Different electrical question...

NM_Shooter · May 15, 2010, 07:45:30 AM

I'm running 240AC to my RV barn. I put some triplex in the ground, and roughed in the barn, and called an electrician to make it hot.

The plan is to use a 30A RV outlet on the side of my house to tap into for power.. he is going to splice into that to bring the power down. I'd prefer to bring it off of a fresh breaker, but he said that to get into the wall and plumb the conduit out would be expensive, and no need to do that. I guess I do not object to using the same circuit, but something else he said has raised my eyebrows.

The existing 30A fixture is a single phase outlet. He said that he is going to take the neutral leg from that outlet, tie it to the other phase, and use that for the two phases to tie into the triplex. When I asked about the neutral for the RV fixture, he said that he was going to split off the neutral line in the fixture box to use as a neutral and ground. This sounds dangerous to me. Any body out there know code on this? I really like the idea of having a separate ground.

ChuckinVa · May 15, 2010, 08:21:48 AM

If I am understanding you correctly. The RV outlet on the existing house is 30 amp 120 volt.Which means it is protected by a 30 amp single pole breaker

You want 30 amps at 240V at the RV garage. If that is the is the case, it would be fed from ( protected by) a 30 amp 2 pole breaker. In that case, what he is proposing will not work.

If he goes back to the panel and adds a 2 pole breaker in lieu of the single pole breaker that is now feeding the RV outlet, he can bring 240 to the RV outlet box, Only wire 1 "hot" conductor to the RV outlet, and let the other one "pass through" to the RV garage. The Bare ground wire from the panel to the would then be used as a neutral. That is where the problem lies as the Neutral does actually carry current sometimes and must be insulated. While it will "work" ,it is not an acceptable wiring method. IF the ground is insulated, you could drive a ground rod at the RV outlet and ground the outlet , and then drive a ground rod at the RV garage to ground the sub panel I am assuming you installed when you wired the RV garage.

If I were doing this, I would want to have a separate circuit for the RV Garage from the panel with 4 wires. 2 hots, a ground and a neutral.Some inspectors would require a second ground rod be driven at the RV garage sub panel to insure a good ground. Since you said you ran "triplex" there are only 3 conductors to the RV garage right now so you will have to drive a ground rod at the garage to have a ground. Your grounds and neutrals should be kept separate. There are a lot of things with electrical work that can be done that work electrically but may get you killed down the road. I believe your electrician is proposing short cuts that I would not want to take.

May 15, 2010, 04:11:59 PM

So... One phase will feed both the RV outlet and the barn. The second phase for the barn will come off of another 30A breaker put into the house panel.

My concern is that he seems to be compromising the wiring for the RV outlet on the side of my house. He wants to use that existing neutral wire and remove it from the RV outlet and attach it to the other phase. Then kerney both of those phases onto the triplex for deliver to the barn.

The RV outlet would then only have one phase, and a ground. The neutral on the RV outlet would be jumped over from the ground on the RV outlet.

I currently have another ground rod driven in down by the barn.

My primary concern is not the barn... it is that the RV outlet will now effectively have only one wire servicing both ground and neutral for the outlet.

MountainDon · May 15, 2010, 05:56:46 PM

I am not an expert but, I can see what you are concerned about. It doesn't seem right at the RV plug. Wish I could say more confidence.

ChuckinVa · May 15, 2010, 06:46:12 PM

If you had the RV plugged into the RV outlet and then needed to use the RV garage power for something else it could be a problem depending on the load. If you were just keeping a refrigerator plugged in for the RV and then needed some lights and receptacles on a the RV garage you would probably be OK.Iif you needed A/C on at the RV outlet and then needed 240 at the garage, or if the outlets you were using in the RV garage were on the same phase conductor as the RV outlet you would likely trip the breaker. If you think you would ever need to have both in use at the same time, I would elect to run a separate circuit for the RV garage.

May 16, 2010, 09:05:35 AM

Wow... I had some good luck. What's up with that?

I decided that I wouldn't let the electrician pigtail off of the ground in the plug to use as a neutral as well, and that I might as well just go ahead and pull an additional conductor. I went to my breaker box to see how things were routed, and when I was in the box, I noticed that the service to the RV plug was already pulled using 8/3 w Gnd. The other phase wire was already run out to the box, and just hanging there waiting for me.

I wonder why the electrician didn't notice that other big honking red wire?

I should just do this all myself.

-f-

ChuckinVa · May 16, 2010, 10:25:41 AM

Frank,
Make sure you put a 2 pole breaker in and not 2 single poles as you could trip one single pole and still have power on in the RV outlet box. You still will have an opportunity for an unbalanced load but as long as you don't get carried away welding or something like that in the RV garage you should be ok.

NM_Shooter · May 16, 2010, 06:35:57 PM

Thanks Chuck,

Yup, I installed a tandem breaker. They are tied at the hip!

The more I thought about it, the more I am annoyed with the electrician. I ended up running all the galvanized and PVC conduit and pulling all the wires into the j-boxes and the sub panel down in the garage. I probably cost him $150 by doing the work, it only took me a couple of hours. I'll leave the kerneys, terminations and grounding to him. Hope he can get that right.

I'm close to having power in my barn. That will be a happy day. I can trickle charge my batteries, run tools, and (wonder of wonders) flip a switch and have light at night. MIght even put in a motion activated flood too, since I am getting crazy. Being able to run my RV fridge on elec to pre cool it without having to pull it up next to the house will be nice too. The water down by the barn has already been a luxury.

-f-