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Default Generator FAQ

On Fri, 23 Jan 2004 08:36:58 -0500, "Stormin Mormon"

Misc.survivalism Generator FAQ

Copyright 1999 by Steve Dunlop.

This FAQ may be redistributed if:
i) it is distributed without charge and without request for donations
ii) it is distributed without advertising
iii) it is distributed intact without changes, deletions, or additions.

This is version 1.0 of the Generator FAQ.


This document provides an overview of the use of generators for standby
power. Use of generators can be dangerous. While an overview of safety
issues is given, READERS
OURCE PRIOR TO USING ANY GENERATOR. This FAQ is not comprehensive and in
particular does not pertain to standby systems used for life support or
other situations where power failure could cause bodily injury or property
damage. Information on transfer s witches and electrical wiring is not
intended as a substitute for competent work by a qualified, licensed

Generator Basics

Generators are shaft-driven machines that produce electric power. Broadly
speaking, they range in size and capacity from the tiny devices used as
sensors to the extremely large machines used at commercial power plants. The
term "alternator" is also used and means essentially the same thing. The
term "generator set" or "genset" is sometimes used to describe a generator
along with a gasoline or diesel engine or other power

This FAQ covers the use of generators to provide standby power in an
emergency for a single family or small group.

Generators are rated in terms of the amount of power they can produce. This
is measured in Watts (W) or Kilowatts (kW). A Kilowatt is equal to 1,000
Watts. Some household items list their power requirement in Watts, such as
light bulbs and small applia nces. Others only list Amperes (abbreviated A
or Amps). Most household electrical loads (including all cord-connected
appliances that plug into a standard outlet) run on
120 Volts, and since Watts = Amps X Volts, you can determine Watts by
multiplying the amp requirement by 120. Large heating and cooling
appliances, and well pumps,
sometimes use 240 Volts. This can be determined from the nameplate. For
these loads, wattage is determined by multiplying amps by 240.


Commercially available generators useful for small-scale standby power
fall into these categories:

Type Wattage Approximate Price Range

Small portable units marketed primarily for camping
Generally less than 2 kW

Midsize portable units
3-5 kW.

Large trailer-mount units without engines, driven by a farm tractor PTO
15-60 kW

Large trailer-mount units designed for construction or industrial use
10 kW or more.

Large standby units designed for permanent installation.
5-40 kW or more

Costs vary depending on ruggedness, reliability, and features.

The more expensive units typically include features like:

Better quality engines, with pressure lubrication, cast iron cylinder
blocks (or cast iron sleeves), oil filters, and electronic ignition. The
primary benefit of these is longevity, although the better engines may be
somewhat more reliable.
Larger fuel tank for long, unattended runs.
Low oil shutdown to prevent engine damage
Electric start
Built in battery charger for 12V car batteries
Quieter design, achieved through better mufflers, soundproofing, and lower
operating RPM
Ground fault circuit interruptors (GFCI) for safety
Wheels. Even the smaller generators are heavy.

There are a wide variety of brands available. All of them work, and
most are adequate for occasional standby use.

The generators that are driven by a farm tractor are a good buy if you
already own one or more farm tractors. Unlike car and truck mount
generators, tractor-driven ones produce ample power. Tractors are better
suited to continuous, stationary operation than cars and trucks.


Generators can be useful in a long-duration power outage by providing power
to run essential equipment, such as refrigerators, freezers, lighting, water
pumps, sump pumps, and furnaces. They are also useful for providing power
where it is inconvenient, costly, or impossible to bring commercially
produced power.


Determining the exact size generator required for a household involves
adding up the wattage required by each load, including the starting power
required by the largest motor and any others that will be started at the
same time. It is difficult to get accurate results since starting current
requirements often vary and because nameplate ratings sometimes
overstate the power required.

If a generator is too small for its load, the voltage will drop. This can
cause damage to the generator, the load, or both. Circuit breakers and
thermal protectors may trip and prevent damage, but cannot be relied upon.
Do not connect loads to the generator that are too large for its capacity.

If you only want to run a few critical items, you can use this chart
as a guide:

Generator size
Loads typically supported
1000W or less
Lights, radio, battery chargers, clocks, fax, or
above items, also small manual defrost freezer or
3500W 240V
same as 1500W, plus H.P. well pump (if 240V)
3500W 120V
Most refrigerators and freezers, clothes washer,
dryer, sump pump, H.P. furnace blower, H.P.
pump (if
120V), nearly any plug-connected appliance with a
120V plug
5000W 240V
Same as 3500W, plus most well pumps up to 2 H.P.
15,000 W 240V
Will run all the loads in most households including electric water
heaters, dryers, well pumps, and ranges; will run many central air
conditioning units. Electric heat systems need to
be considered case by case as many larger systems use more power than even
a big generator like this produces.

Determining the size analytically

To determine the size generator required using pencil and paper, you need to
add up the power used by everything that you want to operate at the same
time. Use the starting power required
for the largest motor and for any ot her motors that will start

For small installations, the large motor loads that need to be served
determine the size generator that is needed. Induction motors, such as those
used in water pumps, sump pumps, washers,
dryers, refrigerators, freezers, air conditioners, and furnace blowers
require a large amount of power to start. These motors will draw 2-3 times
or more their rated amperage for about a second when first started. If the
generator cannot produce this number of amps while still maintaining roughly
90% or more of the r ated voltage, the motor will not start.

Portable hand tools use universal motors still use a lot of power to start,
but they are not as sensitive to voltage drop and will usually start anyway
even if the voltage drops as much as 50%.

Larger motors will list a "code" on the motor nameplate which indicates the
starting current required. This applies primarily to industrial and farm
equipment, and well pumps, since
small household motors do not include the code. Here's a list of the c odes:

Starting kW per horsepower
22.4 and up

If a code is not present, assume that the motor will require at least 3
times its rated amperage to start. Some require much more.

Measuring the Load

Sometimes it helps to measure the amount of power a particular piece of
equipment (or an entire household) uses. This may be the only way to
determine power requirements accurately if
there is no nameplate listing the power required. Clamp-on ammeters are
available at most building supply stores for about $50-$100 that will
measure the number of amps
flowing through a wire. They usually include an attachment that you can use
for cord-and-plug connected devices.

More sophisticated ammeters that measure starting current are available but
are costly ($400) and require some expertise to use.

Electrical Hookup

There are three ways to hook up generators:

Plug in loads directly, using extension cords if necessary.
Transfer switch
Suicide wiring

Plugging in loads to the generator's outlets directly is the simplest and
works OK when only a few small loads are used. This method is used in remote
areas and for construction, where no
electric wiring is present. It also works in standby situations for running
a handful of things, say, a freezer, refrigerator, sump pump, and a couple

Generators must be operated outdoors unless specifically designed for indoor
operation. Those designed for indoor use have an exhaust system that vents

Since the generator is usually outside and the load is inside, extension
cords are needed. Be sure they're big enough. Most of the orange extension
cords sold use 16 gauge wire and are
rated for 13 amps. These are fine for a couple of small appliances but
create a fire hazard when used for heavier loads.

Transfer switches

Transfer switches allow you to connect a load to either the generator or the
commercial power source simply by flipping a switch. They are the only
reasonable and safe alternative for running
an entire house from a generator . They are also the only way to run
equipment that can't be unplugged, such as furnace blowers, well pumps, and
the like. Different configurations are available that allow switching of all
or part of a household's electrical circuits. They are expensive a nd must
be installed by an electrician or other qualified person. Some

Transfer switches that have 4-6 different handles, each of which switches a
single circuit, are available for around $200 from many retailers that sell
generators. They wire into the house's breaker or fuse panel. You only hook
up the circuits that yo u will need in an emergency, which reduces the cost,
and you can switch them one at a time so all the motors don't start at
Some designs include an ammeter so you can see how much power you're using.
Some designs, including one from Square D that I have seen, use circuit
breakers to perform the switching and have an interlock so you can only
turn on one circuit breaker - either the generator breaker or the
commercial power breaker. I have seen the se for as little as $60 plus the
cost of the circuit breakers. Again you only hook up the circuits that you
think you will need in an emergency. These panels hook up to your main
breaker panel as a sub-panel. Large transfer switches switch the power to a
house or group of buildings and are wired between the meter
socket and breaker (or fuse) panel. These cost $300-$600 depending on
capacity. They are costly to install as well.

Automatic transfer switches will start the generator and switch the load to
it without intervention. Some standby systems have these built in. One
catalog I have lists a 200A model as costing almost $2,000. Telephone
companies, hospitals, radio and TV stations, and
the like use larger versions of these.

Transfer switches are wired with a large, flexible cord and plug for use
with portable generators. The cord and plug are not normally included with
the transfer switch and must be purchased separately. Welding supply
companies are a good, inexpensive s ource for the heavy gauge wire required.

If you plan to connect the generator to building wiring, consider the
transfer switch part of the cost of the generator.

Suicide wiring

Any method of connecting a generator to a building's electrical system,
other than by using a transfer switch, falls under the category of suicide

You can be killed. And you can kill an electric lineman if you fail to
isolate your generator from the power company's lines, by causing
electricity to back-feed into the commercial power
system. You can also burn up your generator or your house. It is also
against the law in many jurisdictions.

Plan ahead. Buy a transfer switch. Get it installed. Don't use suicide

There is no safe way to do suicide wiring and the author does not recommend
it under any circumstances. If you choose to go ahead and do it anyway, this
information may help you:

1.Get somebody qualified to help you unless you really know what you're
2.ISOLATE the breaker panel from the commercial power source by
disconnecting and taping the supply connection from the main breaker or
busbars. You can leave the neutral connected, just remove the hot
connections. Follow the precautions for working on live electrical circuits
since the commercial power could come back on without warning while you're
make sure everything is dry, keep your left hand in your pocket, and use
the buddy system.
3.Use wire of adequate capacity for the full rated output of the generator.
For generators up to 4800 watts that would be 12 gauge unless you're going
more than 50 feet or so. Use wire rated for outdoor use. If possible,
connect it to the main breaker o r lugs where you removed the supply
connection. Sometimes the smaller wire won't connect securely to big
breakers or
lugs. You can try folding it over a couple times to make it bigger around
or undo the wires from a non-critical 240V breaker, say for the air
conditioning, and hook the hot up there. Hook up the neutral to the neutral
busbar. If your generator has a separate ground, hook that up to the ground
bus if there is one, or the neutral bus if it is bonded. Be sure everything
is connected securely o r it will overheat. Use the right plug to connect
to your generator.
4.Check everything to make sure there are no signs of overheating while
5.Get a qualified electrician to clean up the mess and put in a transfer
switch when the power comes back on.

Again, the author does not recommend that this type of wiring be used
under any circumstances.


Here's some basic advice on generator safety. Read the instructions
for your generator or check with a dealer or licensed
electrician for authoritative safety rules.

1.Follow the safety instructions that come with the generator.
2.Keep the generator outside so you don't breathe carbon monoxide and die.
Protected locations, such as a garage with the garage door open, are
helpful if the weather is bad.
3.Follow whatever grounding instructions come with the generator.
Generators should be grounded but the recommendations for how this is done
vary depending on
4.You can get a bad shock by touching a wet power cord or plug while the
generator is running. Shut off the engine before fiddling with the power
connections if it is wet out.
5.Don't refuel a hot engine. If you refuel at night, use a source of light
that won't ignite the gas. The cyalume sticks work well for this.
6.Don't overload extension cords.
7.Use a transfer switch.
8.Store gasoline outside, in a safe container.

More accidents happen during power outages than occur when power is
available, particularly fires. Here are some general tips for safety during
power outages:

1.Don't leave candles or oil or gasoline lanterns burning unattended.
2.Realize that smoke and carbon monoxide detectors will not work without
3.Have fire extinguishers at hand.
4.Have some water drawn up in buckets or pans to use in case the water
supply fails.

Fuels and Fuel Storage

Most portable generators run on gasoline. But gasoline is a poor choice for
standby use, because it is unsafe to store in residential areas and is prone
to deterioration when stored for any
length of time.

Gasoline is extremely flammable and should not be stored in any quantity in
a house or garage. There is no safe way to store gasoline in a building.
Building and zoning codes, and
insurance requirements, vary; some municipalities prohibit permanently i
nstalled gasoline tanks and limit the size of portable ones.. In the
author's area gasoline suppliers recommend that bulk storage tanks be at
least 10' away from garages and other buildings. Some of the author's
acquaintances store gasoline in 5 gallon ca ns in a little building not much
larger than a doghouse, that is used for nothing else and is a long way from
all the other buildings.

Gasoline can be stored in full, sealed containers for 1-2 years or more
without deterioration, provided that high temperatures are avoided. Air,
water, and heat all contribute to

The author uses a commercial fuel preserving additive in the gas tank for
his generator, but there is no consensus on misc.survivalism that such
additives materially improve the storage
life of gasoline.

Some, mostly larger, generators are available with diesel engines. These
engines are, as a rule, noisier than gasoline engines and are more difficult
to start in cold weather. For standby
use, they may be worth having because of fuel storage considerat ions.

Diesel fuel and kerosene are much safer to store than gasoline. It is still
common to store fuel oil, which has similar properties, indoors in houses in
quantities up to 250 gallons. Again,
building and zoning codes and insurance rules may limit the am ount or
method of storage. These products should not be stored in red cans because
of the potential for confusion with gasoline. These fuels can be stored 2-3
years before they deteriorate.

Midsize and larger generators designed for permanent installation and
standby use are available for use with LP gas or natural gas. The engines
are like gasoline engines in most respects
but replace the carburetor with a mixing system designed for LP o r natural
gas. LP gas standby generators are widely used in industrial/commercial
settings. The chief benefit is that LP gas can be stored indefinitely
without deterioration.

LP gas conversion kits are available for many small generators.


There are no statistics available, but anecdotal evidence suggests that
generators frequently fail to start when they are needed, even in industrial
settings where regular maintenance and
testing is performed.

Electric start generators sometimes fail to start because the battery is
dead. Batteries that are continuously trickle-charged may start the engine
while being charged but fail when the charger is turned off, as in an actual
emergency. Battery terminal s also have a way of getting corroded.

Stale gasoline can contribute to starting problems, especially in cold
weather. Using starting fluid will sometimes make up for this.

Spare parts and supplies should be kept on hand. At a minimum, some extra
motor oil, suitable starting aids, air and oil filters (if used), and a
spark plug should be available.

You should periodically operate your generator, and hook up whatever loads
you plan to use, to make sure that everything is ready if needed. Once a
month is probably often enough
to catch most problems.

How Practical Is a Generator?

The author has had to resort to using the generator during a couple of
long-duration power outages. Severe weather can be extremely disruptive to
power systems and the unlucky individuals whose own lines are knocked down
in a st orm end up at the end of the power company's list for repairs. Power
losses can be costly if you stand to loose the contents of
your freezer, or if cold weather and no heat threatens to freeze pipes.

On the other hand, unless you can afford a fully automatic, permanently
installed system, you had better be able-bodied. It's work to pull out the
generator and start it and hook it up even
if you have a good setup.

Big generators are noisy. Everyone in the neighborhood will know that you're
running one.

You may wish to consider running the generator during only part of a 24-hour
period. Most refrigerators and freezers will maintain temperature if
operated 50% of the time, depending on
ambient temperature, condition of the door seal, and how often the door is

Fuel availability is a thorny issue. Gas stations require electricity to be
able to pump gas. The author is fortunate enough to live in a setting where
it is possible to store ample quantities
of fuel to run the generator for a week or more. Even the worst power
outages are ordinarily corrected after a week, two at the most.

Those of you concerned about Y2K and other TEOTWAWKI scenarios should
consider other alternatives that do not rely on fuel availability.

Other Ways to Produce Electricity

Several companies sell inverters that produce 120V electricity using the
power from a car or truck's battery and alternator. These are not suitable
for most standby uses because the output power is too low. The largest car
and truck alternators produce no more than 2000 watts, and this only at high
engine speeds. The really big inverters - 2000W and over, capable of running
a refrigerator - are expensive, big, heavy, and require heavy cabling to the
battery. The logistics of ope rating a vehicle while stationary must also be
considered: how do you secure
the vehicle, potential for damage due to low oil or high temperature while
unattended, potential for transmission bearing damage due to extended
idling, poor fuel economy.

There are some belt-driven and PTO-driven generators for cars and trucks
that have similar problems. In addition, most of these units must be
operated at a specific speed. Unless the vehicle is equipped with an engine
governor, this is difficult.

Uninterruptable power supplies (UPS) are designed primarily for use with
computers and communications equipment. They generally are designed for
short-duration outages, 15 minutes or less.

Solar, hydroelectric, and wind generators are a topic in their own right and
are beyond the scope of this FAQ. Many products marketed for use with
alternative power systems are also
useful for standby use. It might make sense in some cases to have low-
voltage DC wiring for lights that can be operated from batteries in an

Non-electric Alternatives

There are a number of low-tech techniques that can reduce your dependence on
electricity. Some are effective by themselves, and others will reduce the
size generator you need or the
hours you need to run it.

1.Use something besides electricity for the primary source of heat.
Although any modern central heating system requires some electricity to
operate, you can run a natural gas, LP gas, or oil-fired furnace from a
generator of modest size. Electric heat s ystems can't be operated except
by very large generators.
2.Replace electric appliances with gas. Houses that are served by a
natural gas supplier rarely have gas outages and electric outages at the
same time (except possibly in earthquake-prone areas). LP gas is stored in
tanks and is independent of electrica l and other utilities. A gas stove
can be used without electricity if the burners are lit with a match. Most
gas water heaters don't require electricity at all (except for horizontal
exhaust and other power-vented units).
3.Have a wood stove or fireplace insert that is capable of heating your
house. Have enough wood on hand to be able to use it in a power outage.

A wide variety of non-electric lighting is available. Aladdin lamps, which
burn kerosene and produce a bright light, are practical and safer to use
inside than gasoline lanterns. Lamps that
operate on LP gas supplied through pipes are available. They m ount
permanently to a wall or ceiling, and are bright, safe, and cheap to
operate. Inexpensive kerosene wick lamps are widely available and produce
more light than candles.

LP gas and kerosene operated refrigerators and freezers are available. Some
will also operate on electricity. Full-size units are expensive but no more
so than a good generator installation.
Smaller refrigerators, such as those used in RVs, are availab le too -
though some require a 12V DC power source to operate the controls and
ignition system even when running on LP gas.

The Author

The FAQ is maintained by Steve Dunlop. Steve lives in Minnesota and has
several off-the-grid friends. He has two generators of his own, one a
20-year old tractor-driven unit and the
other a little 1500 watt Coleman.
Mike S. Medintz,


"A human being should be able to change a diaper, plan an
invasion, butcher a hog, conn a ship, design a building, write
a sonnet, balance accounts, build a wall, set a bone, comfort
the dying, take orders, give orders, cooperate, act alone,
solve equations, analyze a new problem, pitch manure, program
a computer, cook a tasty meal, fight efficiently, die
gallantly. Specialization is for insects." Robert Heinlein

"As my father told me long ago, the objective is not to convince someone
with your arguments but to provide the arguments with which he later
convinces himself."
David Friedman
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