30 amp. wiring for RV

Hi
I am trying to get service to my RV. It has a 30 amp. service. I have a 220 outlet that I use for my welder that I would like to convert for my RV. It has two 40 amp. breakers coupled together with 8 gauge line feeds with a neutral. What I would like to do is take one side, with one breaker for the line feed. This will give me 40 amps. My question is to make this complete can I tie the neutral and ground together? In other words One of the bottom prongs will be hot with the other other empty. The top prong will be a neutral and ground tied together. Will this work?
Thanks for any advice
Roy

 

I didn't understand a lot of what you said, but I know the answer to your question anyway. You may not connect the neutral and ground together anywhere outside the main panel. To do so would be very dangerous.

 

Hi John
Thanks for your reply. I know you must be confused by my post cause I am too. My welder hook up to the panel is two # 8 line feeds side by side with a neutral, and no ground. In other words the neutral is where the ground would be on a 110 plug. Is this a standard practise ? My 30 amp plug has three prongs as does the welder. What I am trying to do is use the welder plug with my 30 amp plug. I was told that I could take the hot wire from my 30 amp plug and go to one side of the welder plug. Then take and tie the groung and neutral from the 30 amp. plug together and go to the neutral on the welder plug. One side of the welder plug would be dead as it plugs in to the receptacle. Does this make any sense? I always thought a ground was a ground and a neutral was a neutral, boy am I ever confused. I hope maybe you can straighten me out.
Thanks
Roy

 

It sounds like that third wire is serving as a ground, not as a neutral. It's likely that your welder doesn't need or use a neutral.

But back to what you are trying to accomplish. Are you trying to get a 30-amp 120-volt connection, or a 30-amp 240-volt receptacle? Is this a permanent conversion (i.e., you're not going to use this for your welder any longer)? Or are you hoping to end up with something that can serve both your RV and welder at different times?

 

John
The two line wires are red and the other wire is white and is tied to the same bar with the other neutral wires. I am trying to get 30 amp. 110 service. I am hoping that I can keep both lines hooked up in the panel and by only having one leg hooked up on the adapter I can use the receptacle outlet for the RV as 30 amp 120 or 220 for my welder.

 

Leave the welder alone,,, run a new 120 line,,, 10/2 wg for the rv.

 

I have to agree with sberry.Run a new 30 amp 120 volt outlet for the RV.

 

Now that I understand what you are doing, the right solution is perfectly clear. sberry and texsparky have already provided it.

 

Thanks for the advice. I wasn't sure which way to go. This adapter thing sounded a little crazy to me also. I will get a sub panel and run a new service for my RV. I will need to run about 150-200 foot of wire. What gauge should I use for this 30 amp service?

Thanks again
Roy

 

You will need a min of number 8 amd 6 is even better. If you were not running AC on it 8 would be fine. You are going to need to dig a deep trench,, probably 24 inches, unless you put gfci breaker on then I think its 12 maybe,, forget exactly but something like that. You wouldnt really need sub for 1 circuit.

 

The question started out fairly simple. But now we seem to have a whole project in front of us. We're going to need more details in order to give you good advice. To start with, tell us about that 150-200 feet. Is that 150-200 feet all within one building? Will the cable need to go outside? Will the RV receptacle be in another building, such as a detached garage? If so, what kind of building? Is the welder receptacle already in that other building? Is there any other power there? Do you already have a subpanel?

 

John
Thanks again for your concern. The 150-200 feet will actually only be about 125 feet from the main electric panel in the house garage to the new 120V 30 amp receptacle that I now plan to put outside close to where I will be parking the RV. I can run part of the cable through the house attic but about 50 foot will be in the yard. My ORIGINAL plan was to use the sub panel in my DETACHED garage where the welder is. This panel has one 120V 20 amp breaker and the one 220V breaker that has two 40 amp breakers tied together.
Thanks
Roy

 

Why not change the 1 pole twenty in the garage sub panel to a 1 pole 30 and feed from there?

 

that one pole 20 is probably for his lights,, so better yet if its closer than the house,, and another 1 pole 30 to the garage panel.

 

I have to agree with most posting, you will need a dedicated 30-amp circuit feeding the RV. #10 Awg will work with the load, and distance your running. There is a few different ways you could do this project.
1. Install (Romex) in the house, then convert to UF underground.
2. Install UF cable from the panel to the RV. (1st choice)
You will need to protect the cable entering the ground, or exiting. If you suspect that a lawn mower or weed eater could damage the conduit protecting the cables then install them in Sch. 80 Pvc, or better.
You will also need a trench at least 24" in the yard.
No GFCI protection is required for this branch circuit.
Install a in-use weather proof adaptor over the receptacle.
It would probable be easy to install the plug on a post next to the RV.
If there is alternate power in the RV (generator), then you will need to install a transfer switch, if not provided with the RV. This will keep the AC voltage from accidentally being on when the generator is also on.