C7 test Flashcards
The grounding conductor for a community antenna TV( CATV or cable) system must be no smaller that_______ solid stranded copper or other corrosion resistance conductive material.
No 14
CATV grounding conductor
the grounding of the electrode system of the building or structure
indoor antennas and indoor lar-ins must be run no closer than____to conductors of other wiring systems in the premises
2 inches
lead-in conductors on the outside of a building must be run so they can swing no closer than blank to the conductors of circuits of 250 volts or less
2 feet
lead-in conductors on the outside of a building must be run so they can swing no closer than blank to the conductors of circuits of more than 250 volts
10 feet
outdoor antennnas and lead in conductors must not cross over open light or power conductors. When closeness to such conductors (less thatn 250 V) cannont be avoided, the NEC requires that the clearance must be a least
2 feet
the correct sequence that a satellite signal follows a dish antenna is
feedhorn, low-noise amplifier, downconverter, receiver, television set
the downconverter in a satelite antenda system passes on the signal to the
receiver
the downconverter
converts signals from high frequency to low frequency
while trenching near an underground CATV cable, you inadvertently damage the cable. you should immedialty contact the cable company becuase
radiating signals from the damaged cable can inerfere with aircraft transmissions
in four-wire telephone cable, the wire colors are usually
black,green, red and yellow
in a four wire telephone cable, the red and green wires carry
the message, 48 v dc and 85 v ac signals
in a four-wire telphone cable, the yellow wire
can be used as a ground wire
which two wires are sometime used as a second line
yellow and black
in the primary wiring pair, which is the ring wire
green
in the primary wiring pair, which is the ring wire
red
in six-wire telephone cable, what are the additional two colors
white and blue
in the six wire telephone cable, what are the white and blue wires used for
functions such as speakerphones, dialers, background music, and security signals
no more than how many phones can be installed without overloading the incoming phone circuit
5
the point whre the phone company wiring ends and the owners interior wiring begins is called the
demarcation point
the most common interior phone wiring for a new home is
4 conductor no. 22 or 24
the recommended circuit length for number 22 phone cable is no more than
200 feet
phone jacks should be installed more than how many feet enter the home
200 feet
phone conductors should be kept how many feet from electrical branch-circuit wiring if the phone cable is run parallel to the branch circuit wiring,
12 inches
how far up should an intecom system be installed from the finished floor for the greatest operating
4 1/2 feet
the intercom system master station should be located at least how far from an adjacent wall, cabinets, or counters
4 inches
The standard installation height for inside phone jacks is
36”
which cable may not be run in the same cable
Class 1 circuits
the following conductors can’t be placed in any raceways, compartments, outlet box, junction box, or similar fitting with the conduction of
electric light circuit, electric power circuits, class one circuits
is a doorbell doesn’t work, the most likely source of failure is the
bell button
if you get 0 volts if a doorbell fails you conclude that the transformer is defective.
true
smoke detectors are powered by the following
black and white pigtails for direct connection to a 120 v line. a cord and plug connected to a standard receptacle and battery
which locations are best for a smoke detector
on the ceiling
the proper location for a heat or smoke detector installed in a room is
as close as possible to the center of the room
standard smoke detectors must be installed
outside each bedroom
in each addional story
in basements
in an unfinished attic, install a smoke detector
on the bottom edge of a rafter or joist
smoke detectors installed in a basement must be located
close to the starway leading to the floor above
smoke detectors in rooms with ceiling slopes greater than how many feet should a detector be located
1 foot rise to 8 foot run
in a residential stairway install a smoke detector
at the top of any open stairway
installed on a ceiling a heat or smoke detector edge must be installed no less than how far from a wall
4 inches
if a smoke detector is installed on a wall the top edge must be installed how far from less than from the ceiling
4 inches
if the smoke detector is installed on the wall the tip edge must be installed no more than how far from the ceiling
12 inches
install a smoke detectror how far from a flouresenct light fixtures
6 feet
never install a smoke detector in the following locations
garage
kitchen near the stove
bathroom with a shower
the wiring of a smoke detector in new construction is usually done
in parallel
the wiring of a security system usually consists of
multiconductor cables made up of no 18 AWG
the installation of security system wiring should be done
after standard house wiring is installed
the wiring of door entry, glass-break, floor matt, and window-foil detectors is usually done
in series
the wiring of alarms, horns and other signaling devices is usually done
in parallel
The supply source for a class 1 power-limited circuit has a rated output of no more than
30 volts and 1000 volt-amperes
The supply source for a class 2 or Class 3 power-limited circuit has a rated output of no more than
30 volts and 100 volt-amperes
when installing the low voltage cable in a remote control system, run the cable from the transformer to
the relay (blue-colored conductor) each switch postion( red and black conductor)
the purpose of a master selector switch in a residential installation of a remote control system is
to activate or deactivate any of the low-voltage switches at remote locations
the lead of the three low-voltage wires is common to both the off-coil and the on the coil
Blue
the low voltage relay of a romote control system of the three low voltage wires connect internally to the on coil
red
the low voltage relay of a romote control system of the three low voltage wires connect internally to the off coil
black
what is the purpose of a thermal breaker in a low voltage remote control system
to open the primary circuit and protect the transformer for overheating
low voltage remote control system use what type of conductors
No 18
when are you likely to be reqired to get a building permit for outdoor wiring
for the GFCI recpticles that recieves a transformer
you are installing a 12 V outdoor lighting system, but 120 v circuits operate a part of the 12 v system, and a GFCI must be installed. What should you do
check with the building inspector to see if you need a permit and check the local codes to see if they have any requirements for low voltage system installation
a contractor is installing outdoor lighting for a lawn by running cable in a trench. If a concrete walkway is encountered, the preferred option is to
run the cable through a sleeve of pipe under the walkway
the most likely source for failure in a low voltage circuit is
switch
type CM (communication cable) need not be installed in a one or two-family dwelling if the following is used instead
Type CMX less than 1/3 in diameter
why do hacksaw teeth face forward
you cut on the down-stroke
what should you do first when testing a transformer with a megger
make sure that the switches or circuits of both sides are open
a master selector switch is best described a
many swiches on one panel
what part of a satelite system changes the frequency of signals
downlink converter
the proper procedure when using a stepladder is
make sure the locks are engages
in the primary wiring pair of a telephone system, whis is the postitive conductor
Green
in the primary wiring pair of a telephone system which is the negative conductor
Red
You are testing a phone system after the installation. You hear a dial tone and dial a number. You continue to hear a dial tone. What is the problem
the red and green wires were reveresed
WATS stand for
Wide area telephone service
the bottom of an outlet for a wall phone is typically insalled
56 “ above the floor
equipment with exposed parts charge with over 50 volts must be
fenced off
For a 24 volt circuit what is the allowable ampacity for a standed AWG N0 16 conductor
18 amps
what type of function reads from right to left on a meter
resistance
what is the most econmical way to dig a short trench
a trencher
if you have installed a string of 12 v outdoor lights and they dim toward the end of the string, what is the most likely cause of the dimming
voltage drop
if you have installed a string of 12 V outdoor lights and one of the fixtures is extinquised what is the most likley cause
faulty lamp
if a workers are exposed to cuts, burns or corrosed or irritating substances, the employer must provide
hand protection
employees exposed to flying or falling objects and/or electric shock or electric burns must wear
head protection
at a construction site hard hand must me worn
by everyone
what is the amount of Asbesotos that need to be reported by dosh if it is found in Dust
0.1%
Asbestos at a jobsite should be handled
Wet
CAL/OSHA inspectors will arrive at you office or jobsite
without an appoitment
Which of the following is not a type of CAL/Osha citation
Judical
in which of the following is a GFCI required by the NEC
Bathroom
all 124-volt single phase and 20 amp receptacles installed with how many feet of a residential kitchen sink and servicing a countertop be equipped with a GFCI
6 feet
What needs to be on every Jobsite
First Aid kits
