What Can Cause Fire in A Generator? Causes + Safety Tips

Last Updated on September 26, 2023 by mfttherese

Having a generator means you can continue to utilize the heat, light, and many other amenities in case of a power outage. Along with it comes the responsibility to maintain it for safe usage. If you ignore maintenance, issues like fires may occur.

Fire in a generator may occur when there is less periodic inspection, improper maintenance, fuel leakage, or careless operation. Additionally, you risk harming the engine and any associated equipment if you exceed the generator’s power rating. The chance of a generator exploding may be considerably decreased with correct installation, handling, and maintenance. 

Read on to learn more about the typical causes of fire in a generator and tips for reducing the danger of fire and explosion.

What Kinds of Fires Do Generators Start?

What Kinds of Fires Do Generators Start

Understanding how generators are a fire hazard is crucial to knowing how an explosion and fire might happen. Four elements must be present for a generator to blow up: oxygen, heat, fuel, and an ignition source. Combustion is a chemical process that occurs when mixing these four components in the proper ratios.

Depending on the circumstances, electrical fires and generator explosions may cause severe property fires.

When generators run unattended overnight with fuel containers left near the generator, these scenarios are made worse.

Then there is the wildfire hazard. A generator that catches fire in the open air may spread swiftly and produce large bushfires.

Without excellent knowledge of generator safety, there may be a higher chance of future fire. Apart from that, there are reports of carbon monoxide deaths caused by portable generators occurring at home.

Causes of Fire in a Generator

Let’s look at how operating a generator increases the fire risk due to heat and human error.

Irregular Maintenance and Inspection

Irregular Maintenance and Inspection

There are many essential components of a generator:

  • A motor engine
  • A fuel system
  • A voltage regulator
  • An alternator
  • Exhaust system
  • Lubrication system
  • Cooling system

These systems are subject to continuous heating and cooling cycles, which leaves them vulnerable to damage. Some components, including the brushes, armature, commutator, and other parts begin to ignite without regular maintenance. The generator might catch fire, and the gas tank could blow up due to the sparks’ ability to ignite gasoline fumes or spills.

Parts breaking down may also be caused by poor maintenance. The device might short-circuit and catch fire due to broken parts, resulting in an explosion. It is crucial to do yearly or even semiannual maintenance and inspections to ensure that your generator is in top condition and will not create problems later on.

Incorrect Location

Location of a Generator

You should follow the NFPA 110 requirements while installing a generator to guarantee safety. Installing your generator in its own room or outside space will keep it away from other combustible items. For indoor generators, they must be in a space with a two-hour fire rating.

When setting up any connections, such as hooking up a hot water heater to a generator, it’s crucial to ensure that both devices are placed correctly and safely. Learn how to safely hook up a hot water heater to a generator here.

Keep anything combustible at least 10 feet away from your generator. When the generator is working and if any hot engine parts and flammable materials come in contact with them, a fire can quickly start.

The radiator and exhaust system are two other places that might quickly become a fire threat. If the radiator or exhaust is clogged, heat may become an explosion because air movement cannot circulate adequately.

Poor Fuel Maintenance

Poor Fuel Contamination

Microbes, debris, subpar additives, and oxygen in your fuel tank may affect your fuel’s quality. Buying inexpensive gasoline at a “great price” might introduce impurities into a fuel tank and engine parts, which can result in severe concealed damage.

Store fuel in sealed containers outside your home, and make sure to routinely check your fuel storage tanks and gasoline caliber to preserve your backup generator.

Diesel and natural gas are the two primary fuel choices for backup generators. These two distinct fuel kinds need regular inspection and different handling.

  1. Diesel: Ensure you continually check your fuel filters and lines for leaks. Ensure there are no cracks, leaks, corrosion, or other issues. Even the slightest leaks pose a risk of fire. Ensure the tank is not overfilled and no fuel is spilled when filling diesel generators. It is advisable to shut down the generator for at least 10 minutes to enable it to cool down before adding fuel.
  2. Natural Gas: Regularly check your generator for gas leaks. If you find a leak, close the fuel valve until the problem is found and remedied. To avoid feeding the generator too much fuel sitting about and not being used, ensure the fuel regulator is at the manufacturer’s suggested level.

Load banking is a component of routine maintenance for diesel or propane generators. Instead of merely turning on the genset, load banking involves connecting a fake load to test its capabilities.

It is possible to prevent the accumulation of carbon deposits in the exhaust system that could have accumulated over time by allowing the generator to operate at total capacity for a certain amount of time.


Overloading of a generator

Watts, the unit of measurement for power or energy, is used to determine a generator’s output. Starting and operating watts are the two different kinds of watts in generators.

The power output of generators varies from 500 watts to 40,000 watts. Since generators need much more power to start the engine, the beginning or surge watts are higher. After a brief while, the operating watts replace the surge watts.

A generator overloads if it receives a full load or excessive electrical current. The generator can heat up and blow up as a result of this. The wiring in the generator must not carry so much voltage to prevent an electrical fire.

Generator Running Without A Circuit Breaker

Circuit Breaker for a generator

The majority of generators can operate for 8 to 24 hours.

Circuit breakers prevent electricity overload. An operating generator risks overheating if exposed to full operating temperature. Never use a generator inside a closed room or when it is hot outside.

Without a circuit breaker, there is more risk of a generator catching fire. The generator may blow up if the fuel lines burn and the fire spreads to the gas tank.

Additionally, the broken pieces of damaged parts can cause the unit to short circuit.

Heat Build Up

Generator Heat Build Up

The wire coils within a generator may start to rub against one another while it runs, generating heat and friction. The heat might build up and ultimately cause the generator to explode if it is not disposed of correctly.

This heat buildup may be caused by various things, such as inadequate ventilation, overheating from excessive usage, or a manufacturing flaw.

In any case, it is critical to understand the risks associated with heat buildup in a generator to prevent a potentially devastating explosion and fire.


Generator Backfeeding

Backfeeding is the term for the unsafe and unlawful practice of using a generator directly plugged into a wall socket to power your house during a blackout. The generator must be connected to the outlet using a cable with male plugs on both ends.

Suicide cords are an alternative name for male-to-male extension cables. When one end connects to a live outlet, the exposed end presents a fire or electrocution risk.

The fire often starts when the usual electrical supply restarts. The electricity flow changes once the grid is operational again.

The generator may spark and risk your life and property if the fire spreads to the gas tank. You must install a transfer switch in your circuit box to eliminate the danger associated with backfeeding and to swap the power load between the grid and the generator. You may connect the generator to the circuit breaker instead of a wall outlet, allowing the regular energy flow.

Utilizing Inferior Cables

Utilizing Inferior Cables

Superior cables are incapable of supporting a generator’s whole electrical demand. Overloaded wiring heats up and poses a greater fire danger. The heat melts the plastic, which may catch fire and cause the generator to explode.

Use heavy-duty generator cables equal to or greater than the generator’s circuit breaker when running a generator. To provide 120/240 volts to the transfer switch in your house, use portable generator cables that link to a 50-amp or 30-amp outlet on the generator.

The wires must be at least 15 feet long to keep the generator away from your windows, doors, and vents.

Additional Safety Tips to Prevent Generator Fire

Here are some other safety measures to prevent generator fires:

  • To have an efficient system for your particular generator system, you must adhere to the precise recommendations in NFPA 110.
  • Having a fire suppression system set up in the exact location of your generator is vital.
  • Have a fire extinguisher ready near your generator enclosure to put out a minor fire and prevent it from spreading.
  • Make sure a qualified technician who regularly does this kind of work installs your generator, and then have it checked by your authority having jurisdiction (AHJ) to guarantee correct installation.
  • Check whether your generator has been certified by a nationally renowned testing organization.
  • It is always a great idea to observe all manufacturer’s directions for proper use.


As you can see, a generator fire may result from various causes. These can be due to human mistakes in some cases and issues with the generator itself in others.

You can increase the lifetime of your generator and guarantee that it never catches fire by using it properly and keeping it maintained.

GeneratorGrid.com is an independent review business. I am not affiliated with any manufacturers and do not accept paid reviews. When you buy through my links, I may earn a commission which helps me purchase more generators for testing. - Scott Krager

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