RV Electricity – Don’t backfeed power to your RV!

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Dear Readers,

I found this question on the Airstream Forum, and it’s so dangerous that I need to comment about it here. Yes, I do troll around on a lot of other forums, but I really only have time to answer these questions here. So much misinformation, so little time… —Mike 

I purchased my ’63 GT 7 months ago and from what I remember, seller had the trailer plugged into an extension cord (regular everyday orange extension cord) from his garage to single exterior outlet on lower street side of trailer.

For the 1st time I am attempting to plug my extension cord into this outlet and I see the outlet is a FEMALE plug in – Not the male style I have used before.

Is there a special adapter (male-male) used for this outlet?? Any help is appreciated! – 1963 19′ Globetrotter


Backfeed in motion, baby. I’m going to have to penalize you, yeah” (sung to the great tune by Mel and Tim, which you can listen to HERE). But I digress…

OK, let’s review exactly what is happening here, why they’re doing it, and why it’s so terribly dangerous. Plus this is something you’ll often see when somebody needs to do a quick (cheap) hookup of a generator into a house for emergency power. So everything that follows is a Code Violation and is VERY Dangerous.

DON’T DO ANY OF THE FOLLOWING. THIS IS A LESSON IN HOW NOT TO FEED ELECTRIC POWER INTO A HOUSE OR RV FROM AN EXTENSION CORD OR GENERATOR.

First of all, here’s a picture from the forum describing what they’re actually doing. Instead of using a regular male shore power inlet on the side of the RV, they’re backfeeding the power into an exterior electrical outlet.

That’s right, this is an exterior female outlet on the side of the RV, which is normally used to supply power to an appliance on the outside of the RV. But in this case it was used to backfeed power from the house into the RV. This is wrong for a lot of reasons. But first, let’s review how they must have done it.

Suicide Cords Are Dangerous

They used something called a “suicide cord,” which is aptly named, as you’ll see shortly. It’s a male-to-male, 15-amp Edison extension cord you can buy on Amazon (believe it or not) to backfeed power from a generator into a house that’s lost power from the electric company. Here’s what one looks like.

There are also versions of this suicide cord (often called a backfeed cord on Amazon, but DON’T buy one) that adapts from the twist-lock outlet on your generator to a dryer plug in your house. The idea is that with a $60 male-to-male adapter cord you can plug a generator into your house electrical system and not have to bother with a proper transfer switch. Just because they sell it does NOT make it safe or legal.

Why is This Dangerous? 

Well, the primary danger is that if you unplug the male cord that’s feeding the outside outlet on the RV, you now have exposed plug contacts that are energized with 120 volts at full circuit breaker current. That’s dangerous enough on an RV, but if you do it in your house there’s a secondary problem that’s even MORE dangerous.

If you use one of these generator backfeed cords to power your house and forget to turn off the main circuit breaker in your service panel coming from the power company, you will begin backfeeding the 120 volts from the generator into the power company transformer on the street. And that 120 volts will now be stepped up to 11,000 volts or so on the street power transformers, energizing the supposedly dead power lines that a utility worker is attempting to fix. Lineman have been injured and even killed from exactly this type of stunt by a homeowner, so NEVER do it. EVEN IN AN EMERGENCY.

For your RV, make sure you have a properly installed male inlet on the outside of the RV, and use the correct shore power cordset to connect it to a portable generator or shore power. If you don’t know how to do this properly, then please find a properly licensed RV technician to do it for you. And if you have to look it up on YouTube to figure it out, then you have no business attempting this yourself. Seriously!

House Dangers

For your house, you’ll need to have an electrician install a proper male electrical inlet on the outside of the building and a transfer switch hooked up to your service panel that will properly isolate the generator from the electrical company wiring, as well as direct the generator power to the proper circuits in your house.

This is the ONLY safe way to provide power to your home from a generator, so please don’t use a backfeed cord in either circumstance. Yes, some municipalities allow you to use a generator interlock, but that’s a little different and potentially dangerous if someone removes the cover of your service panel. Always check with your local AHJ (Authority Having Jurisdiction) before doing anything like this, and have it properly permitted, installed and inspected. Don’t go cheap on this, people, as other lives are in your hands.

I’ve also had numerous requests about what it would take to use the generator you already have in your RV to power your house in the event of electric loss by your utility company. Yes, I do know how to do this safely and to code, so it will be the topic of a future article. Stay tuned…

Let’s play safe out there….

 

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

 


22 COMMENTS

  1. We are installing an inverter in our camper. My husband wants to backfeed this into a nearby outlet to power the camper when we are not able to use the generator. Besides having a live wire on one end when plugged in, is this otherwise safe?

    • Inverter has nothing to do with it. Suicide cord is dangerous and unnecessary. Adapt the normal shore cord.

  2. Now I’m really confused. Can I use a Honda EU2000i generator to run lights in my trailer. Do I just run the generator to charge my battery and let the inverter run what it can? What would I need? It’s a 2018 Jayco 338RETS and it’s under warranty. I don’t want to void it by hooking something in the electrical system. I have already had a misfired inverter.

  3. I understand that safety is key. The issue here is always knowledge. If you understand the simple fact that you have the ability to isolate your breaker box from the street power by closing the mains, then you can utilize your house circuits, to power essential appliances.

    If you don’t understand that concept, then run extension cords. I use a simple cheat cheat to make sure you don’t back feed power past my own breaker panel. Shut the mains, know your circuit feed line limit. Calculate the watt draw of essential only appliances. If you can’t grasp these concepts, moved to a hotel, and wait it out.

    • Remember, a lot of this is about liability in the event of something going wrong. While you can get away with manually shutting off the main breaker and backfeeding power into your house, if someone gets hurt and the insurance company wants to know what went wrong, you don’t want to be the guy with the cheater cord and no generator transfer switch or interlock.

  4. Mike –

    Your article has a photo of a “properly installed” male inlet on an RV. On several occasions, I have run into a variant of this situation, in which the RV has TWO male inlets. One is a 20 amp household inlet, for use with a small generator or garage power. The other is a 30-amp RV inlet , such as the one in your photo, for the RV’s main 30-amp power cord. This setup is simply a more elaborate version of a suicide cord, since if power is connected to one inlet, the other is energized. Yes, it is covered by a cap. But how do you explain to a newbie or a neighbor or a child that one cover should never be opened when power is connected to the other inlet? BAD SITUATION! The owners were apparently unaware that 30-to-20 amp adapters exist.

    A second quick comment. I’m an electrical engineer, and have a friend who is the same. This friend lives in the boonies of NH, so he has a generator for their frequent power outages. To avoid the expense of a transfer switch, he connects his generator to his house with a suicide cord to an outlet near his entrance panel. He understands that this is a bad idea, but his excuse is “I’m an engineer, I understand the situation, I will always remember to turn off the main breaker on my panel, and I never let anyone else fool with the setup.” Bad idea to start with, of course, and you might emphasize that “knowledge” does not equal “safety”. But even worse? My friend died a month ago, and his wife is now living alone in the house. Does she know how to connect the generator? I very much doubt it.

    For a number of reasons, I am in a unique situation where I have 3 houses. All three have 2 KW standby generators, and all three have transfer switches. I have also put a standby generator in my daughter’s house – WITH a transfer switch – and taught her how to use it. I would have it no other way. I don’t want anybody hurt or killed because I was cheap.

    Bill

    • In many cases you don’t need to go through the expense of a full transfer switch. In my county we’re allowed to use a simple generator lock-out, which fits between the panel’s main breaker and a 30 or 50-amp breaker in the top left breaker position for the generator input. To run from the generator you must shut off the mains circuit breaker, lift the interlock into position, and flip the generator breaker to ON. To go back to utility power you just reverse the procedure. I bought one for my dad’s house for around $60, plus another $100 for the proper generator inlet receptacle, box and some wiring. Money well spent for safety, I think.

  5. We used our RV generators to power selected items in the house during power outages by running orange cords to the specific items we wanted to power, i.e, freezers, and rotating them so that we were not exceeding the capacity of the generator but powering each freezer or refrigerator long enough to keep it cool. This meant the item was unplugged from the house/grid wiring before connecting to the generator. We used battery pack/inverter units to power small loads like TVs, radios, fans, and reading light, or used battery powered items. (In our area hurricanes have caused power outages up to several weeks in duration.)

    • I’ve done the exact same thing, and it’s perfectly safe as long as your generator exhaust is far enough away from the house to avoid sucking in carbon monoxide fumes though a window which can be deadly. But it’s a bit inconvenient, so if you do have an onboard generator in your RV, then it would be pretty simple to add a proper transfer switch or interlock breaker in your home service panel and install an inlet receptacle so you can use your RV’s shore power cord to power your house. I have a plan in my head that will work, but these things take time to document properly so I don’t go spreading incorrect and dangerous information like so many do on the Internet. Stay tuned…

      • I (and I imagine many others) eagerly await reading your properly documented plan. I’ve had a few ideas myself (involving $25 motorized 63A@240V Automatic Transfer Switches), but I instinctively don’t like intentionally backfeeding through my RVs “input” cord anytime, any reason. Effectively making a bidirectional grid in your driveway by “reversing” the shore cable seems sketchy for amateurs, and sounds like it would create a very BIG “suicide cord” by energizing the shore lead. Hopefully i misread your intended plan?

    • Bill –

      An unexpected bonus of your approach is that your neighbors will be surprised, and eternally grateful, if you put your generator on a sled or cart and go knock on their doors with an offer to plug in their refrig or freezer for a half hour. With a little effort, you can take care of half a dozen neighbors this way, and their admiration and gratitude will show up in many ways.

      Bill

  6. Mike, what is the difference between flipping the MAIN circuit breakers off at the power panel in the garage before powering any of the house circuits VERSUS installing a transfer switch? I realize a transfer switch is installed per code BUT if one was in a pinch wouln’t this work? Or does it have something to do with the Neutral & Ground wires which do NOT go through any circuit breaker?

    • The big difference is that with a proper generator lockout or transfer switch it’s impossible to have both the generator and utility circuit breakers on at the same time. That’s when you can energize the power lines through the line transformer with 11,000 volts or more. The male-to-male suicide plugs are a different story. The danger with those is that accidentally unplugging the male end not connected to the generator will expose open contacts. And touching that can easily electrocute (kill) you. As in most of the code, it’s really about putting in layers of safety to keep people from hurting themselves and others. For example, you can probably get away without a proper ground wire in many circumstances where there’s very little leakage current (there is ALWAYS some leakage current, really). But if anything occurs to make more leakage current available (broken water heater element, pinched extension cord, water in a junction box, etc…) then the job of that ground wire is to trip the circuit breaker immediately and save your life. For the transfer switch example you asked about, consider what would happen if you weren’t there and a family member who didn’t understand electricity needed to use the generator for house power. They might not understand the proper circuit breaker sequence and could kill a lineman. The only times I’ve tied portable generators into homes without a lockout or transfer switch during an extended power outage, I actually pulled the electric meter off the house and put a plastic bag over the meter box. That was 100% safe since it was very obvious what needed to be done to restore utility power.

  7. I’m not so sure the prior owner of the poster’s RV was actually backfeeding the RV intentionally — they may have just found a normal exterior outlet and had no idea that’s NOT the input. Even if the prior owner showed the poster, he was just passing on his ignorance. I’d recommend figuring out where the original/proper power input went to or (re-)install one.

    As noted, the danger in feeding the RV through an RV outlet like this is the potential to leave exposed male prongs energized when not plugged in (hence, the “suicide” moniker). Beyond that, you’re feeding the RV through 15-20A breakers and on a modern RV would be limited to that amperage instead of able to use 30A through the “normal” power cord. This is perhaps a partial solution to overloading a thin extension cord, but it remains better to wire a proper full power hookup if you expect to need more power than battery float-charging.

    The feeding of RV generator power back through your house back to the grid IS a serious problem, just as Mike noted. However, I didn’t see a generator mentioned in the original post as quoted here. Absolutely correct info that it’s dangerous to linemen when backfeeding a house without a “break before make” transfer switch to isolate the generator from grid — rather than “suicide cords,” these hacks become “homicide cords.”

    You CAN power your house from an RV generator, provided you have either a grid-feed transfer switch (eg. 200A@240) or per-circuit patch-panel (multiple transfer switches). Again the point is “break before make” isolating the generator from the grid at all times, treating the RV generator the same as any other standby generator.

    • I did a little follow-up on this thread, and it does appear the prior owner was using a suicide cord to backfeed power into a regular outlet. I learn a lot about miswiring from reading all these forums (in addition to my RVtravel readers) that I would never think of myself, simply due to my decades of background in electrical safety. I just saw another thread recommending that you park the tire of your RV on top of your shore power cord (even on asphalt) to keep anyone from stealing it. That’s going to destroy the insulation and probably begin to breakdown the stranded conductors, possibly causing a fire. But there were a bunch of readers on the thread recommending this practice. I think that’s just crazy, and I’ll call one of my Southwire engineering contacts (the guys who actually make the wire for your shore power cord) to confirm.

      • If you want another bad wiring Blooper Award winner, this Summer I ran into someone who had proudly custom wired his own “Y” cable to use two 120V RV generators to “make 240V …because 120+120 equals 240.” It might even have worked on his RV if he only uses 120V appliances (?), but anything actually using 240 hot-hot would have gotten fried.

        Obviously, with no synchronization to hold same phase (120V@2xA like a typical 30A buddy cable) nor counter phase (240@1xA as he attempted), I assume he would randomly create 0-240V as the generators drifted in and out of phase, assuming they didn’t just fight into phase lock near minimum mutual load.

        “Nothing is idiot proof to a really determined idiot.”

  8. When we lose power to the house and have a perfectly good TT sitting outside I just hook the Generator up to the camper and spend some time “camping”. Make the best of a bad situation.

    • I generally agree with you, and just go stay in the RV for a couple hours, usually just running on batteries. That said, I DO generator-power my house in prolonged outages for the sake of my multiple freezers I don’t want spoiling.

  9. Mike, I really appreciate all the information you provide. I read many of your articles/comments to my husband. He’s an engineer, so I get him to explain some of the concepts to me in more detail and in ways I can understand. Also, since he’s an engineer and likes to get creative I can test whether he knows about what you are discussing. He had never heard of “suicide or backfeed cords”. I learned about the Progressive 50 Amp surge protector from you a while back, so I ordered it and told my husband we were using it! Thanks again for educating us.

    • You’re very welcome. As I’m sure you can tell, engineers are “my people”. But I do have a lot of fun figuring out the best way to teach complicated technologies to consumers. To me the engineering part is easy, the real trick is teaching it.

  10. Mike, I never realized you could actually buy these cords. That’s an accident waiting to happen. I’ve seen them home made many times.

    • Yeah, go figure. And I can’t believe that Amazon would actually sell them. Think of the liability if something goes wrong.

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