Amp (Ampere)
A
unit that measures the strength/rate of flow of electrical current.
Armored
Cable
Electrical
wires protected by metal sheathing.
Branch
Circuits
The
circuits in a house that branch from the service panel to boxes and devices.
Breaker
A switch-like
device that connects/disconnects power to a circuit.
Buss
Bar (also Bus Bar)
Separate,
metallic strips that extend through the service panel. Breakers slide onto the
"hot" busses and neutral and ground wires screw down in their respective busses.
BX Cable
An old
type of armored cable now illegal.
Cable
Clamps
Metal
clips inside an electrical box that hold wires in place.
Circuit
A continuous
loop of current (i.e. incoming "hot" wire, through a device, and returned by "neutral"
wire).
Circuit
Breaker
The
most common type of "overcurrent protection." A breaker trips when a circuit becomes
overloaded or shorts out.
Conduit
A protective
metal tube that wires run through.
Duplex
Receptacle
The
commonly used receptacle (outlet). Called "duplex" because it has two plug-in
sockets.
Fuses
Removable
devices that link a circuit at the fuse box. Fuse connections blow apart and break
the circuit if an overload or short occurs.
Fixture
Any permanently
connected light or other electrical device that consumes power.
GFCI
or GFI (Ground Fault Circuit Interrupter)
A
specific type of circuit protection (commonly required in kitchens & bathrooms)
that helps safeguard against shocks. GFCI protection can come from an outlet or
a breaker.
Ground
Fault
Current
misdirected from the hot (or neutral) lead to a ground wire, box, or conductor.
Hot,
Neutral, Ground
The
three most common circuit wires. The hot brings the current flow in, the neutral
returns it to the source, and the ground is a safety route for returning current.
The ground and neutral are joined only at the main service panel.
Junction
(Electrical) Box
A
square, octagonal, or rectangular plastic or metal box that fastens to framing
and houses wires, and/or receptacles and/or switches.
Knockout
A removable
piece of an electrical box or panel that's "knocked out" to allow cable to enter
the box.
Lead
The short
length of a conductor that hangs free in a box or service panel. (i.e. a wire
end)
NM
Nonmetallic-sheathed
(plastic).
NMC
Solid plastic
nonmetallic-sheathing used in wet or corrosive areas, but not underground (see
UF).
Ohm
A unit
that measures the resistance a conductor has to electricity.
Pigtail
A short,
added piece of wire connected by a wire connector. Commonly used to extend or connect
wires in a box.
Romex
A brand
name of nonmetallic-sheathed cable made by General Cable Corporation. Often mistakenly
used as a collective term for NM sheathed cable.
Rough-In
Installing
the boxes, cables, and making "in-wall" connections while the walls are still
open. Later, final connections are made and the devices and appliances are installed
during the trim-out.
Service
Entrance (SE)
The
location where the incoming electrical line enters the home.
Service/Supply
Leads
The
incoming electrical lines that supply power to the service panel.
Service
Panel
The
main circuit breaker panel (or fuse box) where all the circuits tie into the incoming
electrical supply line.
Short
Circuit
When
current flows "short" of reaching a device. Caused by a hot conductor accidentally
contacting a neutral or ground. A short circuit is an immediate fault to ground
and should always cause the breaker to trip or the fuse to blow. (also see ground
fault)
Travelers
Wires that
carry current between three-way and/or four-way switches.
UF
(Underground Feeder) cable
Cable
designed and rated for underground, outdoor use. Cable wires are molded into solid
plastic.
Volt
A unit
that measures the amount of electrical pressure.
Watt
A unit
that measures the amount of electrical power.
