Use RV Generator for Back-Up Power

[_Rusty_]

We just recently had a storm related outage at a friend's house. She was without power for 3+ days. On the second day I was able to obtain a generator and get the freezer protected, but she lost the main fridge contents. So my question is:

Has anybody else set up their RV generator to provide external power? I'm thinking a female plug right at the transfer switch would be easy, and related hardware at the other end for power distribution. In her case 2 #10awg extension cords made the reach to appliances, but at the time I had no 240 vac. availability to pump water.

Pro's and Con's?

 

[bigb56]

You're going to need some kind of short circuit and overload protection for your added outlet and the cords. Firing up the generator and just plugging the cords into existing outlets in your RV would do that.

 

[_Rusty_]

You're going to need some kind of short circuit and overload protection for your added outlet and the cords. Firing up the generator and just plugging the cords into existing outlets in your RV would do that.

Good point! I was originally thinking about a lockout switch on her fuse panel and use house distribution and fuses, but I can easily add a breaker in the RV to protect the outgoing cable(s).

 

[Isaac-1]

We powered our household refrigerator and chest freezer, and lived in the motorhome for the week long power outage here after Hurricane Laura then again three weeks later for 4 days with Hurricane Delta in 2020. Running them off a combination of our inverter and generator.

 

[John From Detroit]

Many (Most?) RV generators are 120 volt only so no electric range, cloths dryer, electric furnace or central air.. but I did it and very happy.

 

[NY_Dutch]

I have a 50 amp outlet installed in our electrical bay ("poor man's xfer switch") that's fed by the generator. During extended power outages at campgrounds, I can plug in a 'Y' adapter that provides two 30 amp outlets. I've used one to power our coach, and the other one to power a neighbor that had no generator. I haven't needed to use the coach power at home yet, but since I already have a manual transfer switch installed at the breaker panel, it would be easy to do.

 

[Lou Schneider]

I wired our house in WA and my sister's house in CA to use either an RV generator or an external portable generator using a 30 amp power inlet and a mechanical interlock on the house's breaker panel. Since the RV was 30 amp and had a 3600 watt generator I just added a 30 amp socket across the generator's output. The generator has it's own breaker to protect itself against overload so you don't need to add another breaker on the RV.

The mechanical interlock worked very well and is a code acceptable way to connect a generator to the house's breaker panel, It provides mechanical interference so the generator and main utility breakers cannot both be on at the same time.

This will let you power up any circuit you want so you won't have to run extension cords all over the place, just manually limit the loads so you don't exceed the generator's capacity. And like you said, you won't have 240 volts to run things like a water pump or large loads like a water heater or an electric stove so just leave all of the dual pole 240 volt breakers off.

Mechanical interlock breakers are panel specific and are available on the net or from commercial electrical supply houses. Here's a link to a company that packages them for DIY installation.

Interlock Kit & Accessories For Your Home | Generator Interlock Kit

Ensure safe connections between your electrical panel and emergency power with our easy-to-install manual transfer Interlock Kits, ideal for any setting.

interlockkit.com

 

[Boat Bum]

I had an electrician wire a 50amp breaker to my panel with a 20' length of cord with a 50amp plug on the end. I do a similar routine as above except my whole panel is live, I have to only use what's possible in the house. Thers's no lockout mechanism, I just have to follow my own instruction sheet every time and be careful. I do not plug into the RV generator, I have a separate one for that, I considered it but didn't want the additional wear on the RV genny.

 

[Lou Schneider]

I had an electrician wire a 50amp breaker to my panel with a 20' length of cord with a 50amp plug on the end. I do a similar routine as above except my whole panel is live, I have to only use what's possible in the house. Thers's no lockout mechanism, I just have to follow my own instruction sheet every time and be careful.

I strongly suggest installing a mechanical interlock. They're not that expensive and backfeeding generator power into the grid is extremely serious and can electrocute anyone who comes into contact with downed lines. I'm surprised an "electrician" would install a generator inlet without one.

You may religiously follow your written instructions, but can you say the same for another person like a wife or another untrained person attempting to put the generator on line in your absence?

 

[DutchmenSport]

I don't have a motor home, but we use our Cummins Onan P4500i inverter generators (2 of them for full 50 amp service), at home for power outages. Because we have 2 of them, we can keep one on the camper for 30 amp, and the other for the house. We run electric cords to power the refrigerator, freezer, the television, and fan for the fire place in the winter. We also run a line to power our internet modem and to keep our computers running.

If power outages are very long, we'll use the camper for cooking, bathing, and bathroom as we always have water in the holding tanks, even at home. We have a septic tank at home where I can dump my camper tanks, so that takes care of the bathroom needs. At home, we also have Primo water delivery, so we always have fresh water (the 5 gallon ones) ready at any moment.

So, your plan to use the on-board generator on your motor home is very, very doable. I do NOT recommend plugging anything directly into your breaker box to attempt to run the entire house, unless you hire a qualified electrician to install the necessary transfer switches and such. The LAST thing you want to do is back-feed power to the electric grid and end up sending an electric current out and end up killing someone working on the power lines a mile down the road from your house!

 

[Boat Bum]

I strongly suggest installing a mechanical interlock. They're not that expensive and backfeeding generator power into the grid is extremely serious and can electrocute anyone who comes into contact with downed lines. I'm surprised an "electrician" would install a generator inlet without one.

You may religiously follow your written instructions, but can you say the same for another person like a wife or another untrained person attempting to put the generator on line in your absence?

You're not wrong, I was unaware of the interlock device, looks simple enough, I'll look into it. The electrician did this as a side job and emphatically warned me of all the hazardous. It's just my wife and I and she would never attempt try as I did to teach her. Subsequent owners would be a different story. I appreciate your post.

 

[Kirk]

I strongly suggest installing a mechanical interlock. They're not that expensive and backfeeding generator power into the grid is extremely serious and can electrocute anyone who comes into contact with downed lines. I'm surprised an "electrician" would install a generator inlet without one.

I highly suspect that a licensed electrician who did that would lose his license if the local authorities were to find out. The National Electric Code (NEC) specifically requires BBM switches for generator installations to ensure safety and prevent back-feeding. BBM = break before make)

 

[CharlesinGA]

Many POCOs will, if they discover you are generator powering without an interlock, disconnect you from their system and flag your account in their computers to not reconnect you until you either have the illegal feed removed or a interlock installed. Miss one step in your checklist and you can kill a lineman.

I did like Lou, installed an interlock on my Square D panel that looks almost exactly like the one at the beginning of the video above. It requires you have the two breaker positions at the top right of the panel available for a generator inlet breaker. You use a template to drill holes and bolt the interlock to the front of the panel.

I installed an interlock on our community well house's breaker panel. Someone had installed a power OUTLET with a SUICIDE CABLE to connect the generator to the panel, and no instructions on opening the main breaker. I installed a push<>push breakers and interlock at the top of the panel, along with a correct power inlet and reconfigured the cable correctly. If you try to close the generator breaker, it trips the main which is opposite it. If you try to close the main, it trips the generator inlet breaker. Great system for a small subpanel.

Charles

 

[Isaac-1]

You're not wrong, I was unaware of the interlock device, looks simple enough, I'll look into it. The electrician did this as a side job and emphatically warned me of all the hazardous. It's just my wife and I and she would never attempt try as I did to teach her. Subsequent owners would be a different story. I appreciate your post.

An interlock not only makes you legal (not having one is a criminal violation in some states), it is a seriously good idea. There are way too many stories of incidents where people "knew how to do it safely", either involving them doing things while they are sleep deprived after a storm or someone else trying to switch power over in either direction.

One such incident that I am aware of involved a similar setup to yours, the husband "knew what he was doing", however in this case he was not home after a prolonged storm outage when the power came back on in the neighborhood, and their generator was not large enough to power the clothes dryer, and the wife felt she HAD to do laundry right away, and couple not wait an hour or so for her husband to get home, so she sent the teenage son out to the garage to switch back to utility power, ....

 

[CharlesinGA]

I'm thinking that rather than double tapping the generator input terminals in the transfer switch, would be to add a junction box somewhere between the generator and the Xfer switch and split off a feed to an outlet in a junction box. The whole thing is protected by the breaker in the generator, and this will give you a fixed outlet to plug a cord into going into the house or where ever.

A deep 4x4 junction box with four Polaris taps in it and appropriate gauge cable to the 14-50R receptacle mounted in a box in an easily accessed area would work.

Charles

 

[Firstime RVer]

The way I see it is if you dont know what your doing:

Just run some extension cords to your fridge and appliances
or
Hire a professional to provide you with the proper install

Its Just not worth the risk to your family, utility workers or your property.

Safe travels and all the best.

 

[bigb56]

I'm thinking that rather than double tapping the generator input terminals in the transfer switch, would be to add a junction box somewhere between the generator and the Xfer switch and split off a feed to an outlet in a junction box. The whole thing is protected by the breaker in the generator, and this will give you a fixed outlet to plug a cord into going into the house or where ever.

A deep 4x4 junction box with four Polaris taps in it and appropriate gauge cable to the 14-50R receptacle mounted in a box in an easily accessed area would work.

Charles

What will you use at the load end of that 50 amp setup?

 

[CharlesinGA]

What will you use at the load end of that 50 amp setup?

The 50 amp receptacle. That is what he uses to plug in a suitable cord to run to the house power inlet, or plug in the RV next door if needed.

Charles

 

[John From Detroit]

Mechanical interlock breakers are panel specific and are available on the net or from commercial electrical supply houses. Here's a link to a company that packages them for DIY installation.

I do not like those as they are too easy to damage and get past... I used a switch panel. This is not the one I used.. but close, VEVOR Manual Transfer Switch 50A Generator Transfer Switch Kit

I also left one light connected only to the main. (power restored indicator)