No emergency generator, whatever its size, should ever
be connected directly to household wiring. Any emergency
power system must be directly connected only to those
appliances or equipment it serves unless that generator
is connected to a properly installed and operated
Such a switch is NOT optional.
When any generator, no matter
how small, is connected directly to a home’s wiring, say
by being “plugged” directly into an electrical outlet,
the energy produced by that generator can “back-flow”
through the household wiring, the service wire and even
through the transformer serving that home or business.
Transformers work both ways. It
takes 14,000-volts from a power line and reduces it to
the 120-volts used in your home. But 120 volts generated by an emergency generator, when
it “back-flows” through that same transformer, is
transformed into 14,000 volts that will travel back
along a power line.
Line crews working to restore
service miles away on what should be a “dead” line risk
death or injury from this current. So do any neighbors
who touch a downed power line. Children, pets and
livestock can all be endangered.
If the power comes back on
while that generator is improperly connected, appliances
and electrical equipment can be damaged by power surges.
All generators are sold with
instructions that outline their safe installation and
proper use. No generator should ever be connected to
household wiring without using a special Safety Transfer
Take time to read and obey
safety material that comes with standby generators
because proper hookup is vitally important.
Deficiently or improperly
installed generators can cause damage to the generator,
the appliances connected to it or to utility equipment
and could cause injury or death to service personnel or
The following tips can help
avoid a tragedy.
- Installation is not a
do-it-yourself project—get an expert to do it.
- No matter who does the
installation, make certain your generator has a
double-throw (transfer) switch.
- Follow all regulations
established by your local utility when using
- Once installed, operate
the generator according to manufacture’s
recommendations (proper ventilation,
limited load and preventive maintenance are all essential to safe
The double-throw switch is not
optional equipment. This transfer switch permits a safe
change-over from utility service to an on-site power
supply. The National Electrical Code requires a
double-throw switch on a standby generator installation.
appliances should be plugged into the generator. Never
connect a generator to household wiring that cannot be
isolated from the utility system by a transfer switch.