Downtime is a vampire for your business. It drains productivity and profitability and causes delays in every aspect of your operation. Losing a mission-critical system or your data connection is bad enough, but nothing can bring you to a complete halt like a loss of electrical power.

Back in 2016, Delta Air Lines’ operations center adjacent to Hartsfield Jackson Atlanta International Airport suffered a power outage. In the five hours the center was without power, the airline lost an estimated $150 million – that’s $30 million an hour, or a half million dollars for every minute the facility was dark. And that was eight years ago. The cost of downtime has only increased since then.

While you may not be running an international airline, a power outage can still be catastrophic for your bottom line. That’s why it’s crucial to have a reliable outage prevention system in place, including a quality commercial backup generator. Here are some answers to frequently asked questions about generators for your business to help you understand these vital parts of your business’s preparedness program.

What Is a Commercial Backup Generator?

Just like the small portable generator many people have at their homes to keep the refrigerator and some fans running during a power outage, a commercial generator keeps your facility supplied with electrical power whenever your electrical supply is interrupted.

Commercial generators come in many different sizes and form factors to fit the needs of a wide range of applications, but they can generally be divided into two size classes: portable and standby.

Portable Generators

Portable generators come in sizes ranging from small inverter generators no bigger than a carry-on bag that can run a few appliances for a few hours to massive trailer-mounted units that can supply an entire building with ample power to maintain operations for days and weeks at a time. Portable generators typically run on gasoline, diesel, or propane fuel and need to be refueled regularly.

Standby Generators

Standby generators are permanently installed, wired into the building’s power supply through an automated transfer switch (ATS), and connected to either a continuous-supply fuel source (natural gas) or a large storage tank (diesel or propane). When properly installed and maintained, a standby generator automatically starts and provides a seamless transition from grid power to backup power in the event of an outage.

How Large of a Commercial Backup Generator Do I Need?

This question can take a while to answer in detail, but in general, you can determine what size generator you need by looking at your past electric bills. In the US, generators are labeled according to their output in watts (W) or kilowatts (kW).

Small portable generators can generally put out between 2,000 and 10,000 watts (2-10 kW), while the smallest standby units generate between 25 and 50 kW. Large standby generators can output upwards of 1,000 kW, and multiple units can be run together to create massive amounts of power.

The best way to determine the right generator size is to consult with an electrician or an outage prevention contractor who can use special tools to assess your exact peak, standard, and minimum usage.

What Is an Automatic Transfer Switch?

If you choose a standby generator, your installers will also wire in a component known as an automatic transfer switch (ATS). An ATS has two inputs – the grid and your generator – and a single output into your building’s electrical system. It also includes two other capabilities:

  • A monitoring system to determine whether or not the grid is supplying power to the facility
  • A starting circuit that can automatically trigger the starter on your standby generator and a kill switch to turn it off

When power from the grid is interrupted, the ATS automatically disconnects your facility from the power grid, switches your building’s supply to the generator, and cranks the generator to maintain the power supply inside the building.

When the grid once again supplies power, the ATS will switch the building’s power supply from the generator back to the grid and activate the kill switch to turn off the generator.

In order to make sure that your ATS, generator, and any other associated equipment are working correctly, you should schedule regular tests of your switching circuits and generator according to the manufacturer’s or contractor’s recommendations.

What Kind of Fuel Is Best for a Commercial Backup Generator?

There are four fuels commonly used in commercial backup generators, each with its strengths and weaknesses. Depending on the infrastructure that’s available at your site, one or more of these choices may be an obvious pick.


This fuel is only commonly used in small, portable generators. Of the four, gasoline engines require the most maintenance and have the most moving parts. Gasoline also has the shortest shelf life of any of the fuels, so it must be used within 6-12 months of its purchase, or it will go stale and no longer be able to run the generator.


Diesel is a common choice for larger portable generators and standby generators of all sizes. Diesel engines are less complex than gasoline engines, produce more power for the same amount of fuel, and, with the advent of diesel particulate filters and selective catalyst reduction systems, burn cleaner than previous generations of diesel. Diesel has a longer shelf life than gasoline but will still go stale if left in storage for more than a year or two.


Facilities that are already using propane as a fuel source for other equipment will find that installing a propane-powered generator is a better option. Propane engines burn very clean, generally require less maintenance than liquid-fueled engines, have fewer moving parts, and are quieter. Propane can be stored indefinitely, so even if your facility doesn’t currently have propane storage, it can be a better option for places with highly reliable power grids, where the standby generator will seldom be used.

Natural Gas

Connecting a standby generator to a public natural gas supply ensures that you can enjoy plenty of electricity for as long as the gas supply holds out. Since gas distribution systems are considerably more robust than the electrical grid, the likelihood of losing gas is much lower. Natural gas generators have the same advantages as propane generators in terms of ease of maintenance and removal of any fuel storage considerations.

Multi-Fuel Generators

Many generators are designed to run on multiple fuels or can be easily converted to do so. The most common dual-fuel pairing is gasoline/propane or gasoline/natural gas. Natural gas generators can be converted very easily to burn propane.

Downtime Is a Profit-Killer. Give JLJ and Associates a Call, and Let Us Install a Commercial Backup Generator for Maximum Outage Prevention.

Whether your existing outage protection needs an update or you need a system for your new facility, trust the outage prevention experts at JLJ and Associates to complete your project on time and within budget. Call us today to find out how we can work for you! 770-961-7600

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