Wednesday, February 8, 2023


RVelectricity – Just Ask Mike (J.A.M.): Never plug your RV into a 30-amp outlet without testing the voltage

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer 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) with the subject line – JAM. This week I discuss the potential consequences ofresidential electricians miswiring a home 30-amp receptacle with 240 volts.

Don’t let this happen to you…!

I’ve had a bunch of emails and Facebook group posts this week about residential electricians miswiring a home 30-amp receptacle with 240 volts and frying the RV’s electrical systems. Here’s one example:

Dear Mike,

We have a 2021 Jayco 267BHS. I had an electrician install a 30amp outlet at home so we could plug in. In an excited and regrettable moment I didn’t think to use the surge protector.  Plugged it in and saw a spark and pretty sure I heard a pop at the camper. Put surge protector on and took a picture to send to electrician, who called immediately to tell me to get it unplugged because he didn’t realize it was 120 and he ran it 240.

Unplugged, and everything seems to work fine on battery power. I noticed the AC circuit blew and I switched it back on and seems to work. I have not looked at any fuses at this point. Was away from camper for ten days due to family emergency. Batteries now dead and I used a dog bone to plug in to standard 110 outlet and there is nothing, no power to the rig. I connected to truck power and everything works. Has me feeling better that camper still works, but suspecting we’ve blown the power cord or whatever the connection is where shore power cord connects to unit.

  • How bad is this?
  • Can I consider asking the electrician to fix this? I don’t mean financially, but would this absolutely have to be a dealer issue or can it be repaired if we can troubleshoot and secure parts?
  • Any other thoughts? I don’t even know where to access what I think might be the issue (thinking maybe under lower bunk or possibly remove underbelly?).
  • Appreciate any thoughts about if I’m shut down at a dealer for a long time or it might be something I can handle on my own (or with electrician). The electrician is solid; just miscommunication.


What went wrong?

Dear Erich,

There were many good answers in the Facebook thread, which I’ll sum up here.

  • NEVER trust a residential electrician who may have never installed a 30-amp RV shore power outlet before.
  • The RV TT-30 receptacle closely resembles the old 2-pole, 240-volt dryer receptacle.
  • All 30-amp RVs require a single-pole, 120-volt service
  • Depending on how many fancy electronics you have in your RV and what was turned on during this momentary application of 240 volts, it could fry the converter/charger, microwave, refrigerator, furnace controls, water heater controls, television and lots more. You might be lucky and only blew a few fuses, but I wouldn’t count on it. Think thousands of repair dollars to begin with.

Miswiring mistake was not due to client’s miscommunication

  • This was not a miscommunication on your part as the TT-30 receptacle is plainly marked for 125 volts maximum. It’s up to the electrician to read all documentation and understand the circuit before he wires it.
  • Your electrician is 100% responsible for this error and needs to pay for everything to repair it
  • He may be able to replace everything for you, but you’re rolling the dice. There’s a lot of specialty wiring in an RV that your electrician may never have encountered before, and he’s already had one major failure. But you are correct that many dealerships are really busy and won’t have time to even look at your RV this season. So it could be bad either way.

For everyone else wanting a 30-amp receptacle at home:

Please read one of my dozens of articles I’ve written about this 240-volt issue and show it to ANY electrician before they wire a 30-amp outlet at your house. And always use an advanced/EMS surge protector, especially for 30-amp shore power. Read my latest article on this topic HERE.

And this is my JAM session on how to measure AC voltage with a digital meter. Read it HERE.

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 50+ years in the industry. His excellent book RV Electrical Safety is available at For more info on Mike’s qualifications as an electrical expert, click here.
Join Mike’s popular and informative Facebook group.
And you don’t want to miss Mike’s webcasts on his YouTube channel.

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9 months ago

That is one reason that I do things like that my self. If you don’t know how to do something like that, there are youtube videos or other info on the internet. We had to install a 6-50R for a welder. I was tied up and told my son how to do it. He had no electrical experience. He got it wired up fine. Then we wanted to install an outdoor 14-50R for a camper or welder. Again I was tied up and told my son (now with experience of wiring a 6-50R) how to wire it up. Again, no problems and worked as well as what any expensive professional electrician could do.

1 year ago

This is why electricians should be licenced, bonded and insured. It is the electricians fault. Does he have liability insurance?

1 year ago

I have a 30 anp to 20 amp converter with a standard household circuit tester plugged into that in my compartment with my wire. I plug it in everytime I get ready to plug in. It may not catch everything but it is a quick, easy check for most situations.

John Massengale
1 year ago

I had a box connected to my house and had a circuit breaker and plug for my RV, also had an extension run to the back of the house so I could plug in no matter where I parked. I have never had a problem in 30 yr but I also use a Advanced EMS surge protector

1 year ago

This RV owner failed to take his own power protection advice and never plug into ANY shore power unless his Power EMS device has been plugged in first. Well that’s providing that he HAD an EMS system versus just a “surge protector”. Many RVer’s are being hosed by not spending the extra bucks for a combination EMS Power Protection System that also includes power surge protection. Big difference between the two. Plus power grid surges are the LEAST of a RV owners concern and happen rarely versus other more devastating power problems such as a missing ground or neutral which can kill or cause thousands of dollars worth of damage. Or too high or low voltage which can destroy AC’s and residential refrigerators or anything with motors. As the Fram Oil Filter advertisement we used to see on TV years ago claimed, “pay me now or pay me later”.

1 year ago

Your closing reads, “Please read one of my dozens of articles I’ve written about this 24-volt issue”. Should that be a 240-volt issue?

Thanks, I read you every week and have been a follower since we met three years ago in Hershey.


RV Staff
1 year ago
Reply to  Mike Sokol

Sorry, Mike. Not being an electrician, or nearly as intelligent as you are, I believed you when I proofed your article. Especially since your work is “99+ 44/100% Pure” – or so you keep telling me. 😆 —Diane

RV Staff
1 year ago
Reply to  Mike Sokol

😆 —Diane

1 year ago

Mike, Keep up the good work. I double check everything someone else does. Surge protector always.

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