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


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.


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 these circuit breakers should be SWD rated for switching under load. If not, then the campsite is wasting their money on regular home-rated breakers. Oh, well…

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

Gene Bennington

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.

Teresa Meyer

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


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

I like the JAM idea, whole wheat or white?


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.


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.

Linda Kay

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.


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


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.


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?


What do you have against whole wheat toast?

Steve Kelley

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.