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does electricity get where you need it?
in your home is not rocket surgery, but there
are some basics and some details that will help
you deal with issues on your own, know when to
call an electrician, and what to tell her or him
when you call. In this introduction to electricity
in your home, we'll add enough details about things
you may already know and about house wiring issues
that affect you everyday - especially on the days
when something goes wrong.
time, we will add short articles about specific
electrical topics to our website. If you would
like us to answer your questions about electricity,
lighting, telephone, or computer networking in
our website's Electrical Education section, email
us at TechnologyForTheRestOfUs@onlyconnectelectric.com.
the meter, the service entrance conductors continue
into your home to the circuit breaker or fuse
panel (the service panel) in your basement. The
service panel is really where the story of how
electricity works in your home begins. Behind
the panel cover door or cover, you will find a
switch or a fuse at the very top that regulates
all of the electricity that comes into your home.
Below it, you will see a series of switches (circuit
breakers) or fuses that regulate each of the circuits
that run through your house.
In the service
panel, the service entrance conductors attach
to "the main," a circuit breaker or a set of fuses
that protects your entire house. Typically sized
from 60 to 200 Amperes, the main shuts off the
power to the entire house when you are drawing
more power, through every plug, lamp, or appliance
than you have available. Without the main to protect
you, your wires could get too hot, melting their
insulation and igniting nearby wood or other combustibles.
If the main keeps tripping, and this rarely happens,
it means that you don't have enough power coming
into your home.
and Circuit Breakers
Once the power
passes through the main it is divided into individual
circuits. In the service panel, the power is divided
up and runs through circuit breakers or fuses
that protect each of the wires (circuits) that
leave the panel to do something useful. A circuit
is exactly what it sounds like, a smaller pair
of insulated wires, with a ground, that run through
your home to a number of outlets, lights, fans,
or other appliances. Each circuit is protected
by a smaller circuit breaker that is usually safe
for only 15 or 20 Amperes.
There are a
number of different circuits running through your
home; some might power a string of lights or outlets,
while others may go to a single large appliance
like a stove or the heating system. When there's
a problem on one circuit, the breaker turns off
the power (trips) on just that one circuit;
the rest of the house continues to have electricity
to run your lights, TV, computer, heat, and other
Do Circuit Breakers Trip?
It sounds like
a dumb question, but it's not. There are two ways
your wiring can get too hot and cause problems:
overloads and short-circuits.
If you have
an outlet above your kitchen counter, it should
be on a 20 Ampere circuit with a 20 Ampere circuit
breaker. The wires can safely carry 1920 watts
If you run
a toaster (often 1200 watts) and a microwave (often
1250 watts) on that circuit at the same time without
a circuit breaker, they use 2450 watts: enough
to overload the circuit, overheat the wires, and
damage the insulation. A 20-Ampere circuit breaker
on the line prevents this by slowly warming up
with the wires and then saves the day by shutting
off the power before the wires get too hot, and
preventing damage to their insulation, or the
house. It's a pain in the neck that should and
can be fixed, but in the meantime, you still have
a circuit breaker can be tripped is if you accidentally
drop a kitchen knife on the toaster cord and connect
the two wires in the cord. You would have a short-circuit,
and you would probably see a spark. When a short
circuit occurs, the power goes out through one
wire and then back on the other, without ever
reaching the toaster. Unlike a toaster, the wires
have very little resistance. Suddenly, a huge
electrical current flows through the wire. If
allowed to continue, it would heat the wire and
cause damage very quickly. In this situation,
the circuit breaker trips very quickly. Short
circuits like this can also occur inside a fan
you have plugged in or in the electrical boxes
and cables in your walls.
and fuses are designed to prevent damage or fire
from both overloads and short-circuits.
If a particular
circuit breaker keeps tripping it probably means
that you have too many appliances or lights on
that circuit. It may be time to add a new circuit
and divide the appliances and lights between the
two circuits. It rarely means that you need to
increase the power available in your home with
an expensive "service upgrade."
If you find
that the main fuses are blowing or the main circuit
breaker in the panel is tripping, you may need
more power than is available to the entire house.
Then it's time to investigate whether a service
upgrade may be in order.
good are circuit breakers?
so much depending on circuit breakers, the natural
question is, "How good are circuit breakers?"
And if you have an old fashioned fuse box, "Is
it necessary to upgrade to a panel with circuit
are very reliable, but they are not perfect. We
cannot live safely without them, but like all
electrical-mechanical devices, circuit breakers
are built in ordinary manufacturing plants. Only
a miniscule percentage of them leave the factory
defective, but all of them get old. Eventually
a few of them don't work so well.
may trip when there's no problem or may fail to
trip when there is a problem, but they are typically
extremely reliable and absolutely worth using.
Fuses, which are much older technology, are less
convenient because you have to keep a supply of
replacements on hand and change them when they
blow. But fuses are much simpler and even more
reliable: when there is a problem, they get hot;
the lead melts, the circuit is off. So, unless
there is something wrong with your fuse box, or
the bank with the mortgage money insists, you
might not need to replace a fuse box with circuit
New Circuit or More Power?
had a circuit breaker trip at some time. Your
cat gnawed through a lamp cord, and poof (that's
a technical term), half the lights in your house
went off. Everything that went off was on the
same circuit. This is one way to understand where
each circuit goes in your house, but it is probably
not the best way.
were built for simpler times: fewer electric appliances
and very few circuits. All the lights and receptacles
on a floor were often on the same circuit. We
were recently in a house that had the basement
lights and the receptacles in the front hall,
living room, and one bedroom on the same circuit.
Even if the
service panel was upgraded to 100 or 200 Amperes,
the old circuits may have been merely reattached
to the new circuit breakers. In other words all
of the plugs, lights and appliances in the kitchen
may still be on that same 20 amp circuit. All
that additional power coming into the service
panel won't do any good if you don't split it
up into new circuits. And if you add new circuits,
odds are you won't need that service upgrade.
This is the
big reason why we believe that it is often better
to spend your money on getting more circuits than
getting more power into the house.
often have more circuits that are divided up more
sensibly. Keeping lights and receptacles on different
circuits means that the overhead light still works
when the receptacle circuit goes off. Although
it's a tedious task, it is a good idea to make
an accurate list of which lights, receptacles,
and equipment are controlled by each circuit breaker.
A good list will help you figure out what's going
on when a circuit breaker trips. And a good list
will save you money when you need to call an electrician.
You don't him or her to spend a lot of time figuring
out what is controlled by each circuit breaker.
is Grounding, and Why Should i Care About It?
Short circuits happen. Equipment gets old and
fails. Microwaves, vacuum cleaners, washing machines,
and televisions get old. Trucks bouncing down
the street and kids running up and down the stairs
jiggle wires loose. Insulation dries out and crumbles,
allowing live wires to electrify metal parts.
Short-circuits can destroy equipment and create
dangerous situations. Grounding reduces the chances
An example to
make the value of grounding a little clearer:
Look at your microwave; it has a 3-prong plug,
with an "equipment grounding wire." If a wire
inside your microwave jiggles loose or the insulation
melts, a live wire may touch the metal appliance
case. If you now touch the metal case and the
stove or a faucet at the same time, you can receive
a bad shock.
To prevent this
shock, the grounding wire from the cord is attached
to the metal case and to the grounding terminal
(the round hole) in the wall plug. The grounding
terminal in the outlet connects to a grounding
wire that goes back to the service panel. The
grounding wire provides a low-resistance path
for electricity to get back to the panel. allowing
large amounts of current to flow through the circuit
and trip the circuit breaker.
The house doesn't
burn down, and you don't touch a live metal case
and get injured. The 3-wire grounding plug and
the 3-hole grounding receptacle save the day.
On the other
hand, very few, if any, of the lamps in your house
have 3-prong plugs. Take a look around. On your
kitchen counter, some appliances do and others
don't. Those with 2-prog plugs cannot connect
the live metal case to the house wiring: in this
situation, replacing a 2-hole receptacle with
a 3-hole grounding outlet offers no additional
are those buttons on my bathroom receptacle?
In some situations,
grounding plugs and receptacles do not provide
the edge of safety you need. The solution is a
ground fault receptacle (Ground Fault Circuit
Interrupter-GFCI) that provides extra and
faster protection. The buttons are for testing
the GFCI and then resetting it.
We've all heard
about the dangers of the hair dryer that falls
into the bath water. As we have learned from early
childhood water and electricity don't mix. When
a hair dryer falls into the water, some of the
current continues to travel back through the cord
to the receptacle in the normal way, but some
of it may "leak" and flow through the water to
the pipes and back to the ground (the real earth
ground). GFCIs are designed to detect the tiniest
amount current leakage and shut off the power
extremely quickly. In new installations, they
are required in kitchens, bathrooms, basements,
garages, and outside your house.
If you are in
the tub, some of that current may flow through
you-not a great idea. The problem is that very
small amounts of current flowing across your heart
can destroy the normal rhythms of the heart. Because
there is no huge surge of electricity, the circuit
breaker may not trip quickly enough, or not at
The same danger
exists when your microwave's metal case get livened
up. If you touch the microwave and put your other
hand on the stove or a faucet, you can get livened
up along with it. But you may not stay alive for
are designed to detect the tiniest amount current
leakage (in this case, through you) and shut off
the power extremely quickly. In new installations,
they are required in kitchens, bathrooms, basements,
garages, and outside your house.
should I call an electrician?
First: the emergencies.
You plug in a radio and you see sparks. You go
to turn on a light, and the switch plate seems
very hot. You cannot get the thermostat to turn
on the heat. Call for help right away.
turn on a light switch; nothing happens, and then
you notice that three other rooms are also dark.
So you turn the switch back off, get out a flashlight,
and reset the circuit breaker or change the fuse.
Still nothing. You remove the light bulbs from
the ceiling fixture and unplug everything on the
circuit; reset the breaker again. Still nothing.
It's time to talk with an electrician for advice.
If all goes well, you may be able to track down
the problem and maybe fix it. Last resort, you
need a house call.
Second: the dangerous inconveniences.
The circuit breaker keeps tripping when you forget
and use the toaster and the coffee maker at the
same time. There are extension cords running under
the living room rug because there's no outlet
near the TV. Your new treadmill requires a 20
Ampere circuit, and you need to run an extension
cord to the closest 20 Amp outlet, two rooms away.
You've tripped on the kids' toys on the unlit
basement steps more than once; one of these times,
you're going to get hurt. Not necessarily cause
for an immediate call for help, but it's time
for a temporary fix and thinking about a permanent
Third: comfort and convenience.
Your fourth grader wants a computer in her room
for homework (and IM'ing, of course); you need
a wireless connection to your internet modem.
You'd really like a ceiling fan on the porch.
You can't use your new heavy-duty drill to mount
shelves in the living room because all the outlets
have two holes and no ground. Wouldn't it be nice
(and cheaper to run) if the outdoor lights had
motion detectors? New light fixtures that make
the kitchen look a bit more modern or maybe bright
enough to read the morning paper? And then there's
always the luxury of central air conditioning
or home theater.
rarely does an improvement require more power
to the house and the dreaded, but popular and
expensive, service upgrade. There's usually a
circuit than can support the new installations.
Powering up the enclosed porch or a home theater
may need a new circuit and breaker in the panel,
but we're not talking about rewiring your whole
house to get another light.
looking to answer your questions about electricity
and any related topic. Call us any time; we'd
love to talk and maybe use your question as the
basis of an article in the coming ONLY
"Technology for the Rest of Us" section.