CB 5 Flashcards
Something that would effect the ampacity of a conductor would be
voltage
amperage
length
temperature
temperature
Alternating currents may be increased or decreased by means of a
motor
transformer
dynamo
megger
transformer
Fixtures supported by the framing members of suspended seiling systems shall be securely fastened to the ceiling framing memever by mechanical means such as
bolts or screws
rivets
clips identified for use
any
Which has the highest electrical resistance?
brass
iron
water
paper
paper
Conductor sizes are expressed
only in CMA
in AWG or CMA
in diameter or area
in AWG or millimeters
In AWG or CMA
Of the following, which is not a type of file?
half round
bastard
tubular
mill
tubular
Oil is used in many large transformers to?
prevent breakdown due to friction
lubricate the core
cool and insulate the xfer
lubricate teh coils
cool and insulate the xfer
Fractional horsepower universal motors have brushes usually made of?
copper strands
mica
carbon
thin wire rings
carbon
When administering first aid to a worker suffering from fright as a result of falling from a ladder, the most important thing to do is?
position the person to a sitting position
cover the person and keep them warm
apply artificial respiration immediately
check the rungs of the ladder
cover the person and keep them warm
If a coworker is burned by acid from a storage battery, the proper first aid treatment is to wash with?
iodine and leave it open to the air
vinegar and apply a wet dressing
water and apply vasoline
Iye and apply dry bandage
water and apply vasoline
A type of motor that will not operate on DC is the?
series
short shunt
long shunt compound
squirrel cage
squirrel cage
Receptacles installed on what ampere branch ckts shall be of the grounding type?
15 and 20
25
30
40
15 and 20
Where conductors carrying alternating current are installed in metal enclosures or metal raceways, they shall be so arranges as to avoid heating the surrounding metal by induction, to accomplish this what/which shall be grouped together?
all phase conductors
where used, the neutral
all equipment grounding conductors
all
A (an) changes AC to DC?
battery
capacitor
alternator
rectifier
rectifier
A steel measuring tape is undesirable for use around electrical equipment. The least important reason is the what?
danger of entaglement in rotating machines
shock hazard
short circuit hazard
magnetic effect
magnetic effect
What is the ability of a material to permit the flow of eclectrons?
voltage
current
resistance
conductance
conductance
Which of the following two wires are the grounded wires in a 3 wire cable?
red and white
white and black
bare and red
white and bare
white and bare
A fitting is what?
part of a wiring system that is intended primarily to perform an elecrical function
pulling cable into a confined area
to be suitable or proper for
part of a wiring system that is intended primarily to perform a mechanical function
mechanical function
An appliance that is easily moved from one place to another in normal use is a/an what appliance?
on wheels
dwelling unit
moveable
portable
portable
the neutral conductor is?
always the white grounded conductor
has 70% applied for a household clothes dryer for a branch ckt
never apply ampacity corrections
carries the unbalanced current
carries the unbalanced current
All wiring must be installed so that when completed?
it meets the current carrying requirements of the load
it is free of shorts and unintentional grounds
it is acceptable to code compliance authorities
it will withstand a hy-pot test
It is free of shorts and unintentional grounds
Rosin is preferable to acid as a flux for soldering wire because rosin is?
a dry powder
a better conductor
a nonconductor
noncorrosive
noncorrosive
Utilization equipment is equipment which utilizes what energy for mechanical, chemical, heating, lighting or similar purposes?
chemical
electric
heat
electrical
the main purpose of using cutting fluid when threading conduit is to?
prevent the formation of rust
wash away the metal chips
improve the finish of the thread
prevent the formation of electrolytic pockets
improve the finish of the threads
Of the following, the best indication of the condition of the charge of a lead acid battery is the?
temperature of the electrolyte
level of the electrolyte
open ckt cell voltage
specific gravity
specific gravity
In general, the most important point to watch in the operation of xfers is the?
core loss
exciting current
temperature
primary voltage
temperature
When mounting electrical equipment, wooden plugs driven into holes in what shall not be used?
masonry
concrete
plaster
any
Mica is commonly used in electrical construction for?
commutator bar separators
heater cord insulation
strain insulators
switchboard panels
commutator bar separators
If a fuse becomes hot under normal load, a probable cause is?
excessive tension in the fuse clips
rating of the fuse is too low
insufficient pressure at the fuse clips
rating of the fuse is too high
insufficient pressure at the fuse clip
For maximum safety, the magnetic contactors used for reversing the direction of rotation of a motor should be?
operated from independent sources
electrically interlocked
mechanically interlocked
electrically and mechanically interlocked
electrically and mechanically interlocked
Large squirrel cage induction motors are usually started at a voltage considerably lower than the line voltage to?
allow the rotor current to build up gradually
permit starting under full load
avoid excessive starting current
obtain a lower starting speed
avoid excessive starting current
If the voltage of a light bulb is increased 10%, the bulb will?
fail by insulation breakdown
have a longer life
burn more brightly
consume less power
burn more brightly
all edges that are invisible should be represented in a drawing by lines that are?
dotted
curved
solid
broken
broken
A light bulb usually contains?
air
neon
H2O
either a vacuum or a gas
vacuum or gas
Critical burns are potentially?
life threatening
disfiguring
disabling
all of these
all of these
A set of lights switched from three different places can be controlled by what switches?
two 3 way and a 4 way
two 3 way and a 2 way
2 single pole
four pole
two 3 way and a 4 way
a fellow electrician is not breathing after receiving an electrical shock, but is no longer in contact with the electricity, the most important thing for you to do is?
start artificial respiration immediately
cover the person and keep warm
move the person to a window
remove the persons shoes
start artificial respiration immediately
A wrench you would not use to connect rigid metal conduit is a what wrench?
box end
chain
strap
stillson
box end
the instrument that would prove least useful in testing for opens, grounds, and shorts after the wiring has been completed is the?
voltmeter
ammeter
ohmmeter
megger
ammeter
a stranded wire is given the same size designation as a solid wire if it has the same?
weight per foot
overall diameter
strength
cross sectional area
cross sectional area
A lighting fixture is to be controlled independently from two different locations. the type of switch required in each of the two locations is a?
2p 2t
2p 1t
1p 2t
1p 1t
1p 2t
The rating “ 1000 ohms, 10 watts” would generally be applied to?
xfer
relay
resistor
heater
resistor
The open circuit test on a xfer is a test for measuring its?
insulation resistance
copper losses
iron losses
equivalent resistance of the xfer
iron losses
The proper way to open a knife switch carrying a heavy load is to?
open it with care, to avoid damage to the auxiliary blade by the arc
open it slowly so that there will not be a flashover at the contacts
tie a 5 foot rope on the switch handle and stand clear of the switch
open it with a jerk so as to quickly break any arc
jerk quickly
When thermal overload relays are sued for the protection of polyphase inductions motors, their primary purpose is to protect the motors in case of?
short ckt between phases
low line voltage
reversal of phases in the supply
sustained overload
sustained overload
The NEC is sponsored by?
Underwriters lab
national safety council
national electrical mftg association
NFPA
NFPA
