Is It Safe to Run a Generator in a Detached Shed?

Are you like me and wondering if it’s safe to run a generator in your detached shed? Planning to run a welder, power tools, or even a 3D printer? Well, I’m here to tell you that you may want to re-think your plan.

Is It Safe to Run a Generator in a Detached Shed? Running a Generator in a Detached Shed is not safe. The 3 main reasons why not are:

  • Potential carbon monoxide poisoning
  • Fire and burn hazard
  • Noise hazard

Whether you have a brand new generator or one that has been repaired 100 times by your Uncle Jerry and “she runs like a dream,” the safety factors are the same. My suggestion is always to consult your user manual before operation. If you don’t have one, a quick online search will help produce a manual for you. If you don’t want to read a boring user manual, here’s some information to help you out.

Is It Safe to Run a Generator in a Detached Shed

Why Generators can be Dangerous in a Detached Shed

Detached sheds are awesome for a workshop or storage, but unless you have the most state of the art installation, you likely are lacking air flow and air quality control.

Imagine an old shed with no windows in the middle of summer in Louisiana. It’s hot, sticky and you can barely breathe even before you run any equipment. When considering my 3 reasons why not to run a generator in a shed, think about your shed and the condition of most other sheds.

Here’s what I’m going to discuss in more detail:

  • Carbon monoxide – why you don’t want to be sucking it in.
  • Fire and burn hazards – heat sources and fuel.
  • Noisy environments – you don’t want to be deaf on your 50th birthday, do you?
  • Things to look for outside as well.

Sheds Have Poor Airflow

Detached sheds may have a window or two, but many have zero.

Detached sheds with no windows have terrible airflow and can cause:

  • Uncomfortable work conditions
  • Keep more dust and smoke inside

A lack of air flow leads to poor air quality. Breathing in dust all day is a hazard itself so wear a simple breathing mask. If you don’t have one, they are easy to get from your favorite hardware store.

Even if you leave the door to your shed and any possible windows open, there will still be air quality issues. Dust and harmful gasses will remain airborne for you to breathe or accumulate and become a fire hazard.

Now let’s take a look at the hazards produced when we put a generator into a shed.

Carbon Monoxide

The CDC has much information on why Carbon monoxide is dangerous (Link to CDC government site). Carbon monoxide is odorless and can cause headaches, dizziness, drowsiness, nausea, and death. It’s known as the silent killer, so you shouldn’t take any risks with it.

Considering most of us work alone in our sheds, and even if we had a helper they’d be exposed to the same air, you may not recognize when you start to feel symptoms.

Combustion engines produce many chemicals from the exhaust. So, let’s talk a little chemistry.

Any fuel (gasoline, diesel, propane) can be scientifically referred to as a hydrocarbon. Theoretically, the only by-products of burning hydrocarbons should be:

  • Carbon dioxide (CO2)
  • Water (H2O)
  • Nitrogen (N2)

In practice, chemistry is controlled chaos, and burning fuels produces many more substances than theory would suggest. These substances include:

  • Carbon monoxide (CO)
  • Nitrogen oxides (NOx)
  • Unburned fuel
  • Soot
  • Plus other things

You don’t want these in your shed, do you?

All of these additional molecules are hazardous, but carbon monoxide is the one people are most familiar with. Combine it with a lack of air exchange in your shed, and you could pass out and possibly lose your life.

Carbon monoxide poisoning is the highest risk hazard for running any generator in a closed space (even if you have windows and the door open). If you are in any space where combustion is happening, and you begin to feel dizzy or nauseous, get out immediately.

Fire and Burn Hazards

A fire needs three things to ignite – oxygen, fuel, and a source of ignition. That source of ignition can be anything that gradually becomes very hot like a generator’s engine, a chemical reaction, or an electrical spark.

Your generator has all three of these heat sources, plus its fuel, so it could be a fire waiting to happen. Generator manufacturers take all the possible precautions to prevent fires they can, but they can’t predict how the generator will be used and maintained.

For example, imagine you have a woodworking shop in your shed, and you have been working all day on a project that has produced a lot of sawdust and debris.

Without proper air flow, this dust accumulates on every surface, including the generator you shouldn’t have installed. That generator is hot after running all afternoon, and there is a small oil leak you didn’t notice.

The heat from the generator builds because it can’t cool itself properly, and the sawdust begins to smolder. The smoldering is catalyzed by the oil, and you now have a small fire in your shed which propagates rapidly through all the other piles of dust in your shed and eventually catches the whole shed on fire.

This isn’t a good situation as you can tell.

In addition to simple hot surfaces, old, dirty engines can backfire (where flames can literally come shooting out of the engine air intake piping), and generator wires can fray and cause sparking when in contact with other conductive surfaces. Both can lead to your whole shed burning down.

Even if a fire doesn’t start, you still run the risk of bumping against the generator or frayed wires and receiving a severe burn or electrical shock. Your generator should be far away from your work area (ideally about 20 feet).

Noisy Environments

High levels of noise can damage your hearing, and a generator is a source of loud noises.

Fun fact! Many people think the noise from an engine is the sound of the combustion; in reality, it is the pop of the exhaust air as it is released through the exhaust valve. If you heard the combustion, it would be MUCH louder, and your engine wouldn’t last long.

Avoid working near any source of loud noise without hearing protection. A good rule of thumb is if you have to raise your voice at all to talk to someone next to you, you should be wearing hearing protection.

Moving the Generator Outside

Moving the generator outside is the best idea. However, keep in mind the hazards are still present when you move your generator outside.

  • Place it away from any windows (20 feet) as the exhaust can enter and still be a hazard
  • Avoid placing it near combustible materials such as dry grass or a wood pile that could ignite the same way sawdust could in your shed.
  • Be sure to protect your generator from rain as electricity and water don’t mix. This could be a hazard to you and could permanently damage your generator. Inspect your generator for any frayed wires and never use a damaged extension cord.
  • Muffle the noise as much as possible (you don’t want to be that neighbor do you?) and wear hearing protection if it is still too loud in your work area.

Refer to these links to find some great solutions for running your generator outside:

Pre-fab outdoor solution to protect your generator



It is a deadly idea to run a generator in a detached shed, or any enclosed space for that matter. When in doubt, consult your owner’s manual. If you are still in doubt, trust your instincts and consult an expert online.

If you ever are uncertain whether something is safe or not, it probably isn’t. Take all steps necessary to identify potential hazards and remove or prevent them from occurring.

Leave a Comment