NEC Master practice test with Complete
Solutions
1 in figure - ANS-power connection
7 in figure - ANS-end seal
A 30 degree kick has a hypotenuse of 10". Given that the cosecant of 30 degrees is 2,
determine the side opposite or how far off the surface the end of the kick needs to be. -
ANS-5"
A 30-microfarad capacitor is in parallel with a 15-microfarad capacitor. The total
capacitance is ___ - ANS-45
A 5-ohm and a 20-ohm resistor are connected in parallel. What is the total resistance of
these two resistors? - ANS-4 ohms
A buck-and-boost transformer has a primary current of 10A and the transformation ratio
of 10:1. What is the secondary current? - ANS-100A
A cable hanger elbow is used to - ANS-suspend cables in long vertical runs
A carnival ride properly powered through a disconnect switch withing 6 feet of the
operator can also be opened from the operator's console using a - ANS-shunt trip
A circuit diagram shows that the circuit divides into seperate branches and there are
also series loads. This is a ___ - ANS-series-parallel circuit
A circuit has a peak voltage of 275V. What is the average voltage value? - ANS-175V
A circuit has a source voltage of 50V and a current of 10A. What is the power in watts? -
ANS-500
A clothing manufacturing plant would most likely be classified as ___. - ANS-Class III
A commercial kitchen with more than six pieces of kitchen equipment is subject to a
demand factor of ___ - ANS-65%
A conductor with failed insulation contacts the metal edge of a grounded metal wireway.
This is known as a ____. - ANS-ground fault
A conduit run must pass over a pipe and then over a rectangular duct. This will require a
total of ____ (bends). - ANS-seven bends.
,A conventional thermostat should not be thrown into the regular trash because it _____.
- ANS-may contain mercury
A correction factor must be applied if the ambient temperature is above ___ - ANS-86
degrees Fahrenheit
A current imbalance as low as 4 milliamps may be detected by a - ANS-GFCI Sensor
A current-limiting circuit breaker performs in a manner similar to conventional
thermomagnetic circuit breakers at currents below a threshold of about - ANS-1,000A
A cutaway view of a building or object is known as a - ANS-sectional drawing
A delta-connected motor has ___ - ANS-9 leads
A device that is used to step up generated voltage to make it suitable for commercial
transmission is called a - ANS-power transformer
A device that uses dissimilar metals to control electron flow is known as a - ANS-
thermocouple
A device that uses electromagnetic induction to transfer electrical energy from one
circuit to another is a ___ - ANS-transformer
A die used to - ANS-cut the threads in conduit
A digital device that sends fire alarm information over the public switched telephone
network is called a ____. - ANS-DACT
A downed power line is most likely to result in a - ANS-phase failure
A farm has 3 buildings with loads of 82A, 65A, and 15A. What is the total load? Assume
that there are no dwellings or motors. - ANS-117 A
A feeder circuit with no motor load has a continuous load of 10A and a noncontinuous
load of 10A. The feeder overcurrent protective device should be sized at ____. - ANS-
22.5A
A feeder circuit with no motor load has a continuous load of 5A and a noncontinuous
load of 5A. The feeder overcurrent protective device should be sized at _____. - ANS-
11.25A
A feeder is used to connect - ANS-the main service panel and a subpanel
A fire alarm's secondary power can come from a battery or a ____. - ANS-generator
,A flange hanger is commonly used with a ____. - ANS-suspended fixture.
A freezestat is a - ANS-normally closed bimetal switch
A general-purpose NEMA enclosure is Type - ANS-1
A GFCI sensor will trip when the - ANS-current in the neutral load is less than the
current in the hot load.
A good electrical connection should - ANS-be mechanically and electrically secure
A ground fault is best described as an unintentional - ANS-electrically conducting
connection between an ungrounded conductor of an electrical circuit and the normally
non-current-carrying conductors
A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode
is known as the - ANS-three-point test
A grounding electrode conductor - ANS-made of copper, aluminum, or copper-clad
aluminum
A grounding wire may be which of the following? - ANS-Green
A knee in a leakage current-versus-voltage plot indicates a - ANS-breakdown current
A live-dead-live test is conducted in order to ___ - ANS-verify that a circuit is de-
energized
A medium-size motor has a frame number of 284T. The D dimension of this motor is
___ - ANS-7"
A metric drawing scale of 1:100 typically depicts units in - ANS-millimeters
A mil is equal to - ANS-.001 inch
A motor overload relay consists of a current-sensing unit and a mechanism activated by
the sensing unit that - ANS-opens the motor circuit
A No. 1 isolated conductor must be identified using which of the following colors? -
ANS-Orange
A noncontinuous load of two 120V outlets for heavy-duty lamp holders would have a
load of __ - ANS-1200VA
A pocket knife can be used to deburr - ANS-PVC
, A polyphase synchronous motor has three stator windings that are ___ - ANS-120
degrees apart
A pulling line is usually made of - ANS-nylon or other synthetic
A quick test that can be made to determine if an installation is good is known as a -
ANS-go/no-go test
A relay is designated as a 3PDT-SB relay - ANS-has three normally open contacts and
three normally closed contacts
A residence with 1,000 square feet of living space has a general lighting load of - ANS-
3,000VA
A residence with 120V and 240V loads is likely to be served by a - ANS-single phase
transformer with two secondaries
A resistor has no fourth band. This indicates that the resistor tolerance is ___. - ANS-
20%
A right triangle is any triangle with - ANS-one 90* angle
A self-contained meter installation refers to ____. - ANS-a single meter enclosure
A separately derived system is a premises wiring system that is - ANS-powered from a
source other than a service
A short circuit is a conducting connection between - ANS-any of the conductors of an
electrical system
A sign load cannot exceed ___ - ANS-80% of the branch circuit rating
A single change in direction of less than 90 degrees is known as a ___ - ANS-kick
A single-conversion UPS system ___ - ANS-supplies AC power directly to critical loads
through a series inductor or transformer.
A small imbalance in phase-to-phase voltage can result in - ANS-increased heat
generated in the motor windings
A storage battery must supply at least what percentage of the system voltage for the
total load of circuits supplying legally required standby power? - ANS-87-1/2%
A suitable connector for medium-voltage cable splices is a compression or - ANS-crimp
type
Solutions
1 in figure - ANS-power connection
7 in figure - ANS-end seal
A 30 degree kick has a hypotenuse of 10". Given that the cosecant of 30 degrees is 2,
determine the side opposite or how far off the surface the end of the kick needs to be. -
ANS-5"
A 30-microfarad capacitor is in parallel with a 15-microfarad capacitor. The total
capacitance is ___ - ANS-45
A 5-ohm and a 20-ohm resistor are connected in parallel. What is the total resistance of
these two resistors? - ANS-4 ohms
A buck-and-boost transformer has a primary current of 10A and the transformation ratio
of 10:1. What is the secondary current? - ANS-100A
A cable hanger elbow is used to - ANS-suspend cables in long vertical runs
A carnival ride properly powered through a disconnect switch withing 6 feet of the
operator can also be opened from the operator's console using a - ANS-shunt trip
A circuit diagram shows that the circuit divides into seperate branches and there are
also series loads. This is a ___ - ANS-series-parallel circuit
A circuit has a peak voltage of 275V. What is the average voltage value? - ANS-175V
A circuit has a source voltage of 50V and a current of 10A. What is the power in watts? -
ANS-500
A clothing manufacturing plant would most likely be classified as ___. - ANS-Class III
A commercial kitchen with more than six pieces of kitchen equipment is subject to a
demand factor of ___ - ANS-65%
A conductor with failed insulation contacts the metal edge of a grounded metal wireway.
This is known as a ____. - ANS-ground fault
A conduit run must pass over a pipe and then over a rectangular duct. This will require a
total of ____ (bends). - ANS-seven bends.
,A conventional thermostat should not be thrown into the regular trash because it _____.
- ANS-may contain mercury
A correction factor must be applied if the ambient temperature is above ___ - ANS-86
degrees Fahrenheit
A current imbalance as low as 4 milliamps may be detected by a - ANS-GFCI Sensor
A current-limiting circuit breaker performs in a manner similar to conventional
thermomagnetic circuit breakers at currents below a threshold of about - ANS-1,000A
A cutaway view of a building or object is known as a - ANS-sectional drawing
A delta-connected motor has ___ - ANS-9 leads
A device that is used to step up generated voltage to make it suitable for commercial
transmission is called a - ANS-power transformer
A device that uses dissimilar metals to control electron flow is known as a - ANS-
thermocouple
A device that uses electromagnetic induction to transfer electrical energy from one
circuit to another is a ___ - ANS-transformer
A die used to - ANS-cut the threads in conduit
A digital device that sends fire alarm information over the public switched telephone
network is called a ____. - ANS-DACT
A downed power line is most likely to result in a - ANS-phase failure
A farm has 3 buildings with loads of 82A, 65A, and 15A. What is the total load? Assume
that there are no dwellings or motors. - ANS-117 A
A feeder circuit with no motor load has a continuous load of 10A and a noncontinuous
load of 10A. The feeder overcurrent protective device should be sized at ____. - ANS-
22.5A
A feeder circuit with no motor load has a continuous load of 5A and a noncontinuous
load of 5A. The feeder overcurrent protective device should be sized at _____. - ANS-
11.25A
A feeder is used to connect - ANS-the main service panel and a subpanel
A fire alarm's secondary power can come from a battery or a ____. - ANS-generator
,A flange hanger is commonly used with a ____. - ANS-suspended fixture.
A freezestat is a - ANS-normally closed bimetal switch
A general-purpose NEMA enclosure is Type - ANS-1
A GFCI sensor will trip when the - ANS-current in the neutral load is less than the
current in the hot load.
A good electrical connection should - ANS-be mechanically and electrically secure
A ground fault is best described as an unintentional - ANS-electrically conducting
connection between an ungrounded conductor of an electrical circuit and the normally
non-current-carrying conductors
A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode
is known as the - ANS-three-point test
A grounding electrode conductor - ANS-made of copper, aluminum, or copper-clad
aluminum
A grounding wire may be which of the following? - ANS-Green
A knee in a leakage current-versus-voltage plot indicates a - ANS-breakdown current
A live-dead-live test is conducted in order to ___ - ANS-verify that a circuit is de-
energized
A medium-size motor has a frame number of 284T. The D dimension of this motor is
___ - ANS-7"
A metric drawing scale of 1:100 typically depicts units in - ANS-millimeters
A mil is equal to - ANS-.001 inch
A motor overload relay consists of a current-sensing unit and a mechanism activated by
the sensing unit that - ANS-opens the motor circuit
A No. 1 isolated conductor must be identified using which of the following colors? -
ANS-Orange
A noncontinuous load of two 120V outlets for heavy-duty lamp holders would have a
load of __ - ANS-1200VA
A pocket knife can be used to deburr - ANS-PVC
, A polyphase synchronous motor has three stator windings that are ___ - ANS-120
degrees apart
A pulling line is usually made of - ANS-nylon or other synthetic
A quick test that can be made to determine if an installation is good is known as a -
ANS-go/no-go test
A relay is designated as a 3PDT-SB relay - ANS-has three normally open contacts and
three normally closed contacts
A residence with 1,000 square feet of living space has a general lighting load of - ANS-
3,000VA
A residence with 120V and 240V loads is likely to be served by a - ANS-single phase
transformer with two secondaries
A resistor has no fourth band. This indicates that the resistor tolerance is ___. - ANS-
20%
A right triangle is any triangle with - ANS-one 90* angle
A self-contained meter installation refers to ____. - ANS-a single meter enclosure
A separately derived system is a premises wiring system that is - ANS-powered from a
source other than a service
A short circuit is a conducting connection between - ANS-any of the conductors of an
electrical system
A sign load cannot exceed ___ - ANS-80% of the branch circuit rating
A single change in direction of less than 90 degrees is known as a ___ - ANS-kick
A single-conversion UPS system ___ - ANS-supplies AC power directly to critical loads
through a series inductor or transformer.
A small imbalance in phase-to-phase voltage can result in - ANS-increased heat
generated in the motor windings
A storage battery must supply at least what percentage of the system voltage for the
total load of circuits supplying legally required standby power? - ANS-87-1/2%
A suitable connector for medium-voltage cable splices is a compression or - ANS-crimp
type
