3rd Year Craft Exam Flashcards
__?__ is defined as the shortest distance in inches measured between a point on the top surface of any direct: buried conductor, cable, conduit, or other raceway and the top surface of finished grade, concrete, or similar cover.
Cover
A circuit has two capacitors in series. If C_T = 16.67 µF and C_1 = 25 µF what is the value of C_2?
50 µF
What is the primary voltage for all dry type transformers in the figure?
480 V
What type of study is required to complete an arc flash hazard analysis, including the arc flash boundary and incident energy at a point in
an electrical system?
Short circuit current study
The most important factor used to determine the best place to attach to and lift a load is the load’s __?__.
Center of gravity
A change to the original blueprints or specifications is accomplished by __?__.
Submitting an addendum
The maximum size copper electrode conductor required by the National Electrical Code to a ground rod, pipe, or plate electrode is __?__.
No. 6 AWG
Knots that are used to tie the ends of two ropes together are called __?__.
Bends
In general, an insulated grounded conductor of __?__ or smaller shall be identified by a continuous white or gray outer finish or by three continuous white stripes on other than green insulation along its entire length.
6 AWG
A boom is a long beam that projects from the main part of a crane to __?__ the reach of the hoist.
Extend
In grounded systems, an unspliced __?__ connects the equipment grounding conductor and the service-disconnect enclosure to the system’s grounded conductor at each service
disconnect.
Main bonding jumper
In a pure capacitive circuit, current will __?__ the voltage by __?__.
lead / 90°
Which of the following terms describes the maximum tension that a rigging component may be subjected to while maintaining an appropriate margin of safety?
Rated load
What is the maximum number of 6 AWG conductors that may be installed in the 6 x 4 x 2 inch pull?
9
A coil has an impedance (X) of 188.4 ohms and an internal resistance (R) of 82 ohms. If the coil is connected to a 120-volt, 60-hertz source, what will be the current through the coil?
0.58 A
What is the total impedance (Z_T) in the circuit?
25 Ω | 30 Ω | 240 VAC, 60 Hz
39 ohms
Resonance is defined as the __?__ at which inductive reactance is equal to capacitive reactance.
Frequency
A __?__ condition represents low impedance fault with the highest level of fault current.
Bolted fault
What signal must be given when the load must remain at a constant elevation and move horizontally closer to the crane as the boom is raised?
Raise the boom and lower the load
Three capacitors having values of 10 microfarads, 25 microfarads, and 40 microfarads are connected in series. What is the total capacitance of the circuit?
6 µF
Exposed non-current-carrying metal parts of fixed equipment supplied by or enclosing conductors that are likely to become energized shall be connected to an equipment grounding conductor where within __?__ vertically or __?__ horizontally of ground or grounded metal objects and subject to contact by persons.
8’ / 5’
What kind of crane includes a hoist trolley that travels along a horizontal beam on overhead runways?
Overhead
Under most circumstances, if the answer to a question or problem cannot be found on the blueprint drawings, it can be found in the __?__.
NEC
The figure represents a(n) __?__. (Alarm panel)
Fire alarm-voice/data/video systems plan
What is the name of the structure that extends from the platform of a mobile crane for the purpose of stabilizing the crane?
Outrigger
To get an overview of the job to be constructed, one should consult the __?__.
Site plan
The NEC allows an underground metallic water pipe to be used as a grounding electrode as long as it has direct contact with the earth for __?__.
10’
When looking to see where lighting fixtures will be installed in a T-bar ceiling, one would check the __?__.
Reflected-ceiling drawing
For greater strength and permanence (approximately 85% to 90% of the rope itself), a __?__ is used for fastening two ropes together.
Splice
Type __?__ cable is a factory assembly of one or more insulated circuit conductors with or without optical fiber members enclosed in an armor of interlocking metal tape, or a smooth or corrugated metallic sheath.
MC
In both exposed and concealed locations, where a cable- or raceway-type wiring method is installed through bored holes in joists, rafters, or wood members, holes shall be bored so that the edge of the hole is not less than __?__ from the nearest edge of the wood member.
1-1/4”
The sheepshank is primarily used to __?__.
Temporarily shorten rope without cutting it
A lighting panel is protected by 150-ampere non-timed delay fuses. What is the minimum size of the aluminum equipment grounding conductor?
4 AWG
What is the name of the boundary that an individual worker must observe before he or she works on an energized electrical conductor that has not been placed in an electrically safe work condition?
Limited approach
Identify the formula.
I_T = √([I_R]^2 + [I_X]^2)
Total current in a parallel AC circuit
A drawing that shows conduit size, number of conductors, panel locations, and how the feeders are run is called the __?__.
Riser diagram
The knot illustrated is a __?__.
Bowline
Where insulating fittings or insulating materials are used with conduits, they shall have a temperature rating __?__ the insulation temperature rating of the installed conductors.
Not less than
Where installed in __?__ locations, Type TC Cable shall also be resistant to moisture and corrosive agents.
Wet
According to industry recognized practices, the first step in reading a set of commercial prints is to examine the __?__.
Cover sheet for dates and print designations
A subpanel in a commercial installation shall have the grounding terminal and neutral bar __?__.
Isolated with only grounding terminal bonded to the enclosure
Where Type NM Cable is run at angles with joists in unfinished basements, it shall be permissible to secure cables not smaller than two __?__ or three __?__ conductors directly to the lower edges of the joists. Smaller cables shall either be run through bored holes in joists or on running boards.
6 AWG / 8 AWG
When using a sling, what is the minimum recommended sling angle?
30º
If 10 equal size electric heater strips are connected in parallel with a 120-volt circuit, and the total circuit current is 8.33 amperes, what is
the wattage of each heater strip?
100 W
The maximum current that a fuse or circuit breaker can safely interrupt under standard test conditions is called the
__?__.
Interrupting rating
When applying the (not over) 25 feet long feeder tap rule, conductors shall be permitted to be tapped, without overcurrent protection at the tap, to a feeder provided the ampacity of the tap conductors is not less than __?__ of the rating of the overcurrent device protecting the feeder conductors.
1/3
When branch conductors are increased in size to compensate for voltage drop, the sizing of the equipment grounding conductor is __?__.
Adjusted proportionally to the branch conductors
A grounding terminal and neutral bar are tied together at __?__.
An autotransformer
The characteristic of a fuse in which higher percentage overcurrent faults open faster than lower percentage faults is called the __?__.
Inverse time-current characteristic
When a circuit breaker trips due to a fault current that approaches the interrupting rating of the circuit breaker, what does the NFPA 70E standard 225.3 require be done?
Inspect and test the circuit breaker
How many breakers are in panel “DP”?
6
Which of the following is not considered a common electrical hazard associated with working on or near energized electrical equipment?
Chelation
The figure represents a(n) __?__. (Ceiling)
Reflected ceiling plan
In a 3-phase delta system the line current is __?__ times the phase current.
1.73
What is the total resistance of a circuit containing a branch of three parallel 15-Ω resistors in series with a branch of two parallel resistors (1,000 ohms and 250 ohms)?
5.20 kΩ
What does the variable X represent in the formula? X = Watts/Volts-Amps
Power factor
Occupational Safety and Health (OSHA) requirements state that only __?__ persons may work on electric circuit parts or equipment that have not been deenergized.
Qualified
Where solid rock prevents compliance with the minimum cover depths specified in Table 300.5 of the NEC, the wiring shall be installed in
metal or nonmetallic raceway permitted for direct burial. The raceways shall be covered by a minimum of __?__ of concrete extending down to rock.
2”
What type of jumper is required to connect the grounding terminal of a grounding-type receptacle to a metal enclosure?
Equipment bonding jumper
The grounding electrode conductor in an alternating current system must be sized no less than __?__.
The listing in Table 250.66 of the NEC
The low opposition to current for all grounding or grounded conductors is primarily affected by the system’s __?__.
Impedance
When referring to the specifications for a construction project, in which section of the specifications is information relating to electrical installations located?
Division 16
According to the NEC, aluminum electrode conductors used to ground a rod, pipe, or plate electrode should be no larger than __?__ AWG.
No. 4
The primary purpose of ground-fault circuit-interrupter protection is to protect personnel against which one of the following?
Faults
All 125-volt receptacles located within __?__ from the inside walls of a permanently installed pool shall be protected by a ground-fault circuit-interrupter.
20’
The voltage across a capacitor that is charging from a direct current supply will increase __?__ for each time constant.
63.2%
The minimum size copper equipment grounding conductor required for a branch circuit protected by a 60-ampere fuse is a __?__.
10 AWG
All bends of Type AC Cable shall be made so that the cable will not be damaged, and the radius of the curve of the inner edge of any bend shall not be less than __?__ times the diameter of the Type AC Cable.
5
The grounded conductor for copper service-entrance conductors that are larger than 1,100 kcmil shall not be less than __?__ of the area of
the largest service-entrance phase conductor.
12.5%
Identify the symbol. S_K
Keyed switch
A __?__ is a wheel with a concave edge for supporting a moving rope that is changing direction.
Sheave
What is the total impedance (Z_T) in the circuit?
100 Ω | 2 H | 120 VAC, 60 Hz
760.21
Four branch circuits are installed in the same conduit leaving a distribution panel. One has 15-amp protection, one has 20-amp protection, one has 30-amp protection, and one has 40-amp protection. What is the minimum size of the aluminum equipment ground in the home-run conduit?
8 AWG
The service entrance aluminum conductors are 750 kcmil for a 3-phase, 120/208-volt, 4-wire system. What is the minimum size of the
aluminum grounding electrode conductor to a pipe electrode?
4 AWG
When a copper conductor is used as a grounding electrode conductor, it must be protected if it is smaller than __?__ AWG.
6
Electrical nonmetallic tubing (ENT) shall be installed as a complete system and shall be securely fastened in place at intervals not
exceeding __?__. In addition, ENT shall be securely fastened in place within __?__ of each outlet or device box, junction box, cabinet, or fitting where it terminates.
3’ / 3’
A subpanel in a residential installation shall have the grounding terminal and neutral bar __?__.
Isolated with only the grounding terminal bonded to the enclosure
In a 3-phase wye system the line current is __?__ times the phase current.
1.73
Which one of the following National Fire Protection Association documents is titled the “Standard for Electrical Safety in the Workplace”?
70E
The figure represents a __?__. (cfm)
HVAC plan
A(n) __?__ person, according to OSHA, is “one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.”
Competent
A lighting panel is protected by a 150-ampere circuit breaker. What is the minimum size of the copper equipment grounding conductor?
6 AWG
A detailed list of job requirements covering all work that is to be performed is called a(n) __?__.
Specification
When scaled on an electrical blueprint, a conduit stub-up measures 3-/ inches from a wal. If the stub-up is actually supposed to be
located 14.5 feet from the wall, what is the correct scale for this blueprint?
1/4” = 1”
A parallel RC circuit has a true power of 2,420 watts and an apparent power of 3,102 volt amps. What is the power factor in percent?
78%
One horsepower is equal to __?__.
746 W
A commonly used knot that does not slip, jam, or fail, is easily tied and untied, and has many uses is the __?__.
Bowline
The primary purpose of the main bonding jumper is to __?__.
Carry the ground fault current back to the source
Determine the minimum number of 120-volt, 15-ampere lighting circuits required for a dwelling unit with a computed lighting load of 16,000 volt amps.
5
Occupational Safety and Health Administration (OSHA) requirements state that while any employee is exposed to contact with parts of fixed electric equipment or circuits which have been deenergized, the circuits energizing the parts shall be __?__ or tagged or both
Locked out
The figure represents a(n) __?__.
Feeder riser diagram
The service entrance copper conductors are 750 kcmil for a 3-phase, 120/208-volt, 4-wire system. Given this information, what is the minimum size of the copper grounding electrode conductor to a metal water pipe?
2/0 AWG
NEC 110.24 (with exceptions) requires that the maximum available fault current be marked on __?__.
Service equipment
The provisions in Article 300 are not intended to apply to the conductors that form an integral part of equipment, such as motors, controllers,
motor control centers, or factory assembled control equipment or __?__ utilization equipment.
Listed
The minimum size of the copper main bonding jumper for a service that consists of one 350 kcmil copper conductor per phase is __?__.
2 AWG
The hand signal in the figure is used to tell the crane operator to __?__. (Thumbs down)
Lower the boom
A continuous load is a load where the maximum current is expected to continue for __?__ or more.
3 hours
What is the minimum size AWG copper conductor permitted for conductors with a 0 through 2,000-volt voltage rating?
No. 14
Which item is a suitable grounding electrode?
A 20-foot No. 4 copper conductor encased in 12” of concrete footing
The hand signal in the figure is used to tell the crane operator to __?__. “Baseball safe motion”
Stop
