MSS Ortiz Electrical

Complete Guide on Choosing a Commercial Generator For Your Business

Do you want to make sure the lights stay on when the power goes out? If so, you need a commercial generator. For better or worse many different factors must be considered when choosing one in order to make an informed decision that will stand the test of time. This article will help guide you through this process.

Define Your Needs: Standby, Primary or Emergency Power

Commercial generators are available in several different configurations that are designed to serve specific purposes. For example, a standby generator runs constantly but is used only during power outages. A primary generator powers the building all of the time and is not used exclusively for backup purposes. An emergency backup system can run your business's critical systems, such as lights, heaters, air conditioners, and refrigerators during a power outage.

Emergency Power

When the power goes out, you need to get up and running again as quickly as possible. Emergency generators can help you do this by using battery power to run lights, heaters, air conditioners, and refrigerators so business operations can resume. You'll need enough emergency power to supply your heating, cooling and lighting needs while backup systems are being installed and your business is operating in a reduced capacity.

Standby Power

A standby generator is designed to supply the building with electricity on an ad hoc basis. It can be activated automatically or manually by your business's personnel to reduce electrical demand. The generator supplies all of the building's power while maintaining full voltage output to prevent any downtime.

Primary Power

A primary generator powers the building all of the time. It runs on natural gas or diesel fuel, which is stored in a tank to prevent interruptions. Primary generators should be sized to provide at least 1/3 more power than your business needs so they can maintain critical functions during an outage while keeping backup systems running. The commercial generator can be run during power outages to ensure that lights, heaters, air conditioners, and refrigerators don't shut down.

Types of Generators: Stationary Vs Portable

A stationary generator is located at an off-site location and supplied with fuel via a natural gas or liquid propane (LP) pipeline. It automatically transfers to backup power when the commercial power goes out. Stationary generators provide primary power for critical needs, such as lights, heaters, air conditioners, and refrigerators, and provide secondary power for non-critical needs, such as water pumps and fans.

Portable generators are ideal when you need to power only a few items. These portable generators can run on natural gas or liquid propane (LP) fuel and must be refilled manually when the fuel runs out. Portable generators require your business to remain near the generator during operation to power only essential items. This type of generator is ideal for powering tools, pumps and temporary equipment set-ups.

Portable commercial generators are available in three power ranges:

  • Small, for powering tools and equipment
  • Medium, for powering lights, pumps and temporary equipment set-ups
  • Large, for running air conditioners, heaters and other appliances in the building.

Determine Your Energy Requirements

Your generator's output is measured in kilowatts (kW) and depends on the energy requirements of your business. A small business typically requires a minimum of 1 kW, while a medium to large commercial facility typically requires 5 to 10 kW. When looking at generators, you should know the number of kW you require to run your essential loads. Example: A coffee shop requires 1 kW to power lights, pumps and appliances during a power outage.


Once you've decided on the type of generator, you need to figure out how many watts your business will require. You can make this calculation with this formula: (watts required = number of amps x voltage supplied by company - loss through supply lines). Once you have figured out how many watts your business requires, you can then determine the size of the generator you need.

Single-Phase vs. Three-Phase Power 

Another thing to consider is whether you need single-phase or three-phase power. Generally speaking, it's best to go with three-phase power if the generator will be supplying secondary power for powering motors, like those used in large air conditioners. If your business requires single-phase service, then that's what you should purchase.

Generator Fuel Types

Your generator's fuel type will depend on where you plan to locate it. If your business is located in a rural area, natural gas is the best option because most small businesses are not serviced by liquid propane/LPG pipelines in rural areas. However, if you have a commercial facility in a more populated area and do have access to a liquid propane line, then that's a better option because there are more fueling stations available.

Natural gas: This is the cleanest burning fuel available. It is ideal for generators that need to run all day during an outage since it burns continuously when the pressure in the fuel line remains at a constant level.

Liquid propane (LP): LP is most commonly used in portable generators because this type of generator must be refuelled manually when empty. However, LP is not recommended for large generators because it can produce dangerous levels of carbon monoxide.

Gasoline: Gasoline has the drawback of producing high levels of smoke and creating a fire hazard when used indoors. It should only be used in generators where clean air is circulated to remove smoke from combustion.

Diesel: Diesel produces no significant smoke and is the best choice for generators that will run 8 hours or more in a row.

The experts at MSS-ORTIZ Electrical Services can help you decide what generator fuel type is best for your business. Contact us today!

Location Considerations

Outdoor generators are typically noisier than indoor generators. You'll also need to consider how much vibration your generator will have when placed on a concrete floor. Some manufacturers place rubber feet on the bottom of their generators so they don't vibrate too much for an office environment, while others keep the rubber feet off so users can bolt it down to a cement pad for added stability.

Schedule a Commercial Generator Consultation With us Today

When you need to choose a commercial generator for your business, contact the experts at MSS-ORTIZ Electrical Services. Our technicians have over 20 years of experience in commercial electrical contracting services and can help you choose the right generator for your business. Call us today to schedule a consultation at  (919) 382-0832.

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