Here’s How to Run a Generator in the Rain Safely

For the homestead community, for many workers, and for those who live off-grid, a generator is an essential tool that we demand reliability from in all weather conditions. Here’s how to run a generator in the rain safely.

I have a solar power system that powers most things inside my house, however, I use a generator every day to power water pumps and high demand items in the house such as washing machines.

generator inside concrete enclosure

Even those who have a larger solar system suitable for powering everything in a house still have a generator as a backup.

For anyone living in a hurricane area, a generator is an essential item. A generator can provide lifesaving power in a disaster situation.

Water and power are the two essentials that everyone needs. However, these two essentials not only will not work side by side, when the two come together they can be life-threatening. Does that mean that it is not possible to run a generator in the rain? It is, in fact, possible, and here’s how to run a generator “in the rain”…

To run a generator while it is raining, the most important thing is that it must be covered. You can use one of these:

  • Ready-made Steel enclosure
  • Ad hoc Plastic sheds
  • Pop-up canopies

You can go the DIY route, and build your own enclosure if the alternatives aren’t available or suitable.

No matter how the generator is covered, safety precautions should be taken. There will often be situations where you will need power while it is raining. Read on to find out how to do so safely.

Rule #1: Never Run a Generator in the Garage or the House

If it is not possible to run a generator in the rain, would it be possible to run it inside a garage? Manufacturers’ instructions clearly state that generators should not be operated indoors.

Manufacturers always provide a detailed operations guide. This guide will normally state:
Failure to use this type of equipment as instructed could result in serious injury or even death.

Carbon Dioxide

This is not an alarmist statement. It doesn’t matter if the generator is powered by diesel, gas, or butane the exhaust fumes contain carbon dioxide. Carbon dioxide is a silent killer anyone exposed to sufficient levels will become severely unwell before eventually being killed.

A garage with the door open might seem an ideal place to run a generator. However, fumes travel unpredictably, consequently, people in a house could still be exposed to dangerous fumes.


Apart from this obvious danger the noise created whilst operating a generator would be exceedingly uncomfortable and could lead to hearing damage.

Can a Generator Get Wet and still Work?

We run our vehicles in the rain all the time, so it seems perfectly logical that we should be able to run a generator in the same conditions without causing any problems.

A generator is the same type of engine that can be found in any basic vehicle. It works by sucking air into a piston where it is mixed with fuel before being ignited. The ignition causes the piston to move and it is this movement that drives the car.

The spent gases are pushed out of the cylinder ready for the next cycle. Operating an engine in the rain runs the risk of several problems developing.

Comparing the operation of a generator to using a car in the rain with a little thought it should become obvious that the engine in a car is in an enclosure. The car engine is not in a sealed enclosure as anyone who has ever tried driving in deep water and has experienced engine failure will be aware.

How does Water Create Problems for a Generator?

To be able to understand how it is possible to run a generator in the rain, we must understand how water effects a generator. With the problem areas identified it is then possible to pay particular attention to how to protect them.

Air Inlet

Water can easily enter the air inlet. The air inlet will normally have a filter covering it; however, this filter is to stop small particles from entering the engine. This filter will not stop the water. If water enters the engine and mixes with the fuel and water, it will not combust.

The engine will not operate.


In certain situations, water will enter into the exhaust and gain access to the piston. Adding water to the fuel-air mix will prevent combustion. The engine will not operate.

Spark Plugs

The ignition of the fuel-air mixture is a result of a spark from a spark plug. Water on the spark plug or the cable that supplies the power to the spark plug can prevent the spark plug from working. Water may destroy the spark plug.


With a generator, the engine drives a device that produces electricity. Heat is produced in this process, consequently, the generator requires ventilation to prevent heat damage.

two visible vents next to generator in concrete enclosure
Let’s take another look at my generator in its concrete annex. You can clearly see the two air vents allowing it to get as much air as it needs…

The smallest amount of water that enters the generator will cause the device to stop working and could cause it to blow up.

Electrical Shocks

A far more serious problem that could arise is that of electric shock. Without going into the science, it is widely accepted that electricity will flow very easily through the water.

A generator running in the rain would be dangerous to touch. Simply touching the frame could result in a life-threatening electric shock. Anyone standing in a puddle would only have to be near the generator to run the risk of electricity arcing to them, and deliver a serious shock.

Here’s how to run a generator in the rain safely…

Steel Enclosures

One of the best options to allow a generator to be used in the rain is to use a purpose-built Steel Enclosure. Since this is a purpose-built product, it will be robust and have the required ventilation areas in position.

Remember the generator is an engine, it requires air to be available to enter the piston to create the combustible mix. The air from the exhaust also needs to be able to exit the enclosure so that it does not contaminate the air that is entering the engine.

Without adequate ventilation, the generator could overheat, or the fumes could build up to a level that would prevent it from functioning correctly.

Being constructed of steel the enclosure will be fire-resistant, a necessary feature since significant heat is created from an operating generator.

Wood Enclosure

Wood is a popular material for constructing many things, but it is a dangerous material for housing a generator, as the heat could cause it to burn. Older generators have been known to create sparks that could also burn the enclosure.

Consequently, it is difficult to buy a purpose-built wood enclosure for generators.

Plastic Shed

A plastic shed is a good economical option for housing the generator to enable it to be run in the rain.

Care should be taken in ensuring that the shed is large enough to house the generator so that it leaves a sufficient gap between it and the shed. A generator, when running becomes hot enough to melt the plastic if there isn’t sufficient space.

Some modifications will be needed to make a plastic shed suitable for housing the generator. Vents will be required to ensure the free flow of air to the intake and the exhaust.

Pop-up Canopies

There are various styles of pop-up canopies or tent style covers that can be purchased to cover a generator to enable it to be run whilst it is raining. These are normally waterproof tarps that have a panel covering the sensitive electrical components of the equipment.

This type of covering, whilst perfectly adequate for use in differing locations in normal rain conditions, it is not suitable for heavy rain with high winds, or permanent locations.

It is relatively easy to make a canopy from canvas or any similar waterproof, and preferably fire retardant material.

It is not a good idea to simply cover the equipment just with a tarp, a stable frame should be constructed. Ensure that the canopy is high enough and sufficient distance from the hot surface of the generator. The heat could damage the covering.

The height should also give room for ventilation to prevent the exhaust fumes from collecting under the covering. A build-up of Carbon Monoxide is dangerous.

DIY Enclosure for Generator

For generators that will be situated in a permanent location, the most cost-effective solution is to build an enclosure.

A DIY enclosure has many benefits that allow it to be used when required:

  • Weather: An enclosure will protect your generator from bad weather conditions such as rain, snow, freezing temperatures, and high winds.
  • Noise: The noise created by a generator can be annoying for yourself and any neighbors if it runs for long periods
  • Wildlife: An enclosure keeps wildlife away from your generator. Squirrels, Rats, and other rodents will cause extensive damage by gnawing through wires. Nesting birds or wasps can create fire hazards.
  • Security: Enclosing your generator will prevent theft and also ensure that is safe for other people to be around:
  • Storage: Many people store a generator in a garage when not in use. An enclosure frees up space in your outdoor storage shed or garage.

Now, several factors should be considered before deciding how and where to build an enclosure…


Deciding what materials to use for the construction of an enclosure is an important decision to make. The best option is to use weatherproof materials, Rain will cause some materials to rot or rust.

Sheet metal or powder-coated aluminum are good options as these will make a sturdy enclosure that will not be subject to corrosion or rust.

Concrete blocks will create a sturdy enclosure provided care is taken to seal the joints correctly with mortar, and an adequate roof is constructed. Constructed correctly an enclosure made from concrete blocks will provide good protection from the rain.

Treated lumber is an option, however, care needs to be taken to protect the wood from the heat and the fumes that a generator produces.


The enclosure should be large enough to allow easy access to the generator to ensure easy operation and maintenance.

Ample space is also required to provide adequate airflow that will allow the generator to operate effectively.


The location of a generator enclosure is also an important factor. A good location should have level ground, a firm surface, and away from water.

We’re trying to protect the generator from the rain, so it is best to find a location where if possible, it is protected from the rain.

A generator creates noise and toxic fumes a suitable location would be away from any house windows or doors and any outdoor seating areas. There are various products and techniques that can help to keep noise levels at an acceptable level.


The surface where an enclosure is to be constructed should be firm and watertight. If the ground is firm a simple gravel area may be sufficient, however, the use of patio blocks or a slab of concrete reinforced with steel rebar is a more suitable option.

A soft surface such as gravel will help to dampen noise whilst hard surfaces such as patio blocks or concrete will amplify the sound created by the generator.


The climate is another important factor, especially when deciding what materials to use for the container and surface to set it on. Moisture and temperature extremes pose dangers to your generator, even if you keep it out of snow, direct rain, and wind.


Whatever container that you decide to build it is important to provide adequate access. Access can be provided in several ways:

  • A top cover or lift-up roof
  • One or more single or double doors
  • Swing-open flaps

Whatever the means that the enclosure is to be accessed, these openings must close tightly to ensure that rain cannot enter.


The design of the enclosure must include adequate ventilation. This can be difficult since any ventilation that has been installed can allow rain to enter the enclosure.

A vent is required to allow clean air to be drawn into the combustion chamber. This vent must be protected to prevent any rain from entering. Rain entering the chamber will prevent the equipment from functioning.

A vent is also needed to let the fumes from the combustion escape the generator and the enclosure. Again, this vent must be protected to prevent rainwater from entering.

Electricity Connections

If the generator is to be used to power a home, consider how and where the connection is to be made. If not, carefully designed rain will enter the connection areas and prevent the generator from working to its full potential.

An important part of the electrical connection is a device called GFCI (Ground Fault Circuit Interrupter). This device helps to protect the equipment from damage if water manages to get into any of the electrical outlets.

This simple device is a life saver since by stopping the flow of electricity it can prevent anyone near to the equipment receiving a fatal electric shock.


Although a heavy piece of machinery, a generator is a valuable and desirable device. Any enclosure that is constructed should be sufficiently robust and secure to prevent thieves from gaining access to it.

A secure structure will also prevent inquisitive children or pets from gaining access to this dangerous environment.


We have shown that it is possible, with some thought and planning, to run a generator in the rain. Without protection, it is not safe to run this type of equipment in the rain.

The key to running a generator in the rain is buying or constructing a covering that will protect it.

Don’t be fooled by a manufacturer who states that their equipment has been tested for rain. What the manufacturer means by this statement is that if rain falls on the generator whilst it is switched off it will still function when started after the rain has ceased.

We have shown that many factors need to be considered regarding the site and construction of any cover or enclosure for a generator.

Safety is the most important factor when operating any equipment, especially when failure to operate as designed the equipment has the potential to seriously harm you… or worse.

generator in rain pin

3 thoughts on “Here’s How to Run a Generator in the Rain Safely”

  1. It’s not “carbon dioxide” (CO2) that the harmful emission from a gen set — it’s Carbon Monoxide (CO). that the concern.

    1. Carbon dioxide will replace good air with something that has little or no oxygen in it. It’s not poisonous, but is a potential hazard, as well as a greenhouse gas.

  2. not mentioned and a serious safety concern for wet conditions >>> extension cord connections ….

    the plug-in connection section on the generator needs to be climate protected >>but more importantly where you might connect two extension cords for a long electrical run – it needs to be elevated off the ground and poly wrapped as waterproof as possible ….

    you could get a short and generator failure – but more seriously electrify a puddle or the wet ground around that exposed connection ….

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