp versions. Also remember that this plugging and unplugging under load is wearing out the contacts in the pedestal outlet as well. And that overheating probably contributes to loss of tension in the contacts. I’m sure all of you have plugged into a pedestal outlet that seemed really loose. I’m suggesting the looseness is likely the result of overheating which reduces the tension on the electrical contacts, and this overheating probably started with contact arcing from the shore power cord being plugged and unplugged with the circuit breakers on.

So, break the cycle of shore power contact abuse. ALWAYS make sure the pedestal circuit breakers are OFF before you connect or disconnect your shore power plug. Your contacts will thank you for it.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there….

 

Mike Sokol is an electrical and professional sound expert with 40+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

 

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24 Comments
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Kenneth Neumiller
10 days ago

Everything was working fine woke up no 110 power..checked power supply…gfi…if I turn only the 15 amp brakers on I get some power to read correct on my plug tester
..still won’t turn appliances on.when I turn other brakers on it kill power completely?

Sharon
1 year ago

This is a perfect method for teaching basic essentials and serves as good reminders for seasoned learners. More please!

Gene Bennington
1 year ago

As a state park campground host, one thing we always did when getting a campsite ready for the next Camper was to insure that all circuit breakers in the power pedestal were OFF. I was amazed that at least 75% of them were on when campers pulled their plug.

Admin
RV Staff (@rvstaff)
1 year ago
Reply to  Mike Sokol

That sounds like a “no-brainer” to me, Mike. It seems like a little effort on the campground’s part to mark every pedestal with a reminder to switch off the pedestal circuit breakers before plugging into or unplugging from shore power would benefit everyone, especially the campground (less wear-and-tear on the pedestal equals more safety for everyone and longer life for the pedestal [and maybe the users 😉 ] ). Maybe our readers and members of your Stray Voltage Patrol could make that suggestion (to label pedestals accordingly) as they’re checking into or out of a campground. 😀 —Diane at RVtravel.com

Teresa Meyer
1 year ago

Helpful reminder for this newbie. Hope and need more baseline information to build on for a subject I know very little about. Thanks.

Jerry
1 year ago

Question- As a retired fire fighter we were taught to inspect breaker panels in the businesses that we inspected for life safety issues. We were taught that people that used their breakers to turn lights on or off basically negated the safety aspect of that breaker over time and it became only a switch. Is that true and if so do we do the same thing with the breakers in the RV parks we visit? Would it be better if a throw switch were placed between the power source and the breaker box?

Bill Coady
1 year ago

I like the JAM idea, whole wheat or white?

dan
1 year ago

I would read a dozen of your articles each week, they are very informative and remind those of us that know some basics about voltage. amps, etc. but are a long way an expert, of things forgotten or not thought of, and a lot of the time, just plain don`t know. thank you for sharing your knowledge and experience with us.

Connie
1 year ago

In the question letter it states that the pedestal breakers were left on by a previous rver. All rv parks are overseen by someone (owner, camp host, etc). It would seem to me that if the breakers are on, it would fall to the park to watch that. The overseer usually makes sure the spot is ready for the next camper, this should fall into that category. However, as a good camper and protector of our property, we should remember to check that the breaker is off before plugging in. Just like we make sure the stop on the black tank is fully closed before connecting our hose to dump!
I like the column. Electricity is one of my hardest components to grasp.

Jeff
1 year ago
Reply to  Connie

Connie: Your Idea is correct, Park Owners and Workers should be doing this everyday and every time a Camper Pulls out of the Park. Unfortunately, Campground workers are not always the most reliable people to do the job. (That’s being Nice)!

I think the best way would be to ask Park Management to place a small sticker on all the Pedestals to remind Campers to INSURE the Breakers are off, prior to plugging In or Unplugging from the Pedestal. And explain to Park Management why this is important.

I had asked MIKE what he thought about MY placing one of these stickers on each box I plugged into, Mikes Response and he is correct: It might be considered damaging Property.

Tom Bird
1 year ago
Reply to  Jeff

One of the problems I’ve noted is that the breakers are not clearly marked and are sometimes difficult to see. Use of a Sharpie pen marking the OFF would be helpful!

Linda Kay
1 year ago

Wow. Thanks for this information. Either I did not know or maybe I simply forgot that you are supposed to turn the breaker off before removing or plugging in your shore power cord. I have a 30 amp outlet at my house and the breaker is in the basement. Not too convenient but I sure hope I remember to turn it off before the next time I insert or remove my power cord.

Jeff
1 year ago
Reply to  Mike Sokol

Since I use a Progressive Industries Portable Surge Protector, I usually cycle the Breaker twice when I get ready to hook up.

First, I plug in the Surge Protector and check the pedestal for No Error Codes. Second, I turn off the breaker and plug in My power cord and turn on the breaker again, insuring there are no error codes.

Now, according to Progressive Industries, there is a 2 minute and 16 second delay, before any current is released from the Surge Protector to the RV. Those people who have a Surge Protector may wonder why there is NO Instant Power right away?? Built in Delay helps protect your sensitive electronics in the RV

Please be safe out there!

Bob
1 year ago

I like the idea of the JAM format. Strawberry jam for me.

Loren
1 year ago

The j.a.m. format seems OK. You will probably get a lot of questions about subjects you have already covered, but will be a good way to remind or reinforce people on the subject.

JJ
1 year ago

Mike, I last replaced our house batteries 5 years ago – two 12V AGM “house” batteries bought from CW. They have been working OK and show ~13v at the panel. Now I’m seeing the “white stuff” at the negative pole of one battery. So I’m starting to research deep cycle 12v batteries. Can you suggest any resources that would help compare then and come to a decision on purchasing replacements?

Tom
1 year ago

What do you have against whole wheat toast?

BuzzElectric
1 year ago
Reply to  Mike Sokol

I was brought up with Wonder Bread (white). The advertising convinced me it was good for me because it was Vitamin enriched. Back in the pre-dust days brown bread was for weirdos. It just was brown white bread. White was the bestest. Now my wife makes me buy Killer Dave’s whole grain bread. It’s full of whole chunks seeds and grains and made by some guy that was in jail for murder. Got to keep the wife happy. (But white bread tastes so good and is so smooth with no bumps). Oh the days! I do love a McDonald’s regular hamburger.

Steve Kelley
1 year ago

I just camped at a nice COE campground. When I got ready to plug in my 30 amp cord the breakers were off. When I plugged in the cord the contacts were so worn that the power cord fell out as soon as I released it. I used my “dogbone” and plugged into the 50 amp which was good and reported the problem. An electrician was there in a few hours and fixed the problem. I don’t want to think of the problems that could have come up If the breakers had been on when I plugged in.