Proper Generator Sizing

The Ultimate Guide to Proper Generator Sizing

In the commercial and industrial sectors, machines must run at full capacity during all operating hours. From pressing plants to production houses, a power outage of even a few hours could result in disastrous downtime, costly for all parties. With all the capital that goes into a business, there’s too much at risk when you don’t have a backup for your power supply.

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It’s a fact that power lines can and do get knocked out, whether it’s due to harsh regional weather patterns or locally centered power blackout. According to figures compiled by IE Investigations, power outages across the United States more than quadrupled between 2000 and 2014. Divided into blocks of five years or less, the statistics are alarming:

  • 2000 — 2004, an average of 44 grid outages per year.
  • 2005 — 2009, an average of 100 grid outages per year.
  • 2010 — 2013, an average of 200 grid outages per year.

The last of those periods shows the sharpest hike, with double the reported power outages of the prior period. For obvious reasons, factories and commercial entities risk products and machinery of untold value when all the production equipment, lighting and storage units are left vulnerable to power outages. To stay in operation during hours when lines are down, smart businesses use backup generators.

Granted, generators come in various sizes and power capacities, some of which are suited for smaller operations and others which are optimized for large scale, heavy-duty industrial settings. With so many makes and models of generators to choose from, first-time buyers will often ask the following questions:


A common mistake that buyers often make is to choose a generator that is disproportionate to the size of their operation. Since they only intend to use the generator in emergencies, they figure a small, low-capacity unit will suffice. This assumption can be put to the test if the main generator fails, and suddenly all the machinery needs to be connected to this smaller generator.

In such an event, a low-capacity generator will quickly become overloaded. Consequently, machines connected to the device can wind up underpowered, leading to sporadic failure of items in the system. At worst, various items in this setup — including the small generator — could die outright. Therefore, it’s crucial to learn how to size a standby generator as well as the main one, regardless of whether the purpose is to power a building, shopping center, factory, worksite or outdoor operation.

Businesses and Factories: How to Determine Generator Size

In industries that rely on heavy-duty machinery and complex, high-tech equipment, people often ask, “What size backup generator do I need to run all of my equipment?” The answer can all depend on the size of the setup in question.

If you have a large operation with machinery that is mission-critical, you need a higher capacity generator to keep things running regardless of location or frequency of power outages. On the other hand, a mid-sized operation with less frequent uses would naturally require something smaller.

Here’s what to consider:

Make a List. If you’re wondering how to size a generator for your business needs, your first step should be to make a list of all the items that would be powered by the generator. The generator could power many different items at different times, depending on the location or circumstances. Examples of applicable items in this category include:

  • Industrial tools. Out on a worksite, workers use numerous tools throughout each given shift to erect buildings and pave roads. However, since there are no nearby landlines from which to draw energy, the tools in use — jackhammers, nailers, rivet guns, sanders — are often run on gas-powered generators.
  • Factory machinery. With so much money behind each production, businesses cannot afford to have the machines and conveyors halted by power outages. Therefore, when power lines do go down, generators provide backup energy so that the lights stay on and the machines stay activated. To determine how to size a standby generator, consider the size of the factory in question and the number of machines involved.
  • Remote operations. For events held miles away from the nearest electrical lines, generators allow machines to power on for the festivities. If you’re wondering how to size a portable generator for an outdoor event, consider all the items that it would need to power, such as refrigerators, cooking devices, lighting systems, sound systems, etc.

Note the Wattage. In addition to the number of items you intend to power, you must also determine the total wattage consumed. After all, if the requirements of a given piece of machinery exceed the limits of a particular generator, the machine will fail to power and perhaps cause negative reactions throughout the system.

If you’re wondering how to size a generator for commercial use or any other large-scale endeavor, consider the following:

  • Starting Wattage. How many watts are required to power on each tool or machine within your setup?
  • Running Wattage. How much power is needed to keep each item operating for the time-periods in question?

Calculate the Collective Power Needs. To determine the power needs of an entire factory or remote work site, add up the collective power needs of all the machines and tools included in the system. In other words, the question at hand is more than just how to choose the right generator size — it’s also how to choose the right generator capacity. The latter can be determined by calculating the following power requirements:

  • KVA. A KVA stands for 1,000-volt amps. Volt and amp respectively refer to the pressure and current of electricity.
  • KW. A kilowatt is a symbol for a unit of power. One kW is equal to 1,000 watts.

Based on the number of items in a given setup and their collective power requirements, your best match along the generator size guide could ultimately fall at the low or high end of the 35kW to 2500kW spectrum.

The Benefits of Knowing How to Choose the Right Generator Size

In recent years, Google has been flooded with search strings such as “how to figure out what size generator I need” and “what size power supply do I need?” An increasing number of engineers and entrepreneurs in the commercial and industrial sectors have come to realize just how much they can save on machine maintenance and replacement costs with a properly sized generator. When you learn how to size a generator for the scope of your operations, you’ll reap the following benefits:

  1. No random system failures.
  2. No shutdowns caused by system overload.
  3. A longer lasting generator and collection of machinery.
  4. Smooth performance at all times.
  5. Easy maintenance at rare intervals.
  6. A system that can run intact, without change, for many years.
  7. Physical safety of all personnel.
  8. Little-to-no risk of property damage.

Avoid Random System Failures. Once you’ve learned how to size a generator for the needs of your business, you won’t have to worry about downtime caused by power outages. Considering all the money involved in a typical operation, where thousands of interests are at stake at any given hour, most companies simply can’t afford to have any downtime. With an optimal electric, gas or diesel generator, you will never have to cope with:

  • Lost revenue due to an unforeseen halt in production.
  • Unfulfilled shipments due to an inability to produce wholesale/commercial items as needed.
  • Cancellation of public, outdoor events from being unable to secure sufficient power sources.
  • Delays in construction due to a lack of any power source.

If the business you operate functions on speed, efficiency and a commitment to fulfilling all parties involved — be it wholesalers, customers or other business entities — you need to have a generator on your premises or worksite to keep every piece of machinery running during all hours of operation.

Avoid Sporadic Shutdowns Caused by System Overload. Another key advantage you gain with an appropriately sized generator is maximum power capacity for your operations. You won’t have to worry about system failures from capacity overload since a backup generator prevents the following unforeseen scenarios:

  • System failure due to an overload of a low-capacity power supply.
  • Power systems rendered inadequate by the introduction of higher-powered machinery.
  • System failure caused by power surges with a given piece of machinery.
  • Forced downtime or inability to operate in full-function mode due to capacity limits.

Enjoy a Longer Generator Lifespan. When it comes to industrial operations, few things are as costly as a short lifespan for tools or machines. It’s essential to have a generator that offers optimal capacity for all the items connected within a given system, so nothing powers out prematurely. For the same reason, the machine must have sufficient capacity to handle full-demand loads at all times.

When you determine how to size a generator for commercial use, you gain the following benefits:

  • Full-life expectancy and beyond for heavy-duty machinery.
  • Minimal need for maintenance on high-tech machinery, even after years of use.
  • Full-life expectancy and beyond for electric, diesel and natural gas generators.
  • Little, if any, need for generator maintenance, even after years of heavy-duty usage.

Enjoy Surefire Performance at All Times. When replacing or upgrading an old power system, it’s crucial to choose a generator that gives you maximum power without fail, 24/7, regardless of the size of the overall operation. A search through a generator size guide could be the answer to all of your concerns, especially if you’re among the business owners and factory operators who have asked, “What size backup generator do I need?”

With electric, diesel, or natural gas generators, you can enjoy:

  • Uninterrupted power throughout wind, snow, and other harsh natural events.
  • Continuous power when local systems are down.
  • Consistent power despite brownouts in the area.
  • Unabated performance, even when you change or add new components to the system.

Easy, Trouble-Free Maintenance. When it comes to maintenance, it’s always best if the upkeep in question is low-cost and minor. Likewise, a quality generator should rarely run into much trouble over the course of its life, as the best generators are built to withstand the most demanding uses. However, even the best generator makes and models will sometimes need to be taken in for a tune-up. With a top-quality generator, you’re assured:

  • Generators need only simple and minor servicing.
  • Lengthy durations between maintenance periods.
  • Performance so reliable that basic upkeep can thwart the need for maintenance for years on end.
  • Machines and tools are supplied better and, therefore, require little to no maintenance.

Systems That Last for Many Years. When you properly size a generator for commercial use or industrial applications, your whole entire system could end up lasting for years, if not decades, with few servicing needs and even fewer replacements of any attached machinery. An optimal backup generator largely eliminates the need to replace components on a recurrent basis. In fact, your only reason to replace any of the tools or machines in your facility could simply be down to model upgrades.

Therefore, with a built-to-last electric generator, natural gas generator or diesel generator, you could find yourself reaping the following benefits:

  • An industrial setup that will last for years, perhaps with no need for upgrades throughout your time at a given location.
  • A durable, optimal generator for constant transportation and instant set up virtually anywhere — this is just one of the things you gain by learning how to size a portable generator.

Assured Safety for Everyone Involved. When managing a crew of any size, safety is of utmost importance. Production, no matter how valuable & crucial to your bottom line, is not worth a single injury or life lost.

When machines and tools rely on a generator, every item in the system must have sufficient power, with no risk of short circuits or other mishaps that could lead to electrical or operational failure. Even when a given machine operation takes place at a safe distance from factory personnel, it’s crucial that none of the components malfunction, especially not in any way that could set off a chain reaction.

With a properly sized generator, you don’t have to worry about any of the following scenarios:

  • Dangerous system malfunctions due to power failure.
  • Injury of factory personnel caused by generator-related machine failure.
  • Domino-like mishaps at worksites or pressing plants caused by a faulty generator.
  • Lawsuits stemming from factory personnel due to generator-related injuries.

Minimal Possibility of Asset Damage. When a power system is implemented, upgraded, or replaced, it’s crucial none of the components cause negative reactions between one another that could lead to the costly damage of property. Whether there’s a new generator purchased for a longstanding set of tools and machines or new machines connected to a pre-owned generator, neither must act in a way that would cause adverse reactions. These reactions could lead to outages, blown fuses, destroyed machinery, or ruined products.

That’s why it’s important to learn how to choose the right generator size and capacity for your operation. It spares you from experiencing:

  • Blown fuses that prematurely kills machinery.
  • Chain-reaction power failure from one machine or tool to all others within a facility.
  • Costly damage to factory conveyor systems and surrounding tools.
  • Lawsuits stemming from damage to third-party equipment caused by generator mishaps.

Granted, while it’s important to properly size a generator to reap the most benefits of your purchase, it’s also crucial to buy a generator from an outlet you can trust.

Determine What Size Generator You Need From Woodstock Power

At Woodstock Power, we sell only top-quality new and used electric generators, natural gas generators, and diesel generators. In addition to working for a vast range of industrial and commercial uses, our machines range from 35kW to 2500kW along with the generator size guide.

The question of how to determine the ideal generator size can easily be answered when you speak with the knowledgeable staff who will guide you through the vast inventory of generators offered by Woodstock Power. For many years, we’ve cultivated relationships with clients across all corners of the commercial and industrial sectors. In doing so, we’ve provided generators for pressing plants, hospitals, data centers, and treatment plants, as well as businesses large and small.

What all of these entities have in common is a commitment to quality, which rewarded in spades by the generators we offer. With Woodstock Power, clients get the following features in our services:

  • Top-quality. Whether new or used, each generator we sell is tested and guaranteed to be in optimal working condition.
  • Nationwide assistance. With operations throughout the United States, we have contacts with generator experts that can offer turn-key assistance and power planning to buyers and sellers from coast to coast.
  • Speedy delivery. With our firm belief that there’s no time for downtime, we deliver equipment with unsurpassed speed throughout the nation. Our generators are shipped immediately from different holding locations across the U.S.
  • Rent/lease options. For clients on fixed budgets or with time-based projects who only need a generator for select durations, we also offer generators on a rental or long-term lease basis.
  • Savings. You can save up to 70% off the retail price of generators by purchasing from our used model inventory.
  • Full range. We carry a variety of electric generators, diesel generators and natural gas generators. Since we are not specific to any one brand, we’re able to offer bias-free recommendations on the best generators for any given operation.

When you decide to buy a generator from Woodstock Power, we can guide you through every step of the process. Once an agreement is reached and payment is received, we can usually send out your generator within three days. To learn more about our generators and make an educated purchase today, please fill out our contact form.

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