How to safely use a portable generator is the first thing you should know before you purchase one or begin operation.  It goes without saying that proper periodic maintenance will keep your portable generator running for years.  But safety is not periodic.  Safety is ALWAYS.  Most safety considerations are common sense, and as such, can often be overlooked or ignored.  A portable generator that lasts for years is of no use if YOU don’t.

Whether you use your portable generator around the house, on the job-site, or for recreational power, most safety considerations are common every time you use one.  Remember you are dealing with an internal combustion engine and an electrical power source.  Both have their considerations.

How to Safely Use a Portable Generator

Carbon Monoxide

Most deaths that occur each year relative to portable generator use are not related to electrocution.  Most deaths happen because of the invisible killer, carbon monoxide.  Every year, especially during winter months when we experience power outages and need to keep warm, operating generators indoors kills several people.  We all know not to sit in a running car inside the garage with the garage door closed.  An internal combustion engine produces the same carbon monoxide gas when burning fossil fuel.  It is odorless, invisible and deadly.

Always make sure there is proper ventilation around the unit, and operate well away from doors and windows, vents or air intakes.  Maintain plenty of airflow around the generator.  Never run the unit indoors or even in a garage or basement.  Your home should have working carbon monoxide detectors.  If you begin to feel dizzy or disoriented, get yourself to fresh air immediately, BEFORE you attempt to turn off the portable generator.  Death can occur within minutes with carbon monoxide poisoning.

Fuel Safety

Portable generators need fuel to provide the mechanical energy necessary to run the power head to provide electricity.  Fuel is flammable.  Always have a fully charged, approved fire extinguisher near the generator.

Never refuel while the generator is running.  Fuel vapors can ignite causing an explosion.  Do not operate near an ignition source, including smoking.  Avoid spilling fuel on hot components.

Do not store fuel near the portable generator while the electric generator is in use, as it could start a fire.  Store fuel in an approved storage container or holding tank designed for such use, and only use fuel that is recommended in the owner’s manual. Never store fuel indoors.

Electrical Cord Considerations

The portable generator has electrical outlets of various types.  Although they are designed to plug your device directly in to the unit, often for versatility and carbon monoxide concerns, long extension cords are utilized.

Any cord that you use should be a heavy-duty outdoor-rated extension cord sized for the total electrical load (voltage and amps) you may need.  Choose a cord that exceeds the total expected load in order to prevent excessive heat buildup and degradation of the power cord.   An overloaded power cord can potentially start a fire or damage equipment

Your cord should be a minimum of three pronged to insure proper grounding, with no splits, cuts or holes in the external insulation covering.

Never use or fabricate a male to male power cord.  It is very dangerous and probably illegal.

Keep cords out of the way to avoid injury, but in plain view to allow for visual inspections of any damage, such as fraying or cuts.  Make sure cords are placed to avoid tripping hazards, but don’t put underneath carpets where heat may build up.

For a more extensive review of extension cords, visit the article on this site explaining extension cords and power outlets.

Grounding

Typical power panel with grounding nut on extreme bottom right. Attach copper wire to grounding rod.

Most instruction manuals for portable generators instruct you to ground your generator via their grounding feature anytime you operate the unit to prevent against electric shock.  It is recommended to attach minimum 12 gauge AWG wire (usually copper) from the grounding terminal to a 6 foot grounding rod inserted into the earth.  Most  owners operate their portable generator without properly grounding in this manner.  Portable generator manufacturers know this and build in safety by bonding the neutral to the frame.  See the OSHA insert that follows:

Grounding Requirements for Portable and Vehicle-mounted Generators.

(https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf)

Under the following conditions, OSHA directs (29 CFR1926.404(f)(3)(i)) that the frame of a portable generator need not be grounded (connected to earth) and that the frame may serve as the ground (in place of the earth):

• The generator supplies only equipment mounted on the generator and/or cord- and plug-connected equipment through receptacles mounted on the generator,  § 1926.404(f)(3)(i)(A),

• The noncurrent-carrying metal parts of equipment (such as the fuel tank, the internal combustion engine, and the generator’s housing) are bonded to the generator frame, and the equipment grounding conductor terminals (of the power receptacles that are a part of [mounted on] the generator) are bonded to the generator frame, § 1926.404(f)(3)(i)(B).

Copper grounding rod shown with piercing tip on one end, pounding lug on the other with connectors to increase length.

Thus, rather than connecting to a grounding electrode system, such as a driven ground rod, the generator’s frame replaces the grounding electrode. If these conditions do not exist, then a grounding electrode, such as a ground rod, is required. If the portable generator is providing electric power to a structure by connection via a transfer switch to a structure (home, office, shop, trailer, or similar) it must be connected to a grounding electrode system, such as a driven ground rod. The transfer switch must be approved for the use and installed in accordance with the manufacturer’s installation instructions by a qualified electrician.

Connecting to Your Home’s Power Supply

Typical transfer switch

Grounding requirements for generators connected via transfer switches are covered by Article 250 of the National Electrical Code (NEC).

When a portable generator is used to hook into your home’s wiring system, if you are not a qualified electrician you’ll need to hire one.  It requires the purchase of a transfer switch and proper installation as a separately derived system in accordance with the National Electrical Code, NFPA 70. The generator is connected to the transfer switch that switches all conductors other than the equipment grounding conductor.  The frame of the generator should be connected to an approved grounding electrode, such as the one used for your home’s electrical system usually near your power box.

This properly installed transfer switch will keep the generator from feeding power back into the lines, which could put power company crews working on the lines at risk. This will also protect your generator and home wiring from damage when power is restored.

Even a properly connected portable generator can become overloaded. You must still operate at or below the running watts of your generator.  Overloading can damage as mentioned above.

Do not “back feed” power into your electrical system by plugging the generator into a wall outlet. You would need the highly dangerous male to male connector cord in the first place.  Back feeding will put you and potentially others, including utility line workers, at serious risk because the utility transformer can increase the low voltage from the generator to thousands of volts. Some states have laws that make the generator owner responsible for taking steps to make sure the generator’s electricity cannot feed back into the power lines, and for notifying the local utility of the location of any commercial, industrial or residential generator.  Check with your local power company if such regulations apply to you.

General Precautions

Keep the generator dry. If needed, operate portable generators under an open canopy-type structure with open sides. Short circuits may occur in wet conditions resulting in the generator catching fire.

Be cautious handling electrical cords in wet conditions.

Plug appliances directly into generator, or into a sufficiently rated extension cord.

Unplug appliances or their extension cords from the portable generator when starting the generator.  It can damage your appliance or the generator and can make starting more difficult.

Similarly, unplug your cords from the generator prior to shutting off the generator.  Allow the generator to stabilize prior to shutting down.

If planning to store your generator for a length of time, remove remaining gasoline from the fuel tank either by the equipped fuel drain, or by siphoning the tank.  Let the generator run until fuel is spent from the tank and carburetor.

The exterior portions of a generator, even those operated for only a short period of time, can become hot. Avoid touching the generator without protective gear and keep debris clear to avoid a fire.

BE SAFE.  Properly maintain your portable generator and follow basic safety precautions for years of reliable, safe use.  By no means is this safety article intended to cover all aspects of safe use of a portable generator.  You should always read the manual supplied with your own portable generator and understand fully, all safety precautions prior to operation.

Filed under: Safe Operation