Head’s up: although the information in this article can offer practical advice and tips, for the safety of yourself and others it is always recommended that you contact a licensed electrician before performing any electrical work.
A “subpanel” is sometimes also known as a “breaker box” or a “satellite circuit breaker panel”. Deciding to install a subpanel in your house or garage is often a matter of convenience. For many people, their main circuit breaker box is located in the basement of their house, which may prove insufficient for those of us who spend a lot of time in our garage, whether it be for handwork or entertaining. If this is the case for you, a garage sub-panel might be a good investment.
What are the Benefits of a Detached Garage Subpanel?
As previously mentioned, a garage sub panel can save you many a trip into the basement. However, there are other benefits to this installation that goes beyond this, including:
- Power resource-intensive tools and appliances without worrying about straining your main circuit (i.e., reducing the likelihood of tripping a breaker)
- Benefit from multiple circuits without requiring multiple lines
- Introduce multiple lines into your home even if your main breaker is full
- Cost-saving and efficiency over time, mostly because you are using a shorter length of wires
- Reduce the risk of your voltage dropping, which occurs when power travels long distances
What Kind of Amps Does a Detached Garage Subpanel Need?
When it comes to garage sub-panels, they are not created equally. However, it’s not necessarily a case of “the more amps the better”. The number of amps that you need will greatly depend on your needs and the power of your main circuit breaker panel.
Generally speaking, If you are planning to use one or more 240 voltage appliances, such as a refrigerator or central air conditioning unit, you may need more than the standard 12 openings in your subpanel. However, if you are only planning to power lighting and other low stake electronics, this will not be the case.
Depending on your main breaker, you may be limited in the kind of subpanel that you can install. Most homes will have either a voltage that runs anywhere from 100-amp to 400-amp. If you are dealing with a 100-amp main breaker or lower, there is a good possibility you may need to increase its capacity before even considering a subpanel.
Things to Consider in Running a Subpanel to a Detached Garage:
If you’re sold on the idea of introducing a sub-panel into your garage, there are some things to consider before committing to the modification.
- There may be government regulations in your area that mandate how high off the ground your subpanel must be, as well as the other conditions of your installation area
- Have you accounted for all of your future power needs in the installation of your new panel? It’s better to install roughly 20% in excess of the power that you anticipate needing to reduce the chance of needing to upgrade again in the near future
- Are you really in need of a whole subpanel, or could you use an alternative solution like tandem breakers instead?
5 Steps of Running a Subpanel to a Detached Garage
In light of the things to consider that were listed above, it is usually better to enlist the help of a professional to install your own garage subpanel. However, if you are determined to do it yourself, here are five easy steps:
Step 1: First and Foremost
Ensure that you cut your power before beginning. As in any electrical project, failing to do so can result in risk of injury or even death, and could also be a fire hazard. Once power is disconnected, use a screwdriver to remove your breaker’s cover.
Step 2: Prepare For Your Garage Subpanel
Prepare for your garage subpanel by digging a shallow ditch between the garage and house. You will use this to bury your wire and conduit (your conduit should be 1-inch PVC for a 100-amp subpanel or 1 ¼ inch if your subpanel is less than 50-amp).
Assuming that you do not have any internet or telephone wiring in your garage, you can ground your subpanel with a ground bar that sits outside your garage and runs between the new subpanel box and the ground rod.
Note: if you have concrete flooring in your garage you will have to run the wire up the wall and outside of the garage.
Step 3: Install your Backer
Now it’s time to install your backer, which refers to a plank of wood that will be used to mount your subpanel. It should be at least six inches longer than your sub-panel.
Note: depending on where you live, you may be required by law to paint this backer black.
Step 4: Connect Your Wire to Subpanel
The next step is to connect your wires to the subpanel. The black and red wires both go on the main lugs on top of the main bus. The green wire goes to the ground bus bar, while the white wire goes on the main bus.
Note: #2 THNN wire is appropriate for 100-amp panels, while #1 THNN wire is suited for 50-amp.
Step 5: Main Panel
Lastly, you will need to connect the wires again, this time at your main panel. The white wire goes on the neutral bus bar while the green wire goes into the ground bus bar. The red and black wires go into the breaker screws.
Note: Before calling a job done, it’s a good idea to use a voltage meter to make sure everything is in order with your amperage.
And there you have it: a simple garage subpanel. Take some time to enjoy your new and improved garage. If you need electronics to help, please make sure to contact our Langley electricians.