Your home repair project involves installing a light fixture
and an electrical outlet. You flipped
the breakers and disconnected the existing fixture, but now you’re uncertain
which wire is the “hot” one. What now?
In the United States, household wiring code offers us a clue
as to which wire SHOULD correspond to what.
Extreme caution should be used, however, when dealing with electricity,
even if you feel certain that you know which wire is which. The possibility exists that a misguided
handy-man who came before you made the wrong choice connecting the wires. You can never be too careful when your life
is at risk.
According to code, the black wire is always the “hot” or “live”
wire, meaning, it is connected to a source supplying 110 VAC. If you are connecting this wire to an
electrical outlet, this wire should connect to the narrow spade, or brass
colored terminal. If you have not
switched off the breakers like you’re supposed to and you grab the copper
conductor of this wire, you will probably feel an unmistakable tingling
sensation quickly travel up your arm. If
you do feel it, let go of the wire because this sensation is not good for you. If this happens to you often, be sure to have
someone around who knows CPR and first aid when you do home repairs.
The green wire is your friend. This is the ground wire. Its sole purpose for existing is to save your
life by providing electricity an alternate path to ground. In the case of a short circuit, the current passes
through the ground wire and overloads the breakers, causing them to trip. Sometimes this wire will also have a yellow
stripe. Be sure to connect the ground
wire properly when performing an electrical repair. If the copper conductor of the “hot” wire
that we just discussed were to maneuver it’s way over to the metal casing of,
for example your ceiling fan, and make contact with it without the ground wire
attached, you would be in for a nasty surprise when you touched the metal
casing of the fan.
The white wire is known as the “neutral” wire. In any circuit, whether AC or DC, there has
to be a complete path in order for the electrical current to flow. The white wire alone should not have a charge
and should not hurt you if you touch it.
If installing an electrical outlet, this wire connects to the wide spade
or silver colored terminal.
Sometimes, you will find a red wire living side-by-side with
the black, white, and green wires. This
wire is known as a “traveler” wire and is used to connect power between 3-way
light switches.
Always use caution when working with household wiring. Turn off the breaker that corresponds to the
circuit that you are working on. If you
are not certain which one is which, switch off the main breaker. Even then, it is a good idea to test the
wires with a multimeter to be absolutely certain that the wires are not “hot”. It’s a good idea to test between the black
wire and the white wire and then between the black wire and the green
wire. It is important to note that when
reading AC voltage with a multimeter, if you connect your probes between two
wires that are both “hot” (110VAC) the reading will be 0 volts. (A lesson that
I learned the hard way!) Always know
what you are doing when dealing with electricity. Small mistakes could prove to be fatal.