By Mike Sokol
After being caught at home (Texas) with no electricity during a winter storm, I got to thinking about how I could hook up my RV generator to power my house. I didn’t think of it in time or I would have given it a trial. My RV stays in my RV barn with a 50-amp hookup. This RV does not have an automatic change-over relay. So I wonder if I had just started the generator and left the power cord plugged into the 50 amp circuit would it have powered my house? I thought this might be one to ask you as I have never seen this mentioned before. What do you think? —Jack D.
That’s an interesting idea that I’ve been asked about a number of times, and I casually thought it would be possible with the right kind of home inlet and transfer switch. But now that you’ve asked, I’ve done a deep dive into how installed RV generators are connected. Since I already know all the nuances of how pedestals are wired and what you have to do to use ANY generator to power your house, all I have to do is figure out how the power works for a Cummins-Onan generator.
Take me out to the ball game…
Since it will soon be baseball season, let’s warm up the batter and see how we do at the plate. No, I was never a baseball player. Well, except for a when I was playing in a shale pit less than a mile from my house, a short bike ride away.
Strike 1 – Swing and a miss… with original RV generator idea
Okay, I know for sure that your initial idea won’t work at all, even though it’s been proposed by other readers. It certainly has a big enough shore power cord that one would “think” the power would go both ways. However, it only flows from the house pedestal outlet to the RV shore power inlet. Not the other way around.
Take a look at a typical 50-amp shore power cord as an example. The male plug that connects to your pedestal is an inlet ONLY. The female twist-lock connector is an outlet ONLY. So back-feeding from the RV to the house with this shore power cord won’t work.
Ball 1 – Low and inside…
So I thought about adding a 50-amp female outlet on the side of a typical Cummins-Onan generator that would be found in most RVs. And while it looks like it could work at first, looking at the schematics reveals that RV generators are all wired as two separate legs of in-phase 120-volt power. Therefore, this is NOT the 120/240-volt split phase you need to power your house.
So the sad fact is there’s no practical (or even code compliant) way to wire an outlet on your RV that would plug your Cummins-Onan generator into your house electrical system. Drat!!!
Strike 2 – Foul ball
To top it off, to use any kind of generator to power your house you would first need to add some sort of generator interlock or transfer switch. The type that would be accepted by your local AHJ (Authority Having Jurisdiction / Electrical Inspector) varies from state-to-state and county-to-county.
But I do know that in all cases you would need to mount a male twist-lock inlet on the side of your house and a separate generator panel or lockout breaker to your house service panel.
Strike 3 – Yer out!
If you do want to consider generator power for your house, the time to install it is during the summer. I did exactly this for my dad’s house two years ago. I bought a portable Honda EU7000i generator which can power everything in the house. And even my smaller EU3000is generator can power most of his 120-volt appliances at the same time.
In an emergency, even my Honda EU2200is would work to power a lot of the important things that need electricity in the winter such as my boiler furnace, WiFi connections, computer, and lights, but no air conditioners.
Put me in, coach….
So, yes, if you have a portable inverter generator already (like this EU3000 or a pair of EU2000is generators), you could definitely install a generator inlet on your house with the appropriate transfer switch or circuit breaker lockout.
Then the next time you lose power, simply grab your generator out of storage and hook it up to your generator inlet on the house. Make sure it’s at least 20 feet away from any open windows. You can run it for a week or more on a few 5-gallon gasoline containers (depending on how big of a generator you have).
Don’t strike out next time … with your RV generator
If you all would like, I’ll plan on a future article this summer showing how a generator inlet and transfer switch/lockout is done to code. Yes, you’ll have to pull a permit and get it inspected, but at least you’ll know that it will work safely if there’s another blizzard that takes out the electrical grid.
Don’t strike out… And remember – Failing to plan is planning to fail.
Let’s play (ball) 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 Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
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