Using Portable Generators Safely
Portable generators are internal combustion engines used to generate electricity.
They are useful when temporary or remote power is needed, and are commonly
used during cleanup and recovery efforts following disasters such as hurricanes,
tornadoes, etc. This fact sheet discusses specific hazards inherent with the use
of generators and also provides helpful information to ensure that workers and
others using such equipment remain safe.
Hazards Associated with Generators:
- Shocks and electrocution from improper
use of power or accidentally energizing
other electrical systems.
- Carbon monoxide from a generator’s
- Fires from improperly refueling a generator
or inappropriately storing the fuel for a generator.
- Noise and vibration hazards.
Shock and Electrocution
The electricity created by generators has the
same hazards as normal utility-supplied electricity.
It also has some additional hazards
because generator users often bypass the
safety devices (such as circuit breakers) that
are built into electrical systems. The following
precautions are provided to reduce shock
and electrocution hazards:
- Never attach a generator directly to the
electrical system of a structure (home,
office, trailer, etc.) unless a qualified electrician
has properly installed the generator
with a transfer switch. Attaching a generator
directly to a building electrical system
without a properly installed transfer switch
can energize wiring systems for great distances.
This creates a risk of electrocution
for utility workers and others in the area.
- Always plug electrical appliances directly
into the generator using the manufacturer’s
supplied cords or extension cords that are
grounded (3-pronged). Inspect the cords to
make sure they are fully intact and not
damaged, cut or abraded. Never use frayed or damaged extension cords.
Ensure the cords are appropriately rated in
watts or amps for the intended use. Do not
use underrated cords—replace them with
appropriately rated cords that use heavier
gauge wires. Do not overload a generator;
this can lead to overheating which can create
a fire hazard.
- Use ground fault circuit interrupters
(GFCIs), especially where electrical equipment
is used in or around wet or damp
locations. GFCIs shut off power when an
electrical current is detected outside normal
paths. GFCIs and extension cords with
built-in GFCI protection can be purchased
at hardware stores, do-it-yourself centers,
and other locations that sell electrical
equipment. Regardless of GFCI use, electrical
equipment used in wet and damp
locations must be listed and approved for
- Make sure a generator is properly grounded
and the grounding connections are
tight. Consult the manufacturer's instructions
for proper grounding methods.
- Keep a generator dry; do not use it in the
rain or wet conditions. If needed, protect a
generator with a canopy. Never manipulate
a generator’s electrical components if you
are wet or standing in water.
- Do not use electrical equipment that has
been submerged in water. Equipment
must be thoroughly dried out and properly
evaluated before using. Power off and do
not use any electrical equipment that has
strange odors or begins smoking.
Carbon Monoxide Poisoning
Carbon monoxide (CO) is a colorless, odorless,
toxic gas. Many people have died from
CO poisoning because their generator was
not adequately ventilated.
- Never use a generator indoors or in
enclosed spaces such as garages, crawl
spaces, and basements. NOTE: Open windows
and doors may NOT prevent CO from
building up when a generator is located in
an enclosed space.
- Make sure a generator has 3 to 4 feet of
clear space on all sides and above it to
ensure adequate ventilation.
- Do not use a generator outdoors if its
placement near doors, windows, and vents
could allow CO to enter and build up in
- If you or others show symptoms of CO poisoning—
dizziness, headaches, nausea,
tiredness—get to fresh air immediately and
seek medical attention. Do not re-enter the
area until it is determined to be safe by
trained and properly equipped personnel.
- Generators become hot while running and
remain hot for long periods after they are
stopped. Generator fuels (gasoline, kerosene, etc.) can ignite when spilled on
hot engine parts.
- Before refueling, shut down the generator
and allow it to cool.
- Gasoline and other generator fuels should
be stored and transported in approved containers
that are properly designed and
marked for their contents, and vented.
- Keep fuel containers away from flame producing
and heat generating devices (such
as the generator itself, water heaters, cigarettes,
lighters, and matches). Do not
smoke around fuel containers. Escaping
vapors or vapors from spilled materials can
travel long distances to ignition sources.
- Do not store generator fuels in your home.
Store fuels away from living areas.
Noise and Vibration Hazards
- Generator engines vibrate and create noise.
Excessive noise and vibration could cause
hearing loss and fatigue that may affect job
- Keep portable generators as far away as
possible from work areas and gathering
- Wear hearing protection if this is not possible.
This is one in a series of informational fact sheets highlighting OSHA programs, policies or standards. It does not impose any new compliance requirements. For a comprehensive list of compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal Regulations. This information will be made available to sensory impaired individuals upon request. The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.
For more complete information:
Safety and Health
U.S. Department of Labor