Tiny House / RV Electrical Questions

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Old 03-29-12, 12:10 PM
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Tiny House / RV Electrical Questions

Hello, I am the proud owner of a self built Tiny House. For those unfamiliar, its
basically an RV, but built like a small house/cabin on a heavy duty flat bed trailer. I am experienced in pulling wires and trim/finish electrical. However, that was in residential, and this is slightly different than that, and requires some engineering that I am not comfortable 'winging' at this point.

I am planning a small kitchen, (dorm sized fridge / range exhaust), 8 lights total, desktop computer, an electrically assisted composting toilet and a combo washer / dryer unit. There will also be misc small electrics, but the range will be propane for cooking, heat
from a small wood stove, to alleviate some burden on the electrical.

I plan to one day go completely solar, so I need to factor that into the current design. I would appreciate some help with the planning side of this. From research, 50A RV seems be the best choice. Is that correct? Or could I skate by with the 30A system? What circuit box / breakers / set up would be best for me? If anyone has thoughts, or a website for information (Most that i have found on the subject seem to be outdated) would be greatly appreciated.
 
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Old 03-29-12, 06:47 PM
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First off, since you are not a manufacture, you will have to use wiring methods that is listed in the code. Good thing is you likely already are familiar with these. Bad side is it might be a little more difficult for you.

Is this going to be mobile? What kind of structure are you working with? (framing) Is this going to be in a mobile/camping home park? Cord connected? What is the dimensions of the home?

It sounds like this is more like a mobile home than an RV. Areas you want to look at in the code is Arts: 550 and 552 (2008)

I would also agree with a 50 amp service. Even though you may not need it, the extra capacity will be very helpful if you do at a very minimal cost. It is one of those things where if you don't have it, and you need it, your SOL. I would go with a standard 100 amp value panel as they are the best bang for the buck (about $50)

You might want to google "mobile home parts" You can see a lot of helpful parts that is "normal" to mobile homes, such as self contained devices (switches and receptacles)
 
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Old 03-29-12, 07:49 PM
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I plan to have it be mobile, but that will be rare. Most of the time it will be parked. Most of the time it will be parked in a res environment. Hopefully solar will help at that point. For now, I will have a trailer hook up.

The framing is 2x4 stick framing. I would like it to be able to hooked up to a trailer park if in that setting, hooked up to a 15A extension cord for essential functions if in that setting, or on full solar, when that happens. The home itself is 8x20. Its quite small with a small loft for sleeping.

Thank you for the suggestion of googling mobile homes, somehow, i didnt consider that, so I've been looking at RV and Tiny House sites, neither of which are really doing it for me. I'll check out some of those sites.

Code wise, with the actual wiring, i'll have no problem. The code issues and engineering issues I will run into is the box/cord/etc that I have no experience with.

Again, thank you for your suggestions.
 
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Old 03-30-12, 04:36 AM
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There are many ways of doing what you plan.
You might want to study the method that is used in RV campers.
A combination 120v ac/12v dc may work well.
To go totally 120 volt would require you to when on battery power to use an inverter which is fairly inefficient.

One method used in campers is to have a mix of 120/12 volt lighting with the 12 volts powered directly from the batteries when not plugged in and off a power supply when on shore power.
If you look online there are RV power centers that you can purchase that have built in switching and battery charging.

I'm overhauling my ol' truck camper and have found online, 12v dc auto LED replacement bulbs that appear to be promising in saving battery power.
 
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Old 03-30-12, 12:30 PM
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Regarding inverter efficiency, how much does that really matter? If my electricity at that point is coming from solar panels, I would need slightly more panels to produce enough to compensate for the inefficiency. But would that hurt anything?
 
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Old 03-30-12, 04:05 PM
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What kind of efficiency are we talking about? Everything has power losses, even copper wire.
 
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Old 03-30-12, 04:55 PM
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I was referring to Greg's post where he says if I go full 120v, when I move to Solar and us an inverter it will be inefficient. Im wondering if that will cause any issues other than needing more panels/batteries etc
 
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Old 03-30-12, 06:15 PM
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You really need to start with deciding what you will be doing for lighting and high draw appliances.
Lights fans and electronics would do well on batteries/inverter.
Cooking, heating and clothes drying would do well on propane.
Solar panels are quite expensive and would take a large number of panels for bigger loads.

If you use high efficiency lighting like fluorescent or LED then your draw on an inverter would be fairly low and efficiency would not matter much as has been said.
 
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Old 04-04-12, 09:52 AM
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Out of curiosity, how are you going to get an occupancy permit for this "house?" Or, if it'll be considered an RV, how are you going to register/license it?
 
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Old 04-04-12, 02:07 PM
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This whole idea of "tiny house" is pretty interesting!
Some pics uploaded to a free site like Photo Bucket and some links would be great.
 
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Old 04-04-12, 04:00 PM
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I learned about this particular company not too long ago: Tumbleweed Tiny House Company - Tumbleweed Houses They sell the houses and plans to build them on your own. Dig around on their site. Some interesting info and great photos.
 
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Old 04-04-12, 06:56 PM
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@ md2lgyk

I think this/these is/are more of a mobile home than an RV.
 
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Old 04-05-12, 05:10 AM
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Yeah, you're probably right. I've actually heard of this Tumbleweed company. Interesting concept, but no thanks. I spent several years in the submarine service so have had enough of small living spaces to last a lifetime.
 
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Old 04-06-12, 05:15 PM
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I think the idea of these tiny houses is that you don't spend very much time in them.

I would say these would be RV over mobile homes. Mobile homes really aren't all that mobile.
 
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Old 04-11-12, 07:05 PM
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Sorry, was out of town for a bit.

Tumbleweed Tiny Houses is actually just north of where I live, mine is based on Jay's ideas, and I have talked with him a couple times about it.

Currently, my tiny house is registered as the flatbed trailer that it sits on. I may one day register it as a custom RV.

I ran all the wires out and installed the box inside the house... heres the details:

I currently am running a single 20A circuit for the place, however, I have run the wires for 2 additional 15A circuits.

I bought a 100A circuit breaker box, with 12 available slots for circuits. I am sure that is overkill, but I am all about overkill.

I ran 6-3g wires from a 50A female attached to the exterior wall, into the panel box. I replaced the dual 100A breakers with dual 50A breakers. I ran the black wire to the top breaker, the red to the bottom. I then ran the white to the neutral bar, and the ground to the ground bar.
I flipped the switch for the kitchen light, and nothing happened. So, now I have some questions.....

Should I ground the ground bar to the trailer? Currently, Its attached to the 6-3 ground that runs to the 50A plug on the outside of the house.

I'll post pictures of the house and of the box when I get a chance.
 

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Old 04-11-12, 07:24 PM
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photo.jpg picture by dindinftw - Photobucket

Box Current Set up... Tell me how dangerous / what I've done wrong.

Tiny House pictures by dindinftw - Photobucket

All the photos on my computer of me building my little house....

I am a student (Law School Starts in August)... so I plan to spend most of my time in the library and such. I will also be working part time, so basically I just need a place to shower and sleep. Which my tiny house should provide me and more.
 
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Old 04-12-12, 06:05 PM
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Since your tiny house will be mobile, I hope you installed some substantial bracing in the walls.
 
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Old 04-12-12, 06:27 PM
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I would add a receptacle on your front porch with an in-use cover.

As for the panel, it looks good. I hope you did not use NM type cable to feed it. (which I think you did) It is not rated to be used as a cord. You need to buy/use some "SO" type cord, like SOOW or STOOW, since this will be a cord connected structure.

As for Joe's comment, wouldn't you think the plywood would give it enough lateral bracing? That is if it was also glued and nailed well. I'm just thinking of all the home made ice houses I see on the road and I have never seen any of them break up. A lot of times they are only framed with 2x2's
 
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Old 04-21-12, 02:36 PM
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bracing should be ok, the plywood has a very healthy amount of glues and screws in it, also, the lofts cross members are tied into the walls to help that out. I should expect it to do ok, but if there are any issues, i can address them. I do not plan it to move much at all.

I did use NM type cable to feed it... i had some 6-3 given to me so i wired it up. I'll change that out soon now that you've suggested that to me. Right now im running 4 Amps to it, so i hope the NM holds up in the mean time
 
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Old 04-21-12, 03:52 PM
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You might want to wire it with an inlet and bubble cover so you can just use an extension cord.
 
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