Can You Refuel A Generator While It's Running

Can You Refuel A Generator While It’s Running? Safety Tips

4 Min Read

Noticing the gas in your portable generator is getting low, and need to add more. Debating whether you should shut it off first, or keep it running. Can you refuel a generator while it’s running?

Never add more fuel to your generator while it is running, or even while it’s hot. Doing so puts yourself at risk of being severely burned. Only when your generator is switched off for 15 mins and cool is it safe to refuel.

We all have been there before – the power is out but luckily your trusty portable generator is humming along feeding a healthy does of electricity to all your devices. And while you may have the urge to put a gallon or two in the fuel tank while it’s running, don’t do this.

Despite your steady hands and the use of a fuel funnel, spills and splashes happen. Because, all it takes is a little splash of spilled fuel to ignite and start a fire or worst, severely burn yourself.

Let’s look more closely at why you should never refuel a generator while it’s operating, and what the risks of doing so are.

Why Refueling a Running Generator is a Bad Idea 

Portable generators are small, compact pieces of equipment. They’re designed to be easy to transport, so you can take them with you wherever you go.

That compactness means all components are literarily sandwiched together, creating and absorbing heat. And because all generators place the gas tank at the very top of the unit, it’s very easy for spilled fuel to land on the exhaust, alternator, or even the frame of the generator.

Any one of these components gets hot enough to ignite spilled fuel.

Fact is, gasoline is highly flammable, and just a little spilled fuel on a hot running generator could ignite – severely burning you. As an example, a generator’s exhaust temperature can reach between 550 to 900+ degrees Fahrenheit. It only takes about 495° Fahrenheit for gasoline to ignite.

As you can image, a running generator on fire is a very bad situation.

So now you know the answer to: can you refuel a generator while it’s running. However, how long should you wait to refuel then? Let’s get into that next.

How Long Should I Wait to Refuel my Generator?

As a general rule, always turn off the generator and wait at least 15 to 20 minutes before refueling. However, if in colder climates, it might only take 5 mins to cool down. It’s okay if the generator is warm to the touch before refueling.

And while it’s annoying to have to let your generator cool before you can add more fuel to it, especially if you are depending on it for emergency power, it’s absolutely critical that you do.  

Can Any Generators Be Refueled While Running?

No, you cannot safely refuel any generators while they are running. No matter how they are designed, you will still be adding a highly flammable substance to an extremely hot space, and the risks are simply too high.

If you spill any fuel at all or if the tank is too hot, the fuel will catch fire, and potentially set you or the surrounding area on fire, or cause the generator to explode. Do not take this risk.

However, if you are lucky to own a dual fuel generator, take advantage of this feature and have a propane tank filled, connected and ready to go. This way you won’t have to worry about the gasoline running empty, leaving you without power.

Conclusion: Can You Refuel a Generator While It’s Running?

Hopefully, you now know the answer to “can you refuel a generator while it’s running.” It’s a simple and firm “no,” regardless of your type or style of generator. You must switch the machine off and allow it to fully cool before you refuel the generator.

So, remember the next time you go to refuel your generator – take a break for 15 minutes and let it cool down. Safety should always be your number one concern when using these machines, so don’t put yourself at risk by adding more fuel while it’s running.

Follow these simple tips and you’ll stay safe while powering through any emergency situation.



Brian has spent over 30 years as a general contractor, and in that time seen and faced many challenges. He brings all his knowledge of portable generators, battery powered tools, and outdoor equipment to every post he writes through real life experience. Learn more about us.

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