Outside wiring 30 AMP tiny house cabin

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  #1  
Old 01-02-15, 08:35 PM
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Outside wiring 30 AMP tiny house cabin

Hi,

I'm having a pole and meter loop put up and need some advice on wiring from the loop to the breaker box.

I'm going to use an interior 70 AMP box with two 15 AMP breakers.

Could 12/3 (Two 20 amp legs wired up 230) work to provide enough power given the assumption of a 3% power loss over a 100 ft length and the separate legs wired to individual breakers? Was going to just use 10/2, but given some power loss over length, I'm thinking two 20 amp legs instead.

Also, can wires that thin be wired directly from the meter loop?

Thanks.
 
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Old 01-02-15, 08:48 PM
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The electrical code specifies a 100 amp minimum service for a dwelling. You should ask if your building officials will accept one smaller.

The lugs on a meter socket are not made to accept wires that small like #10 or 12.
 
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Old 01-02-15, 09:00 PM
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That's what I was thinking. I told the engineer that I was going to mount a 50 AMP receptacle to the pole and plug into it like an RV. He said that was fine, but I'm trying figure out a way to save money on wiring.

Maybe I'll mount a 30 AMP receptacle to the pole from the meter loop instead?
 
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Old 01-02-15, 09:10 PM
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What exactly are you doing? We need more details. First of all Is this a permanent structure, or on a trailer?
 
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Old 01-02-15, 10:57 PM
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It is a permanent structure, but only 12'x12' with a 3' gable roof 6 in 12 pitch.

A 200 AMP service is overkill, even the electrical engineer said that. The biggest draw will be a 550 watt AC ~5 AMPS. After adding a few lights and three plugs (one in bathroom, one in kitchen, and one in living area) I'd need no more than two 15 AMP breakers like any standard 30 AMP RV.

Thanks.
 
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Old 01-03-15, 12:57 AM
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Are you planning on running the wiring from the pole/meter to the building overhead or underground? I would use an outdoor rated (NEMA 3R) circuit breaker panel at the meter with a single circuit breaker and then run the appropriate sized conductors to the building where I would then add an indoor panel (NEMA 1) with the branch circuit breakers. I know it sounds like overkill but the reason is that the outdoor panel becomes the service panel and you can use a 100 ampere rated panel to comply with the minimum service requirement and then the conductors to the building become feeder rather than service conductors. You will need to run four conductors; hot, hot, neutral and equipment ground as well as provide proper service grounding at the pole as well as sub-panel grounding at the building.

An added feature is that you can add on to the outside CB panel at a later date if you want an RV receptacle or the like.
 
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Old 01-03-15, 07:19 AM
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After adding a few lights and three plugs (one in bathroom, one in kitchen, and one in living area) I'd need no more than two 15 AMP breakers like any standard 30 AMP RV.
The NEC will require you have two 20A small appliance branch circuits at the kitchen counter, receptacles will need to be GFCI protected. The NEC will also require you have a 20A GFCI protected receptacle at the bathroom.

It is a permanent structure, but only 12'x12' with a 3' gable roof 6 in 12 pitch.
A 6/12 pitch will make the roof 45 degrees, the gable will be higher than 3 feet.
 
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Old 01-03-15, 07:45 AM
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A 6/12 pitch will make the roof 45 degrees, the gable will be higher than 3 feet.
Actually a 12/12 is 45 degrees. A 6/12 will rise 3 ft in 6ft of run. The roof in question is only 6ft per side so the gable is 3 ft. But what does that change?
 
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Old 01-03-15, 08:29 AM
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I would agree with Furd. I would also suggest installing a 100 amp service, however, I would install it on 2 4x4 posts with 2x material horizontal to attach an outdoor panel. Then from that panel run to the cabin to a smaller panel for running everything in there. You can only have one feed to the cabin which is why you need another panel.

Doing it like this will future proof your place and allow adding things down the line. It will also be code compliant and likely cost less then $500 depending on material you buy. If you don't understand, let us know, and we can spec out some stuff for you.
 
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Old 01-03-15, 09:02 AM
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Alright. If I'm getting it so far, a 100 amp outside panel wired to the meter loop, a 50 amp 6/3 wire (two 50 amp legs), a 100 amp breaker inside the cabin, with 20 amp breakers instead of 15?
 
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Old 01-03-15, 09:23 AM
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You would not need a 100 amp panel/breaker in the cabin, the outdoor panel is your main service. You can feed a main lug or back feed a breaker in a main lug panel.

so your setup would be like this:

--power company line--Meter--100 amp feed --Outdoor panel--50 amp feed--cabin panel--branch circuits

For the 100 amp feed you could use 2/2/4 aluminum URD and the 50 amp feed 6/3 w/ground UF. Both are direct burial.

For your branch circuits I would suggest 2 - 20 amp circuits in the kitchen, one 20 amp circuit for the bathroom and one or two 15 amp circuits for the rest of the living area. Not sure how this all fits in a 12 x 12 cabin but I'm sure you have a plan.
 
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Old 01-04-15, 09:45 AM
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Actually a 12/12 is 45 degrees. A 6/12 will rise 3 ft in 6ft of run. The roof in question is only 6ft per side so the gable is 3 ft. But what does that change?
Yea, you are right. Don't know what I was thinking.
 
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Old 01-04-15, 09:50 AM
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a 50 amp 6/3 wire (two 50 amp legs),
If you are using 6-3 UF cable, I'd use a 60 amp breaker instead of the 50.
 
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Old 01-23-15, 07:35 PM
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Alright, this is what they installed. A 200 amp sub panel with about 10 breaker spots in it. So the dilemma now is what size breakers to install in it and what size wire.Name:  10841745_984175551612024_7699264125141191199_o.jpg
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Old 01-23-15, 07:53 PM
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Perfect! That would be your main service panel, not a sub panel.

How far is it from there the cabin will be?
 
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Old 01-24-15, 02:14 PM
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Around 50 feet or so without measuring.
 
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Old 01-24-15, 03:01 PM
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This being your main panel you can run pretty much what ever size feeder to the cabin, however you are still limited to one feed. At that distance voltage drop is not an issue so the previous replies still stand. A sub panel is still the best option IMO and something like a 60 amp feed sounds like it will work for you. This could be as basic as direct burial #6/3 with ground UF, to PVC conduit and #6 THWN wire.
 
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