I have been working in the evenings installing the power system for the house. Its been fairly complicated and with over 600 feet of wire and more than 20 circuits, its been a lot of work.
For a while Ive had a temporary power system set up to run the power tools.
The main service for the house is a 30 amp single pole service. Oringally, I was planning a 50 amp service, so that I would have more than enough power to run a lot of the things in the house at the same time. The problem with this was adapatability. In a 50 amp service, 2 of the 4 wires that run to the house provide power. This is great if you can have a dedicated outlet installed just to power the house or plan to live at a campground where this type of service is common. Not knowing where the house is going to end up, I wanted to make the house as adaptable as possible. The 30 amp service would allow more adaptablilty. In a 30 amp service, 1 of the 3 wires that run to the house provides power. This type of power delivery is much more common in residental houses and would allow me to run the house off of an normal service. Now please take note that most outlets on houses are not rated for 30 amps, but I dont plan to draw more than 20 amps,which is a standard rating for many outdoor outlets.
The inlet above is a marine grade unit I chose for its durability and ease of mounting.
I used a 2 1/2 inch hole saw and cutting oil to cut a hole in the frame for the inlet to mount to. I drilled and tapped holes for the screws to mount the inlet directly to the trailer frame.
The wires that run from the inlet to the distribution panel are American Wire Gauge #6, this means that they are rated to carry up to 55 amps, more than enough for the service to the house. They are run from the panel, through the floor plate of the front wall and down to the inlet at the front of trailer.
The power then goes into the distribution box that I’ve put together. Its using the two distribution panels and the AC/DC converter I mentioned in this previous post.
The power then gets routed through a series of breakers to service the AC circuits in the house. The AC system services the luxury items in the house, mainly the air conditioner and the compact washer and dryer. There are also several standard outlets in the house to power laptops and the like.
Now, part of the AC service gets routed into this AC to DC converter. This convert is rated to provide up to 45 Amps of DC service. This unit will also charge and route power to the battery bank that will be located in a tongue box at the front of the trailer. Those batteries (2 x 210 amp hour marine batteries) will store power from a solar system and provide power to the DC service when the sun is down.
I had originally planned to mount the AC to DC converter elsewhere, but wound up mounting the inverter inside of the box so that all of the power control systems would be easily accessible in one box.
Most of the things in the house are running on DC. This is mainly so that most of the essential items in the house (lights, fans and the refrigerator) can be run on solar power in the future. The luxury items in the house are to be used when an AC source is available.
I chose a DC panel with so many (16) available circuits for several reasons, primary among them is so that each item in the house can be on its own circuit. This means more work when it comes to running the wires for all the lights and fans but it also means that every thing in the house can be controlled individually and isolated if there is ever a problem. Another reason for putting every thing on its own circuit is safety, if there is just one item on each circuit there is less chance of a circuit becoming overloaded and heating up.
Which brings me to the next topic: Wire.
In a few other aspects of the house, I have been prone to over kill. This time really wasn’t too much different. For the smaller AC circuits I chose 14/2 (wire gauge 14 and two carrier lines + 1 for ground), which is standard in most homes. For the larger things on the lines, namely the air conditioner and the washer combo, I chose to use 12/2 which is rated to carry up to 20 amps.
For the DC side of things, all of the wire is marine grade 14 gauge wire. It’s rated to carry up to 15 amps, but will never see anything close to this when its just running lights and fans.
I started laying the system out by putting up tags where items were to be located and then running the wire back from those places to the panel.
This meant drilling lots of holes in the walls to run cables. With so many circuits, this was a lot of holes and a lot of wire.
About 600 feet of wire between both systems.
There are a lot of important things to consider when putting a power system into your tiny house and I recommend spending a lot of time considering your needs and wants and building your system around that. My system is a bit unique and certainly not to code, so please consider what I am doing as just one route that may not be right for every one. I have been very lucky to have some smart friends who have done things like this before and who were able to lend both knowledge and tools. Be careful in there!
As always there is still more work to be done, I still have to patch all the circuits into the panel and power the whole thing up. After that will be a test period where all the lights and fans are installed and the limits of the system will be tested. I want to make sure everything is right before the spray-in insulation is installed, after that point theres really no going back. Best to make sure its right before proceeding.
Happy tinyhousin’ and be well.