What Size Generator Do I Need for a Construction Site?

September 23, 2024 | Nate Cord

Construction sites often lack access to reliable or permanent power sources, especially in remote locations or during the early stages of development. This is where generators come in handy as they provide the temporary power needed to operate tools, machinery, lighting, and other essential site equipment.

It’s so important that you choose the right generator for your construction site, otherwise your equipment may not receive enough power to operate efficiently, leading to delays, potential damage to tools, or even safety hazards due to insufficient power supply.

Whether you’re working on a small residential build or a large commercial project, understanding how to calculate the proper generator size is essential to avoid downtime and prevent costly mistakes. And we’re here to help!

Here are 5 main considerations when it comes to choosing the correct site generator for your construction site:

1. Think about Your Equipment and Power Requirements

First things first, you want to begin by listing all the equipment and tools that will be used on the construction site, and note their power requirements usually indicated in watts (W) or kilowatts (kW). This wattage information can be found in the equipment manuals or on their labels).

If the generator doesn’t meet the site’s power requirements, these tools simply won’t function properly.

Examples for construction equipment include:

1. Power drills: 450-1500 watts
2. Circular saws: 800 to 2500 watts
3. Air compressors: 1000-4000 watts
4. Concrete mixers: 500-2000 watts
5. Welders: 4000-9000 watts
6. Floodlights: 500-1000 watts per light

2. Determine Your Power Needs

It’s important to be aware that many tools have higher starting wattages (surge watts) than their running wattages (continuous watts). The surge power is basically the extra power needed when starting up certain tools.

For example, an air compressor might need twice its running watts to start (3000 watts to start but only 1500 to actually run).

This is why it’s important to choose a generator that can handle both the running and surge wattages of your equipment.

3. Calculate the Total Power Needs

Now you’ll need to add up the power requirements of all the equipment the generator will be powering, and also the highest surge wattage to account for startup power demands.

For example, if you have a circular saw of 1600 watts, work lights for 500 watts and an air compressor of 2000 watts running/4000 watts starting, the total running wattage would be 4100 watts (1600 + 2000 + 500), and the highest surge wattage would be 4000 watts (for the air compressor).

In this instance, you’ll need to look for a generator that can provide at least 4100 watts running and 4000 watts surge power, i.e. a generator rated for around 5000-6000 watts.

Calculating total power needs ensures that the generator can handle these surges without overloading.

4. Consider the Different Types of Generator Available

There are a variety of different types of generators available, all with their own features and benefits, but ultimately, the best type of generator for your construction sites is the one that’s going to meet all your power needs without any problems.

The four most common types of generators used on construction sites are high-powered generators, medium-powered generators, standby generators, and portable generators. Let’s have a look at these in a little more detail…

• High powered generators – High-powered generators are essential for large construction sites or projects that require a lot of energy to run heavy machinery and multiple tools at the same time, for example road laying tools, earth moving equipment or material handling machinery.
• Medium powered generators – Medium powered generators are more suitable for, as the name suggests, medium-sized construction sites, such as house, apartment or small business construction. These generators typically fall within the power range of 5,000 watts (5 kW) to around 20,000 watts (20 kW).
• Standby generators – These are generators that are used as an alternate source of power if the primary source fails, helping you keep the work going if there is a power failure. Check out our wide range of standby generators, here.
• Portable generators – Portable generators are the most common type used at construction sites, as they can be moved to different areas of the site to power different tools and equipment, providing power to heavy-duty equipment at all times.

If you’re not too sure which type of generator is best for your construction site, feel free to give our experts a call on 01639 849847 and we’d be more than happy to guide you.

5. Consider Fuel Types

Considering different fuel types when selecting a generator for a construction site is absolutely vital for optimising fuel efficiency and managing operational costs.

The 3 most common fuel types used in generators are diesel, petrol and LPG.

Diesel Generators

Diesel generators provide a robust power output, making them ideal for powering heavy equipment and multiple tools simultaneously on a construction site. Another benefit is that they are designed to withstand tough environments and continuous use, which is very common on construction sites. Learn more about diesel generators here.

The Pramac P11000 Silent Electric Start Diesel Generator is a great example of a diesel generator designed for professional and intensive use.

Petrol Generators

Petrol generators are typically lighter and easier to move around, which is great for smaller, mobile applications on a construction site. They are also usually less expensive compared to diesel generators, however they have lower fuel efficiency and typically are not as rugged as diesel engines.

LPG Generators

LPG generators are power generators that use liquefied petroleum gas (LPG) as their fuel source. This type of generator burns cleaner than petrol and diesel, producing fewer pollutants and greenhouse gases – great for sites with stringent environmental regulations. They also operate more quietly than diesel generators, which can be beneficial on sites where noise levels need to be minimised, especially in residential or noise-sensitive areas.

Looking For a Quality Generator For Your Construction Site?

At Generators Direct, we offer a wide range of generators for construction sites.

All of our products are manufactured, tested and certified to industry standards, and come with a price promise – you won’t find prices cheaper anywhere on the web, but if you do, we’ll match them. In addition to this, all orders come with free mainland UK shipping and after sales support from our experts.

If you require additional advice or have a question for our team, please get in contact with us using this form or via phone at +441639849847. And for additional tips and insights into the wonderful world of generators, check out our generator blog.