Electrical Wiring Flashcards
a single conductor which material is most commonly being copper or aluminum
wire
two or more insulated wires wrapped in one jacket
cable
types of electrical cable
twisted pair cable, multi conductor cable, coaxial cable, fiber optic cable
has two cables that are twisted across each other
twisted pair cable
this cable is best suited for carrying signals
twisted pair cable
twisting in twisted pair cable can avoid noise that is produced by __________
magnetic coupling
generally used in telecommunication and data communication
twisted pair cable
has two or more conductors that are insulated from each other
multi conductor cable
purpose is to protect signal integrity by reducing hum, noise, and crosstalk
multi conductor cable
its applications include computers, communications, instrumentation, sound, control, audio, and data transmission
multi conductor cable
What are multi conductor and twisted pair cables called?
balanced line configuration cables
composed of an inner solid conductor surrounded by a paralleled outer foil conductor that is protected by an insulating layer
coaxial cable
what separates the two conductors in a coaxial cable?
insulating dielectric
generally used in TV cables
coaxial cable
called an unbalanced line as the signal on the two conductors is not same which result in interference
coaxial cable
performance is more stable than a twisted pair cable
coaxial cable
has a much greater bandwidth than metal cables; can carry more data
fiber optic cable
transmits signals by a bundle of glass threads
fiber optic cable
less susceptible to interference
fiber optic cable
What are the two reasons why fiber optic cables are increasingly being used instead of traditional copper cables despite being expensive?
can carry more data, less susceptible to inteference
Types of Electrical Wire
solid wire, stranded wire
a single conductor that is either bare or insulated by a protective-colored sheath
solid wire
offers low resistance and are perfect for use in higher frequencies
solid wire
consists of thon strands of wires twisted together in a sheath
stranded wire
more flexible and have larger cross-sectional area than solid wires for the same current carrying capacity
stranded wire
Aircraft wire is measured by the _________, with the larger numbers representing the ______ wires.
American Wire Gauge (AWG) System, smaller
also used to describe stranded wire
AWG
The AWG of a stranded wire represents the sum of the ________ of the individual strands; the gaps between the strands are _______.
cross-sectional areas, not counted
When stranded wires are made with circular strands, these gaps occupy about ______ of the wire area, thus requiring the overall bundle diameter to be about ______ larger than a solid wire of equal gauge.
25%, 13%
Stranded wires are specified with three numbers, what are these?
overall AWG size, number of strands, AWG size of a strand
What separates the number of strands and the AWG of a strand?
slash
The smallest size wire normally used in aircraft is ______ wire, which has a diameter of about ______.
22-gauge, 0.025 inch
Conductors carrying large amounts of current are typically of the ______, or ______ size, and have a diameter of about _____.
0000, 4-aught, 0.52 inch
What determines the amount of current a wire is capable of carrying?
its cross-sectional area
One mil is equal to?
0.001 inches or 1/1000 inches
125 mils = ______ inches
0.125
To find the cross-sectional area of a round conductor in circular mils, what do we do?
square the conductor’s diameter
unit of measure for square or rectangular conductors
square mil
To determine the cross-sectional area of such a conductor in square mils, what do we do?
multiply the conductor’s thickness by its width
1 circular mil = _____ square mil
0.7854
To convert a circular mil area to a square mil area, what do we do?
multiply the area in circular mils by 0.7854 mil
To convert a square mil area to a circular mil area, what do we do?
divide the area in square mils by 0.7854
factors to consider in new wire installations
system operating voltage, allowable voltage drop, continuous or intermittent basis
Identification markings should be placed at each end of the wire and at _________ interval along the length of the wire.
12 to 15 inches
Wires less than ____ in length need not be identified.
3 inches
Wires ______ in length should be identified approximately at the center.
3 to 7 inches
Two methods of marking wire or cable
direct marking, indirect marking
accomplished by printing the cable’s outer covering
direct marking
accomplished by printing a heat shrinkable sleeve and installing the printed sleeve on the wire or cables outer covering
indirect marking
Indirectly-marked wire or cable should be identified with printed sleeves at each end and at intervals not longer than ______.
6 feet
The individual wires inside a cable should be identified within ______ of their termination.
3 inches
The identification marking should identify the wire with regards to what?
type of circuit, location within the circuit, wire size
2 P 215 A 4 N ALUM
What is 2?
unit number
2 P 215 A 4 N ALUM
What is P?
circuit function letter
2 P 215 A 4 N ALUM
What is 215?
wire number
2 P 215 A 4 N ALUM
What is A?
wire segment letter
2 P 215 A 4 N ALUM
What is 4?
wire size number
2 P 215 A 4 N ALUM
What is N?
ground, phase, or thermocouple letter
2 P 215 A 4 N ALUM
What is ALUM?
suffix
used to identify the circuit function
circuit function letter
used to differentiate between wires in a circuit
wire number (s)
Wires with the same circuit function having a common terminal connection or junction will have the _____ wire number but _____ segment letters.
same, different
a conductor between two terminals or connections; used to differentiate between conductor segments in a particular circuit
wire segment letter
letters not used as segment letters
I and O
Double letters are used for wire segments when more than ____ segments are required.
24
used to identify the size (AWG) of the wire
wire size number
For coaxial cables and thermocouple wires, a _____ is used in lieu of the wire size number.
dash
used as a suffix to the wire identification code to identify any wire or cable that completes the circuit to the ground network
N
used as a suffix on the wire identification code to identify phase of wires that are in the three-phase power distribution wiring of AC systems
A, B, or C
shall be used as a suffix on the cable identification code to identify the ungrounded wire or cable that is in a single-phase system
V
Chromel consists of
90% nickel and 10% chromium
suffix for Chromel
CHROM
suffix for Constantan
CONS
Constantan consists of
55% copper and 45% nickel
suffix for Alumel
ALML
Alumel consists of
95% nickel, 2% aluminum, 2% manganese, 1% silicon
suffix for copper
COP
suffix for iron
IRON
The inside diameter of the conduit must be _____ larger than the maximum diameter of the wire bundle.
25%
What does the nominal diameter of a conduit represent?
conduit’s outside diameter
method of installation that provides the best mechanical protection for electrical wiring
conduit
quickest and easiest way to install wiring
open wiring
allows easy access when troubleshooting or servicing individual circuits
open wiring
All of the wire bundles installed in aircraft should be routed so they are at least _____ away from any control cable and will not interfere with any moving components.
3 inches
a method of intercepting electrical energy and shunting it to electrical ground
shielding
term used to describe the squeezing of a terminal around a wire to secure the wire and provide a high-quality electrical connection
crimping
process of cutting the protective insulation of a wire and gently pulling it from the end
stripping the wire
