A whole-home or standby generator is a great way to protect against blackouts and power outages. If your home loses power for any reason, the standby generator will automatically kick in and supply electricity to your home. Depending on the size of the generator, you may only be able to run some of the most essential appliances and systems such as your HVAC system, refrigerator, lighting, electric water heater, etc. Still, you can easily find generators that are powerful enough to supply electricity to everything in your home. To understand how whole-home generators work, it helps to look at the specific steps an electrician takes when installing the unit.
Mounting the Generator
The very first thing is to mount the generator outside your home. National Fire Protection Association code requires that the generator is at least 1.5 feet away from the house or any other structures. However, if the generator is located near an exterior wall with any doors, windows or vents, it needs to be a minimum of five feet away from the wall.
Most local regulations also state that the generator cannot be within five feet of your front, side or rear property lines. In addition, the generator cannot be mounted within three feet of any trees, shrubs or other vegetation. Lastly, the generator needs to be mounted so that the exhaust is pointing away from the house.
While these distances are the minimum allowed by code, many manufacturers and installers recommend installing the unit further away. You should always go with whatever the manufacturer’s recommendation is or else you could void the generator’s warranty.
Some local codes also require that the generator be mounted up to 20 feet away from the building. In this case, the generator will also need to be located in an area that is also at least 20 feet away from your neighbor’s house.
After selecting the appropriate location, a concrete pad will need to be poured for the generator to sit on. The size and weight of the generator will determine how large and thick the concrete slab needs to be. The weight of the concrete needs to be at least 125% of the combined weight of the generator and fuel, i.e. a 10,000-pound generator needs a minimum of 12,500 pounds of concrete. Concrete weighs 150 pounds per cubic foot, and this number is used to calculate how large the pad needs to be.
Connecting the Generator to the Fuel Source
Once the concrete has hardened and the generator is set, the next step is to run gas lines to connect it to the fuel source. Whole-home generators can run off of either natural gas or propane. If you live in a residential area, it is always best to simply tie into your home’s existing natural gas line. This is done by using a tee to connect to the main gas line and then running an additional pipe to the generator.
In rural areas without access to natural gas, you will need to have a large propane tank installed if you don’t already have one. In this case, you will also require an additional concrete pad for the propane tank to sit on. Most regulations require that propane tanks be at least 10 feet away from any source of ignition, and this includes a whole-home generator. That being said, the tank shouldn’t be much more than 10 feet away if possible as manufacturers still recommend that the generator is as close as possible to the fuel source.
Installing and Wiring the Transfer Switch
The next step is to install the transfer switch in your electrical panel. The automatic transfer switch is what controls the generator and signals it to run whenever the power goes out. It works by constantly monitoring the flow of electricity coming into your breaker panel. When it detects that no electricity is flowing, it simultaneously isolates your home from the electrical grid and signals the generator to start. As soon as the generator starts, the switch activates so that electricity from the generator flows into your home.
The location of the transfer switch depends on its type and the size of your generator. In most cases, the transfer switch is mounted on the wall next to your main breaker panel. However, some people choose to install smaller generators that are only meant to power the essentials. In this situation, your electrical system will be redesigned so that all of the non-essential circuits are in the main breaker panel and all of the essentials are in a sub-panel. With this setup, the transfer switch is installed at the sub-panel.
Once the transfer switch is mounted, wires are run from the switch, fed through an inlet box and then wired directly into the panel. The wires are connected to breakers within the panel. If no empty breakers are available, they will need to be installed.
However, sometimes there isn’t enough available space inside the panel. When this happens, an electrician may be able to combine some of your other circuits to free up space inside the panel. If this isn’t possible, you will either need to have a larger panel installed or move some circuits to a sub-panel.
Grounding the Generator
Although your home’s electrical system is already grounded, most electricians recommend installing a separate ground rod at the generator itself. This helps to prevent power surges or other issues that could cause your generator to fail during an outage. When grounding a generator, a large copper rod is driven at least eight feet into the ground. A copper wire is then run from the generator and connected to the rod. In the event of a power surge, the electricity will be directed through the rod and into the ground.
Programming and Testing
Once the generator is fully installed, the final step is to test it to make sure everything works correctly. All whole-house generators have a function known as exercise mode, which automatically turns the generator on at a scheduled time. Once on, the generator will typically run for 20 to 30 minutes and then shut off. This is important as it keeps everything lubricated and allows you to monitor the generator for any issues.
The generator can be programmed so that it switches to exercise mode each week on a specific day and time. After the installation is complete, the electrician will set the system so that it turns on in exercise mode. During this time, the generator will run but the transfer switch will not activate. This enables the electrician to inspect the generator and make sure that there are no leaks or other issues.
Once this is done, you can then program the unit so that it switches to exercise mode at a day and time of your choosing. It is always best to set it so that this happens when you will be home and can monitor the generator for any signs of a problem. Most manufacturers recommend that you set it so that the generator runs once a week, but some say it is only necessary every two weeks or even once a month. Whatever the manufacturer recommends is what you should follow.
If you’re considering a whole-home generator, Arc Angel Electric is here for you. Our licensed electricians specialize in standby generator installation, and we can help you determine what size of unit you need to power your home. We carry a range of units from top brands like Generac, and we also service and repair generators from all other manufacturers. Our team also offers a wide range of other electrical services for residents throughout the Atlanta area. To learn more about the benefits of installing a standby generator or to schedule a consultation, give us a call today.