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 Electrical systems can seem like a confusing mess of connections, cables, and boxes hidden inside the walls. But with a little common sense and a few precautions, do-it-yourselfers can handle most projects.
Electrical
work can be intimidating because it can be dangerous, and some accidents can cause
serious injury.
If
you're not confident in your ability to do electrical work, continue to learn
more about it or consider hiring someone to do the work.
Your
project may require a building permit and inspections. It's your responsibility
to get the proper permit and schedule inspection times.
WARNING:
DOING WORK WITHOUT A REQUIRED PERMIT IS NOT ONLY ILLEGAL, BUT MAY ALSO INVALIDATE
YOUR HOMEOWNER'S INSURANCE.
When you're doing a remodeling job, wiring may be old and outdated. If you're
tearing out walls enough to expose wiring, it should be brought up to code. Obviously,
that involves more work and money for materials like cable, boxes, switches, staples,
but you'll feel much better having newer, safer cable in the house.
Safety
Steps 
Before you do any electrical work on a circuit, make sure the power is off.
Turn off the breaker (or pull/unscrew the correct fuse) to the circuit you'll
be working on.
Post
a sign on the service panel so nobody tries to restore power while you're
working on the circuits.
Double-check
the circuit with a circuit tester before you touch it to make sure the
correct breaker has been tripped.
Labeling
or drawing a diagram before unhooking wires will take any guesswork out of how
to reconnect them.
Wear
shoes with non-conductive soles, use tools with rubber grips and don't
stand in water to avoid a potentially dangerous shock.
Finally,
never push yourself to finish a wiring job. That's when mistakes happen. If you
run into a difficult stretch of work, take a break and think about what needs
to be done. If you're still not sure, don't take chances -- contact a professional.
Electrical
System Basics 
Electricity is supplied by a local utility to a house through three underground
or overhead wires (two "hot" leads and one neutral lead) that enter the house
through a conduit and a meter.
Those
wires connect to their respective buss bars inside the service panel
-- usually two hot, one neutral, and one ground buss.
Circuit
breakers slide/snap onto the hot buss bars. They act as safeguards against
short circuits and overloads by "tripping" off. A breaker also functions as a
switch; turning the circuit on and off as desired.
Breakers
also connect to outgoing "hot" wires. The hot wires deliver power to a
device (like a light) and normally have black insulation. Cable with two
hot leads also have a red hot lead.
Once
the electricity has done it's work, it goes back to complete the circuit on the
"neutral" wire, which is most often white.  Electricity
needs this completed circuit to work properly -- a way OUT through the
hot wire, and a way BACK through the neutral wire.
In
addition to the neutral, the green (or bare copper) ground wire
offers current another path back should an electrical short or overload happen.
From
the service panel, the ground has two safe paths to divert electricity: connected
to a long metal rod buried outside the house and/or the house's water
pipes.
All
the wires, called cable, are often housed by a flexible plastic sheathing.
It's nonmetallic-sheathed (NM) cable, but is often mistakenly called "Romex" which
is a brand name made by General Cable Corporation.
Cable
is also identified by gauge (thickness) and the number of leads it has. For example,
NM 14-2G means that the cable is nonmetallic, 14 gauge, has two leads (1 neutral,
1 hot), and a ground wire.
Using
Testers 
If working with electricity scares you, a voltage/neon-light tester can help change
that. It's an inexpensive, but invaluable tool for determining if a circuit is
"live" or "dead."
It's
basically just a small neon light bulb attached to two wires. When the contacts
on the wires are touched to a live circuit, the light goes on. And when there's
no juice coming to the circuit, the light stays off.
But
it's important to get into a good habit of always testing switches, outlets and
wires before your hand actually touches them.
You
can test an outlet without taking off the cover plate, but also check its screw
terminals. For that and for switches, you'll have to take off the cover plate.
To
make sure the power is off before you work on an outlet, test between the
screws on each side, and between the screw on the shorter slot side and the green
ground screw. No light means the "juice" is off.
To
check for proper grounding, test between the shorter slot (hot) and the
round hole (ground). If the tester lights up, there's probably proper grounding.
It should also light when you test between the shorter slot and the cover plate
screw.
To
check that the power is off to a switch, check between both terminals on
the switch and then between the copper ground lead and each terminal.
For
bare wires, hold one tester lead on the bare ground wire (or box if it's
grounded) and the other test lead on the hot, then neutral wire. Also check between
the two leads. If the light stays off, the circuit is off.  Plug-in
circuit testers that fit right into outlets can tell you a lot. On our tester,
two amber lights mean everything's ok.
Other
combinations of lights indicate different potential problems with a circuit --
like an improper ground. They're handy for checking and diagnosing connections
when you're installing several new cable runs and circuits. |
