Difference Between Continuous, Prime & Standby Generators

Learn which type of WPP-supplied genset is best for your project

When selecting the right generator for any application, there are dozens of factors to think about. One key place to start is with the generator’s ratings. Ratings, at their most basic level, are designed to provide insight into how much power the generator is capable of producing. They also define how and what types of applications it can be used for. It’s essential to understand this to ensure you buy a generator capable of powering your equipment within the constraints of budget and efficiency as well.

There are three basic rating types – prime, continuous, and standby. We’ll take a closer look at each of the three and when to utilize them.

Find the Generator with the Perfect Rating for Your Needs in WPP’s Huge Inventory

For the lightest standby applications to the most power-hungry prime power generator jobs, Worldwide Power Products has the genset selection to keep you powered on. With diesel and natural gas units ranging in size from 20 kW to 2.5 MW, there’s virtually no continuous or prime power challenge we can’t help you meet.


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Standby Generators

Standby generator installed via crane onto premisesStandby generator outside on concrete padHipower generator being taken from truck via crane

A standby generator is a backup generator, one used for emergency use only.

It generally has the ability to run for a short amount of time as the main power supply. It is meant to run just long enough to get the other prime power back online. This is the type of generator you need to have for instances when there is a risk of loss of power, which can happen just about anywhere.

Standby generators can be usable in many situations, including residential, commercial, and industrial areas.

The amount of time they can run varies significantly. Operating standby generators longer than the suggested number of hours at one time can lead to more frequent breakdowns and malfunctioning of the unit. They are best when they are the backup for a matter of hours.

Standby generators are necessarily any situation where having access to power is critical. A simple storm can cut off power sources, but the generator can provide a solution for the intermediate time, for example.

Because of their importance, particularly in sectors such as health care and data centers, they are governed by strict standards to ensure they are capable of powering operations when required. One of the core standards, but by no means the only one, is NFPA 110. We’ve put together a simple guide on the NFPA 110 standard to help generator owners understand what they need to get compliant.


Prime Power Generators

2 prime power generators outside supplying prime power

A prime generator is one that serves as the primary source of power for the operation. It is designed to work long term. Most often, the prime generator is designed to offer a variable power load that is drawn over time.

The most common use for a prime generator is for establishing a location that is away from other sources of power, such as a remote building site or hard-to-access area. It works well in situations where there is no real access to power lines. It can also work as a mobile solution. For example, rock crushing plants, mines, oil and gas operations, and remote construction sites are just some of the applications that use prime power.


Continuous Generators

Continuous CAT generator with enclosureTwo continuous CAT generators with enclosures placed outsideWPP-supplied prime generator powering construction site

A continuous generator is one that is used much like the primary power source. It is generally designed to work on a consistent basis as the primary source of power for the facility or function. The difference between a continuous and a prime generator is that the continuous form does not offer a variable amount of power. Instead, it is designed to provide a steady power load over the entire time frame it is used.

There are many situations in which a continuous generator works best. Most of the time, it works well when other sources of power are not accessible or cost-effective, such as when there is a need to install power at a specific remote location, but running power lines isn’t cost-effective. They are also beneficial to use in situations where the power supply is otherwise too unreliable.

These generators are very important tools for remote sites because they provide power at 100 percent load capacity on an ongoing basis. They simply lack the ability to offer variable capacity like prime systems. They are often used in mining, military, and agriculture, but can work for a variety of other applications as deemed beneficial.


What Other Considerations Play a Role in Your Decision on Which Generator to Buy or Rent?

A customized solution is always best. That is why it is so important to consider all aspects of your generator before making a purchase. View selecting the right generator as more than just a budget decision – you don’t have to buy the highest-priced model, but you do need one that fits your operational needs.

Among the decisions necessary to consider are factors such as whether gas or diesel power is accessible. You may need a single-phase or a three-phase system. It is also critically important to determine how the generator will be used – will it function as the primary power source, or will it be a backup solution in times of need? What are the genset components? A standard solution doesn’t fit all needs.

When taking the time to select the right generator for your needs, consider the following: site conditions and applications, peak and continuous demand, and duty cycle (number of hours per day per week per year).  


Need Help Choosing a Generator?

Now you know the difference between a prime, continuous and standby generator, you should be in a better position to make a decision. But the decision making has still just begun. Sizing the generator is the next step and, remember, it’s peak power you need to plan for. Worldwide Power Products has an effective sizing tool that makes choosing the right generator as easy as possible. This sizing tool is a good place to start if you’re not sure what is the best fit for your situation. If you have an understanding of power calculators then you can start sizing your generator.

Also, realize you do not have to make these decisions on your own. In most cases, it is important to work with someone that has the right tools and resources to provide you with more hands-on information and insight.

For businesses in the Texas Gulf Coast region, the WPP team has the resources and technical expertise to handle everything from designing and building a custom power solution to the installation and maintenance.