Elap 2A Final Flashcards
(242 cards)
1
Q
Equipment designed to open circuits under fault conditions shall have an interrupting rating not less than the available voltage and circuit current at the line side of the equipment.
A
True
2
Q
Equipment that is required to be readily accessible shall be capable of being reached quickly without the use of tools, with an exception for ___.
A
Keys
3
Q
A conductors ____ is the amount of amperes it can carry continuously without exceeding its temperature rating.
A
Ampacity
4
Q
The two fold purpose of the NEC is to protect ___ from the hazards associated with the use of electricity
A
Persons and property
5
Q
Most voltages referenced in the NEC are ___ voltages
A
Nominal
6
Q
Interpretations and approval of equipment are granted by the ___
A
AHJ
7
Q
The AHJ can permit alternate ___ for installation.
A
Methods
8
Q
Although installed in conformance with the NEC, all electrical installations may not be adequate for ___ expansion of electrical use.
A
Future
9
Q
The NEC is not intended to be used as a ___ specification
A
Design
10
Q
___ conductors are conductors not encased in a material recognized by the NEC as electrical insulation
A
Covered
11
Q
Connectors, couplings, locknuts, and bushings are electrical ___
A
Fittings
12
Q
___ means recognized as suitable for the use, purpose, ext.
A
Identified
13
Q
Equipment that as been ___ is published in a directory by the testing lab certifying it is acceptable to the AHJ.
A
Listed
14
Q
The purpose of a raceway is to help protect conductors from physical ___
A
Damage
15
Q
The NEC requires that all electric equipment and conductors be ___ to be deemed acceptable to the AHJ
A
Approved
16
Q
All unused openings other than those intended for the operation of equipment are required to be effectively ___ to afford equivalent protection.
A
Closed
17
Q
Terminals for more than one conductor shall be ___
A
Identified
18
Q
One of the ___ shall be readily accessible as required by the NEC.
A
Disconnecting means
19
Q
___ conductors are the conductors form the service point to the service disconnecting means.
A
Service
20
Q
___ conductors are all circuit conductors between the service equipment and the final branch circuit overcorrect device.
A
Feeder
21
Q
The ___ is the portion of the electrical circuit between the last overcorrect device and the outlets or utilization equipment
A
Branch Circuit
22
Q
A ___ load is a load where the waveform of the steady state current does not follow the wave shape of the applied voltage
A
Nonlinear
23
Q
Branch circuits with not over 120 V between conductors are permitted to supply auxiliary equipment of electric discharge lamps
A
True
24
Q
A GFCI receptacle or circuit breaker is set to trip at 10 mA
A
False
25
Receptacle outlets installed in a dwelling for specific appliances shall be located within ___' of the appliance
6
26
At least one receptacle outlet shall be installed in ___' or longer hallways of dwelling units.
10
27
___ is the ratio of the maximum demand of a system, or part of a system, to the total connected load of a system or the part of the system under consideration
Demand Factor
28
Branch circuit EGCs smaller than 4 AWG shall have a continuous outer finish that is either green or green with one or more ___ stripes
Yellow
29
All conductors of a ___ branch circuit shall originate from the same panelboard
Multiwire
30
A current flow of ___ mA will most likely cause the heart to stop pumping
100
31
A ___ is the amount of electricity required at a given time
Demand
32
Each single or multiple receptacle on a single strap is calculated at ___ VA.
180
33
Demand factors may be applied to ___ of the six loads of the standard calculation.
4
34
Four or more appliances that are fastened in place in a one family dwelling are calculated at ___ of the total loader all four appliances.
75%
35
The total load for household clothes dryers is calculated at ___ VA or the nameplate rating, whichever is higher (standard calculation)
5000
36
___ loads are loads that are not on the same time
Noncoincidental
37
The ___ load is the maximum unbalance between any of the ungrounded conductors and the grounded conductor
Feeder Neutral
38
For 1 systems, the formula ___ is used to determine minimum ampacity of the ungrounded conductors
I = VA/A
39
Heating or A/C loads are calculated at ___ of the nameplate rating and the largest load is used (standard calculation)
100%
40
After the minimum ampacity of the dwelling service has been calculated, Table ___ and 310.15(B)(7)(1) are used to determine the size of service entrance conductors
310.15(B)(16)
41
The demand had for household electric ranges rated in excess of ___ kW is calculated per Table 220.55 (Standard Calculation)
1-3/4
42
Feeders for several motors are calculated using the sum of the FLC tables of all motors plus ___% of the largest motor
25%
43
Less than four separately controlled electric space heating units in a dwelling unit are calculated at ___ % of their nameplate ratings (optional calculation)
65%
44
The ___ is the electrical supply, in the form of conductors and equipment, that provides electrical power to the building or structure.
Service
45
The ___ is the overhead conductors between the service point and the utility electric supply system
Service Drop
46
The __ is the underground service conductors that connect the utilities electrical distribution system and the service point.
Service Lateral
47
GFPE is designed to operate at settings not greater than 200 A
False
48
___ conductors are the conductors that extend from the service disconnecting means to the service point where the service point is located at the connections made at the service drip loop.
Overhead Service Entrance
49
Direct buried conductors emerging form the ground shall be protected from physical damage up to a point which is at least ___' above finish grade
8
50
SE cable shall be supported at intervals not exceeding ___" and within ___" of every service head, gooseneck, or point of connection to a raceway or enclosure.
30; 12
51
Plug fuses have a voltage rating of ___ V between conductors in most applications
125
52
Insulated conductors installed in wet locations shall be of a type ___ for the use
Listed
53
No conductor shall be installed in such a manner that the operating temperature of its ___ is exceeded
Insulation
54
Flug fuses of 15A and lower are identified by ___ configuration of the fuse window
Hexagonal
55
Cartridge fuses with no markings are rated for ___ A
10,000
56
Circuit breakers that are not marked have an interrupting rating of ___ A
5,000
57
___ conditions include installations where the conductors are exposed to oils, greases, vapors, etc. that break down the integrity of the conductors insulation
Corrosive
58
Ampacity of feeder taps not over 25' shall not be less than 1/3 of the rating of the overcorrect protective device protecting the ___ conductors
Feeder
59
In general, fuses and circuit breakers shall not be connected in ___.
Parallel
60
A ___ is a circuit breaker with an intentional delay between the time when the fault or overload is sensed and the time when the CB operates
ITCB
61
The next ___ standard size OCPD of 800 A or less is permitted to be used where the OCPD does not correspond to a standard size
Higher
62
A ___ is any current in excess of that for which the conductor or equipment is rated
Overcurrent
63
Type S fuses are designed for circuits not exceeding 100 V
False
64
Locations can be classified as either dry, ___ or wet
Damp
65
The greeks were the first to discover electricity about ___ years ago.
2500
66
A semiconductor contains ___ valence electrons
4
67
Direct current is described as ___
unidirectional
68
Alternating current is described as ___
bidirectional
69
One coulomb per second is equal to one ___
ampere
70
The amount of potential necessary to cause one coulomb to product to produce one joule of work is a ___
Volt
71
The unit of resistance to current flow is the ___
ohm
72
In a DC circuit, the current is directly proportional to voltage and inversely proportional to resistance is know as ___
Ohms Law
73
The force of electrostatic attraction or repulsion is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them?
Coulombs Law
74
The amount of electrical power being used in a circuit is measured in ___
Watts
75
What is another term for electromotive force?
Voltage
76
A voltmeter has a very ___ resistance connected in series with the meter movement
High
77
A test meter that uses a scale and pointer to indicate values is a ___ meter
Analog
78
An ammeter is connected in ___ with the load to permit the load to limit current flow
Series
79
What meter is designed to be connected directly across the power source?
Voltmeter
80
What meter measures an amount of voltage during a period of time and produces a two dimensional image?
Oscilloscope
81
The function that is equal to the adjacent divided by the hypotenuse is the ___
cosine
82
What memory aid will help you remember the trigonometric function relationships?
Oscar had a heap of apples
83
The function that is equal to the opposite divided by the hypotenuse is the ___
Sine
84
A line that indicates both magnitude and direction is a ___
Vector
85
A voltaic cell is constructed of two unlike metals and a(n) _____, alkaline, or salt solution.
Acid
86
Several cells connected together that produce voltage are called a _____.
Battery
87
The LeClanché cell is also known as a(n) _____ cell.
Carbon-zinc
88
Thermocouples produce voltage because of the action of two dissimilar metals. The voltage produced depends on the type of metals used and the _____ difference between the junction and the open ends.
Temperature
89
The amount of energy a cell can deliver is called its _____ capacity.
Current
90
The no-load voltage of a cell is greater than the normal load voltage because of the internal _____ of the cell.
Resistance
91
Piezoelectricity refers to electricity produced by some materials when they are subjected to _____.
Pressure
92
The amount of voltage produced by an individual _____ is determined by the materials from which it is made.
Cell
93
To perform a load test on a lead-acid battery, the amount of test current should be _____ times the ampere-hour capacity.
Three
94
What type of cell can be recharged?
Secondary
95
What type of cell cannot be recharged?
Primary
96
In 1800, Alessandro Volta was experimenting with producing electricity. He called his battery _____.
Voltaic pile
97
The time required for current in an inductor to reach its full Ohm’s law value is called the _____ time constant.
R-L
98
Losses in the core of iron core inductors include _____ and _____ losses.
Eddy Current; Hysteresis
99
What is one device used for spike suppression in either direct or alternating current circuits?
Metal Oxide Varistor
100
An induced voltage opposes the motion that causes it according to _____.
Lenz's Law
101
Exponential curves are always divided into _____ time constants.
Five
102
During the period of time known as the first time constant of an exponential curve, the current will rise to about _____ percent of its full value.
63.2
103
A way of determining the relationships of the motion of the conductor, the magnetic field direction, and the direction of the induced current is by using the _____.
Left-Hand Generator Rule
104
When using the left-hand generator rule, the center finger points to the direction of _____.
Current
105
What is the unit of measurement for inductance?
Henry (H)
106
When a conductor cuts magnetic lines of force, a voltage is induced into the conductor. This principle is called _____.
Electromagnetic Induction
107
The direction of induced current can be determined by using _____’s left-hand generator rule.
Fleming
108
When a closed loop of wire cuts through magnetic flux lines, a current is induced into the loop. The current in the loop sets up a magnetic field that is in opposition to the original magnetic flux. This is essentially _____.
Lenz's Law
109
If a voltage is being induced into a conductor by electromagnetic induction, reversing the direction of motion of the conductor will _____.
Reverse the polarity of the induced voltage
110
When using the left-hand generator rule, the thumb points to the direction of _____.
Thrust
111
What is the unit of measure for the power delivered to the load in a DC circuit?
Watts
112
In a DC circuit, the product of volts times the amperes is called the _____ power.
True
113
What type of load contains pure resistance?
Resistive
114
The maximum point of a waveform is called the _____.
Peak
115
If an AC waveform is rectified and converted into DC, the voltage value that results is the _____ value.
Average
116
Rotating machines normally produce a waveform called a _____ wave.
Sine
117
What type of AC waveform features voltage rising at a constant rate with respect to time?
Linear
118
The number of cycles completed in one second is called a _____.
Frequency
119
When current rises and falls at the same rate as the voltage and reverses the direction of flow when the voltage reverses polarity, the current is said to be _____ with the voltage.
In Phase
120
A term used to indicate the same value as the RMS value is the _____ value.
Effective
121
When AC voltage is rectified and converted into DC, the resulting waveform is normally not pure, flat DC. The pulses that occur are called _____.
Ripples
122
The_____ effect occurs when AC induces eddy currents into the conductor, which cause the electrons to be repelled toward the outer surface of the conductor.
Skin
123
What is the most common of all AC waveforms?
Sine
124
The square root of the mean of the square of the instantaneous currents is known as the _____.
RMS
125
Each complete waveform of 360° is called a _____.
Cycle
126
The amplitude of a waveform is measured from _____.
Zero to the highest value obtained in either direction
127
A voltmeter has a very _____ resistance connected in series with the meter movement.
High
128
An ammeter is connected in _____ with the load to permit the load to limit current flow.
Series
129
In a right triangle, the two non-right angles are each formed by the hypotenuse and one of the other sides. From the perspective of the angle, the side that is not the hypotenuse is called the _____.
Adjacent Side
130
One method of adding two vectors that originate at the same point is the _____ method.
Parallelogram
131
The total current-limiting effect is called _____.
Impedance
132
The symbol for reactive power of an inductor is _____.
VARs
133
The unit of inductance is the _____.
Henry
134
Circuits are generally considered to contain _____ when any type of load that contains a coil is used.
Inductance
135
When a magnetic field continually changes magnitude and direction, a voltage is continually being induced in the coil. This voltage is called _____ voltage.
Induced
136
In a pure inductive circuit, current _____.
lags voltage by 90 degrees
137
The current-limiting property of an inductor is called _____.
Reactance
138
The waveform of the CEMF is _____ out-of-phase with the applied voltage.
180 degrees
139
Eddy currents are small independent currents induced within the conductor because of direct current.
False
140
A common practical use of induction is for _____.
Motors, Transformers, Generators
141
For ac circuits, the ac _____ of a conductor must be taken into consideration.
Eddy currents, skin effect, resistance
142
Conductor resistance is directly proportional to the conductor’s length and cross-sectional area.
False
143
Self-induced voltage is 180º out-of-phase with the _____. When the applied voltage is at its maximum in one direction, the induced voltage is at its maximum in the opposite direction.
Applied Voltage
144
In a purely inductive circuit, the CEMF waveform is _____ out-of-phase with the applied voltage waveform.
180 degrees
145
The magnitude of self-induced voltage within a winding is directly proportional to the current flow, the winding, and the frequency at which magnetic fields cut through the winding.
True
146
The expanding and collapsing magnetic field within the conductor induces a voltage in the conductors (CEMF) that repels the flowing electrons toward the surface of the conductor. This is called _____.
Skin Effect
147
The movement of electrons caused by an external magnetic field is called _____ current, and the associated potential that is established is called _____ voltage.
Induced
148
In dc circuits, the only property that affects current and voltage flow is _____.
Resistance
149
In a parallel circuit, the voltage across the resistor and the voltage across the inductor are _____.
In phase
150
In a parallel circuit, the current flow through the inductor will be _____.
90° out of phase with the voltage
151
In a pure capacitive circuit, the current _____ the applied voltage by _____.
leads; 90°
152
A capacitor is constructed by separating two metal conductors known as _____ with an insulating material known as a(n) _____.
plates; dielectric
153
A charge curve for a capacitor is divided into _____ time constants
Five
154
Polarized capacitors _____.
must be used with DC only
155
The JAN standard is used to mark a capacitor intended for _____.
Military
156
Polarized capacitors are also known as _____ capacitors.
Electrolytic
157
Nonpolarized capacitors _____.
Can by used with either AC or DC
158
When a capacitor is connected in a circuit with a resistor, the amount of time needed to charge the capacitor is called the _____.
RC time constant
159
The capacitive reactance of a capacitor is _____ proportional to frequency.
Inversely
160
When the voltage and current have _____ polarities in a pure capacitive circuit, the capacitor is discharging and the energy is returned to the circuit.
Opposite
161
The material between a capacitor’s plates is rated by a value called the _____.
Dielectric constant
162
The voltage rating of a capacitor _____.
should never be exceeded
163
In a capacitor, the voltage difference between the plates controls the _____.
amount of dielectric stress
164
Of the different power values in an RL circuit, which one is known as quadrature power?
VARs
165
Dividing a circuit’s total applied voltage by the total impedance results in the total _____.
Current
166
Of the different power values in an RL circuit, which one is known as wattless power?
VARs
167
Power factor (PF) is the ratio of the _____ power to the _____ power.
True; apparent
168
In a series circuit, the total _____ is equal to the sum of the individual resistors.
Resistance
169
In a series RC circuit, apparent power can be calculated by _____.
ET × I
170
Of the different power values in an RC circuit, which is known as apparent power?
VA
171
If the voltage is behind the current in a RLC series circuit, the power factor is referred to as _____.
Leading
172
In an RLC series circuit, the ratio of resistance, inductance, and capacitance determines how much the applied _____ leads or lags the circuit current.
Voltage
173
If the voltage in a RLC series circuit is ahead of the current, the power factor is referred to as _____.
Lagging
174
If the current leads the voltage in a RLC series circuit, the power factor is referred to as _____.
Leading
175
In a RLC series circuit, the point at which XL and XC are equal is called _____.
Resonance
176
Because inductive reactance and capacitive reactance are _____ out of phase with each other, they subtract from each other in an AC circuit.
180°
177
If a RLC series circuit contains more capacitive VARs than inductive VARs, then the circuit has a _____ power factor.
Leading
178
In a RLC series circuit, _____ is the same through all components and the _____ are out of phase.
Current; Voltages
179
To correct the power factor to 100 percent an equal amount of capacitive VARs would be connected in _____ with the motor.
Parallel
180
If the power factor is corrected exactly so that the circuit is purely resistive, the power factor has a value of _____.
Unity
181
In an RLC parallel circuit, the _____ is the same through all components and the _____ are out of phase.
Voltage; Currents
182
If a RLC parallel circuit contains more inductive VARs than capacitive VARs, the circuit has a _____ power factor.
Lagging
183
A nonsinusoidal waveform is created when _____ loads distort the voltage and current sine wave.
Nonlinear
184
The movement of electrons themselves does not produce any useful work. It’s the effects that the moving electrons have on the loads they flow through that are important.
True
185
The effective value is equal to the peak value _____.
times 0.707
186
Effective ac voltage or effective ac current is the equivalent value of dc voltage or dc current that would produce the same amount of heat in a resistor.
True
187
The number of complete waveforms in one second is called the frequency. Frequency is expressed as _____ or cycles per second.
Hertz
188
The term “phase” is used to indicate the time or degree relationship between two waveforms, such as voltage-to-current or voltage-to-voltage.
True
189
Output voltage of a generator depends upon the _____.
Number of turns of wire, strength of the magnetic field, speed at which the coil rotates
190
The movement of electrons themselves does not produce any useful work. It’s the effects that the moving electrons have on the loads they flow through that are important.
True
191
n ac generators that produce large quantities of electricity, the conductor coils are stationary and the magnetic field revolves within the coils.
True
192
_____ describes the steps necessary to determine the effective voltage or current value.
"Root-mean-square"
193
The _____ wave is a waveform that is symmetrical with positive above and negative below the zero reference level.
Sine
194
A capacitor is a device that resists changes in current. Because a capacitor introduces reactance to the circuit, it shifts the current waveform to _____.
lead the applied voltage by 90º
195
If a capacitor is overcharged, the electrons from the negative plate could be pulled through the insulation to the positive plate. The capacitor is said to have _____.
Shorted
196
A half-wave rectifier can be used to convert ac voltage into dc voltage to continuously charge a capacitor.
False
197
To discharge a capacitor, all that is required is a(n) _____ path between the terminals of the capacitor. The free electrons on the negative plate then flow through the external circuit to the positive plate.
Conductive
198
_____ is a property of an electrical circuit that enables it to store electrical energy by means of an electric field and to release this energy at a later time.
Capacitance
199
The waveform of the CEMF is _____ out-of-phase with the applied voltage.
180°
200
Conductor resistance is directly proportional to the conductor’s length and cross-sectional area.
False
201
The magnitude of self-induced voltage within a winding is directly proportional to the current flow, the winding, and the frequency at which magnetic fields cut through the winding.
True
202
How many 20A, 120V circuits are required for forty-two, 300W incandescent luminaires (noncontinuous load)?
6 Circuits
203
What size transformer is required for a 100A, 240V, single-phase noncontinuous load (unity power factor)?
25 kVA
204
Efficiency describes how much input energy is used for its intended purpose.
True
205
When sizing circuits or equipment, always size the circuit components and transformers according to the apparent power (VA), not the true power (W).
True
206
To determine the true power consumed by a dc circuit, multiply the volts by the amperes.
True
207
Power factor is a measurement of how far the current is out-of-phase with the voltage.
True
208
Because apparent power (VA) is greater than true power (W), more loads can be placed on a circuit, so fewer circuits and panels, and smaller transformers might be required.
False
209
How many 20A, 120V circuits are required for forty-two, 300W luminaires (assume this is a noncontinuous inductive load) that have a power factor of 85 percent?
7 Circuits
210
If you measure voltage and current in an inductive or capacitive circuit and then multiply them together, you obtain the circuit’s _____.
Apparent power
211
Energy is stored in the electromagnetic field of an inductor and the electric field of a capacitor.
True
212
A transformer that has one winding, which is used for both the primary and secondary, is called a(n) _____.
autotransformer
213
Any transformer flux that does not follow the core and escapes into the surrounding air is called _____.
flux leakage
214
Most transformer cores are assembled from many thin sheets of metal. This type of construction is called _____.
laminated
215
A transformer in which the secondary voltage is more than the primary voltage is called a(n) _____ transformer.
step-up
216
A tape-wound core is also called a(n) _____ core.
toroid
217
The power input winding of a transformer is called the _____ winding.
primary
218
What type of core is often found on high-voltage distribution transformers?
H-Type
219
What is a magnetically operated device that can change values of voltage, current, and impedance without changing frequency?
A transformer
220
A transformer in which the primary and secondary are physically separated and not connected by a conductor is called a(n) _____ transformer.
isolation
221
In a transformer, the turns of primary wire compared to the turns of secondary wire is called the _____ ratio.
turns
222
A transformer supplying a house with 240/120 V has a secondary which is center tapped. The conductor connected to the center is called the _____ conductor.
neutral
223
The industrial use transformer that normally has 240 V or 480 V primary and a 120 V secondary is called a(n) _____ transformer.
control
224
A transformer has a 240 V primary and a 120 V secondary. With a 30 ohm load connected, what is the primary volt-amps?
480
225
The output winding of a transformer is called the _____ winding.
secondary
226
If three-phase transformation is needed and a three-phase transformer of the proper size and turns ratio is not available, three single-phase transformers can be connected to form a _____.
three phase bank
227
For installations that will have both three-phase and single phase loads on a three-phase transformer, the utility company often provides a(n) _____ three-phase transformer.
open delta with one transformer center tapped
228
When using an open delta with a center tapped transformer, one wire is the high leg. The high leg is the one that _____.
has the highest voltage
229
A wye-delta transformer has a primary voltage of 7200 V and a secondary voltage of 360 V. What is the turns ratio?
11.55:1
230
In an open delta with a center-tapped transformer, label the two ends of the center-tapped transformer as L2 and L3 and label the high leg as L1. The current flow in the neutral (center tap) is equal to _____.
AN = A1 + (A2 – A3)
231
The main power distribution system of a large industrial plant is generally shown using a(n) _____ diagram.
one-line
232
When connecting three transformers for three-phase use with a delta secondary, a voltage test should be done before closing the secondary. The correct voltage reading is _____.
zero volts
233
A delta-wye transformer has its _____ connected as a delta and its _____ connected as a wye.
primary; secondary
234
A wye-delta transformer has its _____ connected as a wye and its _____ connected as a delta.
primary; secondary
235
A wye-delta transformer has a primary line voltage of 7200 V and a secondary line voltage of 480 V. What is the turns ratio?
8.66:1
236
In three-phase transformer connections, the primary leads are labeled with the letter _____ and the secondary leads are labeled with the letter _____.
H; X
237
A wye-connected secondary has a phase voltage of 277.14 V. What is the line voltage?
480 V
238
An open delta connection is made using _____ single-phase transformers.
two
239
In an open delta with single-phase loads, the high leg must be identified by _____.
using orange wire; tagging
| both A and B
240
What function is performed by dielectric oil?
It acts as an insulator
It prevents moisture formation
It provides cooling.
(All of the above)
241
The industrial use transformer that normally has 240 V or 480 V primary and a 120 V secondary is called a(n) _____ transformer.
Control
242
If three-phase transformation is needed and a three-phase transformer of the proper size and turns ratio is not available, three single-phase transformers can be connected to form a _____.
three-phase bank
