Backfeed through RV Circuit?

stickboy1375

I'm not sure why it would even be an issue, I don't see how it would back feed.

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5th_Time

Darren: I read through that whole topic you linked to and I get it now. He asked about almost exactly the scenario that I wanted to accomplish. I wish I had seen that topic earlier - it would have saved me a lot of typing .

For several reasons (especially that the male 50A pigtail would be energized - probably while is wet/icy outside), it looks like my idea to do this will not work. Further, I'm sure there is some sort of protection built into the RV so as to not feed current back out of the 50A input under any circumstance.

Since I already own the generator (in the RV) I was hoping to not purchase another full setup in the event of a power failure (this past fall, we had 2 week-long failures here in Connecticut in a six week period).

Running (2) full 120' 6/3 circuits and probably a 2" conduit (the garage is detatched) seems like a real PIA.

Thanks to those with suggestions...

dmxtothemax

There is only one way it can be done safely !
You can not use the same cord how ever!
You will need a change over switch on both the R/V and the house panel !
NOT AN INTERLOCK! ONLY A CHANGE OVER SWITCH !
Instal a 50 amp outlet on the rv,
Instal a 50 amp inlet recepticule on house,
When neccesary run the lead out,
operate both change over switchs,
and your good to go !

So it can be done !
But not easily or cheapily!
There are many safety considerations,
so do it properly, or not at all !

andrew79

if he's feeding the rv through one breaker and feeding the panel through another then his rv is essentially hooked up to the same panel twice in parallel with only one of them interlocked.

the double disconnect is the only way i can figure it to work safely as well.


edit: i get it now, the rv most likely already has a transfer switch built in so that would cut the second line out, you would still liven up the cord feeding it though unless the other breaker was shut off.

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stickboy1375

What is a change over switch?

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AllanJ

A changeover switch is a transfer switch. It has its common terminals connected to the item being served (e.g. a panel). The two other sets of terminals are connected to the two possible power sources, e.g. generator and utility.

You still need two cables going between the panel and the outside wall if you want to feed utility power to the RV some of the time (uses one cable) and feed generator power to the house panel some of the time (uses the other cable).

The RV should already have a changeover switch (transfer switch) to choose between generator power and plugging into the house. When the generator is supplying power to the RV then the RV cord that plugs into the (female) RV outlet on the side of the house could be livened up but should dead end at the RV transfer switch.
.
To feed RV generator power to the house you connect a cord from the male receptacle (inlet) on the side of the house to a receptacle on the side of the RV. When utility power is on then the interlock or transfer switch at the house panel should dead-end the male receptacle's cable.

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stickboy1375

.....................

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AllanJ

Interesting situation:

What happens if you take a cord and plug it into a receptacle on the body of the RV generator?

1. Generator supplies power out this cord to the male receptacle on the side of the house.

2. Power goes to the house panel via the transfer or interlock.

3. Utility power to the panel is blocked by the house transfer switch or interlock.

4. Power goes via the RV branch circuit to the RV (female) receptacle on the side of the house.

5. Power goes out the RV house power cord.

6. Power goes to the RV panel via the RV transfer switch.

7. Direct flow of power from generator to RV panel is blocked by the transfer switch.

8. Everything is safe.

Notes:

3a. If utility power is on then generator power in step 2 is blocked. Utility power can get to the RV in step 4.

7a. If the generator is supplying power directly to the RV then power coming back from the house in step 6 is blocked.

(With the required separate wiring or cables from house panel to side of house for steps 2 and 4.)

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5th_Time

During use, I would not have both the input and output cables attached to the RV simultaneously.

It sounds like the first step should be to run (2) 6/3 circuits to the garage for input and output.

Originally, I had planned to use 6/3 Romex from the breaker box, through the basement to an outside junction box, then THHN in a 1" conduit in a trench to a NEMA 14-50R (female) receptacle on the garage - just to power the RV when home.

Can I run both circuits in a larger conduit and split them in a junction box on the garage to the the separate male and female receptacles? Or, should I run separately all the way. Right now, I just have an empty open trench.

I'd like to do the grunt work myself and then have an electrician make the connections and have it inspected - so I want to do this properly.

Speedy Petey

I've said it a thousand times on boards like this.
The "grunt work" is the hard part, and the most technical and code intensive. The "connections" are by far the easy part.

I also wish you luck in find someone who will get the work inspected. When you file for an inspection you are putting your name on that job. You'd be hard pressed to get me to put my name on someone else's work.
Hopefully in your area you can file for a home owner permit and get the work inspected under your name.

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stickboy1375

Yep, in Connecticut this is allowed....

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stickboy1375

Personally this really isn't all that difficult of a project, Just divide the job in half, you have job (a) which is getting a power outlet out to your RV.
and job (b) installing a generator hook up, which just happens to be installed on the RV.

Job (a) is simple, just run a properly sized branch circuit to specific location and install proper RV receptacle.

Job (b) is a touch more involved, install proper transfer switch, install properly sized conductors from transfer switch to generator power inlet box at specific location.

This really all this is. Of course, lots of codes are involved, I made it sound a lot easier than pie.

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5th_Time

Stickboy1375... really appreciate the reply. It does seem simplier now that I see the logic of the two separate jobs & transfer switch for the input. A couple questions though...

First, I guess using a 6/3 circuit of Red, Black, White & Green THHN in conduit for the outside part of the output circuit seems right (no one has criticized). Now, should the input circuit feeding the transfer switch/panel be the same 6/3 size (50A), or should it be 8/3 or 10/3 (30A)? The generator is an Onan 5500W/120v/45A. It seems like most Gentran or Reliance Transfer switches use 30A male connectors with this size generator.

Lastly, should I combine both circuits in 1 bigger conduit or should I do separate runs? I have to double check the RV outlet box, but it looked like it would take multiple 1" & 1.5" conduit.

stickboy1375

If I was doing this job, I would run two conduits, just for the simple fact that I could terminate them separately into the bottom of each power inlet box without another jbox of sorts, just look cleaner in my opinion, of course, im visualizing this in my head, not what is actually at your house.

Your RV conduit should be #6 AWG, and the generator conduit is generally #10 AWG, check the breaker on the generator, usually 30 amps.

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5th_Time

Haven't been out there yet, but the Onan manual say it has (2) 30A breakers.