What Size Natural Gas Line do I Need for Portable Generator? Pro Tips

By Alex McGill

Wondering about the ideal natural gas line size for your portable generator? Navigating the intricacies of gas line compatibility can be a puzzling task, but fear not—we’ve got you covered. In the realm of portable generators, finding the sweet spot for a natural gas line is crucial for seamless performance.

Whether you’re a seasoned DIY enthusiast or a first-time generator user, understanding the optimal gas line size is key to unlocking the full potential of your equipment. Join us on a journey to demystify the question, What size natural gas line do I need for portable generator?—because powering up should be as effortless as it is empowering.

Core Lessons

  1. Calculate Gas Consumption: Determine the generator’s gas consumption rate in BTUs per hour (BTU/hr) to find the appropriate gas line size.
  2. Consider Pressure Drop: Factor in the length of the gas line and potential bends or restrictions to ensure adequate pressure reaches the generator for efficient operation.
  3. Use Sizing Charts: Consult manufacturer-provided sizing charts or tables to match the generator’s BTU rating with the appropriate gas line diameter.
  4. Consult a Professional: When in doubt, seek advice from a licensed professional or gas utility company to ensure the gas line size meets safety and regulatory standards.
  5. Regular Maintenance: Keep the gas line and generator system well-maintained to prevent any obstructions or issues that could affect performance.

Understanding Gas Line Sizing for Portable Generators

Gas line sizing for portable generators is crucial in ensuring a proper supply of natural gas to meet the equipment’s fuel requirements. When installing a gas line for a portable generator, it is important to consider the fuel consumption of the generator and ensure that the gas line can provide an adequate supply of fuel.

The size of the gas line will depend on factors such as the distance from the source of natural gas and the total BTU (British Thermal Units) rating of the generator. To determine the appropriate size for a gas line installation, one must first calculate the total BTU rating of the generator. This information can usually be found in the manufacturer’s specifications or user manual.

The BTU rating represents how much heat energy is produced by burning one cubic foot of natural gas. Once this value is known, it can be used to calculate how many cubic feet per hour (CFH) of natural gas are required by dividing it by 1,000. After determining the CFH requirement, other factors such as pressure drop and pipe length should be taken into account to select an appropriate pipe size for optimal performance.

Pressure drop refers to a decrease in pressure as natural gas flows through pipes due to friction with pipe walls. Longer pipe lengths or higher flow rates will result in greater pressure drops. By considering these factors along with other variables like elevation changes and fittings, one can accurately determine the appropriate size for their portable generator’s gas line installation.

Understanding how to properly size a gas line for a portable generator is essential to ensure reliable operation and prevent potential issues caused by insufficient fuel supply. Factors such as distance from the source, total BTU rating, pressure drop, pipe length, elevation changes, and fittings all play crucial roles when determining an appropriate size for a gas line installation.

It is necessary to carefully consider these factors before selecting and installing a gas line that will effectively meet your portable generator’s fuel requirements without compromising its performance or reliability.

What Size Natural Gas Line do I Need for Portable Generator

What Size Natural Gas Line Do I Need For Portable Generator?

The size of the natural gas line you need for a portable generator depends on the generator’s BTU (British Thermal Units) rating and the distance between the generator and the gas meter or source. 

Generally, a 3/4-inch natural gas line is sufficient for most portable generators up to 200,000 BTUs and within 100 feet from the gas source. However, for larger generators or longer distances, you may require a larger gas line, such as a 1-inch or 1.5-inch line.

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It is essential to consult with a licensed gas technician or plumber to accurately determine the appropriate gas line size based on your specific generator’s requirements and installation setup.

What Size Natural Gas Line do I Need for Portable Generator

Factors to Consider When Choosing Gas Line Size for Portable Generators

When selecting the gas line size for portable generators, it’s crucial to consider various factors to ensure optimal performance and prevent any issues. The following bullet points highlight key considerations in making the right choice:

  • Generator Fuel Consumption:
    • Begin by understanding the fuel consumption rate of your portable generator. This information is typically provided in the generator’s specifications.
    • The fuel consumption, usually measured in gallons per hour (GPH) or liters per hour (LPH), helps determine the necessary gas flow for a sustained operation.
  • Gas Line Capacity:
    • Assess the capacity of your existing gas line or the line you plan to install for the generator.
    • Ensure that the gas line can provide the required flow rate to meet the generator’s demand during peak operation.
  • Length of Gas Line:
    • Consider the distance between the generator and the gas source. Longer gas lines may experience pressure drops, affecting the generator’s performance.
    • It’s essential to choose a gas line size that compensates for any length considerations, maintaining sufficient pressure.
  • Pressure Regulation:
    • Gas pressure regulation is crucial to prevent overpressure or underpressure situations in the gas line.
    • Install a proper pressure regulator to maintain a consistent gas flow, ensuring the generator operates within its specified pressure range.
  • Elevation Above Sea Level:
    • Take into account the elevation above sea level at your location. Higher elevations can impact the density of the air and, consequently, the combustion process in the generator.
    • Adjust the gas line size accordingly to compensate for any changes in atmospheric pressure.
  • Consult Manufacturer Guidelines:
    • Always refer to the manufacturer’s guidelines and specifications for your portable generator.
    • Manufacturers provide specific recommendations regarding the gas line size and other installation requirements to optimize the generator’s performance and longevity.
  • Professional Assessment:
    • When in doubt, seek the expertise of a professional installer or technician.
    • A professional can assess your specific setup, considering factors like gas line sizing, pressure requirements, and safety protocols to ensure a reliable and safe operation of your portable generator.

Moving forward, let us explore how to precisely calculate the required gas line size for your portable generator without compromising its functionality or effectiveness.

How to Calculate the Gas Line Size for Your Portable Generator?

Portable generators are versatile tools, providing a convenient power source in various situations. However, to ensure their optimal performance, it’s crucial to calculate the gas line size accurately. This calculation ensures that the generator receives an adequate supply of fuel, preventing issues such as low pressure or insufficient flow.

To begin the process of determining the gas line size, you’ll need to consider two primary factors: the generator’s fuel consumption rate and the distance between the generator and the gas source. The fuel consumption rate is usually measured in BTUs (British Thermal Units) per hour and is provided in the generator’s specifications.

Next, you’ll need to calculate the total BTU load by multiplying the generator’s fuel consumption rate by its running time in hours. For example, if a generator consumes 80,000 BTUs per hour and you anticipate running it for 8 hours, the total BTU load would be 640,000 BTUs.

Once you have the total BTU load, you can determine the appropriate pipe size for the gas line. This involves considering factors such as the gas pressure, the length of the gas line, and the number of appliances or devices connected to the line. It’s essential to consult the gas line sizing chart provided by your local gas utility or use the guidance in the National Fuel Gas Code (NFPA 54) to ensure compliance with safety standards.

For example, a generator with a fuel consumption rate of 80,000 BTUs per hour operating at a pressure of 7 inches of water column (wc) and connected to a gas line that is 50 feet long may require a 1-inch gas line. This is a simplified example, and specific circumstances may vary, so it’s crucial to consult the appropriate resources or seek professional advice to determine the exact gas line size for your portable generator.

In summary, calculating the gas line size for your portable generator involves understanding its fuel consumption rate, determining the total BTU load, and considering factors such as gas pressure and line length. Following these steps ensures a properly sized gas line, optimizing the generator’s performance and safety.

Common Gas Line Sizes for Portable Generators

When setting up a portable generator, it’s crucial to ensure that the gas line size is appropriate for seamless operation. The gas line delivers the necessary fuel to the generator, and choosing the right size prevents issues like insufficient fuel supply or pressure drops. Below is a table detailing common gas line sizes for portable generators:

Generator Size (Watts)Minimum Gas Line Size (Inches)Example
Up to 5,000 Watts3/8″For smaller generators, such as those used for camping or basic power needs, a 3/8-inch gas line is typically sufficient. This size ensures an adequate flow of fuel to meet the generator’s demands.
5,000 to 10,000 Watts1/2″Medium-sized generators often require a 1/2-inch gas line to accommodate increased fuel needs. This size prevents restrictions and maintains optimal fuel flow.
10,000 to 15,000 Watts3/4″Larger generators in this range may necessitate a 3/4-inch gas line. This ensures a robust fuel supply, minimizing the risk of pressure drops during operation.
15,000 Watts and above1″ or largerHigh-capacity generators, such as those used for backup power in homes or businesses, may require a 1-inch or larger gas line to deliver the substantial fuel volume needed for extended operation.

It’s crucial to consult both the generator manufacturer’s specifications and a qualified professional to determine the optimal gas line size for your specific generator and installation requirements. Proper sizing ensures efficient performance and prevents potential damage to the generator due to inadequate fuel supply.

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What Kind of Pipe is Used in Natural Gas Lines?

Understanding the types of pipes used in natural gas lines is crucial for ensuring safety and efficiency in gas supply systems. Different pipes are designed to withstand the pressure and composition of natural gas, making them integral components of a reliable gas distribution network.

Pipe MaterialDescriptionExample
Steel PipesThese are robust and durable pipes commonly used in natural gas lines. They have high tensile strength and can withstand the pressure associated with gas distribution.Example: Schedule 40 and Schedule 80
Polyethylene (PE) PipesKnown for their flexibility and corrosion resistance, PE pipes are often used in gas distribution. They are lightweight, easy to install, and can resist damage from external elements.Example: PE 2406 and PE 3408
Polyvinyl Chloride (PVC) PipesPVC pipes are corrosion-resistant and provide a cost-effective option for certain gas distribution applications. However, they may not be suitable for high-pressure systems.Example: Schedule 40 PVC
Corrugated Stainless Steel Tubing (CSST)CSST is a flexible and easily maneuverable tubing that is corrosion-resistant. It is commonly used for residential gas distribution due to its versatility and ease of installation.Example: Gastite® CSST
Cross-Linked Polyethylene (PEX) PipesPEX pipes are known for their flexibility and resistance to corrosion. While not as common as other materials in gas distribution, they can be suitable for specific applications, such as indoor gas lines.Example: PEX-AL-PEX

Understanding the characteristics of each type of pipe is essential for selecting the right material based on the specific requirements of your natural gas distribution system. Always adhere to local building codes and regulations when installing or replacing gas pipes to ensure safety and compliance.

Pros and Cons of Using a Natural Gas Line for Your Portable Generator

When considering the fuel source for your portable generator, using a natural gas line has both advantages and disadvantages.


  • Unlike finite fuel tanks, a natural gas line provides an uninterrupted and essentially limitless fuel source.
  • No need for fuel storage or refueling; the generator runs as long as the gas supply is available.
  • Natural gas is a cleaner-burning fuel, contributing to reduced emissions and environmental impact.


  • Reliance on the gas infrastructure means that a disruption in the gas supply would affect the generator’s operation.
  • Initial setup costs can be higher due to the need for a dedicated natural gas line.
  • Tethered to the gas line, the generator’s mobility is restricted compared to units with onboard fuel tanks.

Potential Issues with Incorrect Gas Line Sizing

When it comes to setting up a gas line for your generator, ensuring the proper sizing is crucial. Incorrect gas line sizing can lead to various issues that might compromise the efficiency and safety of your standby generator.

  • Reduced Generator Performance:
    • Inadequate gas supply restricts the generator’s ability to produce the required power.
    • This can result in reduced performance, affecting the functionality of connected appliances and systems.
  • Overheating and Damage:
    • An undersized gas line may cause the generator to overheat.
    • Prolonged overheating can lead to internal damage, affecting the generator’s lifespan and reliability.
  • Incomplete Combustion:
    • If the gas line is too small, it may not provide enough fuel for proper combustion.
    • Incomplete combustion can produce carbon monoxide, posing serious safety risks to your household.
  • Fluctuating Power Output:
    • Incorrect gas line sizing can lead to inconsistent fuel supply.
    • This results in fluctuating power output, causing disruptions to connected devices and appliances.

Ensure that your gas line is appropriately sized according to the generator’s specifications to avoid these potential issues and maintain optimal performance and safety. If in doubt, consult with a professional to assess and address any gas line sizing concerns.

Consulting a Professional for Gas Line Sizing

Consulting a professional with expertise in gas line sizing can provide valuable insights and ensure the safe and efficient operation of your portable generator. Gas line sizing is a critical aspect when it comes to running a portable generator, as it directly affects the performance and safety of the equipment.

A professional gas line consultant will have extensive knowledge and experience in determining the appropriate size of the gas line needed for your specific generator model, taking into account factors such as pressure requirements, flow rates, and distance from the main gas supply.

When consulting a professional for gas line sizing, there are several important considerations to keep in mind. Firstly, they will assess the total BTU (British Thermal Units) load that your portable generator requires. This information is crucial in determining the correct pipe diameter for optimal gas flow.

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Secondly, a skilled consultant will consider any future expansion plans or additional appliances that may be connected to the same gas supply system. Planning for potential growth ensures that your system remains efficient even if you decide to add more generators or equipment later on.

Moreover, an expert consultant will analyze existing piping infrastructure to determine if any upgrades or modifications are necessary to accommodate your portable generator’s needs. They will evaluate factors such as pipe material, condition, and length to avoid any restrictions or blockages that may hinder proper fuel delivery. By conducting a thorough assessment of all these elements, they can provide you with precise recommendations tailored specifically to your situation.

Consulting a professional for gas line sizing not only guarantees safe and efficient operation but also provides peace of mind knowing that experts have assessed and designed your system according to industry standards. Their expertise helps prevent potential issues like insufficient fuel supply or excessive pressure drops that could damage your portable generator or compromise its performance.

By investing in professional consultation services, you can ensure optimal functionality while minimizing risks associated with improper installation or use of inadequate gas lines.

  • The cost involved in consulting professionals might discourage some individuals from seeking their assistance.
  • Hiring a professional can save time and effort as they have the necessary knowledge and experience to accurately size gas lines.
  • A professional consultant can provide guidance on local building codes and regulations, ensuring compliance with safety standards.
  • By consulting an expert in gas line sizing, you can avoid costly repairs or replacements caused by inadequate or faulty installations.

Tips for Properly Sizing Portable Generator Gas Line

Ensuring the proper sizing of a portable generator gas line is crucial for optimal performance and safety during operation. Here are some tips to consider:

  • Calculate BTU Requirements: Determine the generator’s BTU (British Thermal Unit) requirements based on its wattage and fuel consumption per hour. This helps in choosing an appropriately sized gas line.
  • Check Manufacturer Guidelines: Refer to the manufacturer’s specifications for recommended gas line sizes. Following these guidelines ensures the generator receives the necessary fuel supply for efficient operation.
  • Consider Elevation Changes: Account for elevation changes in the gas line installation. Higher elevations may require larger diameter lines to compensate for reduced gas pressure.
  • Use Proper Materials: Select high-quality materials for the gas line, such as flexible stainless steel tubing or black iron pipes, to ensure durability and compliance with safety standards.
  • Consult Local Codes: Adhere to local building codes and regulations governing gas line installations. This ensures compliance with safety standards and prevents potential hazards.
  • Factor in Distance: Consider the distance between the generator and the gas source. Longer distances may necessitate larger gas lines to maintain adequate pressure.
  • Include Pressure Regulators: Install pressure regulators as needed to maintain consistent gas flow. This is crucial for preventing damage to the generator and ensuring a steady power supply.
  • Professional Assessment: When in doubt, seek a professional assessment from a licensed technician or gas line installer to ensure the generator gas line meets safety standards and local regulations.


In conclusion of what size natural gas line do I need for portable generator, we discussed that selecting the correct size of the natural gas line for your portable generator is paramount for ensuring optimal performance and safety. From smaller 3/4-inch lines suitable for generators up to 200,000 BTUs and shorter distances to larger 1-inch or 1.5-inch lines required for bigger generators and longer distances, the gas line’s diameter plays a significant role in providing a seamless power supply. 

As you embark on your generator installation journey, consult with a licensed gas technician or plumber to accurately determine the ideal gas line size based on your generator’s specifications and installation setup. Embrace the power of precision and efficiency with the right gas line size, ensuring your portable generator stands ready to power up your world.


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Frequently Asked Questions

Can I use a smaller gas line size than recommended for my portable generator?

Using a smaller gas line size than recommended for a portable generator may result in an inadequate fuel supply, leading to reduced performance or even engine damage. It is crucial to use the appropriate gas line size to ensure optimal functionality and longevity of the generator.

What are the potential dangers of using an incorrect gas line size for my portable generator?

The use of an incorrect gas line size for a portable generator can pose potential dangers. These include gas leaks, pressure fluctuations, and overheating, which may lead to fires, explosions, and damage to the generator or surrounding property.

Are there any specific regulations or codes that dictate gas line sizing for portable generators?

Regulations and guidelines exist for gas line sizing to ensure the safe and efficient operation of portable generators. Considerations for gas line installation include factors such as pressure requirements, pipe diameter, and distance from the main gas source.

Can I use multiple portable generators with different gas line sizes on the same gas line?

Mixing different gas line sizes for multiple generators on the same line is not recommended. It can lead to uneven gas distribution and potential damage to the generators. Each generator should have its dedicated gas line of appropriate size for optimal performance and safety.

How do I know if my existing gas line is suitable for my portable generator or if it needs to be upgraded?

To assess the gas line capacity for a portable generator and ensure proper gas line sizing, one must consider factors such as the generator’s fuel consumption rate, pressure requirements, and the existing gas line’s diameter and maximum flow rate.

What size natural gas hose do I need for my generator?

A 3/8″ ID hose is suitable for lengths up to 10ft. If you’re extending it beyond 10ft up to 50ft, it’s recommended to use a 1/2″ ID hose to maintain a consistent fuel flow.

Can you hook up a portable generator to a natural gas line?

Yes, most portable generators run on gasoline or diesel, but they might not generate enough power for an entire house. A standby generator, however, can operate on natural gas, liquid propane, or diesel, providing a reliable source of power.

What size gas pipe is needed for a Generac generator?

According to Generac specifications, for gas inlet pressures of 5-7 inches of water column at the generator inlet: use a 1″ gas line for lengths less than 20ft, a 1.25″ gas line for 20ft to 130ft, and a 1.50″ gas line for lengths between 130ft and 305ft.

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