A note on safety: This post, and all our offerings, are for educational purposes only. We recommend hiring a professional to help with your tiny house electrical system. The information here will give you a great foundation to help you feel confident in your conversations with an electrician. For more info enroll in our tiny house building class
Here is your essential guide to tiny house electrical.
We define technical terminology, discuss electricity needs for small spaces, and even go into solar systems for off-grid tiny houses.
Elements of a tiny house electrical system
The elements of a tiny house electrical system are the same as those for a larger house, there are just fewer of them. Following are some essential terms and parts of a tiny house electrical system. If you’re going off grid and opting for a solar system, these will remain the same, with the addition of solar panels, batteries, and an inverter.
Grounding
GroundingGrounding is one of the most important things when you’re doing tiny house electrical. It’s there for safety, to get electricity back to the earth, where it wants to go. Without grounding, the electrical current may travel through your body to get back to the earth, giving you a shock. Indeed, the ground wire is going to be continuous throughout the whole tiny house electrical system, heading down into the ground.
Volts
Volts are a common unit of measurement that you’re going to hear a lot when dealing with electricity. It’s a form of electrical force. In most homes, AC (alternating current) voltage is what you’ll be working with. Typically, 240 volts are what travel through the wires in a home. For a tiny house, you may be using 240 or 120. That’s because most outlets and gizmos run on half of 240, or 120 volts. However, high-energy appliances like ranges and dryers use 240 and require special breakers and wiring to handle the increased electrical force. What kinds of electrical appliances you’ll be using will help determine whether 240 or 120 volts is appropriate for your tiny house electrical system.
Amps
Amps are another unit of measurement in the world of electricity. They represent flow, or current. In order to understand electrical amps, it’s helpful to think of flowing water. In this case, the current is how much water is actually flowing through. Returning to our tiny house electrical system, amps represent how much electricity is flowing through.
One place you’ll encounter amps is in a breaker box, with the total amperage flowing into the box being broken up by different breakers. These allow different amounts of electricity to flow through them and out into circuits, via wires. It’s extremely important to use the right size wire for the amount of amps coming through; too many amps through an undersized wire can cause a fire. Breakers help to prevent this by limiting the number of amps that travel through each circuit they control.
Watts, kilowatts, kilowatt hours
Watts and kilowatt hours are another important unit of measurement. In this case, they measure overall power consumption. To calculate watts, you simply multiply volts by amps. This number gives us an idea of how much power something is going to need. Finally, since we tend to use electricity over time, you can measure the number of watts per hour, or 1000 watts per hour, which is a kilowatt hour. Since most homes use many thousands of watts per hour, the kilowatt hour is a standard unit for measuring consumption of electricity; you’ll probably see it on your power bill.
Breaker box
The breaker box is where power comes in and gets spread throughout a tiny house electrical system. Individual breakers send a measured amount of flow of electrical current (amps) to each circuit in the house, via wires. If too many appliances are on at once, pulling more current through a circuit than it’s set up for, a breaker will flip. This cuts off power to that circuit and prevents a fire.
Wire
There are many kinds of wire, and many sizes, or gauges, of each kind of wire. It’s extremely important to choose the correct wire for your application. Some wire is better suited for wet conditions, for bringing lots of current to an appliance like a dryer, or for easily bending to fit into small spaces.
To learn more about the different parts of a tiny house electrical system, including how they fit together and how to hook up outlets, light fixtures, and more, enroll in our tiny house building class.
Tiny house electrical requirements
The electrical requirements of a tiny house depend largely on what kinds of electrical appliances you’ll be running. Since tiny houses are smaller than standard houses, you’ll naturally have lower electrical needs for lights, outlets, and heating/cooling. On the other hand, appliances with high electrical needs like refrigerators, stoves, toasters, hair dryers, clothes dryers, etc. will require a similar amount of electricity (except perhaps the fridge, if it’s a small fridge in a smaller space). The range of tiny house electrical requirements can be between 0-30 amps. See below for more details.
In terms of safety, the requirements for a tiny house electrical system are exactly the same as any other house. If you’re excited to dive into building codes for electrical, you can access the “bible of electrical,” also known as the National Electric Code (NEC) online for free! You will have to set up an account. This nearly 1000 page document will tell you all the ins and outs of electrical installations. It’s worth looking through, just to see how things are done, as you plan and design your tiny house electrical system.
Another great resource is the International Code Council Code Check Booklet: An Illustrated Guide to Wiring a Safe House. They really do a great job of consolidating all the rules down to what you’re mostly likely to run into. This is a great reference, even if you’re not going to do your own electrical system.
How many amps do I need for a tiny house?
If you’re planning to run most of the standard electric appliances, your tiny house electrical system will require around 30 amps. This is the most common setup for tiny houses and also for RVs. However, your electrical needs may be significantly lower than this, if you don’t opt for energy-intensive appliances like an electric refrigerator, electric range, or electric water heater.
Many of the participants in our tiny house building classes choose modest solar systems that simply provide electricity for lights and charging small devices. They may have access to a fridge in a community space or outdoor kitchen, use propane or wood for cooking and heating, and use hot water judiciously.
To get a sense of how many amps you might need for your tiny house, you can use this electricity calculator to get a feel for the maximum number of watts you’ll be using (remember, a kilowatt is 1000 watts). Then, divide that watts number by 240 or 120 volts, depending on the voltage your tiny house electrical system will use. The final number will be amps.
Here’s the formula: watts/volts=amps
And here’s an example of a tiny home electrical usage in watts:
- Ceiling fan: 25
- Lights x 5: 35
- Mini-fridge: 60
- Laptop: 60
- Phone: 15
- Electric kettle: 1000
- Space heater: 1500
- 5-gallon water heater: 1500
Total watts: 4,195
watts/volts = amps = 4,195/240 = 17.48 amps
How do you put electricity in a tiny house?
As with any home, it’s ideal to put electricity in a tiny house during construction. As the tiny house is being built, walls will be open and exposed, so wires can easily be run to outlets, appliances, and light fixtures. Including electrical in your tiny house design can be a helpful step in this process. Of course, you can always add to and change your tiny house electrical system later, but it will be more work than setting it up during construction.
For a tiny house on wheels, the most common ways to bring electricity in are through an RV plug, or a twist-lock 120 volt input. These both basically look like outlets on the outside of the tiny house. With them, you’ll plug in the whole house. After electricity comes in through these plugs, it will be distributed via a breaker box.
If you’re building a tiny house on a foundation, the mobile options are still great. In this case, you can also run a direct electrical line to the tiny house through an under or above ground conduit. Such a hard-wired option is what would be used for a shed, cabin, or other outbuilding.
Solar electric for a tiny house
Solar electric power is a great option for your tiny house electrical system, especially if you’re planning to bring your tiny house to remote places. Any solar electric system requires good solar exposure, so if your tiny house will be mostly in the shade, this isn’t going to work.
The basic elements of a solar electric system are: photovoltaic (PV, solar) panels, wiring, batteries, and an inverter. The panels collect solar energy and turn it into electricity; the batteries store that electricity; the inverter changes the electricity into the AC power that’s most common in homes; and the wiring moves the electricity around.
You can choose to mount our PV panels to the roof of your tiny house, or ground-mount them nearby. The batteries and inverter can either be housed within your tiny house, or in a utility space outside. For mobile units, creating a space for everything within the tiny house will be more convenient. For much more detailed information on solar power for tiny homes, enroll in our tiny house building class.