Posted 10/26/26 @ 4:22 pm
The generator you choose for your construction site depends on more than just the amount of power it produces. Contractors also have to consider factors like where it will go, which equipment it’ll power, how often it’ll need to be moved, and how long the site needs power. A towable generator may make more sense for one job, while a portable unit may be a better fit for another. The right choice depends on the jobsite’s demands.
Choosing the Right Portable Generator for Your Jobsite
Whether you need temporary power for a trailer, hand tools, lighting, or equipment, selecting the right generator can improve productivity and keep work moving without interruption. The table below compares available portable generator options, making it easier to match power output and features to your specific jobsite needs.
How Much Power Does Your Jobsite Actually Need?
Unlike days past, you can no longer get away with running a circular saw off of a tow behind generator. With today’s generators you need to make sure you size it specifically for the needs of the job. If you oversize a generator, the generator will wet stack.(Wet stacking is when the generator does not get hot enough to burn off the carbon build up in the exhaust system) If your generator wet stacks it will shut down. If you under size your generator, the generator will keep tripping breakers, and will not provide power.
The secret to properly sizing a generator is as follows:
- Determine the total running wattage of all equipment that will be operating at the same time. This includes tools, lighting, heaters, and any other equipment requiring power.
- Next, you need to account for the highest single motor-starting surge, since equipment with electric motors requires additional power during startup. You add that additional surge requirement to the total running wattage.
- Once you have that total, add a 25% safety margin to account for factors such as temperature, equipment condition, and fluctuations in electrical demand.
The formula for these steps is
(Total Running Watts + Highest Additional Starting Surge) × 1.25 = Required Generator Wattage / 1000= kW required to power your site.
Ultimately, the goal is to properly size the generator so it can handle both the running and starting requirements without being overloaded, while avoiding an unnecessarily oversized generator that increases rental and fuel costs.
Choosing Between Portable and Towable Power
If utility power isn’t available yet, a generator may also be used to power a job trailer while the site gets up and running. For smaller jobs or temporary setups, a portable unit may provide enough power while still being easy to move. This gas-powered 3KW portable generator delivers 3,000 watts of 120v of power and features full GFCI protection, making it a safe, OSHA-compliant option for powering essential tools and equipment on smaller jobsites.
Larger jobs with heavier power demands may call for a towable generator instead, like the Generac MDG25 T4 Diesel Generator, which is engineered to provide dependable continuous making it ideal for construction sites, rental operations, and special events.
How Will the Generator Fit Into Your Jobsite?
When determining whether you need a portable or tow-behind generator, you first need to identify the total power requirements, how long the generator will operate, and the conditions in which it will be used.
A portable generator is typically the more economical option for smaller electrical loads, intermittent use, and applications where the generator needs to be moved frequently around the jobsite. Portable generators are generally easier to transport and have lower rental costs, but they have smaller fuel tanks and require protection from rain, snow, and other weather conditions.
A tow-behind generator is better suited for larger power requirements, extended operating hours, and applications requiring consistent power throughout the workday or around the clock. Tow-behind units generally offer larger fuel capacities, enclosed designs for better weather protection, and greater electrical capacity.
How Long Will You Need Power on the Jobsite?
Since projects run on different schedules, consider how often you’ll be running your generator. You may only need power during working hours, or you may need the generator to run overnight as well. Towable generators generally have larger fuel capacity and suit extended operation, while smaller portable units may make more sense for shorter or more mobile needs.
Fueling Your Generator: Delivery Schedule & Storage
Re-fueling a generator is as important as deciding which kind of generator you will need. Some options you have are:
- 365 Equipment & Supply can schedule a fueling service to come to the jobsite to refill your generator on a set schedule based on use.
- 365 Equipment & Supply has fuel transfer tanks that can be rented and hooked up to the generator. This will expand the run time of the generator without the need of having to have a person on site to refuel it.
This is one reason renting can make sense for construction projects with changing needs. Instead of investing in a generator that may not fit every project, you can rent a unit based on the power requirements of the job you’re working on now.
If you’re not sure which generator fits those requirements, talk with the 365 team about the equipment you’re running and how long you’ll need power.
Choose the Generator That Fits the Jobsite
There’s no single generator that makes sense for every job. The right choice depends on how much power you need and sizing the generator to the project. Thinking through those requirements before you rent can help you avoid ending up with a machine that doesn’t fit how your crew needs to use it.
Need help finding the right generator for your next project? Talk with the 365 Equipment & Supply team about your power requirements and generator rental options.